Abstract:
A high-voltage switch circuit includes an enable control circuit, a feedback circuit, a boosting circuit, and a high voltage switch. The enable control circuit precharges an output node to a set voltage in response to an enable signal. The feedback circuit supplies a feedback voltage to an input node in response to a switch control voltage generated from the output node when the output node is precharged. The boosting circuit boosts the feedback voltage and outputs a boosting voltage to the output node, in response to clock signals, thereby increasing the switch control voltage. The high voltage switch is turned on or off in response to the switch control voltage, and is turned on to receive a high voltage and output the received high voltage. The boosting circuit includes an amplification circuit of a cross-coupled type.

Description:
BACKGROUND 
       [0001]    The present invention relates to a semiconductor device and more particularly to a flash memory device including a high-voltage switch circuit which can increase the switching operating speed. 
         [0002]    A high voltage semiconductor memory device includes a high-voltage switch circuit. The high-voltage switch circuit supplies or cuts off the high voltage to an internal circuit requiring the high voltage in response to a switch control voltage. 
         [0003]      FIG. 1  is a circuit diagram of a high-voltage switch circuit in the related art. A high-voltage switch circuit  10  includes an enable control circuit  11 , a high voltage switch  12 , and a boosting circuit  13 . The enable control circuit  11  and the high voltage switch  12  may be implemented using a high voltage NMOS transistor. Hereinafter, it is assumed that each of the enable control circuit  11  and the high voltage switch  12  is an NMOS transistor. The boosting circuit  13  includes NMOS transistors N 1 , N 2  and capacitors C 1 , C 2 . 
         [0004]    The operation process of the high-voltage switch circuit  10  will be described in short below. If an enable signal EN is set to VCC, the NMOS transistor  11  supplies an output node OUT with VCC−Vth 1 , where Vth 1  is the threshold voltage of the NMOS transistor  11 . As a result, a voltage VCC−Vth 1  is generated by the switch control voltage VO onto the output node OUT. 
         [0005]    The NMOS transistor N 1  is turned on in response to the switch control voltage VO and outputs an internal output voltage VINT=VCC−Vth 1 −Vth 2 , where Vth 2  is the threshold voltage of the NMOS transistor N 1 . At this time, a logic high clock signal CLK is input to the capacitor C 1 . Consequently, the internal output voltage VINT can be expressed by the following Equation. 
         [0000]    
       
         
           
             
               
                 
                   VINT 
                   = 
                   
                     
                       
                         ( 
                         
                           1 
                           + 
                           
                             
                               
                                 C 
                                 c 
                               
                                
                               1 
                             
                             
                               
                                 
                                   C 
                                   c 
                                 
                                  
                                 1 
                               
                               + 
                               
                                 
                                   C 
                                   s 
                                 
                                  
                                 1 
                               
                             
                           
                         
                         ) 
                       
                        
                       VCC 
                     
                     - 
                     
                       Vth 
                        
                       
                           
                       
                        
                       1 
                     
                     - 
                     
                       Vth 
                        
                       
                           
                       
                        
                       2 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
         [0006]    (where C c   1  is capacitance of C 1  and C s   1  is capacitance of CE) 
         [0007]    In Equation 1, CE denotes a parasitic capacitor existing in the node A. When the clock signal CLK goes high, an inverted clock signal CLKB goes low (e.g., a voltage VSS). Thereafter, the diode-connected NMOS transistor N 2  is turned on in response to the internal output voltage VINT and outputs the internal output voltage VINT to the output node OUT. The NMOS transistor N 2  may be implemented using a low-voltage transistor. Accordingly, since the threshold voltage of the NMOS transistor N 2  is significantly smaller than the threshold voltage Vth 2  of the NMOS transistor N 1 , the voltage drop in the internal output voltage VINT by the NMOS transistor N 2  can be ignored. 
         [0008]    Meanwhile, the inverted clock signal CLKB is input to the capacitor C 2  as logic high (VCC). As a result, the switch control voltage VO is boosted by the internal output voltage VINT and the voltage VCC of the inverted clock signal CLKB, as represented by the following Equation. 
         [0000]    
       
         
           
             
               
                 
                   VO 
                   = 
                   
                     VINT 
                     + 
                     
                       
                         ( 
                         
                           
                             
                               C 
                               c 
                             
                              
                             2 
                           
                           
                             
                               
                                 C 
                                 c 
                               
                                
                               2 
                             
                             + 
                             
                               
                                 C 
                                 s 
                               
                                
                               2 
                             
                           
                         
                         ) 
                       
