CN203457116U - CMFB differential amplification circuit and integrated circuit - Google Patents
CMFB differential amplification circuit and integrated circuit Download PDFInfo
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- CN203457116U CN203457116U CN201320472374.4U CN201320472374U CN203457116U CN 203457116 U CN203457116 U CN 203457116U CN 201320472374 U CN201320472374 U CN 201320472374U CN 203457116 U CN203457116 U CN 203457116U
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Abstract
The utility model discloses a CMFB differential amplification circuit and an integrated circuit. A CMFB loop carries out differential pressure on a first common-mode signal to generate a second common-mode signal and a third common-mode signal; a differential amplifier sets the voltage of the signal, with the higher voltage, of the second common-mode signal and the third common-mode signal to be equal to the voltage of a first input end or a second input end; the CMFB loop controls the lowest output voltage of the differential amplifier to be equal to the output signal of the voltage of the first common-mode signal according to the negative feedback principle. By means of the scheme, the differential amplifier does not need to be connected with a high-voltage power source when processing the second common-mode signal and the third common-mode signal at the input stage, and at the same time, the CMFB is achieved without resistance differential pressure on the voltage between the output signals, and the power consumption can be reduced.
Description
Technical field
The utility model relates to differential amplifier circuit, relates in particular to a kind of differential amplifier circuit and integrated circuit of common-mode feedback.
Background technology
Differential amplifier circuit utilizes symmetry and the negative feedback of circuit parameter, can effectively stablize quiescent point, and take amplify difference mode signal, inhibition common-mode signal is notable feature, is widely used in the input stage of direct-coupled circuit and measuring circuit.
In differential amplifier circuit, differential amplifier generally needs common-mode feedback (CMFB, Common Mode Feedback) loop, and described CMFB circuit is used for arranging common-mode voltage.At present, along with the low-power consumption requirement of various electronic products is more and more higher, the differential amplifier circuit that electronic product is used also needs to reduce as much as possible power consumption.
Utility model content
For solving the problems of the prior art, the utility model provides a kind of differential amplifier circuit and integrated circuit of common-mode feedback.
The technical solution of the utility model is achieved in that
The differential amplifier circuit of a kind of common-mode feedback that the utility model provides, this differential amplifier circuit comprises:
The first common-mode signal dividing potential drop is produced to the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier, and control according to negative-feedback principle the CMFB loop of output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
Receive the second common-mode signal and the 3rd common-mode signal, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, according to the control output minimum voltage of CMFB loop, equal the differential amplifier of output signal of the voltage of the first common-mode signal.
The utility model also provides a kind of integrated circuit, and this integrated circuit comprises the differential amplifier circuit of common-mode feedback, and this differential amplifier circuit comprises:
The first common-mode signal dividing potential drop is produced to the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier, and control according to negative-feedback principle the CMFB loop of output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
Receive the second common-mode signal and the 3rd common-mode signal, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, according to the control output minimum voltage of CMFB loop, equal the differential amplifier of output signal of the voltage of the first common-mode signal.
The utility model embodiment provides a kind of differential amplifier circuit and integrated circuit of common-mode feedback, CMFB loop produces the second common-mode signal and the 3rd common-mode signal to the first common-mode signal dividing potential drop, the voltage that differential amplifier arranges the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high equates with the voltage of first input end or the second input, and CMFB loop controls according to negative-feedback principle the output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; So, differential amplifier does not need to be connected the power power-supply of high pressure to the second common-mode signal and the processing of the 3rd common-mode signal in input stage, only need to use the internal electric source of low pressure, can reduce power consumption, and, the differential amplifier circuit that the utility model provides no longer needs that the voltage between output signal is carried out to electric resistance partial pressure and realizes common-mode feedback, the power consumption of avoiding the resistance between output signal to bring.
Accompanying drawing explanation
Fig. 1 is the structural representation of CMFB loop in the differential amplifier of prior art;
The structural representation of the differential amplifier circuit of the common-mode feedback that Fig. 2 provides for the utility model embodiment;
The physical circuit schematic diagram of the differential amplifier circuit of the common-mode feedback that Fig. 3 provides for the utility model embodiment;
In the differential amplifier that Fig. 4 provides for the utility model embodiment, common-mode voltage is selected the schematic diagram of circuit;
The operation simulation figure of the differential amplifier circuit of the common-mode feedback that Fig. 5 provides for the utility model embodiment;
The schematic flow sheet of the differential amplification method of the common-mode feedback that Fig. 6 provides for the utility model embodiment.
