Bus voltage sampling circuit and power supply system

Abstract

The embodiment of the invention discloses a bus voltage sampling circuit and a power supply system, and the circuit comprises a high-voltage sampling unit which is used for sampling a DC bus voltage and outputting a first voltage signal, and is connected with a first controller; the signal conversion unit is used for converting the first voltage signal into a current signal and outputting the current signal, and is connected with the output end of the high-voltage sampling unit; and the signal restoration unit responds to the current signal to output a second voltage signal, is connected with the output end of the voltage-controlled current source, and is also connected with the second controller. According to the embodiment of the invention, the direct current bus voltage of the first controller is converted into the current signal, then the current signal is restored into the voltage signal, and the voltage signal is input to the second controller, so that many mismatching problems of front and rear controllers are solved, and sampling of the direct current bus voltage is completed by one sampling circuit; the power consumption, the hardware cost and the PCB area caused by an extra sampling circuit can be avoided.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of electronic technology, and in particular to a bus voltage sampling circuit and a power supply system. Background Art

[0002] Generally speaking, power supply devices with power greater than or equal to 75W and outputting DC need to use a two-stage combination of a front-stage power factor correction circuit (Power Factor Correction, PFC) and a rear-stage DCDC circuit. In these applications, the standard requirements for energy efficiency are increasing, and corresponding regulations have introduced strict standby power consumption limit requirements.

[0003] In the circuit of a power converter, there is a part of conditioning circuits for high-voltage signal sampling, such as AC voltage sampling, DC bus voltage sampling, etc., which continuously consume energy as passive devices. Generally speaking, in a system, the PFC controller and the subsequent DCDC controller are independent of each other and are produced by different manufacturers. The PFC controller needs to sample the bus voltage as closed-loop feedback, and the subsequent DCDC controller needs the bus voltage as startup control, input voltage feedforward, etc. However, due to the inconsistency of the bus voltage sampling input impedance, input voltage range, input voltage typical value, etc. of each controller, two sets of sampling circuits are required, and they are not shared with each other, so two independent high-voltage sampling circuits are required, resulting in additional power consumption, increasing PCB area and thus increasing system cost. If a set of sampling voltage divider networks is shared and the lower voltage divider resistor is slightly distinguished, it may be easy to introduce interference due to the requirements of PCB layout, resulting in the lower voltage divider resistor of the sampling circuit being far away from one of the controllers. Summary of the invention

[0004] The main technical problem solved by the embodiments of the present invention is to provide a bus voltage sampling circuit and a power supply system, which can solve some problems existing in the DC bus voltage sampling circuit.

[0005] In order to solve the above technical problems, a technical solution adopted in an embodiment of the present invention is: a bus voltage sampling circuit is provided, including: a high-voltage sampling unit, used to sample the DC bus voltage and output a first voltage signal, and the high-voltage sampling unit is connected to a first controller; a signal conversion unit, the input end of the signal conversion unit is connected to the output end of the high-voltage sampling unit, and is used to convert the first voltage signal into a current signal for output; a signal restoration unit, the input end of the signal restoration unit is connected to the output end of the voltage-controlled current source, the signal restoration unit outputs a second voltage signal in response to the current signal, and the signal restoration unit is also connected to a second controller.

[0006] In some embodiments, the high voltage sampling unit includes a resistor R FB1 and resistor RFB2 , the resistor R FB1 The first end of the DC bus capacitor C BUS The first end of the resistor R FB1 The second end of the resistor R FB2 The first end of the resistor R FB2 The second end of is grounded; wherein the voltage dividing node is connected to the input end of the signal conversion unit and the first controller, and the voltage dividing node outputs the first voltage signal.

[0007] In some embodiments, the signal conversion unit includes a voltage-controlled current source VCCS, the input end of the voltage-controlled current source VCCS is connected to the output end of the high-voltage sampling unit, and the output end of the voltage-controlled current source VCCS is connected to the input end of the signal restoration unit and the second controller; the voltage-controlled current source VCCS is used to output the current signal to the signal restoration unit under the control of the first voltage signal.

[0008] In some embodiments, the signal restoration unit includes a resistor R FB3 , the resistor R FB3 The first end of the resistor R is connected to the output end of the signal conversion unit and the second controller. FB3 The second end of the DC bus capacitor C BUS and the ground terminal of the second controller, the current signal flows through the resistor R FB3 The second voltage signal is generated.