                        
                       VCC 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
         [0009]    (where C c   2  is capacitance of C 2  and C s   2  is capacitance of CF) 
         [0010]    In Equation 2, CF is a parasitic capacitor existing in the output node OUT. When the inverted clock signal CLKB goes high, the clock signal CLK goes low. Thereafter, an increased switch control voltage VO is input to the gate of the NMOS transistor N 1  again. The high-voltage switch circuit  10  then repeats the above-mentioned operations until the switch control voltage VO is boosted to a voltage VPP+Vth 3 , where VPP&gt;&gt;VCC and Vth 3  is the threshold voltage of the NMOS transistor  12 . When VO reaches VPP+Vth 3  the NMOS transistor  12  is fully turned on and there is no voltage drop across NMOS transistor  12  when VPP is output to high-voltage HVOUT. 
         [0011]    The NMOS transistor N 1  included in the boosting circuit  13  is implemented using a high-voltage transistor since it receives the high voltage VPP. However, the threshold voltage of the high-voltage transistor is much higher than that of the low-voltage transistor. Accordingly, if the NMOS transistor N 1  is implemented with the high-voltage transistor, a voltage dropped by the NMOS transistor N 1  is much higher than that dropped by the low-voltage transistor. 
         [0012]    If a voltage dropped by the NMOS transistor N 1  is increased as described above, the internal output voltage VINT decreases and the boosting speed of the switch control voltage VO is decreased. As a result, a time T 2  from when the enable signal EN is enabled to when the high-voltage switch circuit  10  (i.e., the NMOS transistor  12 ) is fully turned on is increased. 
         [0013]    In addition, if the voltage VPP input to the drain of the NMOS transistor N 1  increases, there is a possibility that the switch control voltage VO may not be normally boosted because the threshold voltages of the NMOS transistors N 1 , N 2  are excessively increased due to the body effect of the NMOS transistors N 1 , N 2 . In this case, the high-voltage switch circuit  10  cannot perform the switching operation normally. 
         [0014]    Furthermore, in the high-voltage switch circuit  10 , the switch control voltage VO of the output node OUT is boosted directly by the inverted clock signal CLKB. Accordingly, as shown in  FIG. 2 , the switch control voltage VO includes noise components generated as the inverted clock signal CLKB is toggled. The noise components of the switch control voltage VO have a direct effect on the high-voltage HVOUT, and the high-voltage HVOUT also include the noise components as shown in  FIG. 2 . 
         [0015]    Meanwhile, the amplitudes of the clock signal CLK and the inverted clock signal CLKB may be reduced in order to reduce the noise components of the high-voltage HVOUT. If the amplitudes of the clock signal CLK and the inverted clock signal CLKB are reduced, the boosting speed of the switch control voltage VO is decreased and in-turn the operating speed of the high-voltage switch circuit  10  is also decreased. 
       SUMMARY OF THE INVENTION 
       [0016]    An embodiment of the present invention provides a high-voltage switch circuit, in which a switch control voltage can be boosted at high speed by a cross-coupled boosting circuit, increasing the switching operating speed and reducing noise components of a high voltage output. Such a circuit may be used in a flash memory device. 
         [0017]    According to an aspect of the present invention, there is provided a high voltage switching circuit including an enable control circuit, a feedback circuit, a boosting circuit, and a high voltage switch. The enable control circuit precharges an output node to a set voltage in response to an enable signal. The feedback circuit supplies a feedback voltage to an input node in response to a switch control voltage generated from the output node when the output node is precharged. The boosting circuit boosts the feedback voltage and outputs a boosting voltage to the output node, in response to clock signals, thereby increasing the switch control voltage. The high voltage switch is turned on or off in response to the switch control voltage, and is turned on to receive a high voltage and output the received high voltage. The boosting circuit includes a cross-coupled amplification circuit or a plurality of cross coupled amplification circuits. 
         [0018]    According to further another aspect of the present invention, there is provided a flash memory device including a plurality of memory cell blocks, an X-decoder, a plurality of block selection units, a plurality of gate circuits, a first pump, a second pump, a voltage selection circuit, a first high-voltage switch circuit, and a second high-voltage switch circuit. Each memory cell block includes a plurality of memory cells sharing local word lines and bit lines. The X-decoder decodes a row address signal and outputs first decoding signals and second decoding signal. The block selection units output block selection signals, in response to the first decoding signals. The gate circuits connect a global drain selection line, a global source select line, and global word lines to local drain selection lines, local source select lines, and the local word lines of the memory cell blocks, respectively, in response to the plurality of block selection signals. The first pump generates a program voltage in response to a program command. The second pump generates a program pass voltage in response to the program command. The voltage selection circuit selects at least one of the global word lines, and supplies the program voltage to the selected global word line, and the program pass voltage to the remaining global word lines, in response to the second decoding signal. The first high-voltage switch circuit supplies the program voltage to the voltage selection circuit in response to an enable control signal and the clock signals. The second high-voltage switch circuit supplies the program pass voltage to the voltage selection circuit in response to the enable control signal and the clock signals. Each of the block selection units includes; a block switch for receiving the program voltage, and outputting one of the plurality of block selection signals as a voltage level higher than that of the program voltage or a voltage level lower than that of the program voltage in response to a block switch control voltage; and a third high-voltage switch circuit for receiving the program voltage, and outputting the program voltage as the block switch control voltage in response to one of the first decoding signals and the clock signals. Furthermore, each of the first to third high-voltage switch circuits includes a cross-coupled amplification circuit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent and become better understood with reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
           [0020]      FIG. 1  is a circuit diagram of a high-voltage switch circuit in the related art; 
           [0021]      FIG. 2  is a graph showing the relationship between variation in a boosting control voltage and an output voltage in a high-voltage switch circuit shown in  FIG. 1 ; 
           [0022]      FIG. 3  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0023]      FIG. 4  is a timing diagram of signals related to the operation of the high-voltage switch circuit shown in  FIG. 3 ; 
           [0024]      FIG. 5  is a graph showing the relationship between variation in a boosting control voltage and an output voltage in a high-voltage switch circuit shown in  FIG. 3 ; 
           [0025]      FIG. 6  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0026]      FIG. 7  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0027]      FIG. 8  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0028]      FIG. 9  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0029]      FIG. 10  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0030]      FIG. 11  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention; 
           [0031]      FIG. 12  is a circuit diagram of a high-voltage switch circuit according to an eighth embodiment of the present invention; 
           [0032]      FIG. 13  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0033]      FIG. 14  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0034]      FIG. 15  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0035]      FIG. 16  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0036]      FIG. 17  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0037]      FIG. 18  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; 
           [0038]      FIG. 19  is a schematic block diagram of a flash memory device according to one embodiment of the present invention; and 
           [0039]      FIG. 20  is a schematic block diagram of a flash memory device according to an eighth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0040]      FIG. 3  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 3 , a high-voltage switch circuit  100  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , and a boosting circuit  140 . 
         [0041]    The enable control circuit  110  percharges an output node DOUT to a set voltage in response to an enable signal EN. The enable control circuit  110  may be implemented using a high voltage NMOS transistor. Hereinafter, it is assumed that the enable control circuit  110  is an NMOS transistor for illustrative convenience. The NMOS transistor  110  has a drain to which the enable signal EN is input, a gate to which an internal voltage VCC is input, and a source connected to the output node DOUT. When the enable signal EN=VCC, the NMOS transistor  110  supplies a voltage (VCC−Vt 1 ) to the output node DOUT, where Vt 1  is a threshold voltage of the NMOS transistor  110 . The switch control voltage VCTL equals the output node DOUT, since they are on the same line. Furthermore, when the enable signal EN has a ground voltage VSS, the NMOS transistor  110  discharges the output node DOUT to the ground voltage VSS. 
         [0042]    The high voltage switch  120  is turned on or off in response to a switch control voltage VCTL. The high voltage switch  120  may be implemented using a high voltage NMOS transistor. Hereinafter, it is assumed that the high voltage switch  120  is an NMOS transistor for illustrative purpose. The NMOS transistor  120  has a drain to which a high voltage VPP is input and a gate to which the switch control voltage VCTL is input. When the switch control voltage VCTL is equal to VPP+Vt 2 , where Vt 2  is a threshold voltage of the NMOS transistor  120 , the NMOS transistor  120  is fully turned on and high voltage VH=VPP without a voltage drop. 
         [0043]    The feedback circuit  130  supplies a feedback voltage VFB to an input node DIN in response to the switch control voltage VCTL when the output node DOUT=VCC−Vt 1 . The feedback circuit  130  may be implemented using a high voltage NMOS transistor. Hereinafter, it is assumed that the feedback circuit  130  is an NMOS transistor for illustrative purpose. The NMOS transistor  130  has a drain to which the high voltage VPP is input, a gate to which the switch control voltage VCTL is input, and a source connected to the input node DIN. Furthermore, the NMOS transistor  130  is turned on or off in response to the switch control voltage VCTL. The NMOS transistor  130  is turned on by the switch control voltage VCTL to output a feedback voltage VFB to the input node DIN. 
         [0044]    The boosting circuit  140  includes a cross-coupled amplification circuit  141  and capacitors C 11 , C 12 . The amplification circuit  141  includes switches NM 1 , NM 2 , PM 1 , and PM 2 . Preferably, each of the switches NM 1 , NM 2  may be implemented using a low-voltage NMOS transistor and each of the switches PM 1 , PM 2  may be implemented using a low-voltage PMOS transistor. Hereinafter, it is assumed that each of the switches NM 1 , NM 2  is an NMOS transistor and each of the switches PM 1 , PM 2  is a PMOS transistor. 
         [0045]    The NMOS transistors NM 1 , NM 2  have drains connected to the input node DIN. The NMOS transistors NM 1 , NM 2  have sources respectively connected to boosting nodes BN 1 , BN 2 . The NMOS transistor NM 1  has a gate connected to the boosting node BN 2 . The NMOS transistor NM 1  is turned on or off in response to a boosting voltage V 2  of the boosting node BN 2 . The NMOS transistor NM 2  has a gate connected to the boosting node BN 1 . The NMOS transistor NM 2  is turned on or off in response to a boosting voltage V 1  of the boosting node BN 1 . 
         [0046]    The PMOS transistors PM 1 , PM 2  have sources and drains connected to the output node DOUT and the boosting nodes BN 1 , BN 2 . The PMOS transistor PM 1  has a gate connected to the boosting node BN 2 . The PMOS transistor PM 1  is turned on or off in response to the boosting voltage V 2 . The PMOS transistor PM 2  has a gate connected to the boosting node BN 1 . The PMOS transistor PM 2  is turned on or off in response to the boosting voltage V 1 . 
         [0047]    The capacitor C 11  is connected to the boosting node BN 1  and is charged or discharged in response to a clock signal CLK. When the clock signal CLK has a voltage VCC, the capacitor C 11  is charged. When the clock signal CLK has a voltage VSS (or ground voltage), the capacitor C 11  is discharged. 
         [0048]    The capacitor C 12  is connected to the boosting node BN 2  and is charged or discharged in response to the inverted clock signal CLKB. When the inverted clock signal CLKB has a voltage VCC, the capacitor C 12  is charged. When the inverted clock signal CLKB has a voltage VSS (or grounded), the capacitor C 12  is discharged. The clock signals CLK and the inverted clock signal CLKB are complementary. 
         [0049]    The operation process of the high-voltage switch circuit  101  will be described in more detail below. If the enable signal EN is first enabled, the enable control circuit  110  supplies the output node DOUT with VCC−Vt 1 . As a result, the switch control voltage VCTL, which is equal to VCC−Vt 1 , is applied to the output node DOUT. The NMOS transistors  120 ,  130  are partially turned on in response to the switch control voltage VCTL. At this time, the high voltage VH output from the NMOS transistor  120  and the feedback voltage VFB output from the NMOS transistor  130  can be expressed by the following equations. 
         [0000]        VH=VCTL−Vt 2, 
         [0000]        VFB=VCTL−Vt 3, 
         [0000]        VCTL=VCC−Vt 1   Equation 3 
         [0050]    (where Vt 3  is the threshold voltage of the NMOS transistor  130 ). 
         [0051]    Meanwhile, as shown in  FIG. 4 , initially, the clock signal CLK is at VCC and the inverted clock signal CLKB is at VSS. The capacitor C 11  is charged in response to the clock signal CLK and the capacitor C 12  is discharged in response to the inverted clock signal CLKB. As a result, the boosting voltage V 2  of the boosting node BN 2  becomes the ground voltage VSS. Furthermore, the NMOS transistor NM 1  is turned off and the PMOS transistor PM 1  is turned on, in response to the boosting voltage V 2 . Since the NMOS transistor NM 1  remains turned off, the feedback voltage VFB is not supplied to the boosting node BN 1 . At this time, the boosting voltage V 1  of the boosting node BN 1  can be expressed as follows. 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                      
                     
