Positive and negative constant-voltage constant-current adjustable high-voltage power supply structure

Abstract

The invention relates to the technical field of high-voltage power generators, in particular to a positive and negative constant-voltage constant-current adjustable high-voltage power structure which comprises a mode switching module, a digital controller, a load current feedback point, an adjusting module and an external load circuit. And the mode switching module can realize switching of four working modes. The voltage of the load current feedback point is related to the magnitude of the output current of the load so as to sample the load current. The output ends of the first adjusting assembly and the second adjusting assembly are electrically connected with the load current feedback point. The input end of the external load circuit is electrically connected with the load current feedback point, the external load circuit is provided with an in-loop current feedback point, and the in-loop current feedback point and the load current feedback point sample the output voltage together. The output voltage of the first adjusting assembly or the second adjusting assembly is adjusted based on the comparison condition of the in-loop current feedback point and the load current feedback point, the control performance of the superposition loop is improved, four working modes are met, the efficiency is high, and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of high-voltage power supply generators, and in particular to a forward and reverse constant-voltage and constant-current adjustable high-voltage power supply structure. Background Art

[0002] There are various electrical devices on the market. Some of them are suitable for working in CC constant current mode, such as LEDs, while some are suitable for working in CV constant voltage mode, such as mobile phone chargers. The source meter is a multifunctional device used for testing. In order to meet the testing requirements of different devices, the source meter has both constant voltage and constant current functions. Usually, two independent control loops are built into the source meter, one is the CC constant current control loop, and the other is the CV constant voltage control loop, to realize the constant current / constant voltage function of the source meter.

[0003] In the past, the traditional analog loop controller only tracked one feedback parameter, resulting in low control performance of the superimposed loop. The four working modes could not meet the requirements at the same time, especially the output under the superimposed circuit, which could not achieve the ideal constant voltage output. In the past, the traditional analog power supply needed to set up four independent error amplifiers for the four working modes to meet the requirements of the startup characteristics of the four working modes. The traditional analog power supply needs to design an independent protection circuit. In the superimposed loop, the analog controller of the forward and reverse circuits requires a more complex protection circuit to protect the internal components of the power supply from failure when the load is open and short-circuited. The traditional analog power supply circuit structure is complex and the cost is high. Summary of the invention

[0004] In order to solve the technical defects mentioned in the above background technology, the purpose of the present invention is to provide a forward and reverse constant voltage and constant current adjustable high-voltage power supply structure.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A forward and reverse constant voltage and constant current adjustable high voltage power supply structure, comprising:

[0007] A mode switching module, used to switch between positive CC mode, reverse CC mode, positive CV mode or reverse CV mode;

[0008] A digital controller, wherein the mode switching module is electrically connected to the digital controller;

[0009] A load current feedback point, the load current feedback point is connected to the output end of the load and is used to sample the load current;

[0010] A regulating module, comprising a first regulating component and a second regulating component; the first regulating component is used to regulate the voltage or current in a positive CC mode or a positive CV mode working state; the second regulating component is used to regulate the voltage or current in a reverse CC mode or a reverse CV mode working state; the input ends of the first regulating component and the second regulating component are both electrically connected to the digital controller; the output ends of the first regulating component and the second regulating component are both electrically connected to the load current feedback point;

[0011] An external load circuit, one end of which is electrically connected to a load current feedback point, the external load circuit is provided with an in-loop current feedback point, the in-loop current feedback point is used to sample the current in the external load circuit; the output voltage of the first regulating component or the second regulating component is adjusted based on the comparison between the in-loop current feedback point and the load current feedback point; the other end of the external load circuit is grounded.

[0012] By adopting the above technical solution, the positive and negative superposition high-voltage power supply can realize the switching between four working modes through the mode switching module. The digital controller realizes four error amplifiers inside the CPU program, and the circuit structure is greatly simplified. The load current feedback point and the current feedback point in the loop are set in the circuit, and the two feedback parameters are tracked synchronously to improve the control performance of the superposition loop, and the four working modes are satisfied at the same time, with high efficiency and low cost. The load current feedback point and the current feedback point in the loop are combined with the CPU control program to realize open short circuit protection in the control algorithm. The protection algorithm shortens the response time of abnormal protection by detecting the occurrence of abnormalities in advance and limiting the output of loop control, thereby improving the reliability and safety of the power supply.

[0013] Furthermore, the mode switching module includes a forward-reverse switching switch and a constant voltage and constant current switching switch, wherein the forward-reverse switching switch is used to switch the forward and reverse flow direction of the current, and the constant voltage and constant current switching switch is used to switch between CC mode and CV mode. When the mode switching module is switched to the positive CC mode or the positive CV mode, the first regulating component is connected to the digital controller, and the second regulating component is disconnected from the digital controller. When the mode switching module is switched to the reverse CC mode or the reverse CV mode, the second regulating component is connected to the digital controller, and the first regulating component is disconnected from the digital controller.

[0014] Further, when the mode switching module selects the positive CC mode, the load is set with a reference point Vref, and the load current feedback point obtains the input current of the input end of the external load circuit; the first regulation component regulates the current of the external load circuit based on the difference between the voltage of the load current feedback point and the voltage of the reference point.

