Expansion power supply to adapt to multipath BDU voltage sampling circuit

Abstract

The utility model discloses an expansion power supply to adapt to a multipath BDU voltage sampling circuit, comprising a flyback unit used for obtaining an alternating current, converting the alternating current into a direct current power supply and outputting the direct current power supply; the voltage adjusting unit is used for filtering and stabilizing the output direct-current voltage and then outputting a direct-current power supply; and the DCDC power supply unit is used for obtaining an output DC power supply for power supply. According to the expansion power supply, the area of a single PCB (Printed Circuit Board) and the volume of a transformer are effectively reduced by adapting to a multi-path BDU voltage sampling circuit, meanwhile, the use amount of devices is reduced, and the problem that multi-path negative sampling needs a plurality of non-common-ground power supplies is solved in a low-cost manner.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of BDU, specifically relates to an extended power supply to adapt to multichannel BDU voltage sampling circuit. BACKGROUND

[0002] One of the current mainstream DC high voltage system voltage sampling schemes is that resistance divides the high voltage positive and high voltage negative to input the operational amplifier for amplification, and then inputs the operational amplifier to DSP for processing after light coupling isolation. The power supply negative and high voltage negative of the operational amplifier are not the same potential in this scheme, and there is high voltage input in part of the circuit and no high voltage input in another part of the circuit. Due to resistance division, the power supply negative potential of the operational amplifier will be offset relative to the high voltage negative, resulting in that the sampling end without high voltage input still has output voltage, which leads to that the sampling end that should display no high voltage displays high voltage. In some extreme environments, the voltage can reach a high value, so as to affect the judgment of the controller.

[0003] In order to avoid this situation, another sampling method can be used. That is, direct resistance division is first carried out, and then light coupling isolation is carried out, and the operational amplifier sends the signal to DSP for processing after enhancing the signal quality. This sampling method can completely avoid the error of the voltage value displayed by sampling, but this sampling method needs to provide multiple low voltage power supplies with different grounds when multiple negative sampling is carried out. SUMMARY

[0004] The utility model discloses a kind of extended power supply to adapt to multichannel BDU voltage sampling circuit.

[0005] To achieve the above object, the utility model provides the following technical scheme: an extended power supply to adapt to multichannel BDU voltage sampling circuit, comprising:

[0006] Flyback unit for obtaining AC and converting into DC power supply and outputting;

[0007] Voltage adjustment unit for filtering and stabilizing the output DC voltage and outputting DC power supply; and

[0008] DCDC power supply unit for obtaining output DC power supply for power supply.

[0009] Further, the flyback unit includes:

[0010] Flyback drive circuit for generating drive signal for turning on and off MOS tube Q37;

[0011] MOS tube Q37 for generating AC after receiving drive signal; and

[0012] The transformer T1 is used to obtain alternating current and generate alternating current on multiple output windings, which is converted into a direct current power source after rectification by the output end and output.

[0013] Further, the flyback driving circuit comprises a PWM chip U22, resistors R363 and R119, and a capacitor C214, one end of the PWM chip U22 is connected to one end of the resistor R363, the other end of the resistor R363 is connected to the parallel resistor R119 and the capacitor C214.

[0014] Further, the flyback unit further comprises:

[0015] A current feedback circuit is configured to determine the size of the current signal fed back to the flyback driving circuit, adjust the current limiting value of the power supply, and output to the flyback driving circuit. The current feedback circuit comprises resistors R364 and R304, and a capacitor C143. One end of the capacitor C143 is connected to R304 and then connected to the flyback driving circuit. One end of the resistor R364 is connected to the other end of the capacitor C143, and the other end of the resistor R364 is connected to the flyback driving circuit.

[0016] A voltage feedback circuit is configured to divide the output voltage of the flyback unit. When the output voltage changes, the flyback unit adjusts the flyback driving circuit in time. The voltage feedback circuit comprises resistors R382 and R120, and a capacitor C215. The R120 and the capacitor C215 are connected in parallel and then connected to the resistor R382.