                         
                     
                      
                     1 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             C 
                             H 
                           
                            
                           1 
                         
                         
                           
                             
                               C 
                               H 
                             
                              
                             1 
                           
                           + 
                           
                             
                               C 
                               I 
                             
                              
                             1 
                           
                         
                       
                       ) 
                     
                      
                     VCC 
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     4 
                   
                   ] 
                 
               
             
           
         
       
     
         [0052]    (where C H   1  is capacitance of C 11  and C I   1  is capacitance of CP 1 ) 
         [0053]    In Equation 4, CP 1  is a parasitic capacitor existing in the boosting node BN 1 . The PMOS transistor PM 1  outputs the boosting voltage V 1  to the output node DOUT. As a result, the switch control voltage VCTL is increased by as much as the boosting voltage V 1 . Furthermore, the NMOS transistor NM 2  is turned on and the PMOS transistor PM 2  is turned off, in response to the boosting voltage V 1 . 
         [0054]    The NMOS transistor NM 2  outputs the feedback voltage VFB, which is received from the input node DIN, to the boosting node BN 2 . The NMOS transistor NM 2  is a low-voltage transistor and the voltage drop of the feedback voltage VFB by the NMOS transistor NM 2  can be ignored. As a result, the boosting voltage V 2  is boosted by the feedback voltage VFB and the voltage VCC of the inverted clock signal CLKB, and its boosted boosting voltage V 2  can be expressed by the following Equation. 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                      
                     
                         
                     
                      
                     2 
                   
                   = 
                   
                     VFB 
                     + 
                     
                       
                         ( 
                         
                           
                             
                               C 
                               H 
                             
                              
                             2 
                           
                           
                             
                               
                                 C 
                                 H 
                               
                                
                               2 
                             
                             + 
                             
                               
                                 C 
                                 I 
                               
                                
                               2 
                             
                           
                         
                         ) 
                       
                        
                       VCC 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     5 
                   
                   ] 
                 
               
             
           
         
       
     
