CN-121727553-B - R-2R digital-to-analog converter circuit integrating hysteresis voltage control

CN121727553BCN 121727553 BCN121727553 BCN 121727553BCN-121727553-B

Abstract

The invention discloses an R-2R digital-to-analog converter circuit integrating hysteresis voltage control, which relates to the technical field of integrated circuit design and comprises an operational amplifier, an R2R resistor network, a hysteresis voltage control unit and a comparison voltage control unit, wherein the operational amplifier comprises an in-phase input end for receiving threshold voltage, an opposite-phase input end for receiving test voltage and an output end for outputting comparison voltage, the R2R resistor network comprises an output end for outputting the threshold voltage, which is connected with the in-phase input end of the operational amplifier, a plurality of first resistors, a plurality of second resistors and a plurality of selection switches which are connected in series, and the hysteresis voltage control unit comprises a plurality of third resistors, a plurality of first knife switches and a second knife switch, and further comprises an input end for comparing voltage, and the second knife switch is used for selectively connecting a reference voltage end or a grounding end according to the polarity of the comparison voltage. The invention has simple structure and easy use, can flexibly adjust the magnitude and the direction of the hysteresis voltage according to the use requirement, can not generate burr signals in the hysteresis voltage switching process, and realizes the stable and reliable digital-to-analog conversion function.

Inventors

ZHAO XINQIANG
BI JIANXIN
YANG XIANG
XIE LIPING
YANG LIN

Assignees

成都旋极星源信息技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260225

Claims (4)

1. An R-2R digital-to-analog converter circuit integrating hysteresis voltage control, comprising: The operational amplifier comprises a non-inverting input end for receiving the threshold voltage, an inverting input end for receiving the test voltage and an output end for outputting the comparison voltage; The R2R resistor network comprises an output end, a plurality of first resistors, a plurality of second resistors and a plurality of selection switches, wherein the output end is connected with the non-inverting input end of the operational amplifier and outputs threshold voltage; The hysteresis voltage control unit comprises a plurality of third resistors, a plurality of first knife switches and a second knife switch, wherein the plurality of first knife switches are correspondingly connected in series with the plurality of third resistors, the other ends of the plurality of first knife switches are connected with one end of the second knife switch, the other end of the second knife switch is connected with a reference voltage end or a grounding end, the other end of the plurality of third resistors is connected between the two first resistors which are connected in series; The R2R resistor network further comprises an input end connected with a reference voltage end, a grounding end and a digital signal receiving end, wherein n first resistors are n, n+2 second resistors are n+1, n is a positive integer, one second resistor and n first resistors are sequentially connected in series to form a resistor string, one end of the resistor string is grounded, the other end of the resistor string is connected with an output threshold voltage and is connected with an in-phase input end of an operational amplifier, the other n+1 second resistors are respectively connected with n+1 selection switches in series, and the other ends of the other n+1 second resistors are connected with one of a connecting node between two adjacent first resistors, a connecting node between the adjacent second resistors and the first resistors and a threshold voltage output node; the selection switch comprises a first end connected with the rest n+1 second resistors, a second end connected with a reference voltage input end, a third end connected with a grounding end and a fourth end connected with a digital signal receiving end, and is controlled by digital signals and used for selectively connecting the corresponding second resistors to the reference voltage input end or the grounding end; The number of the first knife switches and the third resistors is m, m is a positive integer smaller than n, m first knife switches are represented as S0-Sm, the knife switches S0-Sm can be closed at the same time, the corresponding control branches of the first knife switches respectively correspond to different hysteresis voltage control weights, the hysteresis weight of the S0 switch branch is minimum, the hysteresis weight of the S1 switch branch is 2 times of that of the S0 branch, the hysteresis weight of the S2 switch branch is 2 times of that of the S1 branch, and the hysteresis weight of the Sm branch is 2 times of that of the S0 branch.
2. The R-2R digital-to-analog converter circuit integrated with hysteresis voltage control of claim 1 wherein said second resistor and said third resistor each have a resistance twice that of said first resistor.
3. The integrated hysteresis voltage controlled R-2R digital-to-analog converter circuit of claim 1 wherein the select switches are single pole double throw switches, n+1 single pole double throw switches are controlled by digital signals B <0> through B < n >, when the digital signal is low, their corresponding controlled single pole double throw switches are connected to ground, when the digital signal is high, their corresponding controlled single pole double throw switches are connected to a reference voltage input, and the R2R resistor network outputs different analog signals by adjusting the high and low levels of the digital signals B <0> through B < n >, resulting in a desired threshold voltage.
4. The R-2R digital-to-analog converter circuit integrated with a hysteresis voltage control of claim 1, wherein said hysteresis voltage control unit generates a positive hysteresis voltage when said second knife switch is connected to a reference voltage terminal and generates a negative hysteresis voltage when said second knife switch is connected to a ground terminal.