[0009] In some embodiments, the resistor R FB3 The second controller is arranged close to the input terminal.

[0010] In some embodiments, the ground terminal of the first controller is independent of the ground terminal of the second controller.

[0011] In some embodiments, the bus voltage sampling circuit further includes: a current sampling resistor R CS , the current sampling resistor R CS The first controller is arranged in the loop of the DC bus voltage, and the ground terminal of the first controller is connected to the current sampling resistor R CS The first end of the second controller is connected to the ground end and the current sampling resistor R CS The second end of the connection.

[0012] In some embodiments, the first controller uses the first voltage signal as a bus voltage feedback signal, and the second controller uses the second voltage signal as a startup control signal and an input voltage feedforward signal.

[0013] In some embodiments, the first controller is a power factor correction controller, and the second controller is a DCDC controller; or the first controller is a DCDC controller, and the second controller is a power factor correction controller.

[0014] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present invention is: to provide a power supply system, including: a first controller; a second controller; and the bus voltage sampling circuit as described above.

[0015] The beneficial effects of the embodiments of the present invention are as follows: Different from the prior art, the embodiments of the present invention convert the DC bus voltage of the first controller into a current signal and then restore it to a voltage signal, which is input into the second controller, thereby overcoming many mismatch problems between the front-end and rear-end controllers, and completing the sampling of the DC bus voltage with one sampling circuit, thereby avoiding the power consumption, hardware cost and PCB area caused by the additional sampling circuit, and improving the anti-interference ability of the sampling circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a DC bus voltage sampling circuit;

[0017] Figure 2 It is a schematic diagram of another DC bus voltage sampling circuit;

[0018] Figure 3 It is a structural schematic diagram of a bus voltage sampling circuit provided by an embodiment of the present invention;

[0019] Figure 4 It is a schematic diagram of a bus voltage sampling circuit provided by an embodiment of the present invention;

[0020] Figure 5 is a schematic diagram of another bus voltage sampling circuit provided in an embodiment of the present invention;

[0021] Figure 6 It is a structural schematic diagram of a power supply system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on another element or there can be one or more centered elements therebetween. When an element is described as "connected" to another element, it can be directly connected to another element or there can be one or more centered elements therebetween. The orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "bottom" and the like used in this specification is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are used only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0024] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0025] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0026] Figure 1 The schematic diagram of a DC bus voltage sampling circuit is shown, in which the PFC controller and the DCDC controller use two independent DC bus voltage sampling circuits for sampling respectively. This circuit can solve the problem of bus voltage sampling matching between the PFC controller and the DCDC controller, but it adds an extra circuit, which inevitably brings extra power consumption. In addition, R FB1 and R FB2 Generally, multiple high-voltage resistors are connected in series, which requires a certain creepage distance and electrical clearance on the PCB layout, and requires additional PCB area and cost.

[0027] Figure 2 The schematic diagram of another DC bus voltage sampling circuit is shown, in which the PFC controller and the DCDC controller share the upper voltage divider resistor R FB1 , this circuit is compared with Figure 1The circuit shown in the figure can solve the problem of inconsistency between the PFC controller and the DCDC controller in terms of DC bus voltage sampling input impedance, input voltage range, input voltage typical value, etc., without increasing power consumption. However, due to the strict requirements on the power consumption of passive devices, R FB1 Usually it is a very high impedance, and the divided signal is very susceptible to electromagnetic interference in the system, especially when the line is long. Therefore, in the actual PCB design, it is necessary to reduce the voltage divider resistor R FB2 , R FB3 They are set very close to their respective sampling pins to avoid interference with the system, and have high requirements on the layout and wiring of the system.

[0028] In addition, if the PFC controller and the DCDC controller do not share a common ground, the sampling circuit cannot be used.

[0029] In order to solve the problem that the control of the power circuit by the front and rear controllers in an AC / DC power supply system is independent of each other, the internal sampling circuit impedance, input voltage range, typical voltage value, etc. are often not matched, and two sets of bus voltage sampling circuits are required, resulting in redundancy of the sampling circuit, additional power consumption, additional cost of high-voltage voltage divider resistors, additional PCB area due to the increase in creepage distance and electrical clearance requirements, and impedance above MΩ is selected to reduce the loss of the bus voltage sampling circuit. The layout and wiring are easily interfered and affect the working performance due to long lines and weak signals. The embodiment of the present invention provides a bus voltage sampling circuit, and the structural schematic diagram is shown in FIG. Figure 3 As shown, the bus voltage sampling circuit includes a high voltage sampling unit 110 , a signal conversion unit 120 and a signal restoration unit 130 .