         [0055]    (where C H   2  is capacitance of C 12  and C I   2  is capacitance of CP 2 ) 
         [0056]    In Equation 5, CP 2  is a parasitic capacitor existing in the boosting node BN 2 . Thereafter, the clock signal CLK is low and the inverted clock signal CLKB is high. The capacitor C 11  is discharged in response to the clock signal CLK and the capacitor C 12  is charged in response to the inverted clock signal CLKB. As a result, the first boosting voltage V 1 =VSS. The NMOS transistor NM 2  is turned off in response to the first boosting voltage V 1 , cutting off the feedback voltage VFB to the boosting node BN 2 . Furthermore, the PMOS transistor PM 2  is turned on in response to the first boosting voltage V 1 , thus outputting the boosting voltage V 2  to the output node DOUT. As a result, the switch control voltage VCTL is increased by as much as the boosting voltage V 2 . 
         [0057]    On the other hand, as the boosting voltage V 2  is boosted, the NMOS transistor NM 1  is turned on and the PMOS transistor PM 1  is turned off, in response to the boosting voltage V 2 . The NMOS transistor NM 1  supplies the feedback voltage VFB to the boosting node BN 1 . In this case, the feedback voltage VFB has been increased by as much as the boosting voltage V 2  compared with when it was supplied to the boosting node BN 2  as the NMOS transistor NM 2  was turned on. This is because the PMOS transistor PM 2  outputs the boosting voltage V 2  to the output node DOUT. In other words, the turn-on resistance of the NMOS transistor  130  decreases in proportion to an increase of the switch control voltage VCTL. Accordingly, the higher the switch control voltage VCTL, the higher the feedback voltage VFB. 
         [0058]    Meanwhile, the clock signal CLK is high and the inverted clock signal CLKB is low. The capacitor C 12  is discharged in response to the inverted clock signal CLKB and the capacitor C 11  is charged in response to the clock signal CLK. As a result, the boosting voltage V 2  of the boosting node BN 2  becomes the ground voltage VSS. The NMOS transistor NM 1  is turned off in response to the boosting voltage V 2 , thus cutting off the feedback voltage VFB. Furthermore, the PMOS transistor PM 1  is turned on in response to the boosting voltage V 2 . 
         [0059]    Consequently, the boosting voltage V 1  of the boosting node BN 1  is boosted by the feedback voltage VFB and the voltage VCC of the clock signal CLK. At this time, the boosting voltage V 1  can be expressed as follows. 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                      
                     
                         
                     
                      
                     1 
                   
                   = 
                   
                     VFB 
                     + 
                     
                       V 
                        
                       
                           
                       
                        
                       2 
                     
                     + 
                     
                       
                         ( 
                         
                           
                             
                               C 
                               H 
                             
                              
                             1 
                           
                           
                             
                               
                                 C 
                                 H 
                               
                                
                               1 
                             
                             + 
                             
                               
                                 C 
                                 I 
                               
                                
                               1 
                             
                           
                         
                         ) 
                       
                        
                       VCC 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                      
                     
                         
                     
                      
                     6 
                   
                   ] 
                 
               
             
           
         
       
     
         [0060]    If Equation 3 to Equation 5 are substituted into Equation 6, the boosting voltage V 1  can be expressed as follows. 
         [0000]    
       
         
           
             
               
                 
                     
                   
                     
                       
                         
                           
                             V 
                              
                             
                                 
                             
                              
                             1 
                           
                           = 
                             
                            
                           
                             VFB 
                             + 
                             
                               V 
                                
                               
                                   
                               
                                
                               2 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   
                                     
                                       C 
                                       H 
                                     
                                      
                                     1 
                                   
                                   
                                     
                                       
                                         C 
                                         H 
                                       
                                        
                                       1 
                                     
                                     + 
                                     
                                       
                                         C 
                                         I 
                                       
                                        
                                       1 
                                     
                                   
                                 
                                 ) 
                               
                                
                               VCC 
                             
                           
                         
                       
                     
                     
                       
                         
                           = 
                             
                            
                           
                             VFB 
                             + 
                             
                               [ 
                               
                                 VFB 
                                 + 
                                 
                                   
                                     ( 
                                     
                                       
                                         
                                           C 
                                           H 
                                         
                                          
                                         2 
                                       
                                       
                                         
                                           
                                             C 
                                             H 
                                           
                                            
                                           2 
                                         
                                         + 
                                         
                                           
                                             C 
                                             I 
                                           
                                            
                                           2 
                                         
                                       
                                     
                                     ) 
                                   
                                    
                                   VCC 
                                 
                               
                               ] 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   
                                     
                                       C 
                                       H 
                                     
                                      
                                     1 
                                   
                                   
                                     
                                       
                                         C 
                                         H 
                                       
                                        
                                       1 
                                     
                                     + 
                                     
                                       
                                         C 
                                         I 
                                       
                                        
                                       1 
                                     
                                   
                                 
                                 ) 
                               
                                
                               VCC 
                             
                           
                         
                       
                     
                     
                       
                         
                           = 
                             
                            
                           
                             
                               2 
                                
                               VFB 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   
                                     
                                       C 
                                       H 
                                     
                                      
                                     2 
                                   
                                   
                                     
                                       
                                         C 
                                         H 
                                       
                                        
                                       2 
                                     
                                     + 
                                     
                                       
                                         C 
                                         I 
                                       
                                        
                                       2 
                                     
                                   
                                 
                                 ) 
                               
                                
                               VCC 
                             
                             + 
                             
                               
                                 ( 
                                 
                                   
                                     
                                       C 
                                       H 
                                     
                                      
                                     1 
                                   
                                   
                                     
                                       
                                         C 
                                         H 
                                       
                                        
                                       1 
                                     
                                     + 
                                     
                                       
                                         C 
                                         I 
                                       
                                        
                                       1 
                                     
                                   
                                 
                                 ) 
                               
                                
                               VCC 
                             
                           
                         
                       
                     
                     
                       
                         
                           = 
                             
                            
                           
                             
                               2 
                                
                               
                                 ( 
                                 
                                   VCC 
                                   - 
                                   
                                     Vt 
                                      
                                     
                                         
                                     
                                      
                                     1 
                                   
                                   - 
                                   
                                     Vt 
                                      
                                     
                                         
                                     
                                      
                                     3 
                                   
                                 
                                 ) 
                               
                             
                             + 
                           
                         
                       
                     
                     
                       
                         
