Flyback constant power circuit and power supply

Abstract

The utility model relates to the technical field of power supplies, in particular to a flyback constant power circuit and a power supply. Comprising an input module, a transformer, an output module, a control module and a feedback module, the two sides of the transformer are connected with the input module and the output module respectively, the input end of the feedback module is connected with the output module, the output end of the feedback module is connected with the control module, and the output end of the control module is connected with the primary side of the transformer. A voltage stabilizing diode is arranged between the output end of the feedback module and the control module. The negative electrode of the voltage stabilizing diode is connected with the output end of the feedback module and the control module. The voltage stabilizing diode is arranged between the output end of the feedback module and the control module to clamp and output feedback gain, so that the control module keeps the original duty ratio, the current is increased, the output voltage is forcibly reduced under the condition that the output load needs large current, the current is increased in the maximum constant power range, and the output power is increased. And the charging requirements of small and medium-sized power inductive loads are met.

Description

TECHNICAL FIELD

[0001] The utility model relates to power supply technical field especially a flyback constant power circuit and power supply. BACKGROUND

[0002] At present, switching power supply is used more and more in market, and application scene is more and more wide, output load generally includes resistive load, capacitive load and inductive load etc., in actual application, some inductive load needs large current to support when starting, for example motor, when output current of power supply product does not satisfy the current required by starting, will trigger overcurrent or over power protection of power supply product, so that power supply product cannot be used normally.

[0003] Therefore, design a flyback constant power circuit and power supply that can satisfy the large current output demand of inductive load, it is very important to the person skilled in the art. SUMMARY

[0004] The utility model embodiment solves the technical problem that the output current is difficult to satisfy the current required by starting in the prior art, so that the power supply product cannot be used normally, and provides a flyback constant power circuit and power supply that can satisfy the large current output demand of inductive load.

[0005] The utility model discloses a kind of flyback constant power circuits, and its scheme is to include: input module, transformer, output module, control module and feedback module, the primary side of the transformer is connected with the input module, the secondary side of the transformer is connected with the output module, the input end of the feedback module is connected with the output module, the output end of the feedback module is connected with the input end of the control module, the output end of the control module is connected with the primary side of the transformer, wherein, voltage stabilizing diode is arranged between the output end of the feedback module and the control module, the positive pole of the voltage stabilizing diode is grounded, the negative pole of the voltage stabilizing diode is connected with the output end of the feedback module and the control module respectively, to be used for limiting feedback gain.

[0006] Optionally, the control module includes control chip and MOS tube, the output end of the control chip is connected with the gate of the MOS tube, the drain of the MOS tube is connected with the primary side of the transformer, and the source of the MOS tube is grounded.

[0007] Optionally, the control chip includes compensation feedback pin, and the compensation feedback pin is connected with the negative pole of the voltage stabilizing diode and the output end of the feedback module respectively.

[0008] Optionally, the control chip further includes voltage regulation pin, and the voltage regulation pin is connected with the primary side of the transformer.

[0009] Optionally, the feedback module comprises an optocoupler and a voltage stabilizer, an input end of the optocoupler is connected with the output module, an output end of the optocoupler is connected with the control module and the voltage stabilizer respectively, and the voltage stabilizer is connected with the output module for providing a reference voltage.

[0010] Optionally, a current-limiting resistor is further arranged between the feedback module and the output module, and the current-limiting resistor is connected with the optocoupler and the voltage stabilizer respectively.

[0011] Optionally, the feedback module further comprises an RC compensation circuit, an input end of the RC compensation circuit is connected with the output module, and an output end of the RC compensation circuit is connected with the optocoupler and the voltage stabilizer respectively.

[0012] Optionally, the RC compensation circuit comprises a first resistor, a second resistor and a first capacitor, and the first resistor, the second resistor and the first capacitor are connected in series.

[0013] Optionally, a voltage dividing resistor is arranged at a reference end of the voltage stabilizer for providing an internal reference voltage.

[0014] To solve the problems in the prior art, the utility model further provides a power supply, and the scheme lies in that the power supply comprises a body and a circuit board, the circuit board is arranged in the body, and the circuit board is provided with the flyback constant power circuit as described above.