[0030] The output end of the high voltage sampling unit 110 is connected to the input end of the first controller 20 and the input end of the signal conversion unit 120 respectively, the output end of the signal conversion unit 120 is connected to the input end of the signal restoration unit 130, and the output end of the signal restoration unit 130 is connected to the input end of the second controller 30.

[0031] Among them, the high-voltage sampling unit 110 is used to sample the DC bus voltage and output a first voltage signal, and the first voltage signal is used as the bus voltage feedback signal of the first controller 20. Specific implementations include but are not limited to: the high-voltage sampling unit 110 is a voltage-dividing circuit including a plurality of sampling resistors, and the plurality of sampling resistors divide the DC bus voltage, and by setting a suitable voltage-dividing ratio, the first voltage signal required by the first controller is output; or a differential operational amplifier is used for high-voltage sampling, and the in-phase input terminal and the inverting input terminal of the differential operational amplifier are respectively connected to the positive and negative ends of the DC bus voltage, and by setting a suitable gain, the DC bus voltage is converted into the first voltage signal required by the first controller, which can effectively suppress common-mode interference; or an integrated sampling chip with built-in isolation function is used, and such chips usually use capacitive isolation or magnetic isolation technology, and provide electrical isolation function while realizing voltage sampling, which can effectively protect the safety of the subsequent circuit.

[0032] In some other embodiments, the high voltage sampling unit 110 may include a temperature compensation network. For example, a thermistor with complementary temperature coefficients and a common resistor may be used to form a voltage divider network, so as to maintain a stable voltage divider ratio within a wide temperature range.

[0033] The signal conversion unit 120 is used to convert the first voltage signal into a current signal for output. Specific implementations include but are not limited to: the signal conversion unit 120 is a voltage-controlled current source, the first voltage signal is used as a control signal of the voltage-controlled current source, so that the voltage-controlled current source outputs a current signal that is positively correlated with the first voltage signal, and has good linearity and temperature stability; or a PWM modulation method is used to convert the first voltage signal into a PWM signal with a fixed frequency and an adjustable duty cycle, and then the PWM signal is converted into a corresponding current signal through an LC filter network, which has high conversion efficiency and is easy to implement digital control; or a Hall current sensor is used to convert the voltage signal into a corresponding magnetic field strength using the Hall effect, and then the magnetic field strength is converted into a current signal through a Hall element, which has good electrical isolation characteristics.

[0034] The signal restoration unit 130 outputs a second voltage signal in response to the current signal, and the second voltage signal serves as a start-up control signal and an input voltage feed-forward signal of the second controller 30. Specific implementations include but are not limited to: the signal restoration unit 130 is a conversion resistor, and by setting the resistance value of the conversion resistor, the current signal flows through the conversion resistor to generate the second voltage signal required by the second controller; or an inverting operational amplifier is used to construct a transimpedance amplifier circuit, and the current signal flows through the feedback resistor to generate a voltage drop. By setting a suitable feedback resistance value, the required second voltage signal can be obtained, and the virtual short characteristic of the operational amplifier can maintain a small input impedance; or an I / V conversion circuit with a filtering function is used, and an RC filtering network is added to the feedback loop to filter out high-frequency interference signals and improve the conversion signal-to-noise ratio. By selecting a suitable RC time constant, a balance can be achieved between the response speed and the filtering effect; or a dedicated I / V conversion chip with an overvoltage protection function is used. This type of chip usually integrates a clamping circuit and an overvoltage protection circuit. When the current signal is abnormal, the output voltage can be limited to a safe range to improve the reliability of the system.

[0035] In the implementation manner of the present application, the first controller 20 is a power factor correction controller, and the second controller 30 is a DCDC controller; or the first controller 20 is a DCDC controller, and the second controller 30 is a power factor correction controller.

[0036] The description of the above implementation modes is exemplary, and those skilled in the art may select a suitable circuit implementation mode according to actual needs, as long as the corresponding signal conversion function can be completed.