Embodiment
CMFB loop in current differential amplifier, as shown in Figure 1, in this CMFB loop, the source electrode of two PMOS connects respectively the negative pole of current source, wherein, the grid connection common mode signal V of a PMOS
cM, the grid of another PMOS connects the mid point of two divider resistances, and the positive pole of described current source connects power power-supply PVDD, and two divider resistances are connected between two output signal VOP and VON.Like this, described differential amplifier is when work, and CMFB loop can guarantee the voltage of two output signal VOP and VON and equal the common-mode signal V of two times
cMvoltage, but, due to the voltage of described current source, the power power-supply PVDD by high pressure provides, the electric current of two PMOS of can causing flowing through produces larger power consumption, and, because the divider resistance between two output signal VOP and VON also has larger electric current, flow through, this part electric current is also that the power power-supply PVDD by high pressure provides, and also will produce larger power consumption.
Basic thought of the present utility model is: CMFB loop produces the second common-mode signal and the 3rd common-mode signal to the first common-mode signal dividing potential drop, the voltage that differential amplifier arranges the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high equates with the voltage of first input end or the second input, and CMFB loop controls according to negative-feedback principle the output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal.
The differential amplifier circuit of the common-mode feedback the utility model proposes can reduce the power consumption that current differential amplifier produces.
Below by drawings and the specific embodiments, the utility model is described in further detail.
It should be noted that, below used first, second ... only represent signal or the element of diverse location, parameter or effect are not limited.
The utility model embodiment realizes a kind of differential amplifier circuit of common-mode feedback, as shown in Figure 2, comprising: CMFB loop 11, differential amplifier 12; Wherein,
11 pairs of the first common-mode signal dividing potential drops of described CMFB loop produce the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier 12; Described differential amplifier 12 receives the second common-mode signal and the 3rd common-mode signal in input stage, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, described CMFB loop 11 controls according to negative-feedback principle the output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal;
Described the first common-mode signal generally can obtain according to the differential signal of input;
Described the first input signal and the second input signal are differential signal;
Wherein, described CMFB loop 11 comprises: the first bleeder circuit 111, the second bleeder circuit 112, the first negative-feedback circuit 113, the second negative-feedback circuit 114, wherein,
Voltage between 111 pairs of the first input signals of described the first bleeder circuit and the first common-mode signal carries out dividing potential drop and produces the second common-mode signal, exports the second common-mode signal to differential amplifier 12;
Voltage between 112 pairs of the second input signals of described the second bleeder circuit and the first common-mode signal carries out dividing potential drop and produces the 3rd common-mode signal, exports the 3rd common-mode signal to differential amplifier 12;
Described the first negative-feedback circuit 113 controls according to negative-feedback principle the first output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal; Here, described the first negative-feedback circuit 113 adopts the bleeder circuit with the identical dividing potential drop ratio of described the first bleeder circuit 111, makes differential amplifier 12 output minimum voltages equal the first output signal of the voltage of the first common-mode signal;
Described the second negative-feedback circuit 114 controls according to negative-feedback principle the second output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal; Here, described the second negative-feedback circuit 114 adopts the bleeder circuit with the identical dividing potential drop ratio of described the second bleeder circuit 112, makes differential amplifier 12 output minimum voltages equal the second output signal of the voltage of the first common-mode signal;
Described differential amplifier 12 comprises: input stage circuit 121, gain stage circuit 122, output-stage circuit 123, wherein,
Described input stage circuit 121 receives the second common-mode signal and the 3rd common-mode signals, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input; Here, described input stage circuit 121 comprises common-mode voltage selection circuit, and the voltage of selecting circuit that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set by described common-mode voltage equates with the voltage of first input end or the second input; Described common-mode voltage selects circuit to consist of current source and metal-oxide semiconductor (MOS) (MOS) field effect transistor, and described metal-oxide-semiconductor can be selected PMOS or NMOS;
122 pairs of the first input signals of described gain stage circuit and the second input signal carry out signal amplification;
Described output-stage circuit 123 equals the first output signal or second output signal of the voltage of the first common-mode signal according to the control output minimum voltage of CMFB loop 11; Here, described gain stage circuit 122 and described output-stage circuit 123 can adopt the circuit of gain stage and output stage in current differential amplifier.
The particular circuit configurations of the differential amplifier circuit of the common-mode feedback below the utility model being provided is elaborated, as shown in Figure 3, the differential amplifier circuit of this common-mode feedback comprises: the CMFB loop consisting of first divider resistance R1 to the six divider resistance R1～R6, the first feedback resistance Rf1 and the second feedback resistance Rf2, and differential amplifier A1; Wherein,
In CMFB loop, first divider resistance R1 one end connects the first common-mode signal V
cM1, the other end connects the first common mode input VC1 of the second divider resistance R2 and differential amplifier A1; Second divider resistance R2 one end connects the first input signal V
11, the other end connects the first common mode input VC1 of the first divider resistance R1 and differential amplifier A1; The 3rd divider resistance R3 one end connects the first common-mode signal V
cM1, the other end connects the second common mode input VC2 of the 4th divider resistance R4 and differential amplifier A1; The 4th divider resistance R4 one end connects the second input signal V
12, the other end connects the second common mode input VC2 of the 3rd divider resistance R3 and differential amplifier A1; The 5th divider resistance R5 one end connects the first input signal V
11, the other end connects the first input end VIP of the second feedback resistance Rf1 and differential amplifier A1; The 6th divider resistance R6 one end connects the second input signal V
12, the other end connects the second input VIN of the second feedback resistance Rf2 and differential amplifier A1; First feedback resistance Rf1 one end connects the first input end VIP of the 5th divider resistance R5 and differential amplifier A1, and the other end connects the first output VON of differential amplifier A1; Second feedback resistance Rf2 one end connects the second input VIN of the 6th divider resistance R6 and differential amplifier A1, and the other end connects the second output VOP of differential amplifier A1.