                             
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         [0061]    m Equation 7, it can be seen that the boosting voltage V 1  represented by Equation 7 is higher than the boosting voltage V 1  represented by Equation 4. 
         [0062]    Each time the clock signal CLK and the inverted clock signal CLKB are alternately enabled, the boosting voltages V 1 , V 2  are alternately amplified and are then output to the output node DOUT. Accordingly, the switch control voltage VCTL is gradually increased as shown in  FIG. 4 . For example, when the clock signal CLK is high, the NMOS transistor NM 2  and the PMOS transistor PM 1  are turned on to amplify the boosting voltage V 2 . Furthermore, when the inverted clock signal CLKB is high, the NMOS transistor NM 1  and the PMOS transistor PM 2  are turned on to amplify the boosting voltage V 1 . As a result, when the switch control voltage VCTL is gradually increased to become a voltage VPP+Vt 2  by the boosting circuit  140 , the NMOS transistor  120  is fully turned on to output the high voltage VPP to the high voltage VH without a voltage drop. 
         [0063]    Meanwhile, when the enable signal EN has the ground voltage VSS, the NMOS transistor  110  discharges the output node DOUT to the ground voltage VSS. As a result, the switch control voltage VCTL becomes VSS. Both the NMOS transistors  120 ,  130  are turned off in response to the switch control voltage VCTL. Accordingly, the high-voltage switch circuit  101  stops the switching operation of the high voltage VPP. 
         [0064]    As described above, the cross-coupled amplification circuit  141  can increase the switch control voltage VCTL rapidly for a short period of time. Accordingly, the operating speed of the high-voltage switch circuit  101  can be increased. Furthermore, in the boosting circuit  140 , since the clock signal CLK or the inverted clock signal CLKB is not input onto the output node DOUT, noise components of the switch control voltage VCTL can be reduced as shown in  FIG. 5 . As a result, noise components of the high voltage VH output from the high-voltage switch circuit  101  can be reduced. 
         [0065]    The effects of the high-voltage switch circuit  101  can become more evident when comparing the graphs shown in  FIGS. 2 and 5 .  FIG. 5  is a graph showing the relationship between variation in the boosting control voltage and the output voltage by the operation of the high-voltage switch circuit shown in  FIG. 3 . 
         [0066]    Referring to  FIG. 5 , it takes a time “T 1 ” for the switch control voltage VCTL to equal VPP+Vt 2  after the enable signal EN is enabled. Referring to  FIG. 2 , it takes a time “T 2 ” for the switch control voltage VO to equal VPP+Vt 3  after the enable signal EN is enabled. Accordingly, it can be seen that the time needed for the switch control voltage VCTL to reach VPP+Vt 2  is reduced with the boosting circuit  140 . As a result, the high-voltage switch circuit  101  can perform the switching operation at higher speeds. 
         [0067]      FIG. 6  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 6 , a high-voltage switch circuit  102  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , a boosting circuit  140 , and a voltage limiter  150 . The high-voltage switch circuit  102  has similar construction and operation as the high-voltage switch circuit  101  described in  FIG. 3 . 
         [0068]    Below are some of the differences between the high voltage switch circuits  101 ,  102 . The high voltage switch circuit  102  has the voltage limiter  150  connected to an output node DOUT, and it limits the switch control voltage VCTL (e.g., VPP+Vt 2 ) so that the switch control voltage VCTL is not excessively boosted. The voltage limiter  150  includes self-biased NMOS transistors or diodes, which are connected in series between the output node DOUT and a high-voltage input node HIN. The voltage limiter  150  in  FIG. 6  uses NMOS transistors D 1  to DK, where K is an integer. 
         [0069]    Transistors D 1  to DK are connected in a transistor chain, with the drain of D 1  connected to the output node DOUT and the source of DK connected to the high-voltage input node HIN. Each transistor is also diode-connected, where the gate terminal is shorted to the drain terminal. 
         [0070]    If the switching control voltage VCTL exceeds the voltage limit, the NMOS transistors D 1  to DK are turned on. The NMOS transistors D 1  to DK are turned on to form a current path from the output node DOUT to the high-voltage input node HIN, thus reducing the switching control voltage VCTL. Since the high-voltage switch circuit  102  includes the voltage limiter  150  as described above, the switch control voltage VCTL may be prevented from exceeding a target voltage level. 
         [0071]      FIG. 7  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to FIG.  7 , a high-voltage switch circuit  103  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , and a boosting circuit  160 . The high-voltage switch circuit  103  has similar construction and operation as the high-voltage switch circuit  101  that has been described in  FIG. 3 . 
         [0072]    Below are some of the differences between the high-voltage switch circuits  101  and  103 . The d high-voltage switch circuit  103  has multiple amplification circuits BST 1  to BSTN (N is an integer) and a plurality of capacitors CA 1  to CAN, CB 1  to CBN (N is an integer) in the boosting circuit  160  of the high-voltage switch circuit  103 . The circuits BST 1  to BSTN are connected in series, where the output node of BST 1  is connected to the input node of BST 2  and so on. The capacitors CA 1  to CAN are connected to boosting nodes NA 1  to NAN (N is an integer) of the amplification circuits BST 1  to BSTN, respectively. The capacitors CB 1  to CBN are connected to boosting nodes NB 1  to NBN (N is an integer) of the amplification circuits BST 1  to BSTN, respectively. The amplification circuits BST 1  to BSTN have substantially the same construction as the amplification circuit  141  described in  FIG. 3 . 
         [0073]    Since the boosting circuit  160  includes the plurality of amplification circuits BST 1  to BSTN as described above, the boosting circuit  160  can increase the switch control voltage VCTL more rapidly than the boosting circuit  140 . Consequently, the operating speed of the high-voltage switch circuit  103  is faster than that of the high-voltage switch circuit  101 . 
         [0074]      FIG. 8  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 8 , a high-voltage switch circuit  104  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , a boosting circuit  160 , and a voltage limiter  150 . The enable control circuit  110 , the high voltage switch  120 , and the feedback circuit  130  have substantially the same construction. Furthermore, the boosting circuit  160  is substantially the same as that of  FIG. 7  and the voltage limiter  150  is substantially the same as that of  FIG. 6 . Therefore, the description thereof will be omitted. 
         [0075]      FIG. 9  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 9 , a high-voltage switch circuit  105  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , and a boosting circuit  170 . The high-voltage switch circuit  105  has similar construction and operation as the high-voltage switch circuit  101  in  FIG. 3 . T 
