A flyback loop power supply circuit

Abstract

The application belongs to the field of switching power supply, and particularly relates to a flyback loop power supply circuit, which comprises a main power module, a feedback loop module and an auxiliary winding power supply module; the main power module is connected with a first winding of a transformer, the main power module is connected with the feedback loop, one end of the auxiliary winding power supply module is connected with the feedback loop module, the auxiliary winding power supply module is connected with a second winding, and the other end of the feedback loop module is connected with the auxiliary winding power supply module; the auxiliary winding power supply module comprises a diode V20, a capacitor C3, a capacitor C49 and a resistor R8, the positive electrode of the diode V20 is connected with the second winding, the negative electrode of the diode V20 is connected with the capacitor C3, the capacitor C3 is connected with the capacitor C49, and the capacitor C3 is also connected with the resistor R8 in parallel. The application has the effect of improving the influence of the output voltage fluctuation of the loop power supply caused by the sharp change of the ESR value of the output aluminum electrolytic capacitor at low temperature, and can obviously improve the loop performance at low temperature.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of switching power supply, and particularly relates to a flyback loop power supply circuit. BACKGROUND

[0002] The flyback power supply is a kind of power supply system, which realizes energy conversion and adjustment of the power supply by using a resonant circuit. It is usually composed of a high-frequency transformer, a resonant capacitor, a resonant inductor and a switching element (such as a transistor or a MOSFET). The main function of the flyback power supply is to convert the input electric energy into the form of electric energy required by a specific application.

[0003] In the localization project, the loop characteristics of the flyback power supply will be deteriorated sharply with the decrease of the environmental temperature, and the system's Bode diagram does not meet the requirements. Through the test and comparison of the capacitance value and ESR of the capacitors produced by the domestic mainstream manufacturers at different environmental temperatures, it is found that the ESR parameter of the domestic aluminum electrolytic capacitor will increase significantly with the decrease of the environmental temperature. SUMMARY

[0004] The technical problem to be solved by the application is to prevent the ESR parameter of the domestic aluminum electrolytic capacitor from increasing when the environmental temperature decreases, so as to increase the output voltage fluctuation. The application provides a flyback loop power supply circuit.

[0005] The application provides a flyback loop power supply circuit.

[0006] The application provides a flyback loop power supply circuit.

[0007] The application provides a flyback loop power supply circuit.

[0008] The application provides a flyback loop power supply circuit.

[0009] The application provides a flyback loop power supply circuit.

[0010] The application provides a flyback loop power supply circuit.

[0011] The application provides a flyback loop power supply circuit.

[0012] The negative electrode of the diode V1 is also connected with the positive electrode of the electrolytic capacitor C2, the negative electrode of the electrolytic capacitor C2 is connected with the non-name end of the first winding, the electrolytic capacitor C2 is connected with the electrolytic capacitor C4 in parallel, the positive electrode of the electrolytic capacitor C2 is connected with the positive electrode of the electrolytic capacitor C4, the negative electrode of the electrolytic capacitor C4 is connected with the negative electrode of the electrolytic capacitor C4, and the inductance L1 is connected in series between the positive electrode of the electrolytic capacitor C2 and the positive electrode of the electrolytic capacitor C4.

[0013] Optionally, the feedback loop module comprises:

[0014] The feedback loop module comprises the resistance R22, the resistance R127, the linear optical coupling, the capacitor C45, the resistance R129, the resistance R23, the resistance R21, the capacitor C79, the resistance R131, the resistance R133, the resistance R136 and the voltage stabilizing diode, the resistance R22 is connected with the resistance R127 and the linear optical coupling, the linear optical coupling is connected with the resistance R127 and the capacitor C45 respectively, the capacitor C45 is connected with the resistance R129, the resistance R129 is connected with the resistance R23, the resistance R23 is connected with the resistance R21, the other end of the resistance R21 is connected with the inductance L1, the resistance R23 is also connected with the capacitor C79, the capacitor C79 is connected with the resistance R131, the resistance R131 is connected with the capacitor C83, the capacitor C83 is connected with the resistance R127 and the negative electrode of the voltage stabilizing diode, the resistance R131 is also connected with the resistance R136, the resistance R136 is connected with the positive electrode of the voltage stabilizing diode, the resistance R133 is connected with the resistance R136 in parallel, and one end of the resistance R133 is grounded.

[0015] Optionally, the output of the main power module is 5V.

[0016] Optionally, one end of the resistance R8 is grounded.

[0017] Optionally, the negative electrode of the electrolytic capacitor C4 is grounded.

