Abstract:
A voltage generator for a peripheral circuit, the voltage generator includes: a voltage supplier supplying a peripheral circuit voltage having a voltage level maintained at a reference voltage level, the peripheral circuit voltage outputted in response to a driving signal; and a voltage level compensator increasing the voltage level of the peripheral circuit voltage in response to a column path command.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a semiconductor memory device, and more particularly, to a voltage generator used in a peripheral circuit. 
     DESCRIPTION OF RELATED ARTS 
     Many researchers have focused on achieving low power consumption in a semiconductor memory device for mobile apparatuses. However, it is necessary to consider the fact that an external voltage level becomes unstable depending on a voltage level of a peripheral circuit due to the limited use of power. 
       FIG. 1  illustrates a circuit diagram of a conventional voltage generator for a peripheral circuit. 
     The voltage generator is activated by a driving signal EN. Also, the voltage generator generates a control signal CTR to sustain a feedback voltage VPERI_FD of a peripheral circuit voltage VPERI higher than a reference voltage REF and provides the peripheral circuit voltage VPERI. 
       FIG. 2  illustrates the peripheral circuit voltage VPERI depending on that of an external power supply voltage VDD, wherein the voltage generator illustrated in  FIG. 1  generates the peripheral circuit voltage VPERI based on the external power supply voltage VDD. 
     The peripheral circuit voltage VPERI reaches a plateau at 1.8V even if the voltage level of the external power supply voltage VDD increases continuously. This behavior is specifically to lower an amount of a driving current. For reference, the peripheral circuit voltage is applied to row and column control units, decoders, data transferring paths and so on except for core memory blocks. 
     The conventional voltage generator for the peripheral circuit usually restricts the voltage level of the peripheral circuit voltage to a certain level to minimize the amount of the driving current. Thus, when a large amount of current is dissipated while performing read and write operations, the voltage level of the external power supply voltage tends to be unstable. Furthermore, since the voltage generator for the peripheral circuit is disposed in a specifically designated portion of the semiconductor memory device, those devices located away from the voltage generator often receive a lowered level of the peripheral circuit voltage. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide a voltage generator for a peripheral circuit of a semiconductor memory device, wherein the voltage generator can supply a stabilized peripheral circuit voltage regardless of internal device operations and device arrangements. 
     In accordance with an aspect of the present invention, there is provided a voltage generator for a peripheral circuit, the voltage generator including: a voltage supplier supplying a peripheral circuit voltage having a voltage level maintained at a reference voltage level, the peripheral circuit voltage outputted in response to a driving signal; and a voltage level compensator increasing the voltage level of the peripheral circuit voltage in response to a column path command. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and features of the present invention will become better understood with respect to the following description of the exemplary embodiments given in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates a circuit diagram of a conventional voltage generator for a peripheral circuit; 
         FIG. 2  illustrates a graph of a voltage level of a peripheral circuit voltage generated according to an external power supply voltage; 
         FIG. 3  illustrates a circuit diagram of a voltage generator for a peripheral circuit in accordance with an embodiment of the present invention; 
         FIG. 4  provides an operational waveform diagram of the voltage generator illustrated in  FIG. 3 ; and 
         FIG. 5  depicts a chip layout of a voltage generator for a peripheral circuit in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A voltage generator for a peripheral circuit in accordance with various embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 3  illustrates a simplified circuit diagram of a voltage generator for a peripheral circuit in accordance with an embodiment of the present invention. 
     The voltage generator includes a voltage level compensator  100  and a voltage supplier  200 . The voltage level compensator  100  is configured to temporarily increase a voltage level of a peripheral circuit voltage VPERI in response to a column path command CL_EN. The voltage supplier  200  is configured to sustain a feedback voltage VPERI_FD level of the peripheral circuit voltage VPERI substantially the same as a reference voltage REF level. The peripheral circuit voltage VPERI is outputted in response to a driving signal EN. The column path command CL_EN is enabled when a write command and a read command RD (see  FIG. 4 ) are supplied. 