[0015] Further, the load includes an operational amplifier, a first resistor, a second resistor and a third resistor. One end of the first resistor is electrically connected to the digital controller, and the other end of the first resistor is connected to the non-inverting input terminal of the operational amplifier. One end of the second resistor is grounded, and the other end of the second resistor is connected to the non-inverting input terminal of the operational amplifier. The reverse input terminal of the operational amplifier is connected to the voltage feedback terminal through the third resistor. The output terminal of the operational amplifier is connected to one end of the third resistor, and the other end of the third resistor is the load current feedback point.

[0016] Further, the digital controller includes a first PWM control circuit for adjusting the duty cycle to regulate the voltage. The first regulating component includes a first transformer, a first diode, a first capacitor, a second capacitor, a second diode and a filter resistor. The output end of the first PWM control circuit is connected to the first transformer, the output ends of the first transformer are connected to the positive electrode of the first diode and the first plate of the second capacitor, the negative electrode of the first diode is connected to the input end of the external load circuit, the first plate of the first capacitor is connected to the negative electrode of the first diode and the input end of the external load circuit, the second plate of the first capacitor is connected to the first plate of the second capacitor and one end of the filter resistor, and the second plate of the second capacitor is connected to the positive electrode of the second diode. The negative electrode of the second diode is connected to the positive electrode of the first diode. One end of the filter resistor is connected to the load current feedback point, and the other end of the filter resistor is connected to the input end of the external load circuit.

[0017] Furthermore, when the forward-reverse switching switch is switched to reverse current and the constant voltage and constant current switching switch is switched to constant current mode, the digital controller includes a second PWM control circuit for adjusting the duty cycle to regulate the voltage. The input end of the external load circuit is grounded, and the output end of the external load circuit is connected to the second regulating component and the input end of the load; the load current feedback point is set at the input end of the load. The output end of the second PWM control circuit is connected to the second regulating component, and the second regulating component is used to filter the current at the output end of the external load circuit.

[0018] Furthermore, the regulating module also includes a fourth resistor and a fifth resistor. When the mode switching module is switched to the positive CV mode, the input end of the first regulating component is connected to the digital controller, and the output end of the first regulating component is connected to one end of the fourth resistor, one end of the fifth resistor, and the input end of the external load circuit. The other end of the fourth resistor is connected to the other end of the fifth resistor, and the in-loop current feedback point is provided between the fourth resistor and the fifth resistor. One end of the fifth resistor is connected to the input end of the external load circuit, one end of the fourth resistor is connected to the output end of the load, and the load current feedback point is provided between one end of the fourth resistor and the load. The digital controller adjusts the duty cycle based on the difference between the load current feedback point and the in-loop current feedback point so that the output voltage of the external load circuit is constant.

[0019] Furthermore, the resistance of the fourth resistor is smaller than the resistance of the fifth resistor, the input voltage of the external load circuit is equal to the voltage of the fifth resistor, and the current of the fourth resistor is equal to the current of the fifth resistor.

[0020] Furthermore, the current ic of the fourth resistor is calculated as follows: ic = (|FB1-FB0|) / R4; wherein FB0 is the voltage of the load current feedback point; FB1 is the voltage of the current feedback point in the loop; and R4 is the resistance value of the fourth resistor. The input voltage Vout of the external load circuit is calculated as follows: Vout = R5*ic = R5*(|FB1-FB0|) / R4; wherein R5 is the resistance value of the fifth resistor.

[0021] Further, when the mode switching module is switched to the reverse CV mode, the input end of the second regulating component is connected to the digital controller, and the output end of the second regulating component is connected to one end of the fourth resistor, one end of the fifth resistor, and the output end of the external load circuit. The other end of the fourth resistor is connected to the other end of the fifth resistor, and the in-loop current feedback point is provided between the fourth resistor and the fifth resistor. One end of the fifth resistor is connected to the output end of the external load circuit, one end of the fourth resistor is connected to the input end of the load, and the load current feedback point is provided between one end of the fourth resistor and the load. The digital controller adjusts the duty cycle based on the difference between the load current feedback point and the in-loop current feedback point to make the input voltage of the external load circuit constant.

[0022] In summary, the beneficial effects of the present invention are:

[0023] The present invention realizes switching between four working modes through a mode switching module, and the digital controller realizes four error amplifiers inside the CPU program, and the circuit structure is greatly simplified. The load current feedback point and the current feedback point in the loop are set in the circuit, and the two feedback parameters are tracked synchronously to improve the control performance of the superposition loop, and the four working modes are satisfied at the same time, with high efficiency and low cost. The load current feedback point and the current feedback point in the loop are combined with the CPU control program to realize open-short circuit protection in the control algorithm. The protection algorithm shortens the response time of abnormal protection by detecting the occurrence of abnormalities in advance and limiting the output of loop control, thereby improving the reliability and safety of the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a circuit structure diagram of an embodiment of the positive CC mode of the forward and reverse constant voltage and constant current adjustable high-voltage power supply structure of the present invention.