[0018] Optionally, the electrolytic capacitor C4 is an aluminum electrolytic capacitor.

[0019] Optionally, the diode V1 is a rectifier diode.

[0020] Optionally, the auxiliary winding power supply module is used for supplying power for the feedback loop module.

[0021] Optionally, the voltage stabilizing diode is a three-terminal adjustable voltage stabilizing diode.

[0022] The beneficial effects of the present application are: the auxiliary winding circuit is built by the secondary winding of the transformer, the rectifier diode V20, the filter capacitor C3 and the resistor R8, the feedback optocoupler upper end is connected through the power supply resistor R22, the feedback loop part is stably powered, the power supply circuit is not directly connected with the aluminum electrolytic capacitor, the influence of the output voltage fluctuation caused by the sharp change of the output aluminum electrolytic capacitor ESR value at low temperature on the loop power supply when the traditional output voltage is used as the loop power supply in the domestic anti-reverse power supply can be effectively relieved, and the loop performance at low temperature can be obviously improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The present application is a traditional anti-reverse power supply power supply circuit schematic diagram.

[0024] Figure 2 The present application is a traditional anti-reverse power supply power supply circuit schematic diagram. DETAILED DESCRIPTION

[0025] As shown in the figure, the traditional anti-reverse power supply power supply circuit includes: Figure 1

[0026] The diode V1, the capacitor C6, the electrolytic capacitor C2, the electrolytic capacitor C4 and the inductor L1.

[0027] The anode of the diode V1 is connected with the same name end of the first winding, the cathode of the diode V1 is connected with the capacitor C6, and the other end of the capacitor C6 is connected with the different name end of the first winding.

[0028] The cathode of the diode V1 is also connected with the anode of the electrolytic capacitor C2, the cathode of the electrolytic capacitor C2 is connected with the different name end of the first winding, the electrolytic capacitor C2 is connected with the electrolytic capacitor C4 in parallel, the anode of the electrolytic capacitor C2 is connected with the anode of the electrolytic capacitor C4, the cathode of the electrolytic capacitor C4 is connected with the cathode of the electrolytic capacitor C4, and the inductor L1 is connected in series between the anode of the electrolytic capacitor C2 and the anode of the electrolytic capacitor C4.

[0029] ​The resistor R22, the resistor R127, the linear light coupling, the capacitor C45, the resistor R129, the resistor R23, the resistor R21, the capacitor C79, the resistor R131, the resistor R133, the resistor R136 and the voltage stabilizing diode, the resistor R22 is connected with the resistor R127 and the linear light coupling, the linear light coupling and the resistor R127 are connected with the capacitor C45, the capacitor C45 is connected with the resistor R129, the resistor R129 is connected with the resistor R23, the resistor R23 is connected with the resistor R21, the resistor R21 is connected with the inductor L1 at the other end, the resistor R23 is also connected with the capacitor C79, the capacitor C79 is connected with the resistor R131, the resistor R131 is connected with the capacitor C83, the capacitor C83 is connected with the resistor R127 and the negative electrode of the voltage stabilizing diode, the resistor R131 is also connected with the resistor R136, the resistor R136 is connected with the positive electrode of the voltage stabilizing diode, the resistor R133 is connected with the resistor R136 in parallel, and the resistor R133 is grounded at one end.

[0030] The traditional flyback power supply circuit charges the electrolytic capacitor through the first winding of the transformer, rectifier diode and capacitor C6, and finally charges the electrolytic capacitor to supply power for feedback. In the steady state, the smaller the electrolytic capacitor C is, the greater the electrolytic capacitor parameter ESR is, and the greater the output voltage ripple is. The increase of the output voltage ripple at low temperature will bring certain interference to the power supply end and affect the stability of the loop. In order to stabilize the output voltage, a flyback loop power supply circuit is provided.

[0031] As shown in Figure 2 , a flyback loop power supply circuit comprises:

[0032] a main power module, a feedback loop module and an auxiliary winding power supply module;

[0033] The main power module is connected with the first winding of the transformer, and the main power module is also connected with the feedback loop. One end of the auxiliary winding power supply module is connected with the feedback loop module, and the auxiliary winding power supply module is also connected with the second winding. The other end of the feedback loop module is connected with the auxiliary winding power supply module.

[0034] The auxiliary winding power supply module comprises a diode V20, a capacitor C3, a capacitor C49 and a resistor R8. The positive electrode of the diode V20 is connected with the second winding, the negative electrode of the diode V20 is connected with the capacitor C3, the capacitor C3 is connected with the capacitor C49, and the capacitor C3 is also connected with the resistor R8 in parallel.

