Flyback switching power supply voltage monitoring circuit

Abstract

The utility model discloses a flyback switching power supply voltage monitoring circuit, which relates to the field of power supplies and comprises a power supply module used for converting alternating current into direct current and supplying the direct current to a flyback switching power supply module; the stable voltage supply module is used for generating stable voltage and supplying the stable voltage to an electric load; the sampling output module is used for sampling the output voltage of the stable voltage supply module to obtain a sampling voltage and outputting the sampling voltage to the MCU; the pull-up positive voltage module is used for providing a positive voltage for the sampling output module, so that the sampling negative voltage is changed into a sampling positive voltage; compared with the prior art, the utility model has the beneficial effects that the bus voltage is monitored by ingeniously utilizing the conduction period of the flyback switching power supply switching tube, the bus voltage can be monitored very efficiently without adding an additional winding to the transformer, and the sampling through optocoupler isolation is not needed any more; sampling is not affected by discreteness and temperature excursion of the optocoupler.

Description

TECHNICAL FIELD

[0001] The utility model relates to power supply field, concretely is a flyback switching power supply voltage monitoring circuit. BACKGROUND

[0002] In our life, power grid fluctuation, if cannot monitor in time, power supply is too high and too low can cause some influence to product, light can influence the normal operation of product, serious can lead to product damage, therefore need to monitor the fluctuation of input voltage, when voltage exceeds product application range, handle in time, currently commonly used is that non-isolated ADC special chip samples bus voltage, then through opto-coupler transmission to the data non-isolated side microprocessor MCU, or directly uses linear isolation opto-coupler to transmit, but the discreteness and temperature drift of opto-coupler can lead to voltage sampling inaccuracy, need improvement. UTILITY MODEL CONTENTS

[0003] The utility model discloses a flyback switching power supply voltage monitoring circuit to solve the problem in the background art.

[0004] To achieve the above object, the utility model provides the following technical scheme:

[0005] A flyback switching power supply voltage monitoring circuit, comprising:

[0006] The power supply module is used for converting alternating current into direct current to supply the flyback switching power supply module.

[0007] The stable voltage supply module is used for generating stable voltage to supply the power consumption load.

[0008] The sampling output module is used for sampling the output voltage of the stable voltage supply module to obtain the sampling voltage and output to the MCU.

[0009] The pull-up positive voltage module is used for providing a positive voltage for the sampling output module to make the sampling negative voltage become the sampling positive voltage.

[0010] The power supply module is connected with the stable voltage supply module, the stable voltage supply module is connected with the sampling output module and the pull-up positive voltage module, and the pull-up positive voltage module is connected with the sampling output module.

[0011] As a further scheme of the utility model: the stable voltage supply module includes transformer T1, chip IC2, MOS tube M1, chip IC2 is flyback power supply chip, the first end of transformer T1 connects one end of capacitor C4, one end of resistance R7, one end of resistance R5, power module, the third end of transformer T1 connects the positive pole of diode D3, the D pole of MOS tube M1, one end of resistance R11, one end of resistance R6 connects the negative pole of diode D3, the other end of resistance R6 connects the other end of capacitor C4, the other end of resistance R7, one end of resistance R11 connects one end of capacitor C6, the other end of capacitor C6 connects the S pole of MOS tube M1, one end of resistance R19, one end of resistance R19 connects circuit negative pole, the G pole of MOS tube M1 connects one end of resistance R14, the other end of resistance R14 connects the 6th pin of chip IC2, the other end of resistance R5 connects the 5th pin of chip IC2 through resistance R8, the sixth end of transformer T1 is grounded, the eighth end of transformer T1 connects sampling output module, pull-up positive voltage module.

[0012] As a further scheme of the utility model: the stable voltage supply module further includes voltage regulator U1, optocoupler IC3, voltage regulator U1 is 431 precision voltage regulator chip, the C end of optocoupler IC3 connects the 2nd pin of chip IC2 through resistance R18, the E end of optocoupler IC3 connects circuit negative pole, the K pole of optocoupler IC3 connects the negative pole of voltage regulator U1, one end of resistance R16, one end of capacitor C8, the positive pole of voltage regulator U1 is grounded, the reference pole of voltage regulator U1 connects one end of resistance R21, one end of resistance R20, one end of resistance R13, the other end of resistance R21 is grounded, the other end of resistance R20 connects the other end of capacitor C8, the other end of resistance R16 connects one end of resistance R12, the A end of optocoupler IC3, the other end of resistance R12 connects the other end of resistance R13, one end of capacitor E2, the negative pole of diode D2, the other end of capacitor E2 is grounded, the positive pole of diode D2 connects the eighth end of transformer T1.