[0025] Figure 2 The present invention is a schematic diagram of the circuit structure of an embodiment of a digital controller of a forward and reverse constant voltage and constant current adjustable high-voltage power supply structure.

[0026] Figure 3 It is a circuit structure diagram of an embodiment of the reverse CC mode of the forward and reverse constant voltage and constant current adjustable high-voltage power supply structure of the present invention.

[0027] Figure 4 It is a circuit structure diagram of an embodiment of the positive CV mode of the forward and reverse constant voltage and constant current adjustable high voltage power supply structure of the present invention.

[0028] Figure 5 It is a circuit structure diagram of an embodiment of the reverse CV mode of the forward and reverse constant voltage and constant current adjustable high-voltage power supply structure of the present invention.

[0029] Description of reference numerals in the figures:

[0030] 1. Forward and reverse constant voltage and constant current adjustable high-voltage power supply structure; 2. Mode switching module; 21. Forward and reverse switching switch; 22. Constant voltage and constant current switching switch; 3. Digital controller; PWM0, first PWM control circuit; PWM1, second PWM control circuit; FB0, load current feedback point; FB1, current feedback point in the loop; 4. Load; 41. Operational amplifier; R1, first resistor; R2, second resistor; R3, third resistor; 5. Regulation module; 51, first regulation component; 511, first transformer; 512, first diode; 513, first capacitor; 514, second capacitor; 515, second diode; 516, filter resistor; 52, second regulation component; 6. External load circuit; R4, fourth resistor; R5, fifth resistor. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0032] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0033] In the description of the present invention, if there are words such as "several", it means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there are descriptions of first, second, and third, they are only used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0034] The following is combined with Figure 1-5 , the embodiments of the present invention are described in further detail.

[0035] A forward and reverse constant voltage and constant current adjustable high voltage power supply structure 1, such as Figure 1 , Figure 2 , Figure 4As shown, it includes a mode switching module 2, a digital controller 3, a load current feedback point FB0, a regulating module 5 and an external load circuit 6. The mode switching module 2 is used to switch between positive CC mode, reverse CC mode, positive CV mode or reverse CV mode. The mode switching module 2 is electrically connected to the digital controller 3. The load current feedback point FB0 is connected to the output end of the load 4 for sampling the current of the load 4. The regulating module 5 includes a first regulating component 51 and a second regulating component 52. The first regulating component 51 is used to adjust the voltage or current in the positive CC mode and positive CV mode working state. The second regulating component 52 is used to adjust the voltage in the reverse CC mode and reverse CV mode working state. The input ends of the first regulating component 51 and the second regulating component 52 are both electrically connected to the digital controller 3. The output ends of the first regulating component 51 and the second regulating component 52 are both electrically connected to the load current feedback point FB0. The input end of the external load circuit 6 is electrically connected to the load current feedback point FB0, and the external load circuit 6 is provided with an in-loop current feedback point FB1, and the in-loop current feedback point FB1 is used to sample the voltage in the external load circuit 6. Based on the comparison between the inner-loop current feedback point FB1 and the load current feedback point FB0, the output voltage of the first regulating component 51 or the second regulating component 52 is regulated. The output terminal of the external load circuit 6 is grounded.

[0036] The present positive and negative superposition high-voltage power supply can realize switching between four working modes through the mode switching module 2. The digital controller 3 realizes four error amplifiers inside the CPU program, and the circuit structure is greatly simplified. The load current feedback point FB0 and the loop current feedback point FB1 are set in the circuit to synchronously track the two feedback parameters, improve the control performance of the superposition loop, and meet the four working modes at the same time, with high efficiency and low cost. The load current feedback point FB0 and the loop current feedback point FB1 are combined with the CPU control program to realize open-short circuit protection in the control algorithm. The protection algorithm shortens the response time of abnormal protection by detecting the occurrence of abnormalities in advance and limiting the output of loop control, thereby improving the reliability and safety of the power supply.

[0037] In this embodiment, please refer to Figure 1 , Figure 2 The mode switching module 2 includes a forward-reverse switching switch 21 and a constant voltage and constant current switching switch 22. The forward-reverse switching switch 21 is used to switch the forward and reverse directions of the voltage and current, and the constant voltage and constant current switching switch 22 is used to switch between the CC mode and the CV mode. When the mode switching module 2 is switched to the positive CC mode or the positive CV mode, the first regulating component 51 is connected to the digital controller 3, and the second regulating component 52 is disconnected from the digital controller 3. When the mode switching module 2 is switched to the reverse CC mode or the reverse CV mode, the second regulating component 52 is connected to the digital controller 3, and the first regulating component 51 is disconnected from the digital controller 3. Figure 2The structure of the digital controller in is limited.

[0038] Specifically, the user manually switches the forward / reverse switch 21 and the constant voltage / constant current switch 22, and the digital controller 3 obtains the switched working mode and performs corresponding working processing.