In above-mentioned CMFB loop, the first bleeder circuit consists of the first divider resistance R1 and the second divider resistance R2, and wherein, the mid point that the first divider resistance R1 is connected with the second divider resistance R2 produces the second common-mode signal V
cM2; The second bleeder circuit consists of the 3rd divider resistance R3 and the 4th divider resistance R4, and wherein, the mid point that the 3rd divider resistance R3 is connected with the 4th divider resistance R4 produces the 3rd common-mode signal V
cM3; The first negative-feedback circuit consists of the first feedback resistance Rf1; The second negative-feedback circuit consists of the second feedback resistance Rf2.
In above-mentioned CMFB loop, the first divider resistance R1 is identical with the resistance ratio of the first feedback resistance Rf1 and the 5th divider resistance R5 with the resistance ratio of the second divider resistance R2; The 3rd divider resistance R3 is identical with the resistance ratio of the second feedback resistance Rf2 and the 6th divider resistance R6 with the resistance ratio of the 4th divider resistance R4; Described the second divider resistance R2, the 4th divider resistance R4, the 5th divider resistance R5, the 6th divider resistance R6 can adopt adjustable resistance or switching capacity.
The differential amplifier circuit of the common-mode feedback shown in Fig. 3 is when work, if the first input signal V
11voltage be greater than the second input signal V
12, the second common-mode signal V
cM2voltage be greater than the 3rd common-mode signal V
cM3, the voltage of the first output signal of the first output VON output of differential amplifier A1 is less than the second output signal of the second output VOP output, and differential amplifier A1 arranges the second common-mode signal V in input stage
cM2voltage equal the voltage of first input end VIP and the second input VIN, like this, due to the second common-mode signal V
cM2voltage by the first divider resistance R1 and the second divider resistance R2 dividing potential drop, obtained, the voltage of first input end VIP is obtained by the first feedback resistance Rf1 and the 5th divider resistance R5, and the first divider resistance R1 is identical with the resistance ratio of the first feedback resistance Rf1 and the 5th divider resistance R5 with the resistance ratio of the second divider resistance R2, the voltage of the first output signal of the first output VON output equals the first common-mode signal V
cM1voltage; Otherwise, the voltage of the second output signal of the second output VOP output of differential amplifier A1 be less than the first output VON output the first output signal voltage time, the voltage of the second output signal of the second output VOP output equals the first common-mode signal V
cM1voltage.
In the differential amplifier circuit of the common-mode feedback shown in Fig. 3, described differential amplifier A1 comprises: input stage circuit, gain stage circuit, output-stage circuit, wherein, described input stage circuit comprises common-mode voltage selection circuit as shown in Figure 4, is configured to arrange the second common-mode signal V
cM2with the 3rd common-mode signal V
cM3the voltage of the signal that middle voltage is high equates with the voltage of first input end VIP or the second input VIN; Described common-mode voltage selects circuit to consist of current source Q2 and metal-oxide-semiconductor, described metal-oxide-semiconductor can be selected PMOS or NMOS, Fig. 4 be take PMOS as example, this common-mode voltage selects circuit to consist of current source Q2 and PMOS to the six PMOS P1～P6, wherein, the positive pole of current source Q2 connects internal electric source VDD, and negative pole connects respectively the source electrode of a PMOS P1, the 3rd PMOS P3, the 5th PMOS P5; The grid of the one PMOS P1 and the 2nd PMOS P2 is respectively first input end VIP and the second input VIN of differential amplifier A1; The grid of the 3rd PMOS P3 connects the grid of the 6th PMOS P6, as the second common mode input VC2 of differential amplifier A1, for receiving the 3rd common-mode signal V
cM3; The grid of the 4th PMOS P4 connects the grid of the 5th PMOS P5, as the first common mode input VC1 of differential amplifier A1, for receiving the second common-mode signal V
cM2; Can find out, that the positive pole of current source Q2 connects is the internal electric source VDD of low pressure, rather than the power power-supply PVDD of high pressure, the power consumption that the electric current of PMOS to the six PMOS P1～P6 that can reduce to flow through produces.