Description

R-2R digital-to-analog converter circuit integrating hysteresis voltage control Technical Field The invention relates to the technical field of integrated circuit design, in particular to an R-2R digital-to-analog converter circuit integrating hysteresis voltage control. Background The R-2R digital-to-analog converter circuit (DAC) is a simple and easy-to-use circuit structure, can convert digital signals into analog voltages only by a resistor array and switch control, and has wide application in various fields. Patent US2009146856A1 discloses a specific circuit structure of an R-2R digital-to-analog converter circuit (DAC) and its operation principle. In many application scenarios, the output voltage signal of the digital-to-analog converter circuit (DAC) is used for the reference voltage threshold signal of the comparator, the reference voltage threshold signal is compared with the input signal to be detected, so that the amplitude detection function of the signal is realized, the reference voltage threshold value can be flexibly changed by adjusting the digital control signal of the DAC, and in such application scenarios, the comparator circuit is generally required to have a certain hysteresis voltage control function, so that the oscillation burr signal generated by the output result of the comparator due to the interference of noise when the reference threshold signal and the signal to be detected are equal is avoided, and the detection result of the system is unstable. Patent CN115407180a discloses a DAC circuit structure for threshold voltage adjustment and hysteresis voltage adjustment, wherein different DAC digital control signals are selected by a Multiplexer (MUX) switch according to the output result of a comparator, so as to generate a configurable hysteresis voltage difference, and the hysteresis voltage is controlled by the difference value of dac_ VALA <7:0> and dac_ VALB <7:0 >. The circuit structure needs a plurality of MUX selection switches to realize the hysteresis voltage function, when the digital bit number of the DAC is particularly large, the MUX selection switches are needed to be very much, the chip area is enlarged, meanwhile, as the two-selection switching moments of all MUXs are difficult to ensure to be completely consistent in an actual chip, very large burr signals can be generated at the switching moment, for example, when the digital signal is switched from '01111111' to '10000000', all bit numbers are changed, when delay deviation exists at the switching moment of each MUX switch, the very large burr signals can be generated, the polarity of the burr signals is random, the polarity of the burr signals is possibly higher than that of the correct signals, and the polarity of the burr signals is possibly lower than that of the correct signals, so that the comparator output is possibly inverted, and an erroneous comparison output result is generated, and the system function is possibly wrong. Based on the defect of the existing technical scheme of integrating the hysteresis voltage control by the R-2R digital-analog conversion circuit, a hysteresis voltage control circuit which is simple and easy to use, can not generate burr interference signals in the hysteresis switching process and ensures the monotonicity change of the output voltage is needed to be designed. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides an R-2R digital-to-analog converter circuit integrating hysteresis voltage control, which realizes a stable and reliable digital-to-analog conversion function by outputting hysteresis voltage with adjustable size and direction. The aim of the invention is realized by the following technical scheme: An R-2R digital-to-analog converter circuit integrating hysteresis voltage control, comprising: The operational amplifier comprises a non-inverting input end for receiving the threshold voltage, an inverting input end for receiving the test voltage and an output end for outputting the comparison voltage; The R2R resistor network comprises an output end, a plurality of first resistors, a plurality of second resistors and a plurality of selection switches, wherein the output end is connected with the non-inverting input end of the operational amplifier and outputs threshold voltage; The hysteresis voltage control unit comprises a plurality of third resistors, a plurality of first knife switches and a second knife switch, wherein the first knife switches are correspondingly connected in series with the third resistors, the other ends of the first knife switches are connected with one end of the second knife switch, the other ends of the second knife switches are connected with a reference voltage end or a grounding end, the other ends of the third resistors are connected between the two first resistors which are connected in series, the hysteresis voltage control unit further comprises an input end for comparing voltage, and