Abstract:
A voltage generation circuit includes: a first and second rectification circuits; and one or more amplification units connected between the first and second rectification circuits and configured to amplify an output of the first rectification circuit and provide the amplified output to the second rectification circuit. The second rectification circuit generates a reference voltage.

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
       [0001]    The present application claims priority under 35 U.S.C. §119(a) to Korean Patent Application No. 10-2010-0051324, filed on May 31, 2010, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety as if set forth in full. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a semiconductor circuit and, more particularly, to a voltage generation circuit which may be used in a semiconductor apparatus. 
         [0004]    2. Related Art 
         [0005]    A reference voltage generation circuit in a voltage generation circuit may be implemented in various manners. 
         [0006]      FIG. 1  is a diagram illustrating an example of a conventional reference voltage generation circuit. The depicted reference voltage generation circuit  1  is a Widlar-type reference voltage generation circuit, and includes a plurality of transistors M 1  to M 10  and a plurality of resistors R 1  and R 2 . 
         [0007]    The reference voltage generation circuit  1  generates a reference voltage VREF 1  by converting a current, generated through a current mirroring operation of the transistors M 1  to M 6 , into a voltage. 
         [0008]    A problem with conventional voltage circuits, such as the reference voltage generation circuit  1 , is that the reference voltage VREF 1  may vary widely depending on a power supply voltage VDDV, which may be due to the variations in characteristics of basic analog circuit components such as the transistors used in the circuits. 
       SUMMARY 
       [0009]    Accordingly, there is a need for an improved voltage generation circuit that may obviate the above-mentioned problem. It should be understood, however, that some aspects of the invention may not necessarily obviate the problem. 
         [0010]    In the following description, certain aspects and embodiments will become evident. It should be understood that these aspects and embodiments are merely exemplary, and the invention, in its broadest sense, could be practiced without having one or more features of these aspects and embodiments. 
         [0011]    In one aspect of the present invention, a voltage generation circuit includes a first and second rectification circuits; and one or more amplification units connected between the first and second rectification circuits and configured to amplify an output of the first rectification circuit and provide the amplified output to the second rectification circuit. The second rectification circuit generates a reference voltage. 
         [0012]    In another aspect of the present invention, a voltage generation circuit includes: a first rectification circuit configured to rectify a power supply voltage and generate a first voltage; an amplification unit configured to amplify the first voltage and generate a second voltage; a second rectification circuit configured to rectify the second voltage and generate a reference current; and a current/voltage conversion unit configured to generate a reference voltage by converting the reference current to a voltage. 
         [0013]    In another aspect of the present invention, a semiconductor apparatus includes a voltage generation circuit. The voltage generation circuit in turn includes: a first rectifier; an amplifier, connected to the first rectifier, that receives a first voltage to generate a second voltage; a second rectifier, connected to the amplifier, that receives the second voltage to generate a reference current; and a converter, connected to the second rectifier, that receives the reference current to generate an output reference voltage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The accompanying drawings, which are incorporated in and constitute a part of this specification, explain various embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. 
           [0015]      FIG. 1  is a circuit diagram of a Widlar-type reference voltage generation circuit; 
           [0016]      FIG. 2  is a block diagram of a voltage generation circuit according to one exemplary embodiment of the present invention; 
           [0017]      FIG. 3  is a circuit diagram of the voltage generation circuit according to one exemplary embodiment of the present invention; and 
           [0018]      FIG. 4  is a simulation waveform diagram comparing a reference voltage of the voltage generation circuit according to one embodiment of the present invention with a reference voltage of a conventional voltage generation circuit. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Reference will now be made in detail to the exemplary embodiments consistent with the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. 
         [0020]    In one aspect of the present invention, a circuit block for performing a rectifying operation is configured in a plurality of stages, and a voltage depending on a previous rectifying operation is amplified at a predetermined ratio and then rectified again. Therefore, a variation in a reference voltage depending on a power supply voltage may be reduced exponentially. 
         [0021]      FIG. 2  is an illustration of an exemplary voltage generation circuit according to one embodiment of the present invention, in which a circuit block for performing a rectifying operation is configured in two stages. 
         [0022]    Referring to  FIG. 2 , the voltage generation circuit  100  includes a first and second rectification circuits,  200  and  500 , an amplification unit  300 , and a current/voltage conversion unit  600 . 
         [0023]    The first rectification circuit  200  is configured to rectify a power supply voltage VDDV and generate a first voltage VR 0 . 
         [0024]    The amplification unit  300  is configured to amplify the first voltage VR 0  and generate a second voltage VDDR. 
         [0025]    The amplification unit  300  may include a differential amplifier  310  and a voltage divider  320 . 