[0013] As a further scheme of the utility model: the sampling output module includes diode D1, resistance R2, capacitor C2, resistance R1, capacitor C1, resistance R22, the negative pole of diode D1 connects stable voltage supply module, the positive pole of diode D1 connects one end of resistance R2, the other end of resistance R2 connects one end of capacitor C2, one end of resistance R1, the other end of capacitor C2 is grounded, the other end of resistance R1 connects pull-up positive voltage module, one end of capacitor C1, one end of resistance R22, MCU, the other end of resistance R22 is grounded, the other end of capacitor C1 is grounded.

[0014] As a further scheme of the utility model: the upper pull positive voltage module includes voltage stabilizing chip IC1, the input end of voltage stabilizing chip IC1 is connected with the stable voltage supply module, the grounding end of voltage stabilifying chip IC1 is grounded, and one end of resistance R3 is connected with the output end of voltage stabilizing chip IC1, and the other end of resistance R3 is connected with the sampling output module.

[0015] Compared with the prior art, the utility model has the beneficial effects that: the utility model ingeniously utilizes the switch tube conduction period of the flyback switching power supply to monitor the bus voltage, can very efficiently monitor the bus voltage without additional winding of the transformer, and no longer samples through the optical coupling isolation, and the sampling is not affected by the optical coupling discreteness and temperature drift. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a circuit diagram of a flyback switching power supply voltage monitoring circuit. DETAILED DESCRIPTION

[0017] 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 of 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.

[0018] Please refer to Figure 1 A flyback switching power supply voltage monitoring circuit comprises:

[0019] The power supply module is used for converting alternating current into direct current to supply the flyback switching power supply module.

[0020] The stable voltage supply module is used for generating stable voltage to supply the electric load.

[0021] The sampling output module is used for sampling the output voltage of the stable voltage supply module to obtain a sampling voltage and output the sampling voltage to the MCU.

[0022] The upper pull positive voltage module is used for providing a positive voltage for the sampling output module, so that the sampling negative voltage becomes a sampling positive voltage.

[0023] The power supply module is connected with the stable voltage supply module, the stable voltage supply module is connected with the sampling output module and the upper pull positive voltage module, and the upper pull positive voltage module is connected with the sampling output module.

[0024] In specific embodiments, the power supply module and the stable voltage supply module jointly constitute the flyback switching power supply, and the flyback switching power supply has various structures. Here, the specific structure of Figure 1 is taken as an example for illustration, and actually, the limitation on the flyback switching power supply is not limited toFigure 1 The structure is shown.

[0025] In the power supply module, the input AC power is subjected to EMC filtering, and then AC-DC conversion is completed by the rectifier DB1, and is subjected to filtering processing by the capacitor E1, and is changed into DC power, and is output to the stable voltage supply module.

[0026] In the present embodiment, please refer to Figure 1 The stable voltage supply module includes the transformer T1, the chip IC2, and the MOS tube M1. The chip IC2 is a flyback power supply chip (for example, OB2365PCP, KP3116SGA, etc., not limited to these brands and models). The first end of the transformer T1 is connected to one end of the capacitor C4, one end of the resistor R7, one end of the resistor R5, and the power supply module. The third end of the transformer T1 is connected to the anode of the diode D3, the D pole of the MOS tube M1, and one end of the resistor R11. The cathode of the diode D3 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to the other end of the capacitor C4 and the other end of the resistor R7. The other end of the resistor R11 is connected to one end of the capacitor C6. The other end of the capacitor C6 is connected to the S pole of the MOS tube M1 and one end of the resistor R19. The other end of the resistor R19 is connected to the circuit negative pole. The G pole of the MOS tube M1 is connected to one end of the resistor R14. The other end of the resistor R14 is connected to the No. 6 pin of the chip IC2. The other end of the resistor R5 is connected to the No. 5 pin of the chip IC2 through the resistor R8. The sixth end of the transformer T1 is grounded. The eighth end of the transformer T1 is connected to the sampling output module and the pull-up positive voltage module.