Here, described internal electric source VDD is generally used for the operating voltage that differential amplifier inside is provided, the voltage that the voltage that internal electric source VDD provides will provide well below power power-supply PVDD; Described power power-supply PVDD is generally used for the voltage that output driving part is provided.
Fig. 5 is the operation simulation figure of the differential amplifier circuit of common-mode feedback shown in Fig. 3, wherein, in nethermost oscillogram, solid line 1 and the first dotted line 2 represent respectively the first output VON and the first output signal of the second output VOP output and the waveform of the second output signal, from waveform, can find out, the voltage of the signal that in the first output signal and the second output signal, voltage is lower is 1.5V left and right, is the first common-mode signal V
cM1voltage; In middle oscillogram, the second dotted line 3 and the 3rd dotted line 4 represent respectively the signal waveform of first input end VIP and the second input VIN, can find out, the signal of the signal of first input end VIP and the second input VIN is difference input, and amplitude is 1.5V left and right; Uppermost oscillogram is the complete period analogous diagram of the first output signal and the second output signal, can find out, the waveform of the output signal of the differential amplifier circuit of the common-mode feedback that the utility model provides is for sinusoidal wave, and (THD) is less for total harmonic distortion.
Differential amplifier circuit based on above-mentioned common-mode feedback, the utility model embodiment also provides a kind of differential amplification method of common-mode feedback, and as shown in Figure 6, the method comprises:
Step 101: differential amplifier circuit carries out dividing potential drop to the first common-mode signal, produces the second common-mode signal and the 3rd common-mode signal;
Concrete, the voltage between the first input signal and the first common-mode signal is carried out to dividing potential drop and produce the second common-mode signal, export the second common-mode signal to differential amplifier;
Voltage between the second input signal and the first common-mode signal is carried out to dividing potential drop and produce the 3rd common-mode signal, export the 3rd common-mode signal to differential amplifier.
Step 102: the differential amplifier in differential amplifier circuit receives the second common-mode signal and the 3rd common-mode signal in input stage, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input;
Described arrange the voltage of the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high and the voltage of first input end or the second input equate be:
At input stage circuit, common-mode voltage is set and selects circuit, by described common-mode voltage, select circuit to select the voltage of the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high to equate with the voltage of first input end or the second input; Described common-mode voltage selects circuit to consist of current source and metal-oxide-semiconductor, for example: described metal-oxide-semiconductor is PMOS, as shown in Figure 4, described common-mode voltage selects circuit to consist of current source Q2 and PMOS to the six PMOS P1～P6, wherein, the second common-mode signal V receiving as the first common mode input VC1 of differential amplifier
cM2the 3rd common-mode signal V that receives higher than the second common mode input VC2 of differential amplifier of voltage
cM3voltage time, described the second common-mode signal V
cM2voltage equal the voltage of first input end VIP and the second input VIN; The the second common-mode signal V receiving as the first common mode input VC1 of differential amplifier
cM2the 3rd common-mode signal V that receives lower than the second common mode input VC2 of differential amplifier of voltage
cM3voltage time, described the 3rd common-mode signal V
cM3voltage equal the voltage of first input end VIP and the second input VIN; Here, the positive pole of current source Q2 is connected to internal electric source VDD, and do not need to connect power power-supply PVDD, because the voltage of internal electric source VDD will be well below the voltage of power power-supply PVDD, so the power consumption that the electric current of PMOS to the six PMOS P1～P6 that can reduce to flow through produces.
Step 103: the differential amplifier that differential amplifier circuit is controlled self according to negative-feedback principle is exported the output signal that minimum voltage equals the voltage of the first common-mode signal.
