Direct current detection circuit of radio frequency power supply

Abstract

The utility model discloses a direct current detection circuit of a radio frequency power supply. The direct current detection circuit comprises an isolation voltage module, a reference source module, an isolation operational amplifier module and a differential module, the isolation voltage module is used for isobarically isolating the voltage of the power supply into high-voltage power supply voltage; the reference source module is used for converting the voltage of the power supply through a reference chip and then reducing the voltage to the reference voltage required by the differential module and the ADC through an operational amplifier circuit; the isolation operational amplifier module is used for isolating the voltage of the high-voltage side and outputting the collected voltage in a fixed gain mode. And the differential module is used for receiving the output voltage of the isolation operational amplifier module to form a differential signal to adapt to differential input on the ADC. According to the utility model, high and low voltage complete isolation can be carried out, a post-stage ADC circuit can be protected, differential output is realized, an analog quantity input range of an ADC is easier to match, output of a direct current part is more stable, and stability and purity during output of a radio frequency power supply are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of detection circuits, in particular to a radio frequency power supply direct current detection circuit. Background Art

[0002] How to ensure the stability and purity of RF power has always been a hot topic. Purity and stability are highly dependent on the DC output of the previous stage, so the stability and safety of DC detection are a major issue. Common DC detection circuits include the following:

[0003] (1) Using differential circuit to collect:

[0004] Using differential operation circuits, the common mode signal can be effectively suppressed, and only the differential signal can be amplified, so it has been widely used.

[0005] (2) Resistor voltage sampling:

[0006] Use multiple resistors to perform voltage division operations to control the voltage on one or more resistors within the power supply range of the ADC, then connect to the voltage follower circuit and then enter the ADC.

[0007] The above scenario is the most commonly used voltage detection solution, but it only works for low voltages. This is because the op amp cannot completely isolate the effects of the high-voltage side, resulting in unstable output voltages due to inaccurate detection. The first scenario has differential outputs but lacks isolation, as the grounds in the circuit remain connected, thus lacking complete isolation. In the second scenario, if the sampled voltage suddenly rises too high, the ADC input voltage will be too high, damaging the ADC pins, as the voltage divider will increase with the sampled voltage without an upper limit.

[0008] Based on this, the present invention provides a radio frequency power supply DC detection circuit to solve the above-mentioned problems. Utility Model Content

[0009] The purpose of the utility model is to provide a radio frequency power supply DC detection circuit, which can not only completely isolate high and low voltages, but also protect the subsequent ADC circuit, so that the differential output can more easily match the analog input range of the ADC, making the acquisition more accurate.

[0010] In order to solve the above technical problems, the utility model provides a radio frequency power supply DC detection circuit, including an isolation voltage module, a reference source module, an isolation operational amplifier module and a differential module. The isolation voltage module is used to isolate the voltage of the power supply into a high-voltage power supply voltage VDD1. The reference source module is used to convert the voltage of the power supply through a reference chip and then step down the voltage to the reference voltage required by the differential module and ADC through an operational amplifier circuit. The isolation operational amplifier module is used to isolate the voltage on its high-voltage side and output the collected voltage with a fixed gain. The differential module is used to take over the output voltage of the isolation operational amplifier module to form a differential signal to adapt to the differential input on the ADC.

[0011] Furthermore, the isolation voltage module includes an isolation power supply module U16, pin 1 and pin 2 of the isolation power supply module U16 are respectively connected to the ground GND and the power supply, and a capacitor C51 is connected between pin 1 and pin 2 of the isolation power supply module U16, the pin 4 output and pin 5 output of the isolation power supply module U16 are respectively connected to the isolation ground GND1 and the high-voltage power supply voltage VDD1, and a filter energy storage capacitor C53, a filter energy storage capacitor C54, and a filter energy storage capacitor C55 are connected between pin 4 and pin 5 of the isolation power supply module U16.

[0012] Furthermore, the capacitance values ​​of the capacitor C51, the filtering energy storage capacitor C53, the filtering energy storage capacitor C54 and the filtering energy storage capacitor C55 are 4.7 μf, 0.1 μf, 10 μf and 10 μf respectively.