         [0076]    Below are some of the differences between the high-voltage switch circuits  101 ,  105 . The high-voltage switch circuit  105  has switches NM 3 , NM 4 , PM 3 , and PM 4  in the amplification circuit  171  of the boosting circuit  170 . Each of the switches NM 1  to NM 4  may be implemented using a low-voltage NMOS transistor and each of the switches PM 1  to PM 4  may be implemented using a low-voltage PMOS transistor. Hereinafter, it is assumed that each of the switches NM 1  to NM 4  is an NMOS transistor and each of the switches PM 1  to PM 4  is a PMOS transistor. 
         [0077]    The NMOS transistor NM 3  has a drain connected to a boosting node BN 1 , a gate connected to a boosting voltage V 2 , and a source connected to the body of NMOS transistors NM 1  to NM 4 . The NMOS transistor NM 3  is turned on or off in response to the boosting voltage V 2 . The NMOS transistor NM 3  is turned on to supply the boosting voltage V 1  of the boosting node BN 1  to the body of the NMOS transistor NM 1  and its body. In more detail, when an inverted clock signal CLKB is high and the NMOS transistor NM 1  is turned on, the NMOS transistor NM 3  supplies the boosting voltage V 1  to the body of the NMOS transistors NM 1  to NM 4 . When the inverted clock signal CLKB is high, the clock signal CLK is low. Accordingly, the boosting voltage V 1  of the boosting node BN 1  can be reduced to a minimal value. As a result, when the NMOS transistor NM 1  is turned on, the body of the NMOS transistor NM 1  becomes the boosting voltage V 1  (i.e., V 1 =VSS) by means of the NMOS transistor NM 3 . Therefore, an increase of the threshold voltage of the NMOS transistor NM 1  can be reduced. For example, when the voltage of the body of the NMOS transistor NM 1  is lower than that of its source, the NMOS transistor NM 1  may not operate since the threshold voltage of the NMOS transistor NM 1  continues to rise from the body effect. The NMOS transistor NM 4  has a drain connected to the boosting node BN 2 , a gate to which the boosting voltage V 1  is input, and a source connected to the body of the NMOS transistors NM 1  to NM 4 . The operation of the NMOS transistor NM 4  is the same as that of the NMOS transistor NM 3  and will not be described. 
         [0078]    The PMOS transistor PM 3  has a source connected to the boosting node BN 1 , a gate to which the boosting voltage V 2  is input, and a drain connected to the body of the PMOS transistors PM 1  to PM 4 . The PMOS transistor PM 3  is turned on or off in response to the boosting voltage V 2 . The PMOS transistor PM 3  is turned on to supply the boosting voltage V 1  to the body of the PMOS transistors PM 1  to PM 4 . In more detail, when the inverted clock signal CLKB is low and the PMOS transistor PM 1  is turned on accordingly, the PMOS transistor PM 3  supplies the boosting voltage V 1  to the body of the PMOS transistors PM 1  to PM 4 . Since the clock signal CLK is high when the inverted clock signal CLKB is low, the boosting voltage V 1  of the boosting node BN 1  can be increased. At this time, the boosting voltage V 1  has been amplified as represented by Equation 6 since the NMOS transistor NM 1  has been turned on. As a result, when the PMOS transistor PM 1  is turned on, the body of the PMOS transistor PM 1  becomes the boosting voltage V 1  by the PMOS transistor PM 3 . Accordingly, an increase of the threshold voltage of the PMOS transistor PM 1  can be reduced. For example, when the voltage of the body of the PMOS transistor PM 1  is lower than the voltage of its drain, the PMOS transistor PM 1  may not operate since the threshold voltage of the PMOS transistor PM 1  continues to rise from the body effect. 
         [0079]    The PMOS transistor PM 4  has a source connected to the boosting node BN 2 , a gate to which the boosting voltage V 1  is input, and a drain connected to the body of the PMOS transistors PM 1  to PM 4 . The operation of the PMOS transistor PM 4  is similar to that of the PMOS transistor PM 3  and will not be described. 
         [0080]    As described above, the NMOS transistors NM 3 , NM 4  and the PMOS transistors PM 3 , PM 4  can reduce the threshold voltage increase of the NMOS transistors NM 1 , NM 2  and the PMOS transistors PM 1 , PM 2  from the body effect. Accordingly, the boosting circuit  170  can increase the switch control voltage VCTL rapidly compared with the boosting circuit  140 . Consequently, the operating speed of the high-voltage switch circuit  105  can be increased in comparison with the high-voltage switch circuit  101 . 
         [0081]      FIG. 10  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 10 , a high-voltage switch circuit  106  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , a boosting circuit  170 , and a voltage limiter  150 . The enable control circuit  110 , the high voltage switch  120 , and the feedback circuit  130  have substantially the same construction as those in  FIG. 3 . Description thereof will be omitted for simplicity. Furthermore, the boosting circuit  170  is similar to that of  FIG. 9  and the voltage limiter  150  is similar to that of  FIG. 6 . Accordingly, the boosting circuit  170  and the voltage limiter  150  will not be described. 
         [0082]      FIG. 11  is a circuit diagram of a high-voltage switch circuit according to one embodiment of the present invention. Referring to  FIG. 11 , the high-voltage switch circuit  107  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , and a boosting circuit  180 . The high-voltage switch circuit  107  has similar construction as the high-voltage switch circuit  105  in  FIG. 9 . In the present embodiment, only the difference between the high-voltage switch circuits  105 ,  107  will be described. 
         [0083]    The difference between the high-voltage switch circuits  105 ,  107  is the addition of multiple amplification circuits BST 1  to BSTN and a plurality of capacitors CA 1  to CAN, CB 1  to CBN in the boosting circuit  180  of the high-voltage switch circuit  107 . The construction and operation of the capacitors CA 1  to CAN, CB 1  to CBN are similar to those of the capacitors CA 1  to CAN, CB 1  to CBN of the high-voltage switch circuit  103 . Each of the amplification circuits BST 1  to BSTN has substantially the same construction as that of the amplification circuit  171  in  FIG. 9 . 
         [0084]    As described above, the boosting circuit  180  includes the plurality of amplification circuits BST 1  to BSTN. Accordingly, the boosting circuit  180  can increase the switch control voltage VCTL rapidly in comparison with the boosting circuit  170 . Consequently, the operating speed of the high-voltage switch circuit  107  can be increased further in comparison with the high-voltage switch circuit  105 . 
         [0085]      FIG. 12  is a circuit diagram of a high-voltage switch circuit according to an eighth embodiment of the present invention. Referring to  FIG. 12 , a high-voltage switch circuit  108  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , a boosting circuit  180 , and a voltage limiter  150 . The enable control circuit  110 , the high voltage switch  120 , and the feedback circuit  130  have substantially the same construction as those in  FIG. 3 . The boosting circuit  180  is similar to that of  FIG. 11  and the voltage limiter  150  is similar to that in  FIG. 6 . Accordingly, the boosting circuit  180  and the voltage limiter  150  will not be described. 
         [0086]      FIG. 13  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 13 , a flash memory device  201  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  101 ,  250 . 
