A program-controlled power supply circuit using a power operational amplifier
By adopting power operational amplifier IC3 and integrated digital control unit, the programmable power supply circuit is simplified, solving the complexity and maintenance problems of traditional programmable power supplies. It achieves high-precision, high-stability and low-cost high-voltage and high-current output, which is suitable for integrated circuit testing and precision instruments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIAXING XINLIANG MEASUREMENT & CONTROL TECH CO LTD
- Filing Date
- 2025-09-22
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional programmable power supply circuits are complex, bulky, costly, and difficult to maintain. Furthermore, their accuracy and stability are affected by temperature coefficients, making it difficult to meet the requirements for high precision and high stability.
It adopts the power operational amplifier IC3, which integrates digital control unit, DAC unit, polarity control unit, sine wave modulation unit and differential amplifier circuit unit, simplifying circuit design, integrating current detection and sine wave signal modulation functions, and using high-precision components and compensation circuits to reduce the impact of temperature drift.
It realizes a high-precision, stable four-quadrant programmable power supply, simplifies circuit design, reduces costs, facilitates maintenance, supports high-voltage and high-current output, and is suitable for integrated circuit testing and precision instruments.
Smart Images
Figure CN224596451U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of high-precision programmable power supply technology, specifically relating to a programmable power supply circuit using a power operational amplifier. Background Technology
[0002] Programmable power supplies play a crucial role in integrated circuit testing and precision instrumentation. They provide positive and negative voltage and bidirectional current outputs, accurately simulating the power supply conditions of the device under test (DUT) under different operating conditions. High-precision voltage / current output is key to ensuring accurate parameter measurements, while their rapid response capability supports dynamic characteristic testing. Integrated current sensing allows for real-time monitoring of the DUT's power consumption characteristics, effectively improving testing efficiency and reliability. Furthermore, integrated sine wave modulation functionality can generate controllable test stimuli to characterize the chip's AC characteristics and verify the performance of simulated and mixed-signal circuits.
[0003] Traditional programmable power supplies are typically built using discrete components, resulting in complex circuits and large sizes. They require high parameter matching of components and long debugging times. The temperature coefficient of discrete components affects accuracy, thus necessitating the addition of compensation circuit design. The protection function of the programmable power supply also requires additional circuit design. Furthermore, the maintenance of programmable power supplies is complex and costly. Utility Model Content
[0004] The main purpose of this utility model is to provide a programmable power supply circuit using a power operational amplifier to realize a high-precision four-quadrant programmable power supply, and integrate current detection function and sine wave signal modulation function, while simplifying circuit design, reducing size, reducing cost and facilitating maintenance.
[0005] To achieve the above objectives, this utility model provides a programmable power supply circuit employing a power operational amplifier, comprising a digital control unit, a DAC unit, a polarity control unit, a sine wave modulation unit, a power amplification unit, and a differential amplifier circuit unit, wherein: The input terminal of the digital control unit is connected to the digital signal of the host computer, and the output terminal is connected to the input terminal of the DAC unit; the output terminal of the DAC unit is connected to the input terminal of the polarity control unit, the output terminal of the polarity control unit is connected to the input terminal of the sine wave modulation unit, and the output terminal of the sine wave modulation unit is connected to the input terminal of the power amplifier unit. The first input terminal of the differential amplifier circuit unit is connected to the first terminal of the current sensing resistor R26 in the power amplifier unit, the second input terminal is connected to the second terminal of the current sensing resistor R26 in the power amplifier unit, and the output terminal of the differential amplifier circuit unit is connected to an external voltmeter.
[0006] As a further preferred embodiment of the above technical solution, the polarity control unit includes an operational amplifier IC2A. The non-inverting input terminal of the operational amplifier IC2A is connected to the second terminal of resistor R1, the second terminal of capacitor C5, and the first terminal of switch K5A, respectively. The inverting input terminal of the operational amplifier IC2A is connected to the second terminal of resistor R2, the first terminal of capacitor C6, and the first terminal of resistor R3, respectively. The output terminal of the operational amplifier IC2A is connected to the second terminal of resistor R3 and the second terminal of capacitor C6, respectively, and is connected to the input terminal of the sine wave modulation unit. The positive and negative power supply terminals of operational amplifier IC2A are connected to +15V and -15V respectively. The first end of resistor R1 is connected to the first end of resistor R2 and then connected to the output terminal of DAC unit. The first end of capacitor C5 is connected to the fourth end of switch K5A and then connected to analog ground.
