CN-117193451-B - High-precision absolute value voltage output method and circuit

Abstract

The invention discloses a high-precision absolute value voltage output method and circuit, and belongs to the technical field of integrated circuits. The circuit comprises a comparator module, a first switch module, an operational amplifier module, a V-I conversion module, a P-type current mirror module, an N-type current mirror module, an I-V conversion module and a second switch module. The invention not only solves the problems of nonlinear distortion and low precision of the traditional diode absolute value circuit, but also solves the problems of large area and power consumption and large error near 0 value in the traditional diode-free absolute value circuit, and has the advantages of higher precision, small area, lower power consumption, convenient integration and the like, and can be widely applied to the scenes of readout circuits, audio processing and the like of a large-scale array.

Inventors

• YU ZHIGUO
• ZU WENJUN
• GU XIAOFENG

Assignees

• 江南大学

Dates

Publication Date

20260505

Application Date

20230918

Claims (8)

1. 1. The high-precision absolute value circuit is characterized by comprising a comparator module, a first switch module, an operational amplifier module, a V-I conversion module, a P-type current mirror module, an N-type current mirror module, an I-V conversion module and a second switch module; The comparator module is used for judging the positive and negative of an input voltage signal and controlling the on and off of the first switch module and the second switch module according to the judging result; The operational amplifier module is connected with the first switch module, the V-I conversion module is connected with the operational amplifier module, and the operational amplifier module and the V-I conversion module are used for converting negative voltage signals into current signals; the I-V conversion module is used for converting the current signal into a positive voltage signal and inputting the positive voltage signal into the second switch module; The comparator module comprises a comparator; The positive input end of the comparator is connected with the external input and the first switch module, the negative input end of the comparator is grounded, and the output end of the comparator is respectively connected with the control ends of the first switch module and the second switch module; The first switch module comprises a first switch (S1) and a second switch (S2), one end of the first switch (S1) is connected with an external input, the other end of the first switch is connected with the operational amplifier module, one end of the second switch (S2) is connected with the external input, and the other end of the second switch outputs a final voltage signal.
2. 2. The high-precision absolute value circuit according to claim 1, wherein the operational amplifier module comprises an operational amplifier and an NMOS tube (NM 1), the positive input end of the operational amplifier is connected with the first switch (S1), the negative input end of the operational amplifier is connected with the V-I conversion module and the source electrode of the NMOS tube (NM 1), and the output end of the operational amplifier is connected with the grid electrode of the NMOS tube (NM 1).
3. 3. The high-precision absolute value circuit according to claim 2, wherein the V-I conversion module comprises a first resistor (R1), one end of the first resistor (R1) is connected with a first level voltage V1, and the other end of the first resistor is connected with a source electrode of the NMOS tube (NM 1).
4. 4. The high-precision absolute value circuit according to claim 2, wherein the I-V conversion module comprises a second resistor (R2), one end of the second resistor (R2) is connected to the NM3 drain, and the other end is connected to the second level voltage V2.
5. 5. The high-precision absolute value circuit according to claim 2, wherein the comparator is configured to compare input voltage signals and control on and off of the first and second switch modules according to a result of the comparison; When the input voltage Vin is greater than 0 and the output result of the comparator is 1, the second switch (S2) is turned on, and the first switch (S1) and the second switch module are turned off; The input voltage Vin <0, the output result of the comparator is 0, the second switch (S2) is turned off, and the first switch (S1) and the second switch module are turned on.
6. 6. The high-precision absolute value circuit of claim 2, wherein when the input voltage is a negative value, the output voltage of the circuit is: Wherein, the Is the input voltage; Is the converted voltage; , The level voltages of the V-I conversion module and the I-V conversion module are respectively; , respectively the width-to-length ratio of two PMOS tubes in the P-type current mirror module, , The width-to-length ratio of two NMOS tubes in the N-type current mirror module is respectively; And The resistance values of the resistors in the V-I conversion module and the I-V conversion module are respectively.
7. 7. The high precision absolute value circuit of claim 6, wherein the circuit is implemented based on a SMIC 55nm cmos process.
8. 8. A high-precision absolute value voltage output method is characterized in that the method comprises the step of realizing voltage absolute value output by using the high-precision absolute value circuit according to any one of claims 1-7.