         [0087]    The memory cell array  210  includes a plurality of memory cell blocks MCB 1  to MCBM (M is an integer). Each of the plurality of memory cell blocks MCB 1  to MCBM includes a plurality of memory cells M 111  to M 1 JT that share local word lines WL 11  to W 1 J and bit lines BL 1  to BLT (T is an integer). 
         [0088]    The X-decoder  220  decodes a row address signal RADD and outputs first decoding signals WEN 1  to WENM (M is an integer) and a second decoding signal RDEC. The decoding signals WEN 1  to WENM are input into a plurality of block selection units BS 1  to BSM, respectively. The block selection units BS 1  to BSM then outputs a plurality of block selection signals BSEL 1  to BSELM (M is an integer), respectively, in response to the input signals. In more detail, each of the plurality of block selection units BS 1  to BSM includes a block switch (one of BW 1  to BWM) and a high-voltage switch circuit (one of HW 1  to HWM). Since the plurality of block selection units BS 1  to BSM have substantially the same construction and operation, only the construction and operation of the block selection unit BS 1  will be described below as an example. 
         [0089]    The block selection unit BS 1  includes the block switch BW 1  and the high-voltage switch circuit HW 1 . The block switch BW 1  receives a program voltage VPGM and outputs the block selection signal BSEL 1  with a voltage level that is higher than the program voltage VPGM or lower than the program voltage VPGM in response to a block switch control voltage VC 1 . The high-voltage switch circuit HW 1  receives the program voltage VPGM, and outputs the program voltage VPGM as the block switch control voltage VC 1  in response to the first decoding signal WEN 1  and the clock signals CLK, CLKB. 
         [0090]    As an example, when the first decoding signal WEN is high, the high-voltage switch circuit HW 1  is turned on to output the program voltage VPGM as the block switch control voltage VC 1 . Furthermore, when the first decoding signal WEN 1  is low, the high-voltage switch circuit HW 1  is turned off. Meanwhile, when the high-voltage switch circuit HW 1  outputs the program voltage VPGM as the block switch control voltage VC 1 , the block switch BW 1  outputs the block selection signal BSEL 1  as a voltage level higher than the program voltage VPGM. Furthermore, when the high-voltage switch circuit HW 1  is turned off, the block switch BW 1  outputs the block selection signal BSEL 1  with a voltage level lower than the program voltage VPGM. 
         [0091]    The plurality of gate circuits PG 1  to PBM are controlled by block selection signals BSEL 1  to BSELM, respectively. The plurality of gate circuits PG 1  to PBM connects global drain selection lines GDSL to local drain selection lines DSL; global source select lines GSSL to local source selection lines SSL; and global word lines GWL 1  to GWLJ to local word lines WL 11  to WL 1 J of the memory cell blocks MCB 1  to MCBM, respectively. The construction and operation of the plurality of gate circuits PG 1  to PBM are similar and only PG 1  will be described as an example. The gate circuit PG 1  may include NMOS transistors GD 1 , G 11  to G 1 J, and GS 1 . The NMOS transistor GD 1  is connected between the global drain selection line GDSL and the local drain selection line DSL and is turned on or off in response to the block selection signal BSEL 1 . The NMOS transistors G 11  to G 1 J are connected between the global word lines GWL 1  to GWLJ and the local word lines WL 111  to WL 1 J, respectively, and are turned on or off in response to the block selection signal BSEL 1 . The NMOS transistor GS 1  is connected between the global source select line GSSL and the local source select line SSL and is turned on or off in response to the block selection signal BSEL 1 . 
         [0092]    The first pump  230  generates the program voltage VPGM in response to the program command PGM. The second pump  240  generates a program pass voltage VPASS in response to the program command PGM. The voltage selection circuit  260  selects one of the global word lines GWL 1  to GWLJ in response to a second decoding signal RDEC, and supplies the program voltage VPGM to a selected global word line and the program pass voltage VPASS to the remaining global word lines. 
         [0093]    The high-voltage switch circuit  101  supplies the program voltage VPGM to the voltage selection circuit  260  in response to an enable control signal GWEN and the clock signals CLK, CLKB. For example, when the enable control signal GWEN is high, the high-voltage switch circuit  101  is turned on to supply the program voltage VPGM to the voltage selection circuit  260 . Furthermore, when the enable control signal GWEN is low, the high-voltage switch circuit  101  is turned off to stop the supplying the program voltage VPGM. 
         [0094]    The high-voltage switch circuit  101  includes an enable control circuit  110 , a high voltage switch  120 , a feedback circuit  130 , and a boosting circuit  140 . The construction and operation of the high-voltage switch circuit  101  are similar to those of  FIG. 3  and will not be described. 
         [0095]    The high-voltage switch circuit  250  supplies the program pass voltage VPASS to the voltage selection circuit  260  in response to the enable control signal GWEN and the clock signals CLK, CLKB. For example, when the enable control signal GWEN is high, the high-voltage switch circuit  250  is turned on to supply the program pass voltage VPASS to the voltage selection circuit  260 . Furthermore, when the enable control signal GWEN is low, the high-voltage switch circuit  250  is turned off to stop the supply operation of the program pass voltage VPASS. Each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar manner to the high-voltage switch circuit  101 . 
         [0096]    The program operation of the flash memory device  201  will be described in short below. The first pump  230  generates the program voltage VPGM and the second pump  240  generates the program pass voltage VPASS, in response to the program command PGM. The X-decoder  220  decodes the row address signal RADD and outputs the first decoding signals WEN 1  to WENM and the second decoding signal RDEC. For example, when the X-decoder  220  enables the first decoding signal WEN 1  and disables the first decoding signals WEN 2  to WENM, the high-voltage switch circuit HW 1  may be turned on in response to the first decoding signal WEN 1  and the clock signals CLK, CLKB and the high-voltage switch circuits HW 2  to HWM may be turned off. As a result, the high-voltage switch circuit HW 1  receives the program voltage VPGM and outputs it as the block switch control voltage VC 1 . 
         [0097]    The block switch BW 1  outputs the block selection signal BSEL 1  with a voltage level higher than that of the program voltage VPGEM and a voltage level based on the program voltage VPGM and the block switch control voltage VC 1 . The NMOS transistors GD 1 , G 11  to G 1 J, and GS 1  of the gate circuit PG 1  are all turned on in response to the block selection signal BSEL 1 , thus connecting the global drain selection line GDSL to the local drain select line DSL; the global source select line GSSL to the local source select line SSL; and the global word lines GWL 1  to GWLJ to the local word lines WL 11  to WL 1 J of the memory cell block MCB 1 , respectively. 