[0007] As a further preferred embodiment of the above technical solution, the sinusoidal modulation unit includes an operational amplifier IC2B. The non-inverting input terminal of the operational amplifier IC2B is connected to the negative terminal of diode D1, the positive terminal of diode D2, and ground, respectively. The inverting input terminal of the operational amplifier IC2B is connected to the positive terminal of diode D1, the negative terminal of diode D2, the second terminal of resistor R12, the first terminal of resistor R16, the first terminal of resistor R13, and the first terminal of resistor R15, respectively. The output terminal of the operational amplifier IC2B is connected to the second terminal of resistor R16 and the input terminal of the power amplifier unit, respectively. The positive and negative power supply terminals of the operational amplifier IC2B are connected to +15V and -15V respectively. The second terminal of resistor R13 is connected to the first terminal of switch K7A, and the second terminal of resistor R15 is connected to the first terminal of switch K8A. The fourth terminal of switch K7A is connected to the fourth terminal of switch K8A and then connected to the output terminal of the sine wave generator.
[0008] As a further preferred embodiment of the above technical solution, the power amplification unit includes a power operational amplifier IC3, wherein: The 1, 12, 13, and 14 terminals of the power operational amplifier IC3 are connected to +50V, the 18, 19, 20, and 26 terminals are connected to -50V, the 2, 28, and 29 terminals are connected to analog ground, the 15, 16, 17, and 24 terminals are connected to the first terminal of resistor R20, and the second terminal of resistor R20 is connected to the first terminal of resistor R26 and the 23 terminal of the power operational amplifier IC3, respectively. A capacitor C10 is connected between pins 6 and 4 of the power operational amplifier IC3; pin 30 of the power operational amplifier IC3 is connected to the second terminal of resistor R18, the second terminal of resistor R17, and the first terminal of resistor R19. The first terminal of resistor R17 is connected to the adjustment terminal of the fine-tuning resistor P5; the second terminal of resistor R19 is connected to the first terminal of resistor R25 and the fourth terminal of switch K1A; the second terminal of resistor R25 is connected to the second terminal of resistor R26 and the thirteenth terminal of switch K1C. The sixth terminal of switch K1A is connected to the eleventh terminal of switch K1C. The eighth terminal of switch K1A is VOUT-S, and the ninth terminal of switch K1C is VOUT-F.
[0009] As a further preferred technical solution to the above technical solution, the output terminal of the digital control unit is also connected to the input terminal of the switch drive control unit, which is used to control the on / off state of all relay switches in each unit of the entire programmable power supply.
[0010] As a further preferred embodiment of the above technical solution, resistor R20 is a four-wire connected current-limiting resistor, which is extended into a current-limiting selection circuit, wherein: The first terminals of resistors R20, R21, and R22 are connected to terminals 15, 16, 17, and 24 of the power operational amplifier IC3. The second terminal of resistor R20 is connected to the seventh terminal of switch K9A, and the second terminal of resistor R21 is connected to the seventh terminal of switch K2A. The first terminals of switch K9A, K2A, and R22 are connected to the first terminal of resistor R26.
[0011] As a further preferred technical solution to the above technical solution, the current sensing resistor R26 is extended into a current sensing range selection circuit, including resistor R23, resistor R24, switch K3A, switch K10A, and switch K10C, wherein: The first end of resistor R23 is connected to the seventh and eighth ends of switch K3A. The second end of resistor R23 is connected to the second end of resistor R24, the fourth end of switch K10A, and the thirteenth end of switch K10C. The first and fourteenth ends of switch K3A are connected together and connected to the first end of resistor R24, the eighth end of switch K10A, and the ninth end of switch K10C.
[0012] The beneficial effects of this utility model are as follows: 1. High integration and simplified design: The core component, the power operational amplifier IC3, integrates the driver stage, output stage, and protection circuitry, significantly reducing the number of external components. In typical applications, only a feedback resistor, compensation capacitor, and power supply decoupling components are required for normal operation, simplifying the circuit design process. Simultaneously, fewer external components make the programmable power supply easier to maintain, significantly reducing maintenance costs. Furthermore, the overall size is considerably smaller than traditional programmable power supplies, facilitating miniaturized integration of equipment.