         [0026]    The amplification unit  300  uses the voltage divider  320  to amplify the first voltage VR 0  at a division ratio of the voltage divider  320 , thereby generating the second voltage VDDR. 
         [0027]    The second rectification circuit  500  is configured to rectify the second voltage VDDR and generate a reference current IR. 
         [0028]    The current/voltage conversion unit  600  is configured to convert the reference current IR into a voltage and generate a reference voltage VREF 2 . 
         [0029]      FIG. 3  is a circuit diagram of the voltage generation circuit according to one exemplary embodiment of the present invention. Referring to  FIG. 3 , the first rectification circuit  200  includes a plurality of transistors M 11  to M 16  and a plurality of resistors R 11  and R 12 . 
         [0030]    The first rectification circuit  200  may be configured by using any of a number of configurations of a reference voltage generation circuit as is well known in the art.  FIG. 3  illustrates an exemplary implementation according to the Widlar-type reference voltage generation circuit. 
         [0031]    The differential amplifier  310  may include a plurality of transistors M 17  to M 22 . 
         [0032]    The differential amplifier  310  is configured to receive the second voltage VDDR negatively fed back from the voltage divider  320 . 
         [0033]    The voltage divider  320  may include a plurality of resistors R 13  and R 14 . 
         [0034]    The second rectification circuit  500  may include a plurality of transistors M 23  to M 28  and a plurality of resistors R 15  and R 16 . 
         [0035]    The second rectification circuit  500  may be configured in the same manner as the first rectification circuit  200 . Also, each of the components in the second rectification circuit  500  has a corresponding component in the first rectification circuit  200 . Furthermore, each component in the second rectification circuit  500  may have the same circuit characteristics as the corresponding component in the first rectification circuit  200 . 
         [0036]    The current/voltage conversion unit  600  includes a plurality of diodes composed of a plurality of transistors M 29  to M 32 . 
         [0037]    Referring to  FIG. 3 , the operation of the exemplary voltage generation circuit  100  according to this embodiment will be described as follows. 
         [0038]    The power supply voltage VDDV is rectified through the first rectification circuit  200  to generate the first voltage VR 0 . 
         [0039]    The first voltage VR 0  is amplified at the division ratio of the voltage divider  320 , and negatively fed back to the differential amplifier  310  to generate the second voltage VDDR. In this embodiment which uses the two resistors R 13  and R 14 , the level of the second voltage VDDR corresponds to VR 0 *(1+R 13 /R 14 ). 
         [0040]    The second voltage VDDR generated in such a manner may be rectified through the second rectification circuit  500 . Thus, the level of the third voltage VR 1  is equalized to the first voltage VR 0 . 
         [0041]    A reference current IR corresponding to the same amount as the amount of current flowing in the second rectification circuit  500  passes through the current/voltage conversion unit  600  by a current mirroring operation, depending on the third voltage VR 1 . 
         [0042]    The reference current IR is converted into a reference voltage VREF 2  by the plurality of diodes of the current/voltage conversion unit  600 , which are composed of the transistors M 29  to M 32 . 
         [0043]    As the voltage generation circuit according to this embodiment includes the two-stage rectification circuits, circuits  200  and  500 , the rectification characteristic may improve exponentially as expressed blow: 
         [0000]      {(ΔVREF2)̂2/(ΔVDDV)̂2}*(1+R13/R14)
 
         [0044]      FIG. 4  depicts a simulation waveform diagram showing the reference voltage of the voltage generation circuit according to this embodiment and the reference voltage of the conventional voltage generation circuit. Referring to  FIG. 4 , as the power supply voltage VDDV is varied by 1V in the conventional voltage generation circuit, the reference voltage VREF 1  is varied by 11.46 mV. However, as the power supply voltage VDDV is varied by 1V in the voltage generation circuit according to this embodiment, the reference voltage VREF 2  is varied by 0.22 mV. 
         [0045]    That is, the voltage generation circuit according to this embodiment may reduce the variation in the reference voltage with respect to the same variation in the power supply voltage to about 1/52 of that in the conventional voltage generation circuit. 
         [0046]    Therefore, according to this embodiment, it is possible to expect a 52 times larger performance improvement over the conventional voltage generation circuit  100 . 
         [0047]    According to this embodiment, since the rectification characteristic may be improved by the amplification operations of at least two or more rectification circuits, it is possible to generate the is reference voltage of which the variation depending on the power supply voltage is reduced in comparison with the conventional voltage generation circuit. 
         [0048]    While certain aspects of the present invention have been described above, it will be understood to those skilled in the art that the aspects described are by way of example only. Accordingly, the voltage generation circuit described herein should not be limited based on the described aspects. Rather, the voltage generation circuit described herein should only be limited in light of the claims that follow when taken in conjunction with the above description and accompanying drawings.