The utility model embodiment also provides a kind of integrated circuit, and this integrated circuit comprises the differential amplifier circuit of above-mentioned common-mode feedback, as shown in Figure 2, comprising: CMFB loop 11, differential amplifier 12; Wherein,
11 pairs of the first common-mode signal dividing potential drops of described CMFB loop produce the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier 12; Described differential amplifier 12 receives the second common-mode signal and the 3rd common-mode signal in input stage, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, described CMFB loop 11 controls according to negative-feedback principle the output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal;
Described the first common-mode signal generally can obtain according to the differential signal of input;
Described the first input signal and the second input signal are differential signal;
Wherein, described CMFB loop 11 comprises: the first bleeder circuit 111, the second bleeder circuit 112, the first negative-feedback circuit 113, the second negative-feedback circuit 114, wherein,
Voltage between 111 pairs of the first input signals of described the first bleeder circuit and the first common-mode signal carries out dividing potential drop and produces the second common-mode signal, exports the second common-mode signal to differential amplifier 12;
Voltage between 112 pairs of the second input signals of described the second bleeder circuit and the first common-mode signal carries out dividing potential drop and produces the 3rd common-mode signal, exports the 3rd common-mode signal to differential amplifier 12;
Described the first negative-feedback circuit 113 controls according to negative-feedback principle the first output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal; Here, described the first negative-feedback circuit 113 adopts the bleeder circuit with the identical dividing potential drop ratio of described the first bleeder circuit 111, makes differential amplifier 12 output minimum voltages equal the first output signal of the voltage of the first common-mode signal;
Described the second negative-feedback circuit 114 controls according to negative-feedback principle the second output signal that differential amplifier 12 output minimum voltages equal the voltage of the first common-mode signal; Here, described the second negative-feedback circuit 114 adopts the bleeder circuit with the identical dividing potential drop ratio of described the second bleeder circuit 112, makes differential amplifier 12 output minimum voltages equal the second output signal of the voltage of the first common-mode signal;
Described differential amplifier 12 comprises: input stage circuit 121, gain stage circuit 122, output-stage circuit 123, wherein, described input stage circuit 121 receives the second common-mode signal and the 3rd common-mode signals, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input; Here, described input stage circuit 121 comprises common-mode voltage selection circuit, and the voltage of selecting circuit that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set by described common-mode voltage equates with the voltage of first input end or the second input; Described common-mode voltage selects circuit to consist of current source and metal-oxide-semiconductor, and described metal-oxide-semiconductor can be selected PMOS or NMOS;
122 pairs of the first input signals of described gain stage circuit and the second input signal carry out signal amplification;
Described output-stage circuit 123 equals the first output signal or second output signal of the voltage of the first common-mode signal according to the control output minimum voltage of CMFB loop 11.
The particular circuit configurations of the differential amplifier circuit of the common-mode feedback below the utility model being provided is elaborated, as shown in Figure 3, the differential amplifier circuit of this common-mode feedback comprises: the CMFB loop consisting of first divider resistance R1 to the six divider resistance R1～R6, the first feedback resistance Rf1 and the second feedback resistance Rf2, and differential amplifier A1; Wherein,
In CMFB loop, first divider resistance R1 one end connects the first common-mode signal V
cM1, the other end connects the first common mode input VC1 of the second divider resistance R2 and differential amplifier A1; Second divider resistance R2 one end connects the first input signal V
11, the other end connects the first common mode input VC1 of the first divider resistance R1 and differential amplifier A1; The 3rd divider resistance R3 one end connects the first common-mode signal V
cM1, the other end connects the second common mode input VC2 of the 4th divider resistance R4 and differential amplifier A1; The 4th divider resistance R4 one end connects the second input signal V
12, the other end connects the second common mode input VC2 of the 3rd divider resistance R3 and differential amplifier A1; The 5th divider resistance R5 one end connects the first input signal V
11, the other end connects the first input end VIP of the second feedback resistance Rf1 and differential amplifier A1; The 6th divider resistance R6 one end connects the second input signal V
12, the other end connects the second input VIN of the second feedback resistance Rf2 and differential amplifier A1; First feedback resistance Rf1 one end connects the first input end VIP of the 5th divider resistance R5 and differential amplifier A1, and the other end connects the first output VON of differential amplifier A1; Second feedback resistance Rf2 one end connects the second input VIN of the 6th divider resistance R6 and differential amplifier A1, and the other end connects the second output VOP of differential amplifier A1.
In above-mentioned CMFB loop, the first bleeder circuit consists of the first divider resistance R1 and the second divider resistance R2, and wherein, the mid point that the first divider resistance R1 is connected with the second divider resistance R2 produces the second common-mode signal V
cM2; The second bleeder circuit consists of the 3rd divider resistance R3 and the 4th divider resistance R4, and wherein, the mid point that the 3rd divider resistance R3 is connected with the 4th divider resistance R4 produces the 3rd common-mode signal V
cM3; The first negative-feedback circuit consists of the first feedback resistance Rf1; The second negative-feedback circuit consists of the second feedback resistance Rf2.
In above-mentioned CMFB loop, the first divider resistance R1 is identical with the resistance ratio of the first feedback resistance Rf1 and the 5th divider resistance R5 with the resistance ratio of the second divider resistance R2; The 3rd divider resistance R3 is identical with the resistance ratio of the second feedback resistance Rf2 and the 6th divider resistance R6 with the resistance ratio of the 4th divider resistance R4; Described the second divider resistance R2, the 4th divider resistance R4, the 5th divider resistance R5, the 6th divider resistance R6 can adopt adjustable resistance or switching capacity.