[0039] When the positive CC mode is selected, the user manually switches the forward-reverse switching switch 21 to the positive current working mode and the constant voltage and constant current switching switch 22 to the CC mode. The digital controller 3 is connected to the first regulating component 51 and disconnected from the second regulating component 52. The current in the power supply circuit is output from the load 4 to the external load circuit 6 through the load current feedback point FB0 and the first regulating component 51 in sequence. The digital controller 3 adjusts the voltage at the load current feedback point FB0 in real time through the first regulating component 51 to make the current at the load current feedback point FB0 equal to the input current of the external load circuit 6.

[0040] In some embodiments, please refer to Figure 1 The load 4 is provided with a reference point Vref, and the load current feedback point FB0 obtains the input current of the input end of the external load circuit 6. The first regulating component 51 regulates the current of the external load circuit 6 based on the difference between the voltage of the load current feedback point FB0 and the voltage of the reference point Vref.

[0041] The feedback calculation based on the current of the load 4 in the high voltage power supply is described. The first regulating component 51 in the power supply circuit is regarded as a circuit node. According to the circuit principle of Kirchhoff's current law, the load 4 is set at the input end of the circuit node, and the external load circuit 6 is set at the output end of the circuit node. The current flowing into the node ib is equal to the current flowing out of the node ia.

[0042] The load current feedback point FB0 and the loop current feedback point FB1 are connected to the AD port of the CPU through the circuit of the operational amplifier 41. The operational amplifier 41 usually has a very high input impedance, which means that it hardly draws current from the equivalent node. The input current of the operational amplifier 41 is at the nA level, which is much lower than the load 4 current at the uA level.

[0043] In this embodiment, the load 4 includes an operational amplifier 41, a first resistor R1, a second resistor R2 and a third resistor R3. One end of the first resistor R1 is electrically connected to the digital controller 3, and the other end of the first resistor R1 is connected to the in-phase input terminal of the operational amplifier 41. One end of the second resistor R2 is grounded, and the other end of the second resistor R2 is connected to the in-phase input terminal of the operational amplifier 41. The reverse input terminal of the operational amplifier 41 is connected to the voltage feedback terminal through the third resistor R3. The output terminal of the operational amplifier 41 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is the load current feedback point FB0.

[0044] The amplification factor of the circuit can be set according to the values ​​of the first resistor R1, the second resistor R2 and the third resistor R3. Since the current of the load 4 flows through the third resistor R3, a voltage drop will be generated at both ends thereof, and the voltage is fed back to the operational amplifier 41, thereby realizing the conversion of current to voltage, which can play a role in stabilizing the output current.

[0045] The digital controller 3 includes a first PWM control circuit PWM0 for adjusting the duty cycle to regulate the voltage. The first regulating component 51 includes a first transformer 511, a first diode 512, a first capacitor 513, a second capacitor 514, a second diode 515 and a filter resistor 516. The output end of the first PWM control circuit PWM0 is connected to the first transformer 511, and the output ends of the first transformer 511 are connected to the positive electrode of the first diode 512 and the first plate of the second capacitor 514. The negative electrode of the first diode 512 is connected to the input end of the external load circuit 6. The first plate of the first capacitor 513 is connected to the negative electrode of the first diode 512 and the input end of the external load circuit 6. The second plate of the first capacitor 513 is connected to the first plate of the second capacitor 514 and one end of the filter resistor 516. The second plate of the second capacitor 514 is connected to the positive electrode of the second diode 515. The negative electrode of the second diode 515 is connected to the positive electrode of the first diode 512. One end of the filter resistor 516 is connected to the load current feedback point FB1, and the other end of the filter resistor 516 is connected to the input end of the external load circuit 6. The first PWM control circuit PWM0 generates a pulse width modulated signal to control the current in the coil of the first transformer 511, thereby adjusting the output voltage and current. The first diode 512 and the second diode 515 form a part of the rectifier bridge, which converts the AC power on the secondary side of the transformer into pulsating DC power. The first capacitor 513, the second capacitor 514 and the filter resistor 516 can smooth and filter, reduce the ripple of the output voltage, and provide a current feedback signal to the load 4 to avoid the influence of interference signals on the output current, reduce the accuracy of the output to the operational amplifier 41, and help the closed-loop control system to operate stably.

[0046] Specifically, the second current ib at the load current feedback point FB0 is calculated as follows:

[0047] ib=(Vref-FB0) / R3; ........ Formula 1;

[0048] Vref=3.3*R1 / (R1+R3)=2.46v;

[0049] Wherein, ib is the second current ib, Vref is the voltage of the reference point in the load 4, FB0 is the voltage of the load current feedback point FB0, R3 is the resistance value of the third resistor R3, R1 is the resistance value of the first resistor R1, and the input voltage of the load 4 circuit is 3.3v.

[0050] FB0 serves as the error detection input terminal of the digital loop controller. The digital controller 3 achieves the stability of the voltage at FB0 by changing the duty cycle of the first PWM control circuit PWM0, thereby achieving the stable output of the external load current ia.

