High-side current sampling and quantifying circuit with high anti-interference performance

Abstract

The invention relates to a high-anti-interference high-side current sampling and quantizing circuit, which belongs to the technical field of signal processing, and comprises MOS (Metal Oxide Semiconductor) tubes, a driving circuit, a current signal sampling circuit, a biasing circuit, a comparator and a DAC (Digital-to-Analog Converter) circuit, the grid electrodes of the MOS tubes M1 and M2 are connected with the driving circuit, and the drain electrodes of the M1 and M2 are connected and are connected with a motor driving end; the bias circuit is connected with the sampling circuit and provides bias voltage VBIAS for the sampling circuit; after the power supply VPOWER is connected to the current signal sampling circuit, the current is amplified and output, and after the power supply VPOWER and the output A of the DAC circuit are connected to the comparator together, a result ADCOUT is output. Voltage signals are sampled into current signals through the sampling circuit, current comparison is carried out on the two sides of the comparator, high-power current can be collected and quantized without being interfered through current sampling with small signal attenuation, and the accuracy of signal collection and the convenience of system layout are improved.

Description

Technical Field

[0001] This invention belongs to the field of signal processing technology, specifically relating to a high-side current sampling and quantization circuit with high anti-interference capability. Background Technology

[0002] In modern industrial and automotive electronic power drive circuits, the operating current of load motors or electromagnetic hydraulic systems typically ranges from tens to hundreds of amperes, accompanied by vector switching of current direction. This results in a significant amount of electromagnetic interference leaking from the overall system. These large interference sources severely disrupt small signals, often requiring small signal processing to be performed at a distance. This increases the trace length and makes the system more susceptible to electromagnetic fields.

[0003] To prevent distortion of analog signals, the driving current of voltage signals is significantly reduced during transmission, resulting in a substantial decrease in signal anti-interference capability and making them highly susceptible to strong electric fields. The voltage signal also experiences significant attenuation due to line impedance during transmission. Furthermore, the digital-to-analog converter requires a reference voltage source to generate a test voltage, which is provided to the comparator for comparison with the sampled input signal. This reference voltage signal is also easily affected by strong electric fields. Therefore, the high-side voltage sampling and quantization circuits currently used in industrial control and automotive electronics suffer from severe interference problems. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a high-side current sampling and quantization circuit with high anti-interference capability. By using current sampling with small signal attenuation, high-power current can complete signal acquisition and quantization without interference, thereby improving the accuracy of signal acquisition and the convenience of system layout.

[0005] The technical solution is as follows: A high-side current sampling and quantization circuit with high anti-interference capability includes MOSFETs, a driver circuit, a current signal sampling circuit, a bias circuit, a comparator, and a DAC circuit. The gates of MOSFETs M1 and M2 are connected to the driver circuit, and the drains of M1 and M2 are connected together and connected to the motor drive terminal TOMOTOR. The bias circuit is connected to the sampling circuit to provide it with a bias voltage VBIAS. After the power supply VPOWER is connected to the current signal sampling circuit, the current is amplified and output. It is connected to the comparator together with the output A of the DAC circuit to output the result ADCOUT.

[0006] Furthermore, the current signal sampling circuit includes resistors R1-R6, MOSFET M3, and operational amplifier OP. One end of R1 and R3 is connected to the power supply VPOWER, and the other end of R1 is connected in series with R2 and then connected to the positive terminal of OP. The connection point of R1 and R2 is connected to the source of M1. The positive terminal of OP is also connected to the bias voltage VBIAS provided by the bias circuit. The output of OP is connected to the gate of M3. The other end of R3 is connected in series with R4 and then connected to the negative terminal of the operational amplifier. The connection point of R3 and R4 is connected to the source of M3. The drain of M3 is connected to ground after being connected to R5. The drain of M3 is connected to a comparator after being connected to R6. The current I1 of resistor R1 is used to generate a voltage signal VB. After passing through R2 and OP, the voltage signal VS=VB is obtained. Therefore, the voltages across resistor R4 are the same. At this time, the gate voltage of MOSFET M3 is less than VS, the MOSFET is turned on, and the current I0 flows from VPOWER to GND through R4, M3 and R5. The ratio of I0 to I1 is the ratio of R1 to R3. The current signal I0 with stronger anti-interference performance is obtained by calculation.