Description

High-precision absolute value voltage output method and circuit Technical Field The invention relates to a high-precision absolute value voltage output method and circuit, and belongs to the technical field of integrated circuits. Background The absolute value circuit functions to output the absolute value of the input signal. When the input signal contains both positive and negative polarities, the absolute value circuit will convert these signals into an output signal containing only positive polarity magnitudes. The circuit can be used in the fields of signal shaping, peak detection, amplitude limitation and the like. Common application scenarios include large-scale array readout circuits, audio processing, precision measurement, control systems, and the like. Absolute value circuits are a type of high precision rectifier, the most common implementation being diode-based rectifying circuits. By using a reverse biased diode, the negative half of the input signal is isolated and clipped to zero at the trigger point, leaving the positive half to output the analog voltage signal. The rectifier diode is connected in the feedback loop of the operational amplifier, and the diode can be driven to be turned on or off only by a small change of the signal. Thereby achieving the effect of generating absolute value The absolute value circuit has larger nonlinearity, the precision is greatly influenced by the nonlinearity, and in an actual circuit, the diode volume and the power consumption are larger, which can lead to higher area and power consumption of the absolute value circuit and is unfavorable for the use of the circuit. The patent CN113822086A proposes a novel diode-free absolute value circuit, which uses the inverse proportion inverting function of an operational amplifier, judges the positive and negative of a signal in the working process by a comparator, and converts a negative signal into a positive value by using an inverse proportion inverting circuit module to output, and under the condition of not considering the offset and the resistance offset of the operational amplifier, the circuit has higher requirement on the operational amplifier, large area and power consumption and large error when the operational amplifier is near 0 value. Disclosure of Invention In order to further improve the precision of an absolute value circuit, reduce the circuit area and power consumption, the invention provides a high-precision absolute value voltage output method and a circuit, and the technical scheme is as follows: The first object of the invention is to provide a high-precision absolute value circuit, which comprises a comparator module, a first switch module, an operational amplifier module, a V-I conversion module, a P-type current mirror module, an N-type current mirror module, an I-V conversion module and a second switch module; The comparator module is used for judging the positive and negative of an input voltage signal and controlling the on and off of the first switch module and the second switch module according to the judging result; The operational amplifier module is connected with the first switch module, the V-I conversion module is connected with the operational amplifier module, and the operational amplifier module and the V-I conversion module are used for converting negative voltage signals into current signals; The P-type current mirror module and the N-type current mirror module are used for transmitting the converted current signals, the I-V conversion module is used for converting the current signals into positive voltage signals and inputting the positive voltage signals into the second switch module, and the second switch module outputs final voltage signals. Optionally, the comparator module comprises a comparator; The positive input end of the comparator is connected with the external input and the first switch module, the negative input end of the comparator is grounded, and the output end of the comparator is respectively connected with the control ends of the first switch module and the second switch module. Optionally, the first switch module comprises a first switch S1 and a second switch S2, one end of the first switch S1 is connected with an external input, the other end of the first switch S1 is connected with the operational amplifier module, one end of the second switch S2 is connected with the external input, and the other end of the second switch S2 outputs a final voltage signal. Optionally, the operational amplifier module comprises an operational amplifier and an NMOS tube NM1, wherein the positive input end of the operational amplifier is connected with the first switch S1, the negative input end of the operational amplifier is connected with the V-I conversion module and the source electrode of the NMOS tube NM1, and the output end of the operational amplifier is connected with the grid electrode of the NMOS tube NM 1. Optionally, the V-I conversion module comprises a