[0051] Specifically, the voltage range of the AD port of the CPU is 0v-3.3v. The voltage range used by the digital controller 3 is 0.3v-3.0v, Vref is 2.46v, and the resistance value of the third resistor R3 is 10.8kΩ. When the voltage used by the digital controller 3 is the minimum, the output current of the load 4 is the maximum.

[0052] According to formula 1, the maximum output current of load 4 = (2.46v-0.3v) / 10.8kΩ = 200uA. At the same time, since the voltage FB0 of the load current feedback point FB1 can be maintained above 0.3V by adjusting the PWM signal of the first PWM control circuit PWM0, a continuously adjustable current output from 0μA to a maximum of 200μA can be achieved. Therefore, this high-voltage power supply circuit can achieve positive CC output, and its maximum output current range is: 0uA to 200uA.

[0053] In this embodiment, please refer to Figure 3 , when the forward-reverse switching switch 21 switches to reverse current and the constant voltage and constant current switching switch 22 switches to constant current mode, the digital controller 3 includes a second PWM control circuit PWM1 for adjusting the duty cycle to regulate the voltage. The input end of the external load circuit 6 is grounded, and the output end of the external load circuit 6 is connected to the second regulating component 52 and the input end of the load 4. The load current feedback point FB1 is set at the input end of the load 4. The output end of the second PWM control circuit PWM1 is connected to the second regulating component 52, and the second regulating component 52 is used to filter the current at the output end of the external load circuit 6. Using the feedback signal of the load current feedback point FB0, the second PWM control circuit PWM1 can continuously correct the duty cycle to adjust the voltage, thereby maintaining a constant output current.

[0054] Specifically, when the reverse CC mode is selected, the user manually switches the forward and reverse switching switch 21 to the reverse current working mode and the constant voltage and constant current switching switch 22 to the CC mode, and the high voltage output electrical characteristic is the reverse CC output. The digital controller 3 is connected to the second regulating component 52 and disconnected from the first regulating component 51, and the current in the power supply circuit is output from the external load circuit 6 to the load 4 through the second regulating component 52 and the load current feedback point FB0 in sequence. The digital controller 3 adjusts the voltage at the load current feedback point FB0 in real time through the second regulating component 52 so that the current at the load current feedback point FB0 is equal to the output current of the external load circuit 6.

[0055] The structure of the second regulating component 52 is arranged in the same circuit structure as the first regulating component 51 , and the role it plays in the circuit is also the same. For details, please refer to the relevant content of the above-mentioned first regulating component 51 .

[0056] Specifically, the second current ib at the load current feedback point FB0 is calculated as follows:

[0057] ib=(FB0-Vref) / R3;.............Formula 2

[0058] Vref=3.3*R1 / (R1+R3)=2.46v;

[0059] Wherein, ib is the second current ib, Vref is the voltage of the reference point in the load 4, FB0 is the voltage of the load current feedback point FB0, R3 is the resistance value of the third resistor R3, R1 is the resistance value of the first resistor R1, and the input voltage of the load 4 circuit is 3.3v.

[0060] The voltage FB0 of the load current feedback point FB0 serves as the error detection input terminal of the digital loop controller. The digital controller 3 achieves stability of the voltage FB0 of the load current feedback point FB0 by changing the duty cycle of the second PWM control circuit PWM1, thereby achieving stable output of the external load current ia.

[0061] Specifically, the voltage range of the AD port of the CPU is 0v-3.3v. The voltage range used by the digital controller 3 is 0.3v-3.0v, Vref is 2.46v, and R3 is 10.8kΩ.

[0062] According to formula 2, the maximum output current of load 4 = (3.0v-2.46v) / 10.8kΩ = 50uA. Based on the above circuit analysis, the circuit shown in the figure can realize the reverse CC working mode, and its maximum output current range is: 0uA to 50uA.

[0063] In this embodiment, please refer to Figure 4, the regulating module 5 also includes a fourth resistor R4 and a fifth resistor R5. When the mode switching module 2 is switched to the positive CV mode, the input end of the first regulating component 51 is connected to the digital controller 3, and the output end of the first regulating component 51 is connected to one end of the fourth resistor R4, one end of the fifth resistor R5, and the input end of the external load circuit 6. The other end of the fourth resistor R4 is connected to the other end of the fifth resistor R5, and an in-loop current feedback point FB1 is provided between the fourth resistor R4 and the fifth resistor R5. One end of the fifth resistor R5 is connected to the input end of the external load circuit 6, one end of the fourth resistor R4 is connected to the output end of the load 4, and a load current feedback point FB0 is provided between one end of the fourth resistor R4 and the load 4. The digital controller 3 adjusts the duty cycle based on the difference between the load current feedback point FB0 and the in-loop current feedback point FB1 to make the input voltage of the external load circuit 6 constant.

[0064] Specifically, when the positive CV mode is selected, the user manually switches the forward-reverse switch 21 to the positive output working mode and the constant voltage and constant current switch 22 to the CV mode, the digital controller 3 is connected to the first regulating component 51 and disconnected from the second regulating component 52, and the current in the power supply circuit is output from the load 4 to the external load circuit 6 through the load current feedback point FB0, the fourth resistor R4, the loop current feedback point FB1, and the fifth resistor R5 in sequence. The digital controller 3 adjusts the voltage difference between the second regulating component 52 and the load current feedback point FB0 and the loop current feedback point FB1 in real time to keep the input voltage of the external load circuit 6 constant.