[0037] Based on the bus voltage sampling circuit provided in the above-mentioned embodiment, the embodiment of the present invention provides a specific implementation of the bus voltage sampling circuit. The schematic diagram of the bus voltage sampling circuit is as follows: Figure 4 As shown, the high voltage sampling unit 110 includes a resistor R FB1 and resistor R FB2 The signal conversion unit 120 includes a voltage-controlled current source VCCS, and the signal restoration unit 130 includes a resistor R FB3 .

[0038] In this embodiment, the DC bus capacitor C BUS Used to store and stabilize the DC bus voltage. DC bus capacitor C BUS The capacitance needs to be large enough to ensure that the bus voltage can be maintained stable when the grid voltage fluctuates or the load changes suddenly. High-voltage electrolytic capacitors are usually used.

[0039] In the high voltage sampling unit 110, the resistor R FB1 and resistor R FB2 The voltage divider network is composed of resistor R FB1The first end of the DC bus capacitor C BUS The first end is connected to the high voltage stress, so the resistor R FB1 and resistor R FB2 It is usually composed of multiple high-voltage resistors connected in series to disperse the voltage stress on each resistor and meet the creepage distance requirements in PCB layout. FB1 The second end of the resistor R FB2 The first end of the resistor R FB2 The second end of is grounded, the voltage dividing node is connected to the input end of the voltage-controlled current source VCCS and the first controller 20, and the voltage dividing node outputs a first voltage signal. FB1 and resistor R FB2 The resistance ratio determines the voltage division ratio, which needs to be reasonably set according to the range of the bus voltage and the input voltage range of the first controller 20 to ensure that the first voltage signal is within the normal working range of the first controller 20.

[0040] The signal conversion unit 120 uses a voltage-controlled current source VCCS to convert the divided first voltage signal into a current signal proportional to the voltage signal. The input end of the voltage-controlled current source VCCS adopts a high-impedance design to minimize the load effect on the voltage-dividing network, and the output end of the voltage-controlled current source VCCS has a high-impedance current source characteristic so that the transmitted current signal is not easily affected by interference on the transmission line. It is worth noting that if the first controller 20 already includes a voltage-controlled current source with similar functions, the voltage-controlled current source can be directly reused as the signal conversion unit 120 to simplify the circuit structure and save costs.

[0041] The resistor R in the signal recovery unit 130 FB3 It plays the role of current-voltage conversion. The output end of the voltage-controlled current source VCCS is connected to the resistor R FB3 The first end of the resistor R FB3 The second end of the DC bus capacitor C BUS and the ground terminal of the second controller 30. FB3 When the resistor R FB3 A voltage drop is generated between the two ends, namely the second voltage signal. FB3 The resistance value of needs to be set according to the output current range of the voltage-controlled current source VCCS and the input voltage requirement of the second controller 30 to ensure that the generated second voltage signal meets the working requirements of the second controller 30.

[0042] The working principle of the bus voltage sampling circuit is as follows:

[0043] First, the high voltage sampling unit 110 performs step-down sampling on the DC bus voltage. FB1and resistor R FB2 After the voltage is divided, a first voltage signal proportional to the input voltage is obtained, which is directly used as the bus voltage feedback signal of the first controller 20; then, the first voltage signal is sent to the voltage-controlled current source VCCS, and VCCS outputs a current signal proportional to the input voltage according to the magnitude of the input voltage. This voltage-current conversion process has the following advantages: the current signal transmission method has a strong anti-interference ability, the impedance fluctuation of the transmission line has little effect on the signal, and the signal transmission loss is small; finally, the current signal flows through the resistor R FB3 , the resistor R FB3 The voltage drop generated at both ends is used as the second voltage signal, which is used as the start-up control signal and input voltage feedforward signal of the second controller 30. This current-voltage conversion has the following characteristics: the conversion process is simple and reliable, the linearity is good, the temperature stability is good, and the resistance R FB3 It can be arranged near the second controller 30 to reduce wiring interference.

[0044] Different from the prior art, the embodiment of the present invention converts the DC bus voltage of the first controller into a current signal and then restores it to a voltage signal, which is input into the second controller, thereby overcoming many mismatch problems between the front and rear controllers, and completing the sampling of the DC bus voltage with one sampling circuit, which can avoid the power consumption, hardware cost and PCB area caused by the additional sampling circuit, and improve the anti-interference ability of the sampling circuit.