[0015] Compared with the prior art, the utility model embodiment provides the beneficial effects of 2222, that is, by designing a flyback constant power circuit, the flyback constant power circuit comprises an input module, a transformer, an output module, a control module and a feedback module, a primary side of the transformer is connected with the input module, a secondary side of the transformer is connected with the output module, an input end of the feedback module is connected with the output module, an output end of the feedback module is connected with an input end of the control module, and an output end of the control module is connected with the primary side of the transformer; a voltage stabilizing diode is arranged between the output end of the feedback module and the control module, a positive electrode of the voltage stabilizing diode is grounded, and a negative electrode of the voltage stabilizing diode is connected with the output end of the feedback module and the control module respectively; by arranging the voltage stabilizing diode between the output end of the feedback module and the control module, the output feedback gain is clamped, the control module keeps the original duty cycle, the current is increased, and the output voltage is forcibly reduced under the condition that a large current is required by an output load, so that the current is increased within the maximum constant power range, and the charging demand of a small and medium-sized power inductive load is met. BRIEF DESCRIPTION OF DRAWINGS

[0016] The technical scheme of the utility model will be further explained in detail below with reference to the drawings and embodiments, and the drawings show:

[0017] Figure 1The utility model embodiment provides a module frame of the flyback constant power circuit Figure 1 ;

[0018] Figure 2 The utility model embodiment provides a module frame of the flyback constant power circuit Figure 2 ;

[0019] Figure 3 The utility model embodiment provides a circuit diagram of the flyback constant power circuit. DETAILED DESCRIPTION

[0020] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. Now, the preferred embodiments of the utility model will be described in detail with reference to the drawings.

[0021] As Figures 1 to 3 shown, the utility model provides a specific embodiment of the flyback constant power circuit.

[0022] A flyback constant power circuit, referring to Figure 1 , the flyback constant power circuit includes: input module 100, transformer 200, output module 300, control module 400 and feedback module 500, the primary side of transformer 200 is connected with input module 100, the secondary side of transformer 200 is connected with output module 300, the input end of feedback module 500 is connected with output module 300, the output end of feedback module 500 is connected with the input end of control module 400, and the output end of control module 400 is connected with the primary side of transformer 200.

[0023] Wherein, the output end of feedback module 500 and control module 400 are provided with zener diode ZD1, the positive pole of zener diode ZD1 is grounded, and the negative pole of zener diode ZD1 is connected with the output end of feedback module 500 and control module 400 respectively, so as to limit feedback gain.

[0024] Specifically, referring to Figure 1 , input module 100 is used for connecting external power to obtain input voltage, and the output end of input module 100 is connected with the primary side of transformer 200 to output voltage to the primary side of transformer 200, and the secondary side of transformer 200 is connected with output module 300, and transformer 200 transforms the voltage output by input module 100 into the voltage required by load 600 through the turns ratio of the primary side and the secondary side, and outputs to load through output module 300 to charge load 600.

[0025] Further, referring to Figure 1The input end of the feedback module 500 is connected with the output module 300, and the output end of the feedback module 500 is connected with the control module 400, so as to monitor the output voltage and feed back the amplified signal to the control circuit, so as to adjust the output voltage of the output module 300. Not only can the output module 300 maintain stable voltage output, but also can meet the needs of different loads.

[0026] Further, referring to Figure 1 The output end of the feedback module 500 and the control module 400 are provided with a voltage stabilizing diode ZD1. The feedback gain of the feedback module 500 needs to be given to the control module 400 through the voltage stabilizing diode ZD1. The positive electrode of the voltage stabilizing diode ZD1 is grounded, and the negative electrode of the voltage stabilizing diode ZD1 is respectively connected with the output end of the feedback module 500 and the control module 400, so as to clamp the feedback gain, so that the control module 400 outputs the same duty ratio and the same output gain, thereby increasing the current and reducing the output voltage, so as to increase the current in the maximum constant power range.

[0027] With the wider application of the switching power supply, more and more output loads are connected, such as resistive load, capacitive load and inductive load. In actual application, some inductive loads need large current to support at start-up, such as motors. When the output current of the switching power supply does not meet the starting current of the inductive load, the overcurrent or over-power protection of the switching power supply product is triggered, so that the switching power supply product cannot be normally used.