[0013] 2. High precision and good stability: As a high-precision four-quadrant programmable power supply, its core power operational amplifier IC3 features a precisely matched differential pair and current source. It boasts low temperature drift (typically <10uV / °C), high open-loop gain (>100dB), and good linearity. These characteristics ensure high precision in the output voltage and current of the programmable power supply, maintaining excellent stability even under varying ambient temperatures, making it ideal for precision programmable power supplies with high accuracy requirements.
[0014] 3. Supports high-voltage, high-current output: The power operational amplifier IC3 supports ±50V dual power supply. In the circuit design of this utility model, the actual maximum output voltage is ±42V, and the maximum continuous current is ±250mA. It can also provide pulse currents of 4A / 10ms and 6A / 2ms. No external power transistor is needed for current expansion, simplifying the circuit's thermal design, reducing circuit complexity and cost. It can be used in integrated circuit testing systems and precision instruments, and as a programmable power supply.
[0015] 4. Integrated Multiple Practical Functions: This programmable power supply integrates current detection and sine wave signal modulation functions. For current detection, it provides two current measurement ranges of 25mA and 250mA, in conjunction with a high-precision current sensing resistor and differential amplifier circuit unit, enabling low-noise, high-precision current measurement to meet different current monitoring requirements. For sine wave signal modulation, different modulation ratios (1 or 5) or pure DC signal output can be selected according to testing needs, providing controllable test excitation for scenarios such as chip AC characteristic testing and analog and mixed-signal circuit performance verification, thus expanding the application range of the programmable power supply. Attached Figure Description
[0016] Figure 1 A block diagram of the overall circuit of the programmable power supply provided in this embodiment of the utility model; Figure 2 This is a circuit diagram of the MP38 (power operational amplifier IC3) used in an embodiment of this utility model; Figure 3 The power amplifier unit circuit diagram provided for the embodiments of this utility model; Figure 4 A current limiting selection circuit diagram provided for an embodiment of this utility model; Figure 5 A circuit diagram for selecting the current detection range provided in this embodiment of the utility model; Figure 6 A polarity control circuit diagram provided for an embodiment of this utility model; Figure 7 A sine wave modulation circuit diagram provided for an embodiment of this utility model. Detailed Implementation
[0017] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.
[0018] This utility model discloses a programmable power supply circuit using a power operational amplifier. The specific embodiments of the utility model are further described below with reference to preferred embodiments.
[0019] In the embodiments of this utility model, those skilled in the art will note that the digital control unit, DAC unit, and host computer involved in this utility model can be regarded as prior art.
[0020] Preferred embodiment.
[0021] like Figure 1 As shown, this utility model discloses a programmable power supply circuit using a power operational amplifier, including a digital control unit, a DAC unit, a polarity control unit, a sine wave modulation unit, a power amplification unit, and a differential amplifier circuit unit, wherein: The input terminal of the digital control unit is connected to the digital signal from the host computer, and the output terminal is connected to the input terminal of the DAC unit. The DAC unit internally uses a 12-bit digital-to-analog converter with an output voltage range of 0-10V. The output terminal of the DAC unit is connected to the input terminal of the polarity control unit, transmitting the analog signal to the polarity control unit. The output terminal of the polarity control unit is connected to the input terminal of the sine wave modulation unit, and the output terminal of the sine wave modulation unit is connected to the input terminal of the power amplifier unit. The polarity control unit is used to control the polarity of the programmable power supply output voltage, and the sine wave modulation unit is used to control whether the programmable power supply modulates the output signal with a sine wave. The power amplifier unit, as the core power drive component of the entire circuit, can amplify a small signal of 0-10V to a high-voltage power output of 0-±42V, providing the required output voltage and current, realizing a complete four-quadrant programmable power supply function, and also having overcurrent protection capability. The first input terminal of the differential amplifier circuit unit is connected to the first terminal of the current sensing resistor R26 in the power amplifier unit, the second input terminal is connected to the second terminal of the current sensing resistor R26 in the power amplifier unit, and the output terminal of the differential amplifier circuit unit is connected to an external voltmeter. By detecting the voltage of V-IMEAS, the current flowing through the programmable power supply can be obtained.