[0017] Further, the flyback unit further comprises a filter circuit, which is configured to obtain a power supply voltage for voltage stabilization processing. The filter circuit comprises capacitors C235, C233, and C103. One end of the capacitors C235, C233, and C103 is connected and then connected to the flyback driving circuit.

[0018] Further, the flyback unit further comprises an RCD absorption circuit, which is configured to absorb the resonant voltage generated by the leakage inductance of the primary winding of the transformer and the parasitic capacitance of the MOS tube Q37. The RCD absorption circuit comprises a diode D80, a resistor R369, and a capacitor C225. The resistor R369 and the capacitor C225 are connected in parallel and then connected to the negative electrode of the diode D80. The positive electrode of the diode D80 is connected to the MOS tube Q37.

[0019] Further, the voltage adjustment unit comprises a voltage adjustment chip U28, a filter capacitor C240, and a filter capacitor C238. The input filter capacitor C240 is connected to the input end of the voltage adjustment chip U28. The filter capacitor C238 is connected to the output of the voltage adjustment chip U28.

[0020] Further, the DCDC power supply unit comprises a DCDC power supply PW1, a filter capacitor C44 connected with an input end of the DCDC power supply PW1, and a filter capacitor C105 connected with an output end of the DCDC power supply PW1.

[0021] From the above technical solution, the utility model has the following beneficial effects:

[0022] The expansion power supply is adapted to the multi-channel BDU voltage sampling circuit, and a plurality of non-common low-voltage power supplies are obtained through isolation conversion of the flyback unit. Since the power supply ripple of the transformer T1 output is relatively large, the low-voltage power supply cannot be directly used for power supply of each chip, and therefore a voltage adjustment unit needs to be connected, and a stable low-voltage power supply is provided for each chip through voltage conversion and stabilization of the voltage adjustment unit. In general, the above circuit can meet the sampling demand of the basic project with less negative sampling.

[0023] In the special case of more negative sampling, the DCDC power supply expansion mode used in the scheme can increase a plurality of non-common power supplies with a small PCB area consumption, so as to be used for isolation optocouplers for voltage sampling. A plurality of DCDC power supply modules directly take power from the output end of the single-channel voltage regulator, and only need to use filter capacitors and DCDC modules to complete power supply of a plurality of different isolation optocouplers.

[0024] The scheme effectively reduces the PCB single-board area and the volume of the transformer, and at the same time, reduces the use amount of devices, and solves the problem of multiple non-common power supplies required by multi-channel negative sampling in a low-cost manner. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 It is a flyback unit circuit diagram of the utility model;

[0026] Fig. 2 It is a voltage adjustment unit circuit diagram of the utility model;

[0027] Fig. 3 It is a DCDC power supply unit circuit diagram of the utility model. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0029] For example, Figs. 1-3The utility model provides a kind of extended power supply to adapt multiple BDU voltage sampling circuit, including flyback unit, voltage adjustment unit and DCDC power unit, flyback unit includes flyback drive circuit, MOS tube Q37 and transformer T1, the flyback drive circuit includes PWM chip U22, resistance R363, R119, capacitor C214, one end of the PWM chip U22 is connected with one end of resistance R363, the other end of the resistance R363 is connected the gate of MOS tube Q37 by parallel resistance R119, capacitor C214, the drain of MOS tube Q37 is accessed the input end of transformer T1, the input end of transformer T1 is accessed chip U4, U28, U3 is what. The core of flyback drive circuit is PWM chip U22, by U22 to send drive signal, after drive signal transmission to MOS tube Q37 on the peripheral circuit of R363, R119, C214, the opening and closing of MOS tube are controlled by drive signal, to control the operation of entire flyback power supply circuit. Transformer T1 accepts the alternating current generated by the switch of MOS tube Q37 to generate alternating current on multiple output windings, and becomes direct-current power supply after rectification by the diode and capacitor connected to the output end; transformer stores energy when MOS Q37 is turned on, and releases energy when MOS Q37 is turned off. Reasonable setting transformer parameter can realize the effect of single power input and multiple power output.