[0045] Furthermore, the embodiment of the present invention provides another specific implementation of a bus voltage sampling circuit, the schematic diagram of the bus voltage sampling circuit is as follows: Figure 5 As shown, the high voltage sampling unit 110 includes a resistor R FB1 and resistor R FB2 The signal conversion unit 120 includes a voltage-controlled current source VCCS, and the signal restoration unit 130 includes a resistor R FB3 The bus voltage sampling circuit also includes a current sampling resistor R CS .

[0046] In this embodiment, the ground terminal of the first controller 20 and the ground terminal of the second controller 30 are independent of each other, that is, the ground terminal of the first controller 20 is connected to the first reference ground GND1, and the ground terminal of the second controller 30 is connected to the second reference ground GND2.

[0047] DC bus capacitor C BUS Used to store and stabilize the DC bus voltage. DC bus capacitor C BUS The capacitance needs to be large enough to ensure that the bus voltage can be maintained stable when the grid voltage fluctuates or the load changes suddenly. High-voltage electrolytic capacitors are usually used.

[0048] In the high voltage sampling unit 110, the resistor RFB1 and resistor R FB2 The voltage divider network is composed of resistor R FB1 The first end of the DC bus capacitor C BUS The first end is connected to the high voltage stress, so the resistor R FB1 and resistor R FB2 It is usually composed of multiple high-voltage resistors connected in series to disperse the voltage stress on each resistor and meet the creepage distance requirements in PCB layout. FB1 The second end of the resistor R FB2 The first end of the resistor R FB2 The second end of is grounded, the voltage division node is connected to the input end of the voltage-controlled current source VCCS and the first controller 20, and the voltage division node outputs a first voltage signal. FB1 and resistor R FB2 The resistance ratio determines the voltage division ratio, which needs to be reasonably set according to the range of the bus voltage and the input voltage range of the first controller 20 to ensure that the first voltage signal is within the normal working range of the first controller 20.

[0049] The signal conversion unit 120 uses a voltage-controlled current source VCCS to convert the divided first voltage signal into a current signal proportional to the voltage signal. The input end of the voltage-controlled current source VCCS adopts a high-impedance design to minimize the load effect on the voltage-dividing network, and the output end of the voltage-controlled current source VCCS has a high-impedance current source characteristic so that the transmitted current signal is not easily affected by interference on the transmission line. It is worth noting that if the first controller 20 already includes a voltage-controlled current source with similar functions, the voltage-controlled current source can be directly reused as the signal conversion unit 120 to simplify the circuit structure and save costs.

[0050] The resistor R in the signal recovery unit 130 FB3 It plays the role of current-voltage conversion. The output end of the voltage-controlled current source VCCS is connected to the resistor R FB3 The first end of the resistor R FB3 The second end of the DC bus capacitor C BUS and the ground terminal of the second controller 30. FB3 When the resistor R FB3 A voltage drop is generated between the two ends, namely the second voltage signal. FB3 The resistance value of needs to be set according to the output current range of the voltage-controlled current source VCCS and the input voltage requirement of the second controller 30 to ensure that the generated second voltage signal meets the working requirements of the second controller 30.

[0051] Current sampling resistor R CSThe first controller 20 is provided in the DC bus voltage loop, and the ground terminal of the first controller 20 is connected to the current sampling resistor R CS The first end is connected to the ground end of the second controller 30 and the current sampling resistor R CS The second end of the connection.

[0052] In some embodiments, the first controller 20 needs to use a current sampling resistor R CS Sampling bus capacitance C BUS The current signal in the loop, therefore, there is a certain voltage difference between the reference ground GND1 of the first controller 20 and the GND2 of the second controller 30; but the signal sampled by the second controller 30 is the current signal flowing through the resistor R FB3 Therefore, the bus voltage sampling circuit is still applicable when the first controller 20 and the second controller 30 do not share a common ground.

[0053] The working principle of the bus voltage sampling circuit is as follows:

[0054] First, the high voltage sampling unit 110 performs step-down sampling on the DC bus voltage. FB1 and resistor R FB2 After the voltage is divided, a first voltage signal proportional to the input voltage is obtained, which is directly used as the bus voltage feedback signal of the first controller 20; then, the first voltage signal is sent to the voltage-controlled current source VCCS, and VCCS outputs a current signal proportional to the input voltage according to the magnitude of the input voltage. This voltage-current conversion process has the following advantages: the current signal transmission method has a strong anti-interference ability, the impedance fluctuation of the transmission line has little effect on the signal, and the signal transmission loss is small; finally, the current signal flows through the resistor R FB3 , the resistor R FB3 The voltage drop generated at both ends is used as the second voltage signal, which is used as the start-up control signal and input voltage feedforward signal of the second controller 30. This current-voltage conversion has the following characteristics: the conversion process is simple and reliable, the linearity is good, the temperature stability is good, and the resistance R FB3 It can be arranged near the second controller 30 to reduce wiring interference.

