A dynamic adjustment circuit based on high-voltage amplifier chip power supply

Abstract

The application discloses a kind of dynamic adjustment circuit based on high-voltage amplifier chip power supply, including input buffer stage, isolation control stage and amplifier output stage.Input buffer stage receives input signal and carries out impedance transformation, and the load capacity of output signal is improved;Isolation control stage carries out isolation and amplification to input signal;Amplifier output stage is the arbitrary waveform that input arbitrary waveform signal is amplified and outputs ±110V, and the positive and negative supply end voltage of precision operational amplifier chip in amplifier output stage is dynamically regulated by transient voltage suppression diode network, so that it is in the safe range while keeping the voltage difference of positive and negative power supply end, the maximization of operational amplifier output amplitude is realized.The application breaks through the contradiction between chip voltage difference limit and output amplitude, can significantly improve the output voltage range without replacing the chip, and the circuit structure is simple, low in cost, high in reliability.

Description

Technical Field

[0001] This invention relates to the field of analog signal processing and voltage amplification technology, specifically to a dynamic adjustment circuit for a high-voltage amplifier used for isolation control. Background Technology

[0002] High-voltage amplifiers are widely used in high-voltage probes, medical equipment, and industrial control systems to amplify weak signals or drive high-voltage loads under electrically isolated conditions.

[0003] Currently, high-performance precision high-voltage amplifiers (such as the ADHV4702-1) typically have a wide power supply range (e.g., DC ±12V to ±110V), but their absolute maximum ratings usually limit the voltage difference between the positive and negative power supply terminals (e.g., less than 220V). In practical applications, if the maximum supply voltage (e.g., ±110V) is used directly, although the voltage difference meets the requirements, the actual maximum output amplitude is much less than ±105V due to the redundancy design within the chip, voltage difference limitations, and the long-term reliability of the device. This means that the full voltage range of the power supply cannot be fully utilized.

[0004] In existing technologies, a fixed power supply is typically used, which results in a "ceiling" on the output voltage amplitude, making it unsuitable for applications requiring extremely high output amplitude (such as ±110V at full range). Therefore, there is an urgent need for a circuit structure that can maximize the output amplitude of a high-voltage amplifier without replacing the chip. Summary of the Invention

[0005] The purpose of this invention is to provide a high-voltage amplifier circuit with dynamically adjustable chip power supply, aiming to solve the problem that existing high-voltage amplifiers cannot output the maximum theoretical voltage under the safety differential voltage limit, and to maximize the output amplitude of the high-voltage operational amplifier.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A dynamic adjustment circuit based on a high-voltage amplifier chip power supply includes: Input buffer stage: contains operational amplifier U2A, used to receive input signals and perform impedance transformation; Isolation control stage: Includes a precision operational amplifier chip U1, used for isolation and amplification of input signals; Amplifier output stage: includes operational amplifier U2B, optocoupler U3, optocoupler U4, and transient voltage suppressor diode network; The output of the input buffer stage is connected to the input of the isolation control stage; The input terminal of the operational amplifier U2B is connected to the signal reference ground or the input detection point, and its output terminal is connected to the input side of optocoupler U3 and optocoupler U4 respectively, for controlling the conduction of the optocoupler according to the polarity of the input signal. The output side of the optocoupler U3 is connected in series with transient voltage suppression diodes D2 and D3 to the negative power supply terminal VEE of the precision operational amplifier chip U1; The output side of the optocoupler U4 is connected in series with transient voltage suppression diodes D5 and D6, which are connected to the positive power supply terminal VCC of the precision operational amplifier chip U1.

[0007] Preferably, the breakdown voltage of the transient voltage suppression diodes D2, D3, D5, and D6 is 36V.

[0008] Preferably, the high-voltage operational amplifier chip U1 is model ADHV4702-1.

[0009] Working principle: The core of this invention lies in the dynamic adjustment technology of the amplifier chip power supply. When the input signal is at its maximum positive value (e.g., +5V), the control circuit turns on optocoupler U3, clamping the negative power supply terminal VEE of the high-voltage amplifier to -110V through the 36V TVS diode. Simultaneously, it cuts off or reduces the voltage of the positive power supply terminal VCC (e.g., to +74V), keeping the power supply voltage difference within a safe range (184V). At this time, the output terminal can output a full-scale voltage of -110V. Conversely, when the input signal is at its maximum negative value, optocoupler U4 turns on, maintaining the positive power supply terminal VCC at +110V, and adjusting the voltage of the negative power supply terminal VEE, thereby outputting a full-scale voltage of +110V.