[0028] In the embodiment, a flyback constant power circuit is designed, which comprises an input module 100, a transformer 200, an output module 300, a control module 400 and a feedback module 500. The primary side of the transformer 200 is connected with the input module 100, the secondary side of the transformer 200 is connected with the output module 300, the input end of the feedback module 500 is connected with the output module 300, the output end of the feedback module 500 is connected with the input end of the control module 400, and the output end of the control module 400 is connected with the primary side of the transformer 200. A voltage stabilizing diode ZD1 is arranged between the output end of the feedback module 500 and the control module 400. The positive electrode of the voltage stabilizing diode ZD1 is grounded, and the negative electrode of the voltage stabilizing diode ZD1 is respectively connected with the output end of the feedback module 500 and the control module 400. The voltage stabilizing diode ZD1 is arranged between the output end of the feedback module 500 and the control module 400, so as to clamp the output feedback gain, so that the control module 400 maintains the original duty ratio, thereby increasing the current, reducing the output voltage, and increasing the current in the maximum constant power range, so as to meet the charging needs of the small and medium power inductive load.

[0029] In one of the embodiments, referring to Figure 2 andFigure 3 The control module 400 comprises a control chip U1 and a MOS tube Q1, an output end of the control chip U1 is connected with a gate electrode G of the MOS tube Q1, a drain electrode D of the MOS tube Q1 is connected with a primary side of the transformer 200, and a source electrode S of the MOS tube Q1 is grounded.

[0030] Specifically, referring to Figure 2 and Figure 3 , the control chip U1 comprises 6Pin pins, specifically, a positive pin VCC, a negative pin GND, an output pin OUT, a current sampling pin CS, a compensation feedback pin COMP, and an internal oscillation frequency control pin RT, which are used for corresponding control of the MOS tube Q1 according to a feedback signal, so as to adjust an output voltage of the transformer 200. The control chip U1 can specifically adopt an ob2362 chip, and the MOS tube Q1 is used as a switching tube. The gate electrode G of the MOS tube Q1 is connected with the output pin OUT of the control chip U1, so as to be turned on or turned off according to a level signal output by the control chip U1. The source electrode S of the MOS tube Q1 is grounded, and the drain electrode D of the MOS tube Q1 is connected with the primary side of the transformer 200. The control chip U1 can control the turn-on and turn-off of the MOS tube Q1 to adjust the working state of the transformer 200, so as to realize adjustment of the output voltage.

[0031] Specifically, referring to Figure 3 , the control chip U1 adopts a pulse width modulation technology to control the turn-on time of the MOS tube Q1. The working state of the transformer 200 is controlled by adjusting the switching frequency and duty cycle of the MOS tube Q1. When it is needed to increase the output voltage, the control chip U1 will increase the turn-on time of the MOS tube Q1, so that the transformer 200 outputs more electric energy. When it is needed to decrease the output voltage, the control chip U1 will decrease the turn-on time of the MOS tube Q1, so that the output electric energy of the transformer 200 is decreased.

[0032] Further, referring to Figure 3 , the compensation feedback pin COMP of the control chip U1 is connected with a negative electrode of a voltage stabilizing diode ZD1 and an output end of the feedback module 500 respectively. The feedback gain output by the output end of the feedback module 500 is clamped and output by the voltage stabilizing diode ZD1, so that the control module 400 outputs a constant duty cycle and a constant output gain, thereby increasing the current and lowering the output voltage, so as to realize the effect of increasing the current in a maximum constant power range.

[0033] Specifically, referring to Figure 3The feedback module 500 monitors the output voltage and feeds back the voltage information to the control chip U1, and the control chip U1 adjusts the working state of the switch tube according to the comparison between the feedback signal and the set value, so that the output voltage is stabilized near the set value; by increasing the zener diode ZD1, the output negative feedback gain is clamped, and the control chip U1 will keep the original duty cycle, so that the output gain of the transformer 200 remains unchanged, thereby increasing the current and lowering the output voltage, and realizing the effect of increasing the current in the maximum constant power range.