[0013] Furthermore, the reference source module includes a reference chip U21 REF198, an operational amplifier U23A, and an operational amplifier U23B. Pin 1 of the reference chip U21 REF198 is connected to the power supply as an input terminal, pin 2 of the reference chip U21 REF198 is grounded through capacitors C66 and C67, pin 4 of the reference chip U21 REF198 is directly grounded GND, and pin 6 of the reference chip U21 REF198 is used as a voltage output terminal and enters the reverse input pin of pin 2 of the operational amplifier U23A through resistors R96 and R97 and is grounded GND through capacitor C63, and is connected to pin 3 of the operational amplifier U23A.

[0014] A feedback resistor R94 is connected between pins 1 and 2 of the op amp U23A, and the output of pin 1 of U23A is connected to the input of the op amp U23B through resistor R98. Pin 5 of the op amp U23B is grounded GND. Feedback resistor R95 is connected to both ends of the op amp U23B. Pin 7 of the op amp U23B is the output pin, which is grounded GND through capacitor C68, and pin 7 of the op amp U23B is connected to the differential module to provide a reference voltage.

[0015] Furthermore, the capacitances of the capacitor C66, capacitor C67, capacitor C63 and capacitor C68 are 22μf, 22μf, 0.1μf and 1μf respectively, and the resistances of the feedback resistor R94, resistor R98, feedback resistor R95, resistor R96 and resistor R97 are 10kΩ, 10kΩ, 10kΩ, 0Ω and 16kΩ respectively.

[0016] Furthermore, the isolation operational amplifier module includes an isolation amplifier U20 and a J5 terminal, wherein pins 1 and 3 of the J5 terminal are used to input a DC high voltage, and are divided by voltage divider resistors R86, R87, R88, R90, R91, R92, and R93;

[0017] One end of the voltage divider resistor R90 is connected to the positive input pin of the isolation amplifier U20, and the other end of the voltage divider resistor R90 is connected to pin 4 of the isolation amplifier U20 and resistor R89. The end of the resistor R89 ​​away from the voltage divider resistor R90 is connected to the negative input pin 3 of the isolation amplifier U20;

[0018] Pins 1 and 4 of the isolation amplifier U20 are connected to the high-voltage power supply voltage VDD1 and the isolation ground GND1 respectively, pins 8 and 5 of the isolation amplifier U20 are connected to the power supply and the ground GND respectively, and capacitors C56 and C59 are connected in parallel between pins 8 and 5 of the isolation amplifier U20. Pins 7 and 6 of the isolation amplifier U20 are output pins connected to the differential module input.

[0019] Furthermore, the resistance values ​​of the voltage-dividing resistor R86, the voltage-dividing resistor R87, the voltage-dividing resistor R88, the voltage-dividing resistor R90, the voltage-dividing resistor R91, the voltage-dividing resistor R92, the voltage-dividing resistor R93 and the resistor R89 ​​are 100kΩ, 100kΩ, 25Ω, 333Ω, 100kΩ, 100kΩ, 25Ω and 333Ω respectively, and the capacitance values ​​of the capacitor C56 and the capacitor C59 are 0.1μf and 2.2μf respectively.

[0020] Furthermore, the differential module includes a differential chip U19, and pins 2 and 3 of the differential chip U19 are connected to the output end of the isolation operational amplifier module through resistors R84 and R85 respectively. The two ends of the output of the isolation operational amplifier module are incorporated into a filter capacitor C61, and the two ends of the output of the isolation operational amplifier module are respectively connected to the ground with filter capacitors C60 and C62;

[0021] A feedback resistor R82 is connected between pin 1 and pin 2 of the differential chip U19, a feedback resistor R83 is connected between pin 3 and pin 4 of the differential chip U19, pins 13, 14, 15 and 16 of the differential chip U19 are directly connected to ground GND and grounded to GND through capacitor C58, pins 5, 6, 7 and 8 of the differential chip U19 are respectively connected to the power supply and grounded to GND through capacitor C57, pin 12 of the differential chip U19 is connected to the PD pin, pin 9 of the differential chip U19 is connected to the standard power supply REF+2.65V, pins 10 and 11 of the differential chip U19 are output pins, and are connected to ADC for acquisition through resistors R81 and R80 respectively, and filter capacitor C52 is connected in parallel on the output sides of the resistors R81 and R80.