[0022] Specifically, such as Figure 6As shown, the polarity control unit includes an operational amplifier IC2A. The non-inverting input of the operational amplifier IC2A is connected to the second terminal of resistor R1, the second terminal of capacitor C5, and the first terminal of switch K5A. The inverting input of the operational amplifier IC2A is connected to the second terminal of resistor R2, the first terminal of capacitor C6, and the first terminal of resistor R3. The output of the operational amplifier IC2A is connected to the second terminal of resistor R3 and the second terminal of capacitor C6, and is also connected to the input of the sine wave modulation unit. The positive and negative power supply terminals of operational amplifier IC2A are connected to +15V (A+15V) and -15V (A-15V), respectively. The first end of resistor R1 is connected to the first end of resistor R2 and then to the output terminal of the DAC unit. The first end of capacitor C5 is connected to the fourth terminal of switch K5A and then to analog ground A-GND. When K5A is closed, the polarity control unit forms an inverting amplifier circuit (amplification factor -1), outputting a voltage from 0 to -10V, and the programmable power supply outputs a negative voltage. When switch K5A is open, it forms a voltage follower (amplification factor 1), outputting a voltage from 0 to +10V, and the programmable power supply outputs a positive voltage. Capacitor C5 is a filter capacitor used to eliminate contact bounce of switch K5A, suppress voltage transients during switch switching, and also reduce electromagnetic interference generated during switch switching. Resistors R2 and R3 are precision resistors to ensure output accuracy.
[0023] More specifically, such as Figure 7 As shown, the sinusoidal modulation unit includes an operational amplifier IC2B. The non-inverting input of the operational amplifier IC2B is connected to the negative terminal of diode D1, the positive terminal of diode D2, and ground, respectively. The inverting input of the operational amplifier IC2B is connected to the positive terminal of diode D1, the negative terminal of diode D2, the second terminal of resistor R12, the first terminal of resistor R16, the first terminal of resistor R13, and the first terminal of resistor R15, respectively. The output of the operational amplifier IC2B is connected to the second terminal of resistor R16 and the input terminal of the power amplifier unit (i.e., the first terminal of resistor R18). The positive and negative power supply terminals of operational amplifier IC2B are connected to +15V (A+15V) and -15V (A-15V) respectively. The second terminal of capacitor C32 is connected to +15V (A+15V), and the first terminal is connected to A-GND. The first terminal of capacitor C33 is connected to -15V (A-15V), and the second terminal is connected to A-GND. The second terminal of resistor R13 is connected to the first terminal of switch K7A, and the second terminal of resistor R15 is connected to the first terminal of switch K8A. The fourth terminals of switches K7A and K8A are connected to the output terminal of the sine wave generator (SWG-IN-MOD). When switches K7A and K8A are open, the unit forms an inverting amplifier circuit (amplification factor -1), outputting a DC voltage from -10V to +10V. When switch K7A is open and switch K8A is closed, the output is a sine wave superimposed with DC (modulation ratio 1). When switch K7A is closed and switch K8A is open, the output is a sine wave superimposed with DC (modulation ratio 5). Capacitors C32 and C33 are used for filtering; diodes D1 and D2 protect IC2B; and resistors R12, R13, R15, and R16 are precision resistors to ensure accuracy.