[0035] The main power module comprises:

[0036] a diode V1, a capacitor C6, an electrolytic capacitor C2, an electrolytic capacitor C4 and an inductor L1.

[0037] The positive pole of diode V1 is connected with the same name end of the first winding, the negative pole of diode V1 is connected with capacitor C6, the other end of capacitor C6 is connected with the different name end of the first winding;

[0038] The negative pole of diode V1 is also connected with the positive pole of electrolytic capacitor C2, the negative pole of electrolytic capacitor C2 is connected with the different name end of the first winding, electrolytic capacitor C2 is connected with electrolytic capacitor C4 in parallel, the positive pole of electrolytic capacitor C2 is connected with the positive pole of electrolytic capacitor C4, the negative pole of electrolytic capacitor C4 is connected with the negative pole of electrolytic capacitor C4, inductance L1 is connected in series between the positive pole of electrolytic capacitor C2 and the positive pole of electrolytic capacitor C4.

[0039] The feedback loop module comprises resistance R22, resistance R127, linear photo-coupler, capacitor C45, resistance R129, resistance R23, resistance R21, capacitor C79, resistance R131, resistance R133, resistance R136 and stabilizing diode, resistance R22 is connected with resistance R127 and linear photo-coupler, linear photo-coupler is connected with resistance R127 and capacitor C45 respectively, capacitor C45 is connected with resistance R129, resistance R129 is connected with resistance R23, resistance R23 is connected with resistance R21, the other end of resistance R21 is connected with inductance L1, resistance R23 is also connected with capacitor C79, capacitor C79 is connected with resistance R131, resistance R131 is connected with capacitor C83, capacitor C83 is connected with resistance R127 and negative pole of stabilizing diode, resistance R131 is also connected with resistance R136, resistance R136 is connected with positive pole of stabilizing diode, resistance R133 is connected with resistance R136 in parallel, one end of resistance R133 is grounded.

[0040] Resistance R8, negative pole of electrolytic capacitor C4 and resistance R133 are grounded.

[0041] In the embodiment, the output voltage is set to 5V, and the component parameters in the flyback loop power supply circuit can be: the rectifier diode can be SS36B type, the inductor L1 is 10μH, the capacitor C6 is 4.7μF / 50V, the electrolytic capacitor C2 is 1000μF / 16V, the electrolytic capacitor C4 is 1000μF / 16V, the diode V20 is 400V / 1A, the capacitor C3 is 2.2μF / 25V, the capacitor C49 is 2.2μF / 16V, the resistor R8 is 3.3KΩ, the resistor R22 and the resistor R21 are 470Ω, the resistor R127 is 1000Ω, the capacitor C45 is 4.7nF / 50V, the resistor R129 is 47KΩ, the resistor R23 is 4.7KΩ, the capacitor C79 is 10nF / 100V, the resistor R131 is 1000Ω, the capacitor C83 is 47nF / 50V, the resistor R36 is 4.7kΩ, and the resistor R133 is 470K. The embodiment only provides the component parameters of the circuit when the output voltage is 5V, and in actual use, the component parameters are different according to the output voltage (the positive electrode voltage of the electrolytic capacitor C4).

[0042] The first winding and the second winding are two windings of a transformer secondary side, and the rectifier diode V1, the output inductor L1, and the output aluminum electrolytic capacitor C4 and the like constitute the basic structure of the flyback power supply on the secondary side. The resistor R23, the capacitor C79, the resistor R131, the capacitor C45, the resistor R129, and the capacitor C83 constitute a 3-type operational amplifier compensation network. The error signal is fed back to the primary side through the linear optical coupling and the voltage stabilizing diode V14. The voltage stabilizing diode can be a TL431 voltage stabilizing tube (three-terminal adjustable voltage stabilizing tube). When the output voltage changes, the error signal is compared with the voltage reference of the TL431 through the feedback voltage division, and after correction in the compensation network, the error signal is fed back to the PWM control chip on the primary side through the TL431 and the feedback optical coupling for processing. Finally, the output voltage is stabilized by adjusting the duty cycle of the main power MOS tube on the primary side.

[0043] The transformer secondary side winding, the rectifier diode V20, the filter capacitor C3, and the resistor R8 build an auxiliary winding circuit. The feedback optical coupling upper end is connected through the power supply resistor R22 to stably supply power to the feedback loop part. Since the power supply loop is not directly connected to the aluminum electrolytic capacitor, the influence of the output voltage fluctuation caused by the sharp change of the ESR value of the output aluminum electrolytic capacitor on the loop power supply at low temperature can be effectively alleviated, and the loop performance at low temperature can be obviously improved.