         [0098]    Meanwhile, if the enable control signal GWEN is high, the high-voltage switch circuits  101 ,  250  are turned on in response to the enable control signal GWEN and the clock signals CLK, CLKB. As a result, the high-voltage switch circuits  101 ,  250  outputs the program voltage VPGM and the program pass voltage VPASS, to the voltage selection circuit  260 . The voltage selection circuit  260  selects at least one (e.g., GWL 1 ) of the global word lines GWL 1  to GWLJ, and supplies the program voltage VPGM to the selected global word line GWL 1  and the program pass voltage VPASS to the remaining global word lines GWL 2  to GWLJ, in response to the second decoding signal RDEC. 
         [0099]    Consequently, a page of memory cells including the memory cells M 111  to M 11 T connected to the local word line WL 11  of the memory cell block MCB 1  is programmed. Since the high-voltage switch circuits ( 101 ,  250 , HW 1  to HWM) can perform the switching operation at high speed, the program operation speed of the flash memory device  201  can be increased. 
         [0100]      FIG. 14  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 14 , a flash memory device  202  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  102 ,  250 . 
         [0101]    The flash memory device  202  has substantially the same construction and operation as those of the flash memory device  201  shown in  FIG. 13 . One of the differences between the flash memory devices  201 ,  202  is that the high-voltage switch circuit  250  includes a voltage limiter (such as the voltage limiter  150 ). Each of the high-voltage switch circuits  250 , and HW 1  to HWM) may be implemented using the high-voltage switch circuit  102  or  101 . 
         [0102]      FIG. 15  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 15 , a flash memory device  203  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  103 ,  250 . The flash memory device  203  has similar construction and operation as the flash memory device  201  shown in  FIG. 13 . One of the differences between the flash memory devices  201 ,  203  is that the boosting circuit  160  of the high-voltage switch circuit  103  includes a plurality of capacitors CA 1  to CAN, CB 1  to CBN (N is an integer) and a plurality of amplification circuits BST 1  to BSTN (N is an integer). The construction and operation of the high-voltage switch circuit  103  is similar to the high-voltage switch circuit  103  shown in  FIG. 7 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  103 . 
         [0103]      FIG. 16  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 16 , a flash memory device  204  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  104 ,  250 . The flash memory device  204  has similar construction and operation as the flash memory device  203  shown in  FIG. 15 . One of the differences between the flash memory devices  203 ,  204  is the addition of the voltage limiter  150  in the high-voltage switch circuit  104 . The construction and operation of the high-voltage switch circuit  104  is similar to the high-voltage switch circuit  104  shown in  FIG. 8 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  104 . 
         [0104]      FIG. 17  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 17 , a flash memory device  205  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  105 ,  250 . The flash memory device  205  has similar construction and operation as the flash memory device  201  shown in  FIG. 13 . One of the differences between the flash memory devices  201 ,  205  is the addition of the switches NM 3 , NM 4 , PM 3  and PM 4  in the high-voltage switch circuit  105 . The construction and operation of the high-voltage switch circuit  105  are the same as the high-voltage switch circuit  105  shown in  FIG. 9 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  105 . 
         [0105]      FIG. 18  is a schematic block diagram of a flash memory device according to one embodiment of the present invention.Referring to  FIG. 18 , a flash memory device  206  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  106 ,  250 . The flash memory device  206  has similar construction and operation as the flash memory device  205  shown in  FIG. 17 . One of the differences between the flash memory devices  205 ,  206  is the addition of the voltage limiter  150  in the high-voltage switch circuit  106 . The construction and operation of the high-voltage switch circuit  106  are the same as the high-voltage switch circuit  106  shown in  FIG. 10 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  106 . 
         [0106]      FIG. 19  is a schematic block diagram of a flash memory device according to one embodiment of the present invention. Referring to  FIG. 19 , a flash memory device  207  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  107 ,  250 . The flash memory device  207  has similar construction and operation as the flash memory device  205  shown in  FIG. 17 . 
         [0107]    One of the differences between the flash memory devices  205 ,  207  is that the boosting circuit  180  of the high-voltage switch circuit  107  includes a plurality of capacitors CA 1  to CAN, CB 1  to CBN (N is an integer) and a plurality of amplification circuits BST 1  to BSTN (N is an integer). The construction and operation of the high-voltage switch circuit  107  is similar to the high-voltage switch circuit  107  shown in  FIG. 11 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  107 . 
         [0108]      FIG. 20  is a schematic block diagram of a flash memory device according to an eighth embodiment of the present invention. Referring to  FIG. 20 , a flash memory device  208  includes a memory cell array  210 , a X-decoder  220 , a plurality of block selection units BS 1  to BSM (M is an integer), a plurality of gate circuits PG 1  to PBM (M is an integer), a first pump  230 , a second pump  240 , a voltage selection circuit  260 , and high-voltage switch circuits  108 ,  250 . The flash memory device  208  has similar construction and operation as the flash memory device  207  shown in  FIG. 19 . One of the differences between the flash memory devices  207 ,  208  is the addition of the voltage limiter  150  in the high-voltage switch circuit  108 . The construction and operation of the high-voltage switch circuit  108  are similar to the high-voltage switch circuit  108  shown in  FIG. 12 . In this case, each of the high-voltage switch circuits  250  and HW 1  to HWM may be implemented in a similar way to one of the high-voltage switch circuits  101  to  108 . 
         [0109]    As described above, the high-voltage switch circuits  101  to  108 ,  250 , HW 1  to HWM included in the flash memory devices  201  to  208  can perform the switching operation at high speed. Accordingly, the program operation speed of the flash memory device can be enhanced and noise components of an output high voltage can be reduced. 
         [0110]    Furthermore, in the above-mentioned embodiments, constituent elements for the program operation of the flash memory device and the operations of the constituent elements have been described as examples. However, the above-mentioned embodiments may be applied to a variety of operations, such as an erase operation or a read operation of the flash memory device that executes the switching operation of a high voltage. 
         [0111]    While the invention has been described in connection with what is presently considered to be specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.