[0010] Compared with the prior art, the present invention has the following beneficial effects: Maximizing output amplitude: It breaks through the contradiction between chip voltage difference limitation and output amplitude, and achieves full-amplitude output of ±110V, which improves the output voltage range compared with traditional circuits.

[0011] Low cost: No need to replace expensive special custom chips, it can be achieved with only simple external optocoupler and Zener diode circuit.

[0012] Maintain high performance: It retains the low noise and low drift characteristics of the original precision operational amplifier chip (such as ADHV4702-1), and has a simple circuit structure and high reliability. Attached Figure Description

[0013] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a typical application circuit diagram of a high-voltage amplifier in existing technology; Figure 2 This is a schematic diagram of a dynamic adjustment circuit based on a high-voltage amplifier chip power supply provided in an embodiment of the present invention. Detailed Implementation

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0016] Reference Figure 2 This embodiment uses the precision operational amplifier chip U1 with model number ADHV4702-1 as an example for illustration.

[0017] Circuit connection structure: The power supply (input signal) Vi is connected to one end of resistors R5 and R8 respectively. The other end of resistor R8 is grounded to G. The other end of resistor R5 is connected to one end of capacitor C2 and pin 3 of the non-inverting input of operational amplifier U2A (SGM8255-2). The other end of capacitor C2 is grounded to G. Pin 2 of the inverting input of operational amplifier U2A is connected to pin 1 of the output and one end of resistors R11 and R6 respectively. Pin 8 of the power supply of operational amplifier U2A is connected to +12V, and pin 4 of the ground is connected to -12V. The other end of resistor R11 is connected to one end of resistor R12 and the non-inverting input of operational amplifier U2B respectively. The input pin 5 and one end of capacitor C6 are connected. The other end of capacitor C6 is connected to ground G and the inverting input pin 6 of operational amplifier U2B, respectively. The other end of resistor R12 is connected to the output pin 7 of operational amplifier U2B, the anode of diode D1 and the cathode of diode D4, respectively. The cathode of diode D1 is connected to one end of resistor R15. The other end of resistor R15 is connected to the anode pin 1 of the LED of optocoupler U3. The cathode pin 2 of the LED of optocoupler U3 is connected to ground G and the anode pin 1 of the LED of optocoupler U4, respectively. The cathode pin 2 of the LED of optocoupler U4 is connected to the anode of diode D4 through resistor R16. The collector pin 4 of optocoupler U3 is connected to one end of resistor R13 and one end of bidirectional TVS transistor D3, respectively. The other end of bidirectional TVS transistor D3 is connected to the emitter pin 3 of optocoupler U3 via bidirectional TVS transistor D2. The emitter pin 3 of optocoupler U4 is connected to one end of resistor R14 and one end of bidirectional TVS transistor D6, respectively. The other end of bidirectional TVS transistor D6 is connected to the collector pin 4 of optocoupler U4 via bidirectional TVS transistor D5. The other end of resistor R13 is connected to one end of capacitor C4 and pin 4 (negative high voltage source VEE) of precision operational amplifier chip U1, and the other end of capacitor C4 is grounded to G. The other end of resistor R14 is connected to one end of capacitor C5 and pin 7 (positive high voltage source VCC) of precision operational amplifier chip U1, and the other end of capacitor C5 is grounded to G. The other end of resistor R6 is connected to one end of resistor R1, one end of resistor R2, and pin 12 of precision operational amplifier chip U1. Pin 2 of precision operational amplifier chip U1 is grounded to ground G through resistor R9. The other end of resistor R1 is connected to one end of capacitor C1, one end of resistor R7, and pin 6 of precision operational amplifier chip U1, respectively. The other end of capacitor C1 is connected to the other end of resistor R2; The other end of resistor R7 is connected to one end of resistor R10 and the circuit output terminal VO, and the other end of resistor R10 is grounded to ground G through capacitor C3. Furthermore, pins 5 and 8 of the precision operational amplifier chip U1 are connected to one end of resistor R3, and the other end of resistor R3 is grounded to G. Furthermore, pin 9 of the precision operational amplifier chip U1 is grounded to G via resistor R4; Furthermore, pin 10 of the precision operational amplifier chip U1 is grounded to G; Furthermore, pin 0 of the precision operational amplifier chip U1 is grounded to G.