[0007] Furthermore, the DAC circuit includes multiple parallel precision current sources, each consisting of a variable resistor and a matching transistor. The collector of the matching transistor is connected to a bias resistor and the drain of a MOSFET, respectively. The emitter is connected to VPWR1 via an adjustable resistor and directly connected to VPWR2, which provides the bias current. The gate of the MOSFET is connected to a digital input signal DA, and the source outputs a precision current through a diode. The precision current output by each precision current source is collected by a precision resistor with a proportional resistance to form the output A of the DAC circuit.

[0008] Furthermore, the precision current source has 8-12 channels, and each single precision current source provides the exact same precision current.

[0009] Beneficial effects: 1) This invention samples the voltage signal into a current signal through a sampling circuit, compares the currents on both sides of the comparator, and uses current sampling with small signal attenuation to enable high-power current to complete signal acquisition and quantization without interference, thereby improving the accuracy of signal acquisition and the convenience of system layout.

[0010] 2) The DAC circuit based on current uses a precision current source implemented with a matching transistor, and outputs a controllable precision current through a precision resistor. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall circuit structure of the present invention; Figure 2 A schematic diagram of a DAC circuit using a 9-channel precision current source; Figure 3The waveforms of the sampled signal and the DAC output current signal are shown below. Wherein: DA0-DA8 are 9-channel digital input signals, and R7-R15 are 9-channel precision current source bias resistors. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Terms such as "upper," "lower," "front," "rear," "left," "right," "bottom," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of describing the invention. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0013] like Figure 1 The diagram illustrates a high-interference-resistant high-side current sampling and quantization circuit, comprising MOSFETs, a driver circuit, a current signal sampling circuit, a bias circuit, a comparator, and a DAC circuit. The gates of MOSFETs M1 and M2 are connected to the driver circuit, and the drains of M1 and M2 are connected together and connected to the motor drive terminal. The bias circuit is connected to the sampling circuit to provide a bias voltage VBIAS. The power supply VPOWER is connected to the current signal sampling circuit, and the current is amplified and output. This current, along with the output A of the DAC circuit, is connected to the comparator to output the result ADCOUT.

[0014] The current signal sampling circuit includes resistors R1-R6, MOSFET M3, and operational amplifier OP. One end of R1 and R3 is connected to the power supply VPOWER. The other end of R1 is connected in series with R2 and then connected to the positive terminal of OP. The connection point of R1 and R2 is connected to the source of M1. The positive terminal of OP is also connected to the bias voltage VBIAS provided by the bias circuit. The output of OP is connected to the gate of M3. The other end of R3 is connected in series with R4 and then connected to the negative terminal of the operational amplifier. The connection point of R3 and R4 is connected to the source of M3. The drain of M3 is connected to ground after being connected to R5. The drain of M3 is connected to a comparator after being connected to R6. The current I1 in resistor R1 is used to generate a voltage signal VB. After passing through R2 and OP, the voltage signal VS=VB is obtained. Therefore, the voltage across resistor R4 is the same. At this time, the gate voltage of MOSFET M3 is less than VS, the MOSFET is turned on, and the current I0 flows from VPOWER to GND through R4, M3 and R5. The ratio of I0 to I1 is the ratio of R1 to R3. The current signal I0 with stronger anti-interference performance is obtained by calculation.