[0027] The input DC power supplies power to the chip IC2 through the resistors R5 and R8. The No. 6 pin of the chip IC2 controls the conduction of the MOS tube M1 based on the output level. When the MOS tube M1 is turned on, the first end and the third end of the transformer T1 are coupled to the eighth end and the sixth end of the transformer T1, and the voltage of the first end is positive and the voltage of the third end is negative.

[0028] When the MOS tube M1 is turned off, the first end and the third end of the transformer T1 are coupled to the eighth end and the sixth end of the transformer T1, and the voltage of the first end is negative and the voltage of the third end is positive.

[0029] In the present embodiment, please refer to Figure 1The stable voltage supply module further comprises a voltage stabilizer U1 and an optocoupler IC3, the voltage stabilizer U1 is a 431 precision voltage stabilizer chip, the C terminal of the optocoupler IC3 is connected to the No. 2 pin of the chip IC2 through a resistor R18, the E terminal of the optocoupler IC3 is connected to the negative pole of the circuit, the K terminal of the optocoupler IC3 is connected to the negative pole of the voltage stabilizer U1, one end of a resistor R16 and one end of a capacitor C8, the positive pole of the voltage stabilizer U1 is grounded, the reference pole of the voltage stabilizer U1 is connected to one end of a resistor R21, one end of a resistor R20 and one end of a resistor R13, the other end of the resistor R21 is grounded, the other end of the resistor R20 is connected to the other end of the capacitor C8, the other end of the resistor R16 is connected to one end of a resistor R12 and the A terminal of the optocoupler IC3, the other end of the resistor R12 is connected to the other end of the resistor R13, one end of a capacitor E2, the negative pole of a diode D2, the other end of the capacitor E2 is grounded, and the positive pole of the diode D2 is connected to the eighth terminal of the transformer T1.

[0030] When the eighth terminal of the transformer T1 is a positive voltage and the sixth terminal is a negative voltage, the output voltage VCC after rectification by the diode D2 and filtering by the capacitor E2 is supplied to the electric load, and at the same time, the output voltage VCC is supplied to the pull-up positive voltage module. The reference pole of the voltage stabilizer U1 samples the output voltage VCC to feed back the voltage signal to the K terminal of the optocoupler IC3, change the current flowing through the light-emitting diode inside the optocoupler IC3, and finally feed back to the No. 2 pin of the chip IC2 through the photosensitive triode inside the optocoupler IC3. The No. 2 pin of the chip IC2 receives the feedback voltage to adjust the conduction state of the MOS tube M1, so as to realize the stable output of the output voltage VCC.

[0031] In the embodiment, please refer to Figure 1 The sampling output module comprises a diode D1, a resistor R2, a capacitor C2, a resistor R1, a capacitor C1 and a resistor R22, the negative pole of the diode D1 is connected to the stable voltage supply module, the positive pole of the diode D1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C2 and one end of the resistor R1, the other end of the capacitor C2 is grounded, the other end of the resistor R1 is connected to the pull-up positive voltage module, one end of the capacitor C1, one end of the resistor R22 and the MCU, the other end of the resistor R22 is grounded, and the other end of the capacitor C1 is grounded.

[0032] When the eighth terminal of transformer T1 is at a negative voltage and the sixth terminal is at a positive voltage, the positive voltage at the sixth terminal of high-frequency transformer T1 flows to the negative electrode (the eighth terminal of high-frequency transformer T1) through resistor R22, resistor R1, resistor R2, and diode D1. Since the voltage sampling point AC-V is a negative voltage relative to the reference ground of the isolation terminal, a positive voltage pull-up module is used to pull up the voltage sampling point AC-V to a positive voltage, converting the voltage of AC-V to a positive voltage. The microprocessor MCU monitors the voltage at this point in real time. This cleverly completes AC voltage monitoring. The AC voltage is fed back to V-BUS, which is coupled to AC-V through transformer T1, and AC-V is output to the microprocessor MCU.

[0033] In this example: See Figure 1 The pull-up positive voltage module includes a voltage regulator chip IC1, the input end of the voltage regulator chip IC1 is connected to the stable voltage supply module, the ground end of the voltage regulator chip IC1 is grounded, the output end of the voltage regulator chip IC1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the sampling output module.

[0034] The voltage regulator chip IC1 is a common three-terminal voltage regulator that outputs a positive voltage to supply the sampling output module.