The differential amplifier circuit of the common-mode feedback shown in Fig. 3 is when work, if the first input signal V
11voltage be greater than the second input signal V
12, the second common-mode signal V
cM2voltage be greater than the 3rd common-mode signal V
cM3, the voltage of the first output signal of the first output VON output of differential amplifier A1 is less than the second output signal of the second output VOP output, and differential amplifier A1 arranges the second common-mode signal V in input stage
cM2voltage equal the voltage of first input end VIP and the second input VIN, like this, due to the second common-mode signal V
cM2voltage by the first divider resistance R1 and the second divider resistance R2 dividing potential drop, obtained, the voltage of first input end VIP is obtained by the first feedback resistance Rf1 and the 5th divider resistance R5, and the first divider resistance R1 is identical with the resistance ratio of the first feedback resistance Rf1 and the 5th divider resistance R5 with the resistance ratio of the second divider resistance R2, the voltage of the first output signal of the first output VON output equals the first common-mode signal V
cM1voltage; Otherwise, the voltage of the second output signal of the second output VOP output of differential amplifier A1 be less than the first output VON output the first output signal voltage time, the voltage of the second output signal of the second output VOP output equals the first common-mode signal V
cM1voltage.
In the differential amplifier circuit of the common-mode feedback shown in Fig. 3, described differential amplifier A1 comprises: input stage circuit, gain stage circuit, output-stage circuit, wherein, described input stage circuit comprises common-mode voltage selection circuit as shown in Figure 4, is configured to arrange the second common-mode signal V
cm2with the 3rd common-mode signal V
cM3the voltage of the signal that middle voltage is high equates with the voltage of first input end VIP or the second input VIN; Described common-mode voltage selects circuit to consist of current source Q2 and metal-oxide-semiconductor field effect transistor, described metal-oxide-semiconductor can be selected PMOS or NMOS, Fig. 4 be take PMOS as example, this common-mode voltage selects circuit to consist of current source Q2 and PMOS to the six PMOS P1～P6, wherein, the positive pole of current source Q2 connects internal electric source VDD, and negative pole connects respectively the source electrode of a PMOS P1, the 3rd PMOS P3, the 5th PMOS P5; The grid of the one PMOS P1 and the 2nd PMOS P2 is respectively first input end VIP and the second input VIN of differential amplifier A1; The grid of the 3rd PMOS P3 connects the grid of the 6th PMOS P6, as the second common mode input VC2 of differential amplifier A1, for receiving the 3rd common-mode signal V
cM3; The grid of the 4th PMOS P4 connects the grid of the 5th PMOS P5, as the first common mode input VC1 of differential amplifier A1, for receiving the second common-mode signal V
cM2; Can find out, that the positive pole of current source Q2 connects is the internal electric source VDD of low pressure, rather than the power power-supply PVDD of high pressure, the power consumption that the electric current of PMOS to the six PMOS P1～P6 that can reduce to flow through produces.
The above, be only preferred embodiment of the present utility model, is not intended to limit protection range of the present utility model.
Claims (18)
1. a differential amplifier circuit for common-mode feedback, is characterized in that, this differential amplifier circuit comprises:
The first common-mode signal dividing potential drop is produced to the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier, and control according to negative-feedback principle the common-mode feedback CMFB loop of output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
Receive the second common-mode signal and the 3rd common-mode signal, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, according to the control output minimum voltage of CMFB loop, equal the differential amplifier of output signal of the voltage of the first common-mode signal.
2. differential amplifier circuit according to claim 1, is characterized in that, described CMFB loop, comprising:
Voltage between the first input signal and the first common-mode signal is carried out to dividing potential drop and produce the second common-mode signal, export the second common-mode signal to the first bleeder circuit of differential amplifier;
Voltage between the second input signal and the first common-mode signal is carried out to dividing potential drop and produce the 3rd common-mode signal, export the 3rd common-mode signal to the second bleeder circuit of differential amplifier;
According to negative-feedback principle, control the first negative-feedback circuit of the first output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
According to negative-feedback principle, control the second negative-feedback circuit of the second output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal.
3. differential amplifier circuit according to claim 1, is characterized in that, described differential amplifier, comprising:
Receive the second common-mode signal and the 3rd common-mode signal, and the input stage circuit that the voltage of the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high and the voltage of first input end or the second input equate is set;
The gain stage circuit that the first input signal and the second input signal are carried out to signal amplification; And
According to the control output minimum voltage of CMFB loop, equal the first output signal of voltage or the output-stage circuit of the second output signal of the first common-mode signal.
4. differential amplifier circuit according to claim 1, is characterized in that, described CMFB loop consists of the first divider resistance to the six divider resistances, the first feedback resistance and the second feedback resistance.