[0015] like Figure 2As shown, the DAC circuit includes multiple parallel precision current sources, each composed of a variable resistor and a matching transistor. The collector of the matching transistor is connected to a bias resistor and the drain of a MOSFET, while its emitter is connected to VPWR1 via an adjustable resistor and directly to VPWR2, which provides the bias current. The gate of the MOSFET receives a digital input signal DA, and its source outputs a precision current through a diode. The precision current from each source is collected by a proportionally proportional precision resistor to form the output A of the DAC circuit, which is then input to a comparator and compared with the sampled input current signal. By using a gradual approximation method to quantize the current signal, the accuracy is gradually improved, ultimately resulting in an accurate ADC output.

[0016] The precision current source has 8-12 channels, and each single precision current source provides the exact same precision current.

[0017] Example: A high-side current sampling and quantization circuit with high anti-interference capability is connected to the power supply VPOWER. After passing through the current signal sampling circuit, the current of the power supply VPOWER is amplified and output. This current, along with the precise output current of the DAC circuit, is then fed into a comparator to obtain a high-precision ADCOUT. Figure 3 As shown, the blue signal is the sampling current signal waveform, the red signal is the successive approximation quantization current signal waveform, and the yellow signal is the switching signal. When the switching signal is high, the sampling current signal begins to build up and stabilize, almost unaffected by any large current interference. After the sampling current signal stabilizes, the ADC begins quantization successive approximation. The entire process is very stable and unaffected by interference.

[0018] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the principles and spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-side current sampling and quantization circuit with high anti-interference capability, characterized in that: It includes MOSFETs, a driver circuit, a current signal sampling circuit, a bias circuit, a comparator, and a DAC circuit. The gates of MOSFETs M1 and M2 are connected to the driver circuit, and the drains of M1 and M2 are connected together and connected to the motor drive terminal. The bias circuit is connected to the sampling circuit to provide it with a bias voltage VBIAS. After the power supply VPOWER is connected to the current signal sampling circuit, the current is amplified and output. It is connected to the comparator together with the output A of the DAC circuit to output the result ADCOUT.

2. The high-interference-resistant high-side current sampling and quantization circuit as described in claim 1, characterized in that: The current signal sampling circuit includes resistors R1-R6, MOSFET M3, and operational amplifier OP. One end of R1 and R3 is connected to the power supply VPOWER. The other end of R1 is connected in series with R2 and then connected to the positive terminal of OP. The connection point of R1 and R2 is connected to the source of M1. The positive terminal of OP is also connected to the bias voltage VBIAS provided by the bias circuit. The output of OP is connected to the gate of M3. The other end of R3 is connected in series with R4 and then connected to the negative terminal of the operational amplifier. The connection point of R3 and R4 is connected to the source of M3. The drain of M3 is connected to ground after being connected to R5. The drain of M3 is connected to a comparator after being connected to R6. The current I1 of resistor R1 is used to generate a voltage signal VB. After passing through R2 and OP, the voltage signal VS=VB is obtained. Therefore, the voltages across resistor R4 are the same. At this time, the gate voltage of MOSFET M3 is less than VS, the MOSFET is turned on, and the current I0 flows from VPOWER to GND through R4, M3 and R5. The ratio of I0 to I1 is the ratio of R1 to R3. The current signal I0 with stronger anti-interference performance is obtained by calculation.

3. The high-interference-resistant high-side current sampling and quantization circuit as described in claim 1, characterized in that: The DAC circuit includes multiple parallel precision current sources, each consisting of a variable resistor and a matching transistor. The collector of the matching transistor is connected to a bias resistor and the drain of a MOSFET, respectively. The emitter is connected to VPWR1 via an adjustable resistor and directly connected to VPWR2, which provides the bias current. The gate of the MOSFET is connected to a digital input signal DA, and the source outputs a precision current through a diode. The precision current output by each precision current source is collected by a precision resistor with a proportional resistance to form the output A of the DAC circuit.

4. The high-interference-resistant high-side current sampling and quantization circuit as described in claim 3, characterized in that: The precision current source has 8-12 channels, and each single precision current source provides the exact same precision current.

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