[0024] Furthermore, such as Figure 1-3 As shown, the power amplification unit includes a power operational amplifier IC3 (APEX MP38), wherein: Terminals 1, 12, 13, and 14 of the power operational amplifier IC3 are connected to +50V, terminals 18, 19, 20, and 26 are connected to -50V, and terminals 2, 28, and 29 are connected to analog ground A-GND. A parallel connection of capacitors C8 (0.47μF) and C9 (100μF) connects one end to A-GND and the other end to +50V. A parallel connection of capacitors C11 (100μF) and C12 (0.47μF) connects one end to A-GND and the other end to -50V for power supply filtering. Terminals 15, 16, 17, and 24 are connected to the first terminal of resistor R20 (0.09Ω). The second terminal of resistor R20 is connected to the first terminal of resistor R26 (10Ω, a precision power resistor) and terminal 23 of the power operational amplifier IC3, respectively. A capacitor C10 is connected between terminals 6 and 4 of the power operational amplifier IC3; terminal 30 of the power operational amplifier IC3 is connected to the second terminal of resistor R18 (50KΩ, precision resistor), the second terminal of resistor R17 (10MΩ), and the first terminal of resistor R19 (210KΩ, precision resistor). The first terminal of resistor R17 is connected to the adjustment terminal of the fine-tuning resistor P5; the second terminal of resistor R19 is connected to the first terminal of resistor R25 (100Ω) and the fourth terminal of switch K1A; the second terminal of resistor R25 is connected to the second terminal of resistor R26 and the thirteenth terminal of switch K1C. The sixth terminal of switch K1A is connected to the eleventh terminal of switch K1C. The eighth terminal of switch K1A is VOUT-S, and the ninth terminal of switch K1C is VOUT-F. IC3 and its components constitute an inverting amplifier circuit with an amplification factor Avo = -R19 / R18. C10 (100pF-220pF) compensates for IC3, R20 provides overcurrent protection, and resistor R17 and fine-tuning resistor P5 (100KΩ) are used for zeroing. The output uses a Kelvin connection. It is worth mentioning that, regarding the power amplification unit: like Figure 1-3 As shown, the core component used in this embodiment is the power operational amplifier IC3, which is the APEX MP38 cost-effective high-voltage MOSFET power operational amplifier. Its core characteristics include: first, high power, voltage / current up to ±100V (total 200V) / 10A; second, fast speed: slew rate of 10V / µs; third, support for 4-wire current limit detection; fourth, low cost: built on a thermally conductive and electrically isolated substrate using surface-mount components, offering better cost-effectiveness than hybrid power amplifiers; and fifth, small size: dimensions (length / width / height) of 52.32mm x 41.5mm x 11.43mm. Additionally, key specifications of the MP38 include: maximum output current within SOA: 25A; junction temperature: 175°C (requires heatsink); input offset voltage: typical 5mV; and gain-bandwidth product: 2MHz. The MP38 is a cost-effective power op-amp suitable for high-voltage, high-current applications, ideal for designing and manufacturing programmable power supplies, and requires a good heatsink for application.
[0025] The power operational amplifier IC3 has a voltage / current capacity of 200V / 10A. When the supply voltage of this device is increased to its maximum value, it can be designed and manufactured as a programmable power supply with a maximum voltage of ±95V. In this embodiment, a dual power supply of ±50V is used, and the maximum output voltage is ±42V. The power operational amplifier IC3 and its components constitute an inverting amplifier circuit. The ratio of resistor R18 to resistor R19 is the amplification factor of the power operational amplifier IC3, i.e., Avo = -R19 / R18. By changing the value of the resistor, the amplification factor can be changed, i.e., the output voltage can be changed. The selection of Avo must ensure that the first power operational amplifier operates within the linear range to ensure the accuracy of the output voltage across the entire range. Resistors R18 and R19 are precision resistors to ensure the accuracy and stability of the output voltage. The power operational amplifier IC3 uses a dual ±50V power supply. The positive supply voltage +50V is coupled and filtered through electrolytic capacitor C9 and ceramic capacitor C8, while the negative supply voltage -50V is coupled and filtered through electrolytic capacitor C11 and ceramic capacitor C12 to improve the stability of the voltage output.
[0026] The capacitor C10 is used to compensate the power operational amplifier IC3. According to the amplification factor of the circuit and referring to the device manual, C10 can be selected from 100 pF to 220 pF; the resistor R20 is a current-limiting resistor with four-wire connection. The IC3 realizes current limiting protection by detecting the voltage across R20, and it needs to be connected correctly according to Figure 1 and Figure 3 to avoid the influence of additional resistance on the current limiting accuracy. The relationship between the resistor R20 and the expected current limiting value is: expected current limiting value = 0.7 V / R20 = 7.8 A; multiple current limiting resistors can be added and selected to obtain different current limiting values, see Figure 4 ; the resistors R17 and the trimming resistor P5 form a zero adjustment circuit; the output voltage is connected in a Kelvin connection manner, and VOUT-F and VOUT-S are connected together near the device under test.