[0055] Different from the prior art, the implementation mode of the present invention converts the DC bus voltage of the first controller into a current signal and then restores it to a voltage signal, which is input into the second controller, thereby overcoming many mismatch problems between the front-end and rear-end controllers, and completing the sampling of the DC bus voltage with one sampling circuit. This can avoid the power consumption, hardware cost and PCB area caused by the additional sampling circuit, and improve the anti-interference ability of the sampling circuit. At the same time, it is suitable for scenarios where the first controller and the second controller do not share a common ground.

[0056] Based on the bus voltage sampling circuit provided in the above embodiment, the embodiment of the present invention provides a power supply system, and its structural diagram is as follows: Figure 6 As shown, the power supply system includes a bus voltage sampling circuit 10, a first controller 20 and a second controller 30 as provided in any of the above embodiments, wherein the first controller 20 is connected to the bus voltage sampling circuit 10, and the bus voltage sampling circuit 10 is connected to the second controller 30.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A bus voltage sampling circuit, characterized in that: include: A high-voltage sampling unit, used for sampling the DC bus voltage and outputting a first voltage signal, wherein the high-voltage sampling unit is connected to the first controller; A signal conversion unit, the input end of which is connected to the output end of the high-voltage sampling unit, and is used to convert the first voltage signal into a current signal for output; A signal restoration unit, wherein the input end of the signal restoration unit is connected to the output end of the voltage-controlled current source, the signal restoration unit outputs a second voltage signal in response to the current signal, and the signal restoration unit is also connected to a second controller.

2. The circuit according to claim 1, characterized in that The high voltage sampling unit includes a resistor R FB1 and resistor R FB2 , The resistor R FB1 The first end of the DC bus capacitor C BUS The first end of the resistor R FB1 The second end of the resistor R FB2 The first end of the resistor R FB2 The second end of is grounded; The voltage dividing node is connected to the input end of the signal conversion unit and the first controller, and the voltage dividing node outputs the first voltage signal.

3. The circuit according to claim 1, characterized in that The signal conversion unit includes a voltage-controlled current source VCCS, the input end of the voltage-controlled current source VCCS is connected to the output end of the high-voltage sampling unit, and the output end of the voltage-controlled current source VCCS is connected to the input end of the signal restoration unit and the second controller; The voltage-controlled current source VCCS is used to output the current signal to the signal restoration unit under the control of the first voltage signal.

4. The circuit according to claim 1, characterized in that The signal restoration unit includes a resistor R FB3 , the resistor R FB3 The first end of the resistor R is connected to the output end of the signal conversion unit and the second controller. FB3 The second end of the DC bus capacitor C BUS and the ground terminal of the second controller, the current signal flows through the resistor R FB3 The second voltage signal is generated.

5. The circuit according to claim 4, characterized in that The resistor R FB3 The second controller is arranged close to the input terminal.

6. The circuit according to claim 1, characterized in that The ground terminal of the first controller is independent of the ground terminal of the second controller.

7. The circuit according to claim 6, characterized in that Also includes: Current sampling resistor R CS , the current sampling resistor R CS The first controller is arranged in the loop of the DC bus voltage, and the ground terminal of the first controller is connected to the current sampling resistor R CS The first end of the second controller is connected to the ground end and the current sampling resistor R CS The second end of the connection.

8. The circuit according to claim 1, characterized in that The first controller uses the first voltage signal as a bus voltage feedback signal, and the second controller uses the second voltage signal as a startup control signal and an input voltage feedforward signal.

9. The circuit according to claim 1, characterized in that The first controller is a power factor correction controller, and the second controller is a DCDC controller; or The first controller is a DCDC controller, and the second controller is a power factor correction controller.

10. A power supply system, characterized in that: include: a first controller; A second controller; A bus voltage sampling circuit as described in any one of claims 1 to 9.

Images