[0022] Furthermore, the resistance values ​​of the resistor R84, resistor R85, feedback resistor R82, feedback resistor R83, resistor R81 and resistor R80 are 499kΩ, 499kΩ, 499kΩ, 499kΩ, 33Ω and 33Ω respectively, and the capacitance values ​​of the filter capacitor C61, filter capacitor C60, filter capacitor C62, capacitor C58, capacitor C57 and filter capacitor C52 are 100pf, 100pf, 100pf, 0.1μf, 0.1μf and 20pf respectively.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] The RF power supply DC detection circuit proposed in this utility model can not only completely isolate high and low voltages, but also protect the subsequent ADC circuit, making it easier for the differential output to match the analog input range of the ADC, making the DC part output more stable, and ensuring the stability and purity of the RF power supply output. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall structure of the radio frequency power supply DC detection circuit of the utility model. DETAILED DESCRIPTION

[0026] The following is a more detailed description of the RF power supply DC detection circuit of the present invention, with reference to a schematic diagram. This diagram illustrates a preferred embodiment of the present invention. It should be understood that those skilled in the art may modify the present invention as described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as a general guide for those skilled in the art and not as a limitation of the present invention.

[0027] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0028] An embodiment of the utility model provides a radio frequency power supply direct current detection circuit, which includes an isolation voltage module, a reference source module, an isolation operational amplifier module, and a differential module.

[0029] Specifically, with reference Figure 1 The isolation voltage module is used to isolate the voltage of the power supply into a high-voltage power supply voltage VDD1, including an isolation power supply module U16. The model of the isolation power supply module U16 is B0505XT-1WR3. Pin 1 and pin 2 of the isolation power supply module U16 are grounded to GND and the power supply, respectively, and a capacitor C51 is connected between pin 1 and pin 2 of the isolation power supply module U16. The output of pin 4 and pin 5 of the isolation power supply module U16 are connected to the isolation ground GND1 and the high-voltage power supply voltage VDD1, respectively, and a filter energy storage capacitor C53, a filter energy storage capacitor C54, and a filter energy storage capacitor C55 are connected between pin 4 and pin 5 of the isolation power supply module U16; the capacitance values ​​of capacitor C51, filter energy storage capacitor C53, filter energy storage capacitor C54, and filter energy storage capacitor C55 are 4.7μf, 0.1μf, 10μf, and 10μf, respectively.

[0030] The reference source module is used to convert the voltage of the power supply through the reference chip and then step it down to the reference voltage required by the differential module and ADC through the operational amplifier circuit. It includes the reference chip U21 REF198, the operational amplifier U23A and the operational amplifier U23B. Pin 1 of the reference chip U21 REF198 is connected to the power supply as the input terminal, pin 2 of the reference chip U21 REF198 is grounded through capacitors C66 and C67, pin 4 of the reference chip U21 REF198 is directly grounded to GND, and pin 6 of the reference chip U21 REF198 is used as the voltage output terminal and enters the reverse input pin 2 of the operational amplifier U23A through resistors R96 and R97 and is grounded to GND through capacitor C63, and is connected to pin 3 of the operational amplifier U23A.

[0031] Feedback resistor R94 is connected between pins 1 and 2 of op amp U23A, and the output of pin 1 of U23A is connected to the input of op amp U23B through resistor R98. Pin 5 of op amp U23B is grounded to GND. Feedback resistor R95 is connected to both ends of op amp U23B. Pin 7 of op amp U23B is the output pin, which is grounded to GND through capacitor C68. Pin 7 of op amp U23B is connected to the differential module to provide a reference voltage.