     Particularly, the voltage level compensator  100  drives a terminal connected to the peripheral circuit voltage VPERI with a voltage applied to a terminal connected to an external power supply voltage VDD during the activation of the column path command CL_EN, and stops supplying the external power supply voltage VDD when a deep power down mode signal DPD_SIG is enabled. 
     The voltage level compensator  100  includes a driving unit PM 1  and a control unit  120 . The driving unit PM 1  drives the terminal connected to the peripheral circuit voltage VPERI with the voltage applied to the terminal connected to the external power supply voltage VDD. The control unit  120  controls the driving unit PM 1  in response to the deep power down mode signal DPD_SIG and the column path command CL_EN. 
     The control unit  120  includes an inverter  11  and a NAND gate ND 1 . The inverter  11  inverts the deep power down mode signal DPD_SIG, and the NAND gate ND 1  receives the column path command CL_EN and an output signal of the inverter  11  and outputs a driving control signal CTR_SH. 
     The driving unit PM 1  includes a P-channel metal-oxide semiconductor (PMOS) transistor, which has a gate receiving the driving control signal CTR_SH and is coupled between the terminal connected to the external power supply voltage VDD and the terminal connected to the peripheral circuit voltage VPERI. 
       FIG. 4  provides an operational waveform diagram of the voltage generator illustrated in  FIG. 3 . With reference to  FIG. 4 , operation of the voltage generator will be described in detail. 
     If the read command RD is inputted, the column path command CL_EN becomes enabled. Thus, the control unit  120  of the voltage level compensator  100  generates the driving control signal CTR_SH enabled to a logic low level ‘L’. The driving unit PM 1  is activated in response to the enabled driving control signal CTR_SH and thus, drives the terminal connected to the peripheral circuit voltage VPERI with the external power supply voltage VDD. 
     If a deep power down mode command DPD is inputted, the deep power down mode signal DPD_SIG is enabled to a logic high level ‘H’, and the control unit  120  disables the driving control signal CTR_SH to turn off the driving unit PM 1 . 
     The voltage generator for the peripheral circuit in the present embodiment detects the case where a large amount of current is consumed, e.g., read and write operations, by using the voltage level compensator  100  activated during the read and write operations, and connects the terminal connected to the external power supply voltage VDD with the terminal connected to the peripheral circuit voltage VPERI. As a result, the peripheral circuit voltage VPERI and the external power supply voltage VDD are less likely to drop down. For reference, the voltage drop down incidence usually occurs during the column path operation. 
     In such a mode that requires the minimization of the power consumption, e.g., the deep power down mode, the driving unit PM 1  of the voltage level compensator  100  is turned off to avoid unnecessary power consumption. 
       FIG. 5  depicts a layout of the voltage generator for the peripheral circuit in accordance with an embodiment of the present invention. 
     The voltage supplier  200  is disposed in a predetermined region of a target device structure, whereas the voltage level compensator  100  is disposed in multiple regions. That is, the voltage level compensator  100  is formed in multiple numbers. This layout prevents supplying of the peripheral circuit voltage VPERI that is usually dropped down to peripheral circuits when the peripheral circuits are located away from the voltage supplier  200 . 
     The peripheral circuit voltage VPERI is dissipated in the peripheral region disposed outside the core blocks. Hence, the voltage generator for the peripheral circuit is configured to include a plurality of voltage compensators disposed at several places of a device to supply the external power supply voltage to the terminal connected to the peripheral circuit voltage after detecting the supply of a command that is expected to cause high current consumption. As a result, it is possible to reduce the voltage drop down incidence caused by the column path operation and the remote distance from the level compensator to the voltage supplier. Accordingly, the voltage generator can stably supply the peripheral circuit voltage regardless of the high current consumption and the device layout. 
     The present application contains a subject matter related to the Korean patent application Nos. KR 2005-090843 and 2005-0123980, filed in the Korean Patent Office respectively on Sep. 28, 2005, and Dec. 15, 2005, the entire contents of which are incorporated herein by reference. 
     While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.