[0065] The fourth resistor R4 and the fifth resistor R5 form a voltage divider network, and the in-loop current feedback point FB1 is used to monitor the feedback signal of the output voltage. The load current feedback point FB0 can monitor the actual current value output by the load 4 in real time. The digital controller 3 compares the signals of the in-loop current feedback point FB1 and the load current feedback point FB0 to calculate the required adjustment amount. Based on the difference between the in-loop current feedback point FB1 and the load current feedback point FB0, the first PWM control circuit PWM0 adjusts the duty cycle of the PWM signal to change the output of the first regulating component 51, ensuring that the system can quickly adapt to changes in the load 4 and other disturbances, maintain voltage stability, and keep the input voltage of the external load circuit 6 constant.

[0066] Among them, according to the circuit principle, the currents of the same branch are equal, and the current of the fourth resistor R4 is equal to the current of the fifth resistor R5. The resistance of the fourth resistor R4 is much smaller than the resistance of the fifth resistor R5. In this embodiment, the resistance of the fifth resistor R5 is set to 5MΩ, and the resistance of the fourth resistor is 50Kω. The output voltage of the external load circuit 6 is equal to the voltage of the fifth resistor R5. Due to the influence of external factors, in fact, the output voltage of the external load circuit 6 is approximately equal to the voltage of the fifth resistor R5. Since the resistance of the fifth resistor R5 is much larger than the resistance of the fourth resistor R4, the output voltage Vout input to the external load circuit 6 is substantially equal to the voltage on the fifth resistor R5.

[0067] The calculation formula of the current ic of the fourth resistor R4 is:

[0068] ic=(FB1-FB0) / R4;…………Formula 3

[0069] In the formula, FB0 is the voltage of the load current feedback point FB0; FB1 is the voltage of the current feedback point FB1 in the loop; R4 is the resistance value of the fourth resistor R4.

[0070] The calculation formula of the input voltage Vout of the external load circuit 6 is:

[0071] Vout=R5*ic=R5*(FB1-FB0) / R4;………………Formula 4

[0072] Wherein, R5 is the resistance value of the fifth resistor R5.

[0073] Using (FB1-FB0) as the error detection input terminal of the digital loop controller, the digital controller 3 achieves the stability of the (FB1-FB0) voltage by changing the duty cycle of the first PWM control circuit PWM0, thereby achieving a constant voltage output of the high voltage output Vout.

[0074] Specifically, the voltage range of the AD port of the CPU is 0v-3.3v. The voltage range used by the digital controller 3 is 0.3v-3.0v, FB1>FB0, and at the maximum current, FB0=0.3v. Then the maximum value of (FB1-FB0) is 3.0v-0.3v=2.7v.

[0075] According to Formula 4, maximum Vout = 50MΩ*2.7v / 50kΩ = 2700v.

[0076] Therefore, the present high voltage power supply circuit can realize the positive CV working mode.

[0077] In this embodiment, please refer to Figure 5, when the mode switching module 2 switches to the reverse CV mode, the input end of the second regulating component 52 is connected to the digital controller 3, and the output end of the second regulating component 52 is connected to one end of the fourth resistor R4, one end of the fifth resistor R5, and the output end of the external load circuit 6. The other end of the fourth resistor R4 is connected to the other end of the fifth resistor R5, and an in-loop current feedback point FB0 is provided between the fourth resistor R4 and the fifth resistor R5. One end of the fifth resistor R5 is connected to the output end of the external load circuit 6, one end of the fourth resistor R4 is connected to the input end of the load 4, and a load current feedback point FB1 is provided between one end of the fourth resistor R4 and the load 4. The digital controller 3 adjusts the duty cycle based on the difference between the load current feedback point FB0 and the in-loop current feedback point FB1 to make the input voltage of the external load circuit 6 constant.

[0078] Specifically, when the reverse CV mode is selected, the user manually switches the forward and reverse switching switch 21 to the reverse output working mode and the constant voltage and constant current switching switch 22 to the CV mode. The digital controller 3 is connected to the second regulating component 52 and disconnected from the first regulating component 51. The current in the power supply circuit is output from the external load circuit 6 to the load 4 through the fifth resistor R5, the loop current feedback point FB1, the fourth resistor R4, and the load current feedback point FB0 in sequence. The flow direction of the current is opposite to that of the positive CV mode. The digital controller 3 adjusts the voltage difference between the second regulating component 52 and the load current feedback point FB0 and the loop current feedback point FB1 in real time to keep the input voltage of the external load circuit 6 constant.

[0079] According to the circuit principle, the currents in the same branch are equal, and the current of the fourth resistor R4 is equal to the current of the fifth resistor R5. The resistance of the fourth resistor R4 is much smaller than the resistance of the fifth resistor R5, and the input voltage of the external load circuit 6 is approximately equal to the voltage of the fifth resistor R5. Since the resistance of the fifth resistor R5 is much larger than the resistance of the fourth resistor R4, the input voltage Vout of the external load circuit 6 is substantially equal to the voltage on the fifth resistor R5.