[0030] Flyback unit also includes current feedback circuit and voltage feedback loop, current feedback circuit includes resistance R364, R304, capacitor C143, one end of the capacitor C143 is connected with R304 and then accessed flyback drive circuit, one end of resistance R364 is connected with the other end of capacitor C143, and the other end of resistance R364 is accessed flyback drive circuit, the current feedback circuit determines the current signal size fed back to the control chip by the voltage division formula of U=IR, and controls the current limiting value of flyback power supply by adjusting the size of R364, the voltage feedback loop includes resistance R382, R120, capacitor C215, R120 and capacitor C215 are connected in parallel and then accessed resistance R382, the voltage feedback loop directly divides the output voltage of flyback unit by resistance, and adjusts the PWM chip in time when the output voltage changes.

[0031] Flyback unit also includes filter circuit, filter circuit obtains power voltage and carries out voltage stabilizing treatment, the filter circuit includes capacitor C235, C233, C103, one end of the capacitor C235, C233, C103 is connected and then accessed flyback drive circuit, the stability of flyback unit input voltage is maintained by the filter effect of capacitor C235, C233, C103, guarantee the normal operation of overall circuit.

[0032] The flyback unit further comprises an RCD absorption circuit, which comprises a diode D80, a resistor R369, and a capacitor C225. The resistor R369 and the capacitor C225 are connected in parallel and then connected to the negative electrode of the diode D80. The positive electrode of the diode D80 is connected to the MOS tube Q37. The RCD absorption circuit is mainly used to absorb the resonance voltage generated by the leakage inductance of the primary winding and the parasitic capacitance of the MOS tube. If the resonance voltage is too high, the MOS tube will be damaged by overvoltage or the service life of the MOS tube will be reduced. Selecting appropriate device combinations can significantly reduce the impact of the resonance voltage on the MOS tube, while optimizing the EMI of the flyback unit.

[0033] The voltage adjustment unit comprises a voltage adjustment chip U28, a filter capacitor C240, and a filter capacitor C238. The filter capacitor C240 is connected to the input end of the voltage adjustment chip U28, and the filter capacitor C238 is connected to the output of the voltage adjustment chip U28. Since the output ripple of the flyback unit is large for the power supply of the chip, the voltage adjustment unit is further needed to output a DC power supply with smaller ripple and more stable voltage after the flyback unit outputs the DC voltage. The DC output by the flyback unit is first filtered by the filter capacitor C240 and then input to the voltage adjustment chip. After voltage conversion by the voltage adjustment chip and filtering by the filter capacitor C238, a stable DC power supply is obtained. This power supply is mainly used for the power supply of various chips, including the optocoupler chip necessary for high-voltage DC voltage sampling.

[0034] The DCDC power supply unit comprises a DCDC power supply PW1, a filter capacitor C44, and a filter capacitor C105. The filter capacitor C44 is connected to the input end of the DCDC power supply PW1, and the filter capacitor C105 is connected to the output end of the DCDC power supply PW1. When the number of negative sampling requirements is large, the number of optocouplers powered by different power grounds will increase. To meet the design requirements of different power grounds, additional transformer windings and matching voltage regulator circuits can be added, but this approach requires a larger transformer and occupies more PCB area. When the PCB single board area is limited, the DCDC power supply unit is needed to provide low-voltage power supplies with different grounds while occupying a smaller PCB area.

[0035] The input of the DCDC power supply unit directly uses the output DC power supply of the voltage regulator unit after filtering by the filter capacitor C44, without the need for additional transformer windings, avoiding the problem of increased PCB area caused by additional transformer windings. After isolation conversion output by the DCDC power supply module, a low-voltage output power supply with a different ground is obtained, which can be provided to the isolation optocoupler required for sampling after filtering by the output filter capacitor C105. Since only one isolation optocoupler is powered, a very small power package can be selected for the DCDC power supply module, without worrying about the load exceeding the power of the voltage regulator providing the input power.