5. differential amplifier circuit according to claim 4, is characterized in that, described first divider resistance one end connects the first common-mode signal, and the other end connects the first common mode input of the second divider resistance and differential amplifier; Second divider resistance one end connects the first input signal, and the other end connects the first common mode input of the first divider resistance and differential amplifier; The 3rd divider resistance one end connects the first common-mode signal, and the other end connects the second common mode input of the 4th divider resistance and differential amplifier; The 4th divider resistance one end connects the second input signal, and the other end connects the second common mode input of the 3rd divider resistance and differential amplifier; The 5th divider resistance one end connects the first input signal, and the other end connects the first input end of the second feedback resistance and differential amplifier; The 6th divider resistance one end connects the second input signal, and the other end connects the second input of the second feedback resistance and differential amplifier; First feedback resistance one end connects the first input end of the 5th divider resistance and differential amplifier, and the other end connects the first output of differential amplifier; Second feedback resistance one end connects the second input of the 6th divider resistance and differential amplifier, and the other end connects the second output of differential amplifier.
6. differential amplifier circuit according to claim 5, is characterized in that, described the first divider resistance is identical with the resistance ratio of described the first feedback resistance and described the 5th divider resistance with the resistance ratio of described the second divider resistance;
Described the 3rd divider resistance is identical with the resistance ratio of described the second feedback resistance and described the 6th divider resistance with the resistance ratio of described the 4th divider resistance.
7. differential amplifier circuit according to claim 6, is characterized in that, described the second divider resistance, the 4th divider resistance, the 5th divider resistance, the 6th divider resistance are adjustable resistance or switching capacity.
8. differential amplifier circuit according to claim 3, is characterized in that, described input stage circuit comprises common-mode voltage selection circuit, and described common-mode voltage selects circuit to consist of current source and metal-oxide semiconductor (MOS) (MOS) field effect transistor.
9. differential amplifier circuit according to claim 8, it is characterized in that, when described metal-oxide-semiconductor is selected PMOS, described common-mode voltage selects circuit to consist of current source and PMOS to the six PMOS, wherein, the positive pole of current source connects internal electric source, and negative pole connects respectively the source electrode of a PMOS, the 3rd PMOS, the 5th PMOS; The grid of the one PMOS and the 2nd PMOS is respectively first input end and second input of differential amplifier; The grid of the 3rd PMOS connects the grid of the 6th PMOS, as the second common mode input of differential amplifier, for receiving the 3rd common-mode signal; The grid of the 4th PMOS connects the grid of the 5th PMOS, as the first common mode input of differential amplifier, for receiving the second common-mode signal.
10. an integrated circuit, is characterized in that, this integrated circuit comprises the differential amplifier circuit of common-mode feedback, and this differential amplifier circuit comprises:
The first common-mode signal dividing potential drop is produced to the second common-mode signal and the 3rd common-mode signal, export the second common-mode signal and the 3rd common-mode signal to differential amplifier, and control according to negative-feedback principle the CMFB loop of output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
Receive the second common-mode signal and the 3rd common-mode signal, and the voltage that the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high is set equates with the voltage of first input end or the second input, according to the control output minimum voltage of CMFB loop, equal the differential amplifier of output signal of the voltage of the first common-mode signal.
11. integrated circuits according to claim 10, is characterized in that, described CMFB loop, comprising:
Voltage between the first input signal and the first common-mode signal is carried out to dividing potential drop and produce the second common-mode signal, export the second common-mode signal to the first bleeder circuit of differential amplifier;
Voltage between the second input signal and the first common-mode signal is carried out to dividing potential drop and produce the 3rd common-mode signal, export the 3rd common-mode signal to the second bleeder circuit of differential amplifier;
According to negative-feedback principle, control the first negative-feedback circuit of the first output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal; And
According to negative-feedback principle, control the second negative-feedback circuit of the second output signal that differential amplifier output minimum voltage equals the voltage of the first common-mode signal.
12. integrated circuits according to claim 10, is characterized in that, described differential amplifier, comprising:
Receive the second common-mode signal and the 3rd common-mode signal, and the input stage circuit that the voltage of the signal that in the second common-mode signal and the 3rd common-mode signal, voltage is high and the voltage of first input end or the second input equate is set;
The gain stage circuit that the first input signal and the second input signal are carried out to signal amplification; And
According to the control output minimum voltage of CMFB loop, equal the first output signal of voltage or the output-stage circuit of the second output signal of the first common-mode signal.
13. integrated circuits according to claim 10, is characterized in that, described CMFB loop consists of the first divider resistance to the six divider resistances, the first feedback resistance and the second feedback resistance.
14. integrated circuits according to claim 13, is characterized in that, described first divider resistance one end connects the first common-mode signal, and the other end connects the first common mode input of the second divider resistance and differential amplifier; Second divider resistance one end connects the first input signal, and the other end connects the first common mode input of the first divider resistance and differential amplifier; The 3rd divider resistance one end connects the first common-mode signal, and the other end connects the second common mode input of the 4th divider resistance and differential amplifier; The 4th divider resistance one end connects the second input signal, and the other end connects the second common mode input of the 3rd divider resistance and differential amplifier; The 5th divider resistance one end connects the first input signal, and the other end connects the first input end of the second feedback resistance and differential amplifier; The 6th divider resistance one end connects the second input signal, and the other end connects the second input of the second feedback resistance and differential amplifier; First feedback resistance one end connects the first input end of the 5th divider resistance and differential amplifier, and the other end connects the first output of differential amplifier; Second feedback resistance one end connects the second input of the 6th divider resistance and differential amplifier, and the other end connects the second output of differential amplifier.