[0018] Input stage: The power supply (input signal) Vi is divided by resistors R5 and R8 and filtered by capacitor C2, and then connected to the non-inverting input of operational amplifier U2A (SGM8255-2). U2A is configured as a voltage follower, and the output signal is sent to the inverting input pin 2 of precision operational amplifier chip U1.

[0019] Control stage: The non-inverting input of operational amplifier U2B (the other half of SGM8255-2) is connected to reference ground, and the inverting input is connected to the detection point. The output pin 7 of U2B is connected to the anode of the LEDs of optocouplers U3 and U4 through resistors R15 and R16, respectively.

[0020] Output stage: The collector of optocoupler U3 is connected to the negative high voltage source VEE, and the emitter is connected to the negative power supply (VEE) pin 4 of precision operational amplifier chip U1 through bidirectional TVS diodes D2 and D3.

[0021] The collector of optocoupler U4 is connected to the positive high voltage source VCC, and the emitter is connected to the positive power supply (VCC) pin 7 of precision operational amplifier chip U1 through bidirectional TVS diodes D5 and D6.

[0022] Working principle: Positive half-cycle output (target output -110V): When the input signal is positive (e.g., +5V), the operational amplifier U2B outputs a positive voltage, driving the optocoupler U3 to conduct. The optocoupler U3 pulls the negative power supply terminal VEE down to -110V through a 36V TVS diode. At this time, to ensure that the voltage difference between pins 4 and 7 is less than 220V (absolute maximum rating), the voltage at the positive power supply terminal VCC is limited to +74V (because 74V - (-110V) = 184V < 220V). At this point, the op-amp output can reach the negative limit of -110V.

[0023] Negative half-cycle output (target output +110V): When the input signal is negative (e.g., -5V), the operational amplifier U2B outputs a negative voltage (or a low level, depending on the specific bias), driving the optocoupler U4 to conduct. The optocoupler U4 maintains the positive power supply terminal VCC at +110V, while the voltage at the negative power supply terminal VEE is adjusted accordingly (e.g., reduced to -74V), thereby allowing the output terminal to output a positive full-scale voltage of +110V.

[0024] Through the aforementioned alternating conduction mechanism, this circuit achieves the theoretical maximization of the output voltage amplitude without violating the chip's differential voltage safety limits.

[0025] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dynamic adjustment circuit based on a high-voltage amplifier chip power supply, characterized in that, include: The input buffer stage includes a first operational amplifier U2A, which is used to receive the input signal and perform impedance transformation. The isolation control stage includes a precision operational amplifier chip U1, which is used to isolate and amplify the input signal; The amplifier output stage includes a second operational amplifier U2B, a first optocoupler U3, a second optocoupler U4, and a transient voltage suppression diode network; The output of the input buffer stage is connected to the input of the isolation control stage; The input terminal of the second operational amplifier U2B is connected to the signal reference ground or the input detection point, and its output terminal is connected to the input side of the first optocoupler U3 and the second optocoupler U4 respectively, for controlling the conduction of the optocouplers according to the polarity of the input signal; The output side of the first optocoupler U3 is connected in series with the first transient voltage suppression diode D2 and the second transient voltage suppression diode D3, and is connected to the negative power supply terminal VEE of the precision operational amplifier chip U1; The output side of the second optocoupler U4 is connected in series with the third transient voltage suppression diode D5 and the fourth transient voltage suppression diode D6, and is connected to the positive power supply terminal VCC of the precision operational amplifier chip U1.

2. The dynamic adjustment circuit for power supply of the high-voltage amplifier chip according to claim 1, characterized in that, The breakdown voltages of the first transient voltage suppression diode D2, the second transient voltage suppression diode D3, the third transient voltage suppression diode D5, and the fourth transient voltage suppression diode D6 are all 36V.

3. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to claim 1, characterized in that, The precision operational amplifier chip U1 is model ADHV4702-1.

4. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to any one of claims 1 to 3, characterized in that, When the input signal is in the positive half-cycle, the second operational amplifier U2B controls the first optocoupler U3 to turn on, so that the negative power supply terminal VEE is clamped to the first negative voltage through the transient voltage suppression diode. At the same time, the voltage of the positive power supply terminal VCC is limited to the first positive voltage, so as to keep the voltage difference between the positive and negative power supply terminals of the precision operational amplifier chip U1 within a safe range. When the input signal is in the negative half-cycle, the second operational amplifier U2B controls the second optocoupler U4 to turn on, so that the positive power supply terminal VCC is maintained at the first positive voltage, and the voltage of the negative power supply terminal VEE is adjusted accordingly to keep the voltage difference within a safe range.

5. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to claim 1, characterized in that, Power supply Vi is connected to one end of resistors R5 and R8 respectively. The other end of resistor R8 is grounded to G. The other end of resistor R5 is connected to one end of capacitor C2 and pin 3 of the non-inverting input of operational amplifier U2A. The other end of capacitor C2 is grounded to G. Pin 2 of the inverting input of operational amplifier U2A is connected to pin 1 of the output and one end of resistor R11 and one end of resistor R6 respectively. Pin 8 of the power supply of operational amplifier U2A is connected to +12V, and pin 4 of the ground is connected to -12V. The other end of resistor R11 is connected to one end of resistor R12, pin 5 of the non-inverting input of operational amplifier U2B, and capacitor... One end of capacitor C6 is connected to ground G and the other end of operational amplifier U2B, respectively. The other end of resistor R12 is connected to the output pin 7 of operational amplifier U2B, the anode of diode D1, and the cathode of diode D4. The cathode of diode D1 is connected to one end of resistor R15. The other end of resistor R15 is connected to the anode pin 1 of the LED of optocoupler U3. The cathode pin 2 of the LED of optocoupler U3 is connected to ground G and the anode pin 1 of the LED of optocoupler U4. The cathode pin 2 of the LED of optocoupler U4 is connected to the anode of diode D4 via resistor R16. The collector pin 4 of optocoupler U3 is connected to one end of resistor R13 and one end of bidirectional TVS transistor D3, respectively. The other end of bidirectional TVS transistor D3 is connected to the emitter pin 3 of optocoupler U3 via bidirectional TVS transistor D2. The emitter pin 3 of optocoupler U4 is connected to one end of resistor R14 and one end of bidirectional TVS transistor D6, respectively. The other end of bidirectional TVS transistor D6 is connected to the collector pin 4 of optocoupler U4 via bidirectional TVS transistor D5. The other end of resistor R13 is connected to one end of capacitor C4 and pin 4 of precision operational amplifier chip U1, and the other end of capacitor C4 is grounded to G. The other end of resistor R14 is connected to one end of capacitor C5 and pin 7 of precision operational amplifier chip U1, and the other end of capacitor C5 is grounded to G. The other end of resistor R6 is connected to one end of resistor R1, one end of resistor R2, and pin 12 of precision operational amplifier chip U1. Pin 2 of precision operational amplifier chip U1 is grounded to ground G through resistor R9. The other end of resistor R1 is connected to one end of capacitor C1, one end of resistor R7, and pin 6 of precision operational amplifier chip U1, respectively. The other end of capacitor C1 is connected to the other end of resistor R2; The other end of resistor R7 is connected to one end of resistor R10 and the circuit output terminal VO, respectively. The other end of resistor R10 is grounded to ground G through capacitor C3.

6. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to claim 5, characterized in that, After pins 5 and 8 of the precision operational amplifier chip U1 are connected, one end of resistor R3 is connected, and the other end of resistor R3 is grounded to G.

7. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to claim 5, characterized in that, Pin 9 of the precision operational amplifier chip U1 is grounded to ground G via resistor R4.

8. The dynamic adjustment circuit for power supply of a high-voltage amplifier chip according to claim 5, characterized in that, Operational amplifiers U2A and U2B are two operational amplifiers in the SGM8255-2 chip.

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