[0036] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. An extended power supply to accommodate a multiplexed BDU voltage sampling circuit, characterized by, The application relates to a power supply device, which comprises the following units: a flyback unit for obtaining AC power and converting the AC power into DC power and outputting the DC power; a voltage adjustment unit for filtering and stabilizing the output DC voltage and outputting the DC power; and a DC-DC power supply unit for obtaining the output DC power and supplying power.

2. The switching power supply circuit with over-temperature protection according to claim 1, characterized in that: The flyback unit comprises: a flyback drive circuit for generating a drive signal for turning on and off a MOS tube Q37; the MOS tube Q37 for generating AC power after receiving the drive signal; and a transformer T1 for obtaining the AC power and generating AC power on multiple output windings, converting the AC power into DC power through rectification of the output end, and outputting the DC power.

3. An extended power supply to adapt voltage sampling circuit for cable BDU according to claim 1, characterized in that: The flyback drive circuit comprises a PWM chip U22, resistors R363 and R119, and a capacitor C214, one end of the PWM chip U22 is connected with one end of the resistor R363, the other end of the resistor R363 is connected with the resistors R119 and the capacitor C214 in parallel.

4. The extended power supply to adapt multi-path BDU voltage sampling circuit according to claim 2, characterized in that: The flyback unit further comprises: a current feedback circuit for determining the current signal size fed back to the flyback drive circuit, adjusting the current limiting value of the power supply, and outputting the current limiting value to the flyback drive circuit, the current feedback circuit comprises resistors R364 and R304 and a capacitor C143, one end of the capacitor C143 is connected with the resistor R304 and then connected to the flyback drive circuit, one end of the resistor R364 is connected with the other end of the capacitor C143, and the other end of the resistor R364 is connected to the flyback drive circuit; a voltage feedback circuit for dividing the output voltage of the flyback unit, and adjusting the flyback drive circuit in time through the flyback unit when the output voltage changes, the voltage feedback circuit comprises resistors R382 and R120 and a capacitor C215, the resistor R120 and the capacitor C215 are connected in parallel and then connected to the resistor R382.

5. The extended power supply to fit multi-channel BDU voltage sampling circuit according to claim 2, characterized in that: The flyback unit further comprises a filter circuit, the filter circuit is used for stabilizing the power voltage, and the filter circuit comprises capacitors C235, C233 and C103, one end of the capacitors C235, C233 and C103 is connected and then connected to the flyback drive circuit.

6. The extended power supply to adapt multi-path BDU voltage sampling circuit according to claim 2, characterized in that: The flyback unit further comprises an RCD absorption circuit, the RCD absorption circuit is used for absorbing the resonance voltage generated by the leakage inductance of the primary winding of the transformer and the parasitic capacitance of the MOS tube Q37, and the RCD absorption circuit comprises a diode D80, a resistor R369 and a capacitor C225, the resistor R369 and the capacitor C225 are connected in parallel and then connected to the negative electrode of the diode D80, and the positive electrode of the diode D80 is connected to the MOS tube Q37.

7. The extended power supply to fit multi-channel BDU voltage sampling circuit according to claim 1, characterized in that: The voltage adjustment unit comprises a voltage adjustment chip U28, a filter capacitor C240 and a filter capacitor C238, the input filter capacitor C240 is connected with the input end of the voltage adjustment chip U28, and the filter capacitor C238 is connected with the output of the voltage adjustment chip U28.

8. The extended power supply to adapt multi-path BDU voltage sampling circuit according to claim 1, wherein: The DC-DC power supply unit comprises a DC-DC power supply PW1, a filter capacitor C44 and a filter capacitor C105, the filter capacitor C44 is connected with the input end of the DC-DC power supply PW1, and the filter capacitor C105 is connected with the output end of the DC-DC power supply PW1.

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