[0032] The capacitance values ​​of capacitor C66, capacitor C67, capacitor C63 and capacitor C68 are 22μf, 22μf, 0.1μf and 1μf respectively, and the resistance values ​​of feedback resistor R94, resistor R98, feedback resistor R95, resistor R96 and resistor R97 are 10kΩ, 10kΩ, 10kΩ, 0Ω and 16kΩ respectively.

[0033] The isolation operational amplifier module is used to isolate the voltage on its high-voltage side and output the collected voltage with a fixed gain. It includes an isolation amplifier U20 and a J5 terminal. Pins 1 and 3 of the J5 terminal are used to input a DC high voltage, which is then divided by voltage divider resistors R86, R87, R88, R90, R91, R92, and R93. The model of the isolation amplifier U20 is AMC1301.

[0034] One end of the voltage divider resistor R90 is connected to the positive input pin of the isolation amplifier U20, and the other end of the voltage divider resistor R90 is connected to pin 4 of the isolation amplifier U20 and resistor R89. The end of the resistor R89 ​​away from the voltage divider resistor R90 is connected to the negative input pin 3 of the isolation amplifier U20.

[0035] Pins 1 and 4 of the isolation amplifier U20 are connected to the high-voltage power supply voltage VDD1 and the isolation ground GND1 respectively. Pins 8 and 5 of the isolation amplifier U20 are connected to the power supply and the ground GND respectively. Capacitors C56 and C59 are connected in parallel between pins 8 and 5 of the isolation amplifier U20. Pins 7 and 6 of the isolation amplifier U20 are output pins connected to the differential module input.

[0036] The resistance values ​​of the voltage divider resistor R86, voltage divider resistor R87, voltage divider resistor R88, voltage divider resistor R90, voltage divider resistor R91, voltage divider resistor R92, voltage divider resistor R93 and resistor R89 ​​are 100kΩ, 100kΩ, 25Ω, 333Ω, 100kΩ, 100kΩ, 25Ω and 333Ω respectively, and the capacitance values ​​of capacitor C56 and capacitor C59 are 0.1μf and 2.2μf respectively.

[0037] The differential module is used to receive the output voltage of the isolation operational amplifier module to form a differential signal to adapt to the differential input on the ADC. It includes a differential chip U19. The model of the differential chip U19 is ADA4932. Pins 2 and 3 of the differential chip U19 are connected to the output end of the isolation operational amplifier module through resistors R484 and R85 respectively. The two ends of the output of the isolation operational amplifier module are incorporated into the filter capacitor C61, and the two ends of the output of the isolation operational amplifier module are connected to the ground with filter capacitors C60 and C62 respectively.

[0038] A feedback resistor R82 is connected between pins 1 and 2 of the differential chip U19, a feedback resistor R83 is connected between pins 3 and 4 of the differential chip U19, pins 13, 14, 15 and 16 of the differential chip U19 are directly connected to ground GND and grounded to GND through capacitor C58, pins 5, 6, 7 and 8 of the differential chip U19 are respectively connected to the power supply and grounded to GND through capacitor C57, pin 12 of the differential chip U19 is connected to the PD pin, pin 9 of the differential chip U19 is connected to the standard power supply REF+2.65V, pins 10 and 11 of the differential chip U19 are output pins, and are connected to the ADC for acquisition through resistors R81 and R80 respectively, and filter capacitor C52 is connected in parallel on the output sides of resistors R81 and R80;

[0039] The resistance values ​​of resistor R84, resistor R85, feedback resistor R82, feedback resistor R83, resistor R81 and resistor R80 are 499kΩ, 499kΩ, 499kΩ, 499kΩ, 33Ω and 33Ω respectively, and the capacitance values ​​of filter capacitor C61, filter capacitor C60, filter capacitor C62, capacitor C58, capacitor C57 and filter capacitor C52 are 100pf, 100pf, 100pf, 0.1μf, 0.1μf and 20pf respectively.