[0080] The calculation formula of the current ic of the fourth resistor R4 is:

[0081] ic=(FB0-FB1) / R4;………………Formula 5

[0082] In the formula, FB0 is the voltage of the load current feedback point FB0; FB1 is the voltage of the current feedback point FB1 in the loop; R4 is the resistance value of the fourth resistor R4.

[0083] The calculation formula of the output voltage Vout of the external load circuit 6 is:

[0084] Vout=R5*ic=R5*(FB0-FB1) / R4;………………Formula 6

[0085] Wherein, R5 is the resistance value of the fifth resistor R5.

[0086] Using (FB0-FB1) as the error detection input terminal of the digital loop controller, the digital controller 3 achieves the stability of the (FB0-FB1) voltage by changing the duty cycle of the second PWM control circuit PWM1, thereby achieving a constant voltage output of the high voltage output Vout.

[0087] The voltage range of the CPU AD port is 0v-3.3v. The voltage range of digital controller 3 is 0.3v-3.0v, FB0>FB1, and at the maximum current, FB0=3.0v, then the maximum value of (FB0-FB1) is 3.0v-0.3v=2.7v. According to formula 6, it can be calculated that the maximum Vout=50MΩ*2.7v / 50kΩ=2700v.

[0088] Therefore, the high voltage power supply circuit can realize the reverse CV working mode.

[0089] This constant voltage and constant current adjustable high voltage power supply structure switches 4 groups of numbers inside the CPU through 2 digital IOs. The digital controller 3 realizes the switching of the working mode. When the output is positive, the second PWM control circuit PWM1 driving the reverse output is turned off; when the output is reverse, the first PWM control circuit PWM0 of the positive output is turned off. This constant voltage and constant current adjustable high voltage power supply structure can achieve an output accuracy of less than or equal to 3% in various modes, an external load range of 1M-1500M, and a load change of less than or equal to 3%.

[0090] The circuit structure of the voltage sampling (|FB1-FB0|) of the external load circuit and the circuit structure of the current sampling (FB0) of the external load circuit do not affect the control accuracy of the CC mode or the CV mode under different working modes (CC / CV), solve the mutual influence of ordinary voltage and current sampling circuits on the CC mode and the CV mode, and improve the control accuracy under multiple working modes and complex topology structures.

[0091] This constant voltage and constant current adjustable high-voltage power supply structure can realize the forward and reverse CC working modes by setting the voltage of the appropriate reference point Vref and the resistance value of the third resistor R3, and only needs to use one load current feedback point FB0, thereby efficiently realizing the feedback of the output current at different forward and reverse CC outputs of the power supply.

[0092] This constant voltage and constant current adjustable high voltage power supply structure can efficiently realize the feedback of the output voltage when the power supply has different positive and reverse CV outputs by setting a suitable third resistor R3 and a fourth resistor R4 and using only the load current feedback point FB0 and the in-loop current feedback point FB1.

[0093] This constant voltage and constant current adjustable high voltage power supply structure uses a composite feedback value (the difference between the load current feedback point FB0 and the current feedback point FB1 in the loop) as the input of the digital controller 3 in the constant voltage working mode, and solves the feedback of the output voltage of different positive and reverse outputs.

[0094] The circuit structure of the voltage and current feedback points of the constant voltage and constant current adjustable high-voltage power supply structure, when used in conjunction with the digital controller 3, solves the mutual interference of feedback signals during constant voltage and constant current control of the traditional analog power supply in a complex circuit topology, and greatly improves the constant voltage and constant current performance of the power supply.

[0095] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A forward and reverse constant voltage and constant current adjustable high voltage power supply structure, characterized in that: include A mode switching module, used to switch between positive CC mode, reverse CC mode, positive CV mode or reverse CV mode; A digital controller, wherein the mode switching module is electrically connected to the digital controller; A load current feedback point, the load current feedback point is connected to the output end of the load and is used to sample the load current; A regulating module, comprising a first regulating component and a second regulating component; the first regulating component is used to regulate the voltage or current in a positive CC mode or a positive CV mode working state; the second regulating component is used to regulate the voltage or current in a reverse CC mode or a reverse CV mode working state; the input ends of the first regulating component and the second regulating component are both electrically connected to the digital controller; the output ends of the first regulating component and the second regulating component are both electrically connected to the load current feedback point; An external load circuit, one end of which is electrically connected to a load current feedback point, and the external load circuit is provided with an in-loop current feedback point, and the in-loop current feedback point is used to sample the voltage of the external load circuit; The output voltage of the first regulating component or the second regulating component is adjusted based on the comparison between the current feedback point in the loop and the load current feedback point; and the other end of the external load circuit is grounded.

2. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 1 is characterized in that: The mode switching module includes a forward and reverse switching switch and a constant voltage and constant current switching switch, wherein the forward and reverse switching switch is used to switch the forward and reverse directions of the output voltage or current, and the constant voltage and constant current switching switch is used to switch between CC mode and CV mode; When the mode switching module is switched to the positive CC mode or the positive CV mode, the first regulating component is connected to the digital controller, and the second regulating component is disconnected from the digital controller; when the mode switching module is switched to the reverse CC mode or the reverse CV mode, the second regulating component is connected to the digital controller, and the first regulating component is disconnected from the digital controller.

3. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 2 is characterized in that: When the mode switching module selects the positive CC mode, the load is set with a reference point Vref, and the load current feedback point obtains the input current of the input end of the external load circuit; the first regulation component regulates the current of the external load circuit based on the difference between the voltage of the load current feedback point and the voltage of the reference point.

4. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 3 is characterized in that: The load includes an operational amplifier, a first resistor, a second resistor and a third resistor; one end of the first resistor is electrically connected to the digital controller, and the other end of the first resistor is connected to the non-inverting input terminal of the operational amplifier; one end of the second resistor is grounded, and the other end of the second resistor is connected to the non-inverting input terminal of the operational amplifier; the reverse input terminal of the operational amplifier is connected to the voltage feedback terminal through the third resistor; the output terminal of the operational amplifier is connected to one end of the third resistor, and the other end of the third resistor is the load current feedback point.

5. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 4 is characterized in that: The digital controller includes a first PWM control circuit for adjusting the duty cycle to regulate the voltage; the first regulating component includes a first transformer, a first diode, a first capacitor, a second capacitor, a second diode and a filter resistor; the output end of the first PWM control circuit is connected to the first transformer, and the output ends of the first transformer are both connected to the positive electrode of the first diode and the first plate of the second capacitor, and the negative electrode of the first diode is connected to the input end of the external load circuit; the first plate of the first capacitor is connected to the negative electrode of the first diode and the input end of the external load circuit, the second plate of the first capacitor is connected to the first plate of the second capacitor and one end of the filter resistor, and the second plate of the second capacitor is connected to the positive electrode of the second diode; the negative electrode of the second diode is connected to the positive electrode of the first diode; one end of the filter resistor is connected to the load current feedback point, and the other end of the filter resistor is connected to the input end of the external load circuit.

6. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 2, characterized in that: When the forward-reverse switching switch is switched to reverse output and the constant-voltage and constant-current switching switch is switched to constant-current mode, the digital controller includes a second PWM control circuit for adjusting the duty cycle to regulate the voltage; the input end of the external load circuit is grounded, and the output end of the external load circuit is connected to the second regulating component and the input end of the load; the load current feedback point is set at the input end of the load; the output end of the second PWM control circuit is connected to the second regulating component, and the second regulating component is used to filter the current at the output end of the external load circuit.

7. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 1, characterized in that: The regulating module further includes a fourth resistor and a fifth resistor; when the mode switching module is switched to the positive CV mode, the input end of the first regulating component is connected to the digital controller, the output end of the first regulating component is connected to one end of the fourth resistor, one end of the fifth resistor, and the input end of the external load circuit, the other end of the fourth resistor is connected to the other end of the fifth resistor, and the in-loop current feedback point is provided between the fourth resistor and the fifth resistor; one end of the fifth resistor is connected to the input end of the external load circuit, one end of the fourth resistor is connected to the output end of the load, and the load current feedback point is provided between one end of the fourth resistor and the load; The digital controller adjusts the duty cycle based on the difference between the load current feedback point and the in-loop current feedback point to make the output voltage of the external load circuit constant.

8. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 7, characterized in that: The resistance of the fourth resistor is smaller than the resistance of the fifth resistor, the output voltage of the external load circuit is equal to the voltage of the fifth resistor, the current of the fourth resistor is equal to the current of the fifth resistor, and the voltage of the external load circuit is equal to the voltage of the fifth resistor.

9. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 8, characterized in that: The calculation formula of the current ic of the fourth resistor is: ic=(FB1-FB0) / R4; wherein FB0 is the voltage of the load current feedback point; FB1 is the voltage of the current feedback point in the loop; R4 is the resistance value of the fourth resistor; The calculation formula of the input voltage Vout of the external load circuit is: Vout=R5*ic=R5*(|FB1-FB0|) / R4; wherein R5 is the resistance value of the fifth resistor.

10. The forward and reverse constant voltage and constant current adjustable high voltage power supply structure according to claim 1, characterized in that: When the mode switching module is switched to the reverse CV mode, the input end of the second regulating component is connected to the digital controller, and the output end of the second regulating component is connected to one end of the fourth resistor, one end of the fifth resistor, and the output end of the external load circuit; the other end of the fourth resistor is connected to the other end of the fifth resistor, and the in-loop current feedback point is provided between the fourth resistor and the fifth resistor; one end of the fifth resistor is connected to the output end of the external load circuit, one end of the fourth resistor is connected to the input end of the load, and the load current feedback point is provided between one end of the fourth resistor and the load; The digital controller adjusts the duty cycle based on the difference between the load current feedback point and the in-loop current feedback point to make the input voltage of the external load circuit constant.

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