15. integrated circuits according to claim 14, is characterized in that, described the first divider resistance is identical with the resistance ratio of described the first feedback resistance and described the 5th divider resistance with the resistance ratio of described the second divider resistance;
Described the 3rd divider resistance is identical with the resistance ratio of described the second feedback resistance and described the 6th divider resistance with the resistance ratio of described the 4th divider resistance.
16. integrated circuits according to claim 15, is characterized in that, described the second divider resistance, the 4th divider resistance, the 5th divider resistance, the 6th divider resistance are adjustable resistance or switching capacity.
17. integrated circuits according to claim 12, is characterized in that, described input stage circuit comprises common-mode voltage selection circuit, and described common-mode voltage selects circuit to consist of current source and metal-oxide semiconductor (MOS) (MOS) field effect transistor.
18. integrated circuits according to claim 17, it is characterized in that, when described metal-oxide-semiconductor is selected PMOS, described common-mode voltage selects circuit to consist of current source and PMOS to the six PMOS, wherein, the positive pole of current source connects internal electric source, and negative pole connects respectively the source electrode of a PMOS, the 3rd PMOS, the 5th PMOS; The grid of the one PMOS and the 2nd PMOS is respectively first input end and second input of differential amplifier; The grid of the 3rd PMOS connects the grid of the 6th PMOS, as the second common mode input of differential amplifier, for receiving the 3rd common-mode signal; The grid of the 4th PMOS connects the grid of the 5th PMOS, as the first common mode input of differential amplifier, for receiving the second common-mode signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320472374.4U CN203457116U (en) | 2013-07-31 | 2013-07-31 | CMFB differential amplification circuit and integrated circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320472374.4U CN203457116U (en) | 2013-07-31 | 2013-07-31 | CMFB differential amplification circuit and integrated circuit |
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| CN203457116U true CN203457116U (en) | 2014-02-26 |
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| CN201320472374.4U Withdrawn - After Issue CN203457116U (en) | 2013-07-31 | 2013-07-31 | CMFB differential amplification circuit and integrated circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104348431A (en) * | 2013-07-31 | 2015-02-11 | 快捷半导体(苏州)有限公司 | Common-mode feedback differential amplification circuit, method and integrated circuit |
| CN106411278A (en) * | 2016-09-19 | 2017-02-15 | 上海大学 | Full symmetric common-mode and differential-mode signal separator and multi-input addition and subtraction operator thereof |
| CN108983065A (en) * | 2017-06-02 | 2018-12-11 | 中兴通讯股份有限公司 | A kind of voltage amplifier circuit, detection circuit and its circuit detecting method |
| CN113659946A (en) * | 2019-08-15 | 2021-11-16 | 深圳市汇顶科技股份有限公司 | Amplifying circuit, chip and electronic device |
-
2013
- 2013-07-31 CN CN201320472374.4U patent/CN203457116U/en not_active Withdrawn - After Issue
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104348431A (en) * | 2013-07-31 | 2015-02-11 | 快捷半导体(苏州)有限公司 | Common-mode feedback differential amplification circuit, method and integrated circuit |
| CN104348431B (en) * | 2013-07-31 | 2017-04-26 | 快捷半导体(苏州)有限公司 | Common-mode feedback differential amplification circuit, method and integrated circuit |
| CN106411278A (en) * | 2016-09-19 | 2017-02-15 | 上海大学 | Full symmetric common-mode and differential-mode signal separator and multi-input addition and subtraction operator thereof |
| CN106411278B (en) * | 2016-09-19 | 2019-02-22 | 上海大学 | Holohedral symmetry common mode difference mode signal separator and its multi input addition and subtraction arithmetic unit |
| CN108983065A (en) * | 2017-06-02 | 2018-12-11 | 中兴通讯股份有限公司 | A kind of voltage amplifier circuit, detection circuit and its circuit detecting method |
| CN108983065B (en) * | 2017-06-02 | 2022-07-29 | 中兴通讯股份有限公司 | Voltage amplifying circuit, detection circuit and circuit detection method thereof |
| CN113659946A (en) * | 2019-08-15 | 2021-11-16 | 深圳市汇顶科技股份有限公司 | Amplifying circuit, chip and electronic device |
| US11575357B2 (en) | 2019-08-15 | 2023-02-07 | Shenzhen GOODIX Technology Co., Ltd. | Amplifier circuit, chip and electronic device |
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