[0040] The specific use process of the RF power supply DC detection circuit provided above is as follows:

[0041] First, the isolation voltage module isolates the power supply to provide power for the isolation op amp. The reference voltage source is modulated by the op amp to output a 2.56V reference voltage to supply the differential chip and ADC.

[0042] The DC voltage reduces the voltage across resistor R90 from 300V to 250mV through seven voltage-dividing resistors. Since 250mV is the maximum input voltage of the isolation amplifier U20, the isolation amplifier U20 will measure all fluctuations within 300V at full scale. After the 250mV voltage is sent to the isolation amplifier U20, the input voltage will be fixedly amplified by 8.2 times, so that the output becomes 0-2.05V. The amplified voltage is sent to the differential chip U19. The differential chip U19 can convert the differential voltage transmitted from the isolation amplifier U20 into a differential signal with a reference voltage of 2.56V and send it to the ADC. Since the ADC reads the set reference voltage of 2.56V, it must be modulated by the differential chip before it can be sent in. The ADC parses the analog signal into a digital signal and transmits it to the MCU for control calculation.

[0043] In summary, the RF power supply DC detection circuit proposed in the present invention can not only completely isolate high and low voltages, but also protect the subsequent ADC circuit, making it easier for the differential output to match the analog input range of the ADC, making the DC part output more stable, and ensuring the stability and purity of the RF power supply output.

[0044] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A radio frequency power supply DC detection circuit, characterized in that: Including isolated voltage module, reference source module, isolated operational amplifier module and differential module; The isolation voltage module is used to isolate the voltage of the power supply into a high voltage supply voltage VDD1; The reference source module is used to convert the voltage of the power supply through the reference chip and then step down the voltage to the reference voltage required by the differential module and ADC through the operational amplifier circuit; The isolation operational amplifier module is used to isolate the voltage on its high-voltage side and output the collected voltage with a fixed gain; The differential module is used to receive the output voltage of the isolation operational amplifier module to form a differential signal to adapt to the differential input on the ADC.

2. The radio frequency power supply DC detection circuit according to claim 1, characterized in that: The isolated voltage module includes an isolated power supply module U16, pin 1 and pin 2 of the isolated power supply module U16 are respectively connected to the ground GND and the power supply, and a capacitor C51 is connected between pin 1 and pin 2 of the isolated power supply module U16, the pin 4 output and the pin 5 output of the isolated power supply module U16 are respectively connected to the isolation ground GND1 and the high-voltage power supply voltage VDD1, and a filter energy storage capacitor C53, a filter energy storage capacitor C54, and a filter energy storage capacitor C55 are connected between pin 4 and pin 5 of the isolated power supply module U16.

3. The radio frequency power supply DC detection circuit according to claim 2, wherein: The capacitance values ​​of the capacitor C51, the filtering energy storage capacitor C53, the filtering energy storage capacitor C54 and the filtering energy storage capacitor C55 are 4.7 μf, 0.1 μf, 10 μf and 10 μf respectively.

4. The radio frequency power supply DC detection circuit according to claim 1, wherein: The reference source module includes a reference chip U21 REF198, an operational amplifier U23A and an operational amplifier U23B; Pin 1 of the reference chip U21 REF198 is connected to the power supply as an input terminal, pin 2 of the reference chip U21 REF198 is grounded through capacitors C66 and C67, pin 4 of the reference chip U21 REF198 is directly grounded GND, and pin 6 of the reference chip U21 REF198 is used as a voltage output terminal and enters the reverse input pin 2 of the operational amplifier U23A through resistors R96 and R97 and is grounded GND through capacitor C63, and is connected to pin 3 of the operational amplifier U23A at the same time; A feedback resistor R94 is connected between pins 1 and 2 of the op amp U23A, and the output of pin 1 of U23A is connected to the input of the op amp U23B through resistor R98. Pin 5 of the op amp U23B is grounded GND. Feedback resistor R95 is connected to both ends of the op amp U23B. Pin 7 of the op amp U23B is the output pin, which is grounded GND through capacitor C68, and pin 7 of the op amp U23B is connected to the differential module to provide a reference voltage.