[0035] The working principle of the utility model is as follows: the power supply module is used to convert AC power into DC power and supply it to the flyback switching power supply module; the stable voltage supply module is used to generate a stable voltage and supply it to the power load; the sampling output module is used to sample the output voltage of the stable voltage supply module, obtain the sampled voltage, and output it to the MCU; the pull-up positive voltage module is used to provide a positive voltage for the sampling output module, so that the sampled negative voltage becomes a sampled positive voltage.

[0036] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive.

[0037] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A flyback switching power supply voltage monitoring circuit, characterized in that: The flyback switching power supply voltage monitoring circuit includes: A power supply module is used to convert AC power into DC power to supply the flyback switching power supply module; A stable voltage supply module is used to generate a stable voltage to supply the electrical load; The sampling output module is used to sample the output voltage of the stable voltage supply module, obtain the sampled voltage, and output it to the MCU; The pull-up positive voltage module is used to provide a positive voltage for the sampling output module, so that the sampled negative voltage becomes a sampled positive voltage; The power supply module is connected to the stable voltage supply module, the stable voltage supply module is connected to the sampling output module and the pull-up positive voltage module, and the pull-up positive voltage module is connected to the sampling output module.

2. The flyback switching power supply voltage monitoring circuit according to claim 1, wherein: The stable voltage supply module includes a transformer T1, a chip IC2, and a MOS transistor M1. The chip IC2 is a flyback power supply chip. The first end of the transformer T1 is connected to one end of the capacitor C4, one end of the resistor R7, one end of the resistor R5, and the power supply module. The third end of the transformer T1 is connected to the positive electrode of the diode D3, the D electrode of the MOS transistor M1, and one end of the resistor R11. The negative electrode of the diode D3 is connected to one end of the resistor R6. The other end of the resistor R6 is connected to the other end of the capacitor C4 and the other end of the resistor R7. The other end of the resistor R11 is connected to one end of the capacitor C6. The other end of the capacitor C6 is connected to the S electrode of the MOS transistor M1 and one end of the resistor R19. The other end of the resistor R19 is connected to the negative electrode of the circuit. The G electrode of the MOS transistor M1 is connected to one end of the resistor R14. The other end of the resistor R14 is connected to pin 6 of the chip IC2. The other end of the resistor R5 is connected to pin 5 of the chip IC2 through the resistor R8. The sixth end of the transformer T1 is grounded. The eighth end of the transformer T1 is connected to the sampling output module and the pull-up positive voltage module.

3. The flyback switching power supply voltage monitoring circuit according to claim 2, wherein: The stable voltage supply module also includes a voltage regulator U1 and an optocoupler IC3. The voltage regulator U1 is a 431 precision voltage regulator chip. The C end of the optocoupler IC3 is connected to pin 2 of the chip IC2 through a resistor R18. The E end of the optocoupler IC3 is connected to the negative pole of the circuit. The K pole of the optocoupler IC3 is connected to the negative pole of the voltage regulator U1, one end of the resistor R16, and one end of the capacitor C8. The positive pole of the voltage regulator U1 is grounded. The reference pole of the voltage regulator U1 is connected to one end of the resistor R21, one end of the resistor R20, and one end of the resistor R13. The other end of the resistor R21 is grounded. The other end of the resistor R20 is connected to the other end of the capacitor C8. The other end of the resistor R16 is connected to one end of the resistor R12 and the A end of the optocoupler IC3. The other end of the resistor R12 is connected to the other end of the resistor R13, one end of the capacitor E2, and the negative pole of the diode D2. The other end of the capacitor E2 is grounded. The positive pole of the diode D2 is connected to the eighth end of the transformer T1.

4. The flyback switching power supply voltage monitoring circuit according to any one of claims 1 to 3, characterized in that: The sampling output module includes a diode D1, a resistor R2, a capacitor C2, a resistor R1, a capacitor C1, and a resistor R22. The cathode of the diode D1 is connected to the stable voltage supply module, the anode of the diode D1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C2 and one end of the resistor R1, the other end of the capacitor C2 is grounded, the other end of the resistor R1 is connected to the pull-up positive voltage module, one end of the capacitor C1, one end of the resistor R22, and the MCU, the other end of the resistor R22 is grounded, and the other end of the capacitor C1 is grounded.

5. The flyback switching power supply voltage monitoring circuit according to claim 1, wherein: The pull-up positive voltage module includes a voltage regulator chip IC1, the input end of the voltage regulator chip IC1 is connected to the stable voltage supply module, the ground end of the voltage regulator chip IC1 is grounded, the output end of the voltage regulator chip IC1 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the sampling output module.

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