[0034] In one embodiment, the feedback module 500 includes a light coupling U2 and a voltage stabilizer U3, the input end of the light coupling U2 is connected with the output module 300, the output end of the light coupling U2 is connected with the control module and the zener diode ZD1 respectively, and the voltage stabilizer U3 is connected with the output module 300 for providing a reference voltage. Figure 3

[0035] Specifically, the feedback module 500 adopts the scheme of the voltage stabilizer U3 and the light coupling U2, and sets a current limiting resistor R8 between the light coupling U2 and the output module 300 for sampling the output current, the sampling current can be transmitted to the control module 400 through the light coupling U2 to generate a corresponding electrical signal, and the current limiting resistor R8 can also provide the voltage required for the operation of the voltage stabilizer U3; the voltage stabilizer U3 can specifically adopt a TL431 controllable precision voltage stabilizer, the zener diode ZD1 corresponds to a 43V zener diode, and works in the reverse conduction region; wherein, the reference end of the voltage stabilizer U3 is provided with a voltage dividing resistor to provide an internal reference voltage for the voltage stabilizer U3, that is, when the output voltage reaches the target value, the junction voltage of the voltage dividing resistor is just equal to the internal reference voltage of the voltage stabilizer U3. Figure 3 In one embodiment, the feedback module 500 further includes an RC compensation circuit, the input end of the RC compensation circuit is connected with the output module 300, and the output end of the RC compensation circuit is connected with the light coupling U2 and the voltage stabilizer U3 respectively; wherein, the RC compensation circuit includes a first resistor R11, a second resistor R14 and a first capacitor C7, and the first resistor R11, the second resistor R14 and the first capacitor C7 are connected in series.

[0036] Figure 3 Further, the utility model also provides a specific embodiment of a power supply.

[0037] A power supply includes a body and a circuit board, the circuit board is arranged in the body, and the circuit board is provided with the flyback constant power circuit as described above.

[0038] A power supply includes a body and a circuit board, the circuit board is arranged in the body, and the circuit board is provided with the flyback constant power circuit as described above.

[0039] ​​It should be understood that the above embodiments are only used to illustrate the technical solutions of the present application, but not limit them, and for those skilled in the art, the technical solutions recorded in the above embodiments can be modified, or some technical features therein can be replaced equivalently; and all these modifications and replacements shall belong to the protection scope of the present application.

Claims

1. A flyback constant power circuit, characterized by, The power supply comprises an input module, a transformer, an output module, a control module and a feedback module, the primary side of the transformer is connected with the input module, the secondary side of the transformer is connected with the output module, the input end of the feedback module is connected with the output module, the output end of the feedback module is connected with the input end of the control module, the output end of the control module is connected with the primary side of the transformer, wherein a voltage stabilizing diode is arranged between the output end of the feedback module and the control module, the positive pole of the voltage stabilizing diode is grounded, and the negative pole of the voltage stabilizing diode is connected with the output end of the feedback module and the control module respectively, so as to limit the feedback gain. The control module comprises a control chip and a MOS tube, the output end of the control chip is connected with the gate of the MOS tube, the drain of the MOS tube is connected with the primary side of the transformer, and the source of the MOS tube is grounded.

2. The flyback constant power circuit of claim 1, wherein, The control chip comprises a compensation feedback pin, the compensation feedback pin is connected with the negative pole of the voltage stabilizing diode and the output end of the feedback module respectively.

3. The flyback constant power circuit of claim 2, wherein, The control chip further comprises a voltage regulation pin, and the voltage regulation pin is connected with the primary side of the transformer.

4. The flyback constant power circuit of claim 2, wherein, The feedback module comprises an optical coupler and a voltage stabilizer, the input end of the optical coupler is connected with the output module, the output end of the optical coupler is connected with the control module and the voltage stabilizing diode respectively, and the voltage stabilizer is connected with the output module, so as to provide a reference voltage.

5. The flyback constant power circuit of claim 1, wherein, A current limiting resistor is further arranged between the feedback module and the output module, and the current limiting resistor is connected with the optical coupler and the voltage stabilizer respectively.

6. The flyback constant power circuit of claim 5, wherein, The feedback module further comprises an RC compensation circuit, the input end of the RC compensation circuit is connected with the output module, and the output end of the RC compensation circuit is connected with the optical coupler and the voltage stabilizer respectively.

7. The flyback constant power circuit of claim 5, wherein, The RC compensation circuit comprises a first resistor, a second resistor and a first capacitor, and the first resistor, the second resistor and the first capacitor are connected in series.

8. The flyback constant power circuit of claim 7, wherein, The reference end of the voltage stabilizer is provided with a voltage dividing resistor, so as to provide an internal reference voltage.

9. The flyback constant power circuit of claim 5, wherein, The power supply comprises a body and a circuit board, the circuit board is arranged in the body, and the circuit board is provided with the flyback constant power circuit according to any one of claims 1-9.

10. A power supply, characterized by, ​

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