5. The radio frequency power supply DC detection circuit according to claim 4, characterized in that: The capacitance values ​​of the capacitor C66, the capacitor C67, the capacitor C63 and the capacitor C68 are 22 μf, 22 μf, 0.1 μf and 1 μf respectively; The resistance values ​​of the feedback resistor R94 , the resistor R98 , the feedback resistor R95 , the resistor R96 and the resistor R97 are 10 kΩ, 10 kΩ, 10 kΩ, 0Ω and 16 kΩ respectively.

6. The radio frequency power supply DC detection circuit according to claim 4, characterized in that: The isolation operational amplifier module includes an isolation amplifier U20 and a J5 terminal; Pins 1 and 3 of the J5 terminal are used to input DC high voltage, and are divided by voltage divider resistors R86, R87, R88, R90, R91, R92, and R93; One end of the voltage divider resistor R90 is connected to the positive input pin of the isolation amplifier U20, and the other end of the voltage divider resistor R90 is connected to pin 4 of the isolation amplifier U20 and resistor R89. The end of the resistor R89 ​​away from the voltage divider resistor R90 is connected to the negative input pin 3 of the isolation amplifier U20; Pins 1 and 4 of the isolation amplifier U20 are connected to the high-voltage power supply voltage VDD1 and the isolation ground GND1 respectively, pins 8 and 5 of the isolation amplifier U20 are connected to the power supply and the ground GND respectively, and capacitors C56 and C59 are connected in parallel between pins 8 and 5 of the isolation amplifier U20. Pins 7 and 6 of the isolation amplifier U20 are output pins connected to the differential module input.

7. The radio frequency power supply DC detection circuit according to claim 6, characterized in that: The resistance values ​​of the voltage divider resistor R86, the voltage divider resistor R87, the voltage divider resistor R88, the voltage divider resistor R90, the voltage divider resistor R91, the voltage divider resistor R92, the voltage divider resistor R93 and the resistor R89 ​​are 100 kΩ, 100 kΩ, 25Ω, 333Ω, 100 kΩ, 100 kΩ, 25Ω and 333Ω respectively; The capacitances of the capacitor C56 and the capacitor C59 are 0.1 μf and 2.2 μf respectively.

8. The radio frequency power supply DC detection circuit according to claim 1, wherein: The differential module includes a differential chip U19, and pins 2 and 3 of the differential chip U19 are connected to the output end of the isolation operational amplifier module through resistors R84 and R85 respectively. The two ends of the output of the isolation operational amplifier module are incorporated into a filter capacitor C61, and the two ends of the output of the isolation operational amplifier module are connected to the ground through filter capacitors C60 and C62 respectively. A feedback resistor R82 is connected between pin 1 and pin 2 of the differential chip U19, a feedback resistor R83 is connected between pin 3 and pin 4 of the differential chip U19, pins 13, 14, 15 and 16 of the differential chip U19 are directly connected to ground GND and grounded to GND through capacitor C58, pins 5, 6, 7 and 8 of the differential chip U19 are respectively connected to the power supply and grounded to GND through capacitor C57, pin 12 of the differential chip U19 is connected to the PD pin, pin 9 of the differential chip U19 is connected to the standard power supply REF+2.65V, pins 10 and 11 of the differential chip U19 are output pins, and are connected to ADC for acquisition through resistors R81 and R80 respectively, and filter capacitor C52 is connected in parallel on the output sides of the resistors R81 and R80.

9. The radio frequency power supply DC detection circuit according to claim 8, characterized in that: The resistance values ​​of the resistor R84, the resistor R85, the feedback resistor R82, the feedback resistor R83, the resistor R81 and the resistor R80 are 499 kΩ, 499 kΩ, 499 kΩ, 33Ω and 33Ω respectively; The capacitance values ​​of the filter capacitor C61, filter capacitor C60, filter capacitor C62, capacitor C58, capacitor C57 and filter capacitor C52 are 100pf, 100pf, 100pf, 0.1μf, 0.1μf and 20pf respectively.

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