[0027] The resistance value of the resistor R19 is relatively large, and the input terminal of the power operational amplifier IC3 is virtually grounded. Therefore, the voltage across R19 is equal to the output voltage. Thus, the current through the R19 path is very small and can be ignored. All the current flowing into or out of the programmable power supply enters the path of the current sensing resistor R26 and generates a voltage drop across the current sensing resistor R26. This voltage drop is amplified by the differential amplifier circuit unit and then output to the V-IMEAS terminal. By detecting the magnitude of the voltage of V-IMEAS, the current flowing through the programmable power supply can be obtained; the current sensing resistor R26 = 10 ohms, corresponding to a current measurement range of 0 - ±250 mA; the resistor R26 is a precision power resistor to ensure accurate and stable current sampling.
[0028] Furthermore, the output terminal of the digital control unit is also connected to the input terminal of the switch drive control unit, which is used to control the on and off of all relay switches (such as K1A, K1C, K3A, K5A, K7A, K8A, K9A, K10A, K10C, K2A, etc.) in all units of the entire programmable power supply.
[0029] Preferably, the resistor R20 is a current-limiting resistor with four-wire connection, which is extended to a current limiting selection circuit, as shown in Figure 4 : The first ends of the resistor R20, the resistor R21, and the resistor R22 are connected and then connected to the 15th, 16th, 17th, and 24th terminals of the power operational amplifier IC3. The second end of the resistor R20 is connected to the seventh terminal of the switch K9A, and the second end of the resistor R21 is connected to the seventh terminal of the switch K2A; the first ends of the switch K9A, the switch K2A, and the second end of the resistor R22 are connected and then connected to the first end of the resistor R26 (multiple current limiting resistors are added and selected to obtain different current limiting values).
[0030] Preferably, the current sensing resistor R26 is extended to a current sensing range selection circuit, as shown in Figure 5As shown, it includes resistor R23, resistor R24, switch K3A, switch K10A, and switch K10C, wherein: The first terminal of resistor R23 is connected to terminals 7 and 8 of switch K3A. The second terminal of resistor R23 is connected to the second terminal of resistor R24, terminal 4 of switch K10A, and terminal 13 of switch K10C. Terminals 1 and 14 of switch K3A are connected together and then connected to the first terminal of resistor R24, terminal 8 of switch K10A, and terminal 9 of switch K10C. By selecting different current sensing resistors, we can extend the current measurement range. (Refer to...) Figure 5 For the current sensing range selection circuit, when switches K10A and K10C are open and switch K3A is closed, resistors R23 and R24 are connected in parallel, and the current sensing resistor has a resistance of 10R, corresponding to a current measurement range of 0-±250mA. When switches K10A and K10C are open and switch K3A is open, the current sensing resistor has a resistance of 100R, corresponding to a current measurement range of 0-±25mA. This allows for two current measurement ranges. A smaller resistance current sensing resistor can be selected to obtain a higher current measurement range. When switches K10A and K10C are closed, the circuit can obtain the maximum voltage and current output.
[0031] It is worth mentioning that the technical features of the digital control unit, DAC unit and host computer involved in this utility model patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement of these technical features can be adopted by conventional choices in the field and should not be regarded as the inventive point of this utility model patent. This utility model patent will not be further elaborated in detail.
[0032] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A programmable power supply circuit employing a power operational amplifier, characterized by, It includes a digital control unit, a DAC unit, a polarity control unit, a sine wave modulation unit, a power amplifier unit, and a differential amplifier circuit unit, wherein: The input terminal of the digital control unit is connected to the digital signal of the host computer, and the output terminal is connected to the input terminal of the DAC unit; the output terminal of the DAC unit is connected to the input terminal of the polarity control unit, the output terminal of the polarity control unit is connected to the input terminal of the sine wave modulation unit, and the output terminal of the sine wave modulation unit is connected to the input terminal of the power amplifier unit. The first input terminal of the differential amplifier circuit unit is connected to the first terminal of the current sensing resistor R26 in the power amplifier unit, the second input terminal is connected to the second terminal of the current sensing resistor R26 in the power amplifier unit, and the output terminal of the differential amplifier circuit unit is connected to an external voltmeter.