[0044] Those skilled in the art should understand that the above discussion of any of the embodiments is merely exemplary and is not intended to be limiting of the scope of protection as set forth in the appended claims; the above embodiments or technical features among different embodiments can also be combined, steps can be implemented in any order, and there are many other changes, such as the above-mentioned different aspects of one or more embodiments of the present application, which are not provided in detail for the sake of brevity.

[0045] One or more embodiments of the present application are intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the application. Accordingly, any and all such alternatives, modifications, equivalents, improvements and the like as are deemed by those of ordinary skill in the art to fall within the spirit and scope of one or more embodiments of the present application are intended to be included within the scope of the present application.

Claims

1. A flyback loop power supply circuit, characterized in that: include: Main power module, feedback loop module and auxiliary winding power supply module; The main power module is connected to the first winding of the transformer, and the main power module is also connected to the feedback loop. One end of the auxiliary winding power supply module is connected to the feedback loop module, and the auxiliary winding power supply module is also connected to the second winding. The other end of the feedback loop module is connected to the auxiliary winding power supply module; The auxiliary winding power supply module includes a diode V20, a capacitor C3, a capacitor C49, and a resistor R8. The anode of the diode V20 is connected to the second winding, the cathode of the diode V20 is connected to the capacitor C3, the capacitor C3 is connected to the capacitor C49, and the capacitor C3 is also connected in parallel with the resistor R8. The main power module includes: Diode V1, capacitor C6, electrolytic capacitor C2, electrolytic capacitor C4 and inductor L1; The anode of the diode V1 is connected to the same-name end of the first winding, the cathode of the diode V1 is connected to the capacitor C6, and the other end of the capacitor C6 is connected to the opposite-name end of the first winding; The cathode of the diode V1 is also connected to the positive electrode of the electrolytic capacitor C2, the negative electrode of the electrolytic capacitor C2 is connected to the opposite end of the first winding, the electrolytic capacitor C2 is connected in parallel with the electrolytic capacitor C4, the positive electrode of the electrolytic capacitor C2 is connected to the positive electrode of the electrolytic capacitor C4, the negative electrode of the electrolytic capacitor C4 is connected to the negative electrode of the electrolytic capacitor C4, and the inductor L1 is connected in series between the positive electrode of the electrolytic capacitor C2 and the positive electrode of the electrolytic capacitor C4; The feedback loop module includes: The feedback loop module includes a resistor R22, a resistor R127, a linear optocoupler, a capacitor C45, a resistor R129, a resistor R23, a resistor R21, a capacitor C79, a resistor R131, a resistor R133, a resistor R136 and a voltage stabilizing diode. The resistor R22 is connected to the resistor R127 and the linear optocoupler. The linear optocoupler is connected to the resistor R127 and the capacitor C45 respectively. The capacitor C45 is connected to the resistor R129. The resistor R129 is connected to the corresponding resistor R23. The resistor R23 is connected to the The resistor R21 is connected, the other end of the resistor R21 is connected to the inductor L1, the resistor R23 is also connected to the capacitor C79, the capacitor C79 is connected to the resistor R131, the resistor R131 is connected to the capacitor C83, the capacitor C83 is connected to the resistor R127 and the cathode of the Zener diode, the resistor R131 is also connected to the resistor R136, the resistor R136 is connected to the anode of the Zener diode, the resistor R133 is connected in parallel with the resistor R136, and one end of the resistor R133 is grounded.

2. The flyback loop power supply circuit according to claim 1, wherein: include: The output of the main power module is 5V.

3. The flyback loop power supply circuit according to claim 1, wherein: include: One end of the resistor R8 is grounded.

4. The flyback loop power supply circuit according to claim 1, wherein: include: The negative electrode of the electrolytic capacitor C4 is grounded.

5. The flyback loop power supply circuit according to claim 1, wherein: include: The electrolytic capacitor C4 is an aluminum electrolytic capacitor.

6. The flyback loop power supply circuit according to claim 1, wherein: include: The diode V1 is a rectifier diode.

7. The flyback loop power supply circuit according to claim 1, wherein: include: The auxiliary winding power supply module is used to supply power to the feedback loop module.

8. The flyback loop power supply circuit according to claim 1, wherein: include: The voltage stabilizing diode is a three-terminal adjustable voltage stabilizing diode.

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