2. The programmable power supply circuit employing a power operational amplifier according to claim 1, wherein, The polarity control unit includes an operational amplifier IC2A. The non-inverting input of the operational amplifier IC2A is connected to the second terminal of resistor R1, the second terminal of capacitor C5, and the first terminal of switch K5A. The inverting input of the operational amplifier IC2A is connected to the second terminal of resistor R2, the first terminal of capacitor C6, and the first terminal of resistor R3. The output of the operational amplifier IC2A is connected to the second terminal of resistor R3 and the second terminal of capacitor C6, and is also connected to the input of the sine wave modulation unit. The positive and negative power supply terminals of operational amplifier IC2A are connected to +15V and -15V respectively. The first end of resistor R1 is connected to the first end of resistor R2 and then connected to the output terminal of DAC unit. The first end of capacitor C5 is connected to the fourth end of switch K5A and then connected to analog ground.
3. A programmable power supply circuit employing a power operational amplifier as claimed in claim 2, wherein, The sinusoidal modulation unit includes an operational amplifier IC2B. The non-inverting input of the operational amplifier IC2B is connected to the negative terminal of diode D1, the positive terminal of diode D2, and ground. The inverting input of the operational amplifier IC2B is connected to the positive terminal of diode D1, the negative terminal of diode D2, the second terminal of resistor R12, the first terminal of resistor R16, the first terminal of resistor R13, and the first terminal of resistor R15. The output of the operational amplifier IC2B is connected to the second terminal of resistor R16 and the input of the power amplifier unit. The positive and negative power supply terminals of the operational amplifier IC2B are connected to +15V and -15V respectively. The second terminal of resistor R13 is connected to the first terminal of switch K7A, and the second terminal of resistor R15 is connected to the first terminal of switch K8A. The fourth terminal of switch K7A is connected to the fourth terminal of switch K8A and then connected to the output terminal of the sine wave generator.
4. A programmable power supply circuit employing a power operational amplifier as claimed in claim 3, wherein, The power amplification unit includes a power operational amplifier IC3, wherein: The 1, 12, 13, and 14 terminals of the power operational amplifier IC3 are connected to +50V, the 18, 19, 20, and 26 terminals are connected to -50V, the 2, 28, and 29 terminals are connected to analog ground, the 15, 16, 17, and 24 terminals are connected to the first terminal of resistor R20, and the second terminal of resistor R20 is connected to the first terminal of resistor R26 and the 23 terminal of the power operational amplifier IC3, respectively. A capacitor C10 is connected between pins 6 and 4 of the power operational amplifier IC3; pin 30 of the power operational amplifier IC3 is connected to the second terminal of resistor R18, the second terminal of resistor R17, and the first terminal of resistor R19. The first terminal of resistor R17 is connected to the adjustment terminal of the fine-tuning resistor P5; the second terminal of resistor R19 is connected to the first terminal of resistor R25 and the fourth terminal of switch K1A; the second terminal of resistor R25 is connected to the second terminal of resistor R26 and the thirteenth terminal of switch K1C. The sixth terminal of switch K1A is connected to the eleventh terminal of switch K1C. The eighth terminal of switch K1A is VOUT-S, and the ninth terminal of switch K1C is VOUT-F.
5. A programmable power supply circuit employing a power operational amplifier as claimed in claim 4, wherein, The output of the digital control unit is also connected to the input of the switch drive control unit, which is used to control the on / off state of all relay switches in each unit of the entire programmable power supply.
6. A programmable power supply circuit employing a power operational amplifier as claimed in claim 5, wherein, Resistor R20 is a four-wire current-limiting resistor, which can be extended into a current-limiting selection circuit, wherein: The first terminals of resistors R20, R21, and R22 are connected to terminals 15, 16, 17, and 24 of the power operational amplifier IC3. The second terminal of resistor R20 is connected to the seventh terminal of switch K9A, and the second terminal of resistor R21 is connected to the seventh terminal of switch K2A. The first terminals of switch K9A, K2A, and R22 are connected to the first terminal of resistor R26.
7. A programmable power supply circuit employing a power operational amplifier as claimed in claim 6, wherein, The current sensing resistor R26 is expanded into a current sensing range selection circuit, including resistor R23, resistor R24, switch K3A, switch K10A, and switch K10C, wherein: The first end of resistor R23 is connected to the seventh and eighth ends of switch K3A. The second end of resistor R23 is connected to the second end of resistor R24, the fourth end of switch K10A, and the thirteenth end of switch K10C. The first and fourteenth ends of switch K3A are connected together and connected to the first end of resistor R24, the eighth end of switch K10A, and the ninth end of switch K10C.