CN110881232A - Flyback switching power supply circuit - Google Patents
Flyback switching power supply circuit Download PDFInfo
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- CN110881232A CN110881232A CN201911304634.5A CN201911304634A CN110881232A CN 110881232 A CN110881232 A CN 110881232A CN 201911304634 A CN201911304634 A CN 201911304634A CN 110881232 A CN110881232 A CN 110881232A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Abstract
The invention discloses a flyback switching power supply circuit which is characterized by comprising a surge protection circuit, an EMI (electro-magnetic interference) filtering module, a bridge rectifier module, a dimmer detection starting circuit, a chopper circuit, a feedback circuit, a clamp RCD (resistor capacitor diode) absorption circuit, a temperature detection circuit, a bias power supply, a driving circuit, an overcurrent detection module, a switching loop circuit, a rectifying circuit and a filtering circuit, wherein the surge protection circuit is connected with the chopper circuit; the surge protection circuit is sequentially connected with an EMI filtering module, a bridge rectifier module, a dimmer detection starting circuit, a chopper circuit, a clamp RCD absorption circuit, a feedback circuit, a bias power supply and a driving circuit, the driving circuit is respectively connected with a temperature detection circuit and a switch loop circuit, the switch loop circuit is connected with a rectifying circuit, the rectifying circuit is connected with the filtering circuit, and the temperature detection circuit is connected with an overcurrent detection module; the invention has simple structure, less used components, energy saving and good market application value.
Description
Technical Field
The invention relates to the field of power supplies, in particular to a flyback switching power supply circuit.
Background
The input of the LED driving power supply comprises high-voltage power frequency alternating current, low-voltage direct current, high-voltage direct current, low-voltage high-frequency alternating current such as the output of an electronic transformer and the like, the output of the LED driving power supply is mostly a constant current source which can change the voltage along with the change of the forward voltage drop value of the LED, the current output by the constant current driving circuit is constant, the output direct current voltage changes in a certain range along with the difference of the load resistance value, the load resistance value is small, the output voltage is low, and the output voltage is higher if the load resistance value is larger; the constant current driving circuit is ideal for driving the LED, but is relatively high in price and difficult to control a light source;
accordingly, the prior art is deficient and needs improvement.
Disclosure of Invention
The invention provides a flyback switching power supply circuit which solves the problems.
In order to solve the above problems, the technical scheme provided by the invention is as follows:
a flyback switching power supply circuit comprises a surge protection circuit, an EMI (electro-magnetic interference) filtering module, a bridge rectifier module, a dimmer detection starting circuit, a chopper circuit, a feedback circuit, a clamp RCD (resistor-capacitor-diode) absorption circuit, a temperature detection circuit, a bias power supply, a driving circuit, an overcurrent detection module, a switching loop circuit, a rectifying circuit and a filtering circuit; the surge protection circuit is connected with the EMI filtering module, the bridge rectifier module, the dimmer detection starting circuit, the chopper circuit, the clamp RCD absorption circuit, the feedback circuit, the bias power supply and the driving circuit in sequence, the driving circuit is respectively connected with the temperature detection circuit and the switch loop circuit, the switch loop circuit is connected with the rectifying circuit, the rectifying circuit is connected with the filtering circuit, and the temperature detection circuit is connected with the overcurrent detection module.
In one embodiment, the surge protection circuit comprises a fuse F1 and a voltage dependent resistor, wherein a first end of the fuse F1 is connected with the live wire, the other end of the fuse F1 is connected with a first end of the voltage dependent resistor, and a second end of the voltage dependent resistor is connected with the live wire.
In one embodiment, the EMI filter module includes a capacitor CX1, a resistor R1, a fixed resistor R2 and a transformer T1, a first end of the capacitor CX1 is connected to a second end of the fuse F1, a first end of the varistor and a tap 1 of the transformer T1, a second end of the capacitor CX1 is connected to a tap 3 of the transformer R2 and a second end of the varistor, a first end of the fixed resistor R2 is connected to a tap 3 of the transformer and a second end of the capacitor CX1, the rectifier bridge circuit includes a rectifier bridge BR1, a pin 1 of the rectifier bridge BR1 is connected to a tap 2 of the transformer T1, a pin 4 of the rectifier bridge BR1 is grounded, and a pin 3 of the rectifier bridge BR1 is connected to a second end of the fixed resistor R2 and a tap 4 of the transformer T1.
In one embodiment, the dimmer detection start circuit comprises a fixed resistor R3, a fixed resistor R4, and a capacitor C1; the first end of the fixed resistor R3 is connected with pin 2 of a rectifier bridge BR1, the second end of the fixed resistor R3 is connected with the first end of a fixed resistor R4, and the second end of the fixed resistor R4 is connected with the first end of a capacitor C2.
In one embodiment, the chopper circuit comprises a diode D1, diodes D3-D4, a MOS transistor Q1, an inductor L1, capacitors C2-C4 and fixed resistors R5-R8; the anode of the diode D3 is connected to pin 2 of the rectifier bridge BR1, the first end of the fixed resistor R3, and the anode of the diode D1, the cathode of the diode D1 is connected to the first end of the inductor L1 and the first end of the capacitor C2, the second end of the inductor L1 is connected to the first end of the capacitor C3, the first end of the fixed resistor R7, and the anode of the diode D4, the cathode of the diode D4 is connected to the cathode of the diode D1 and the first end of the capacitor C4, the second end of the capacitor C3 is connected to the second end of the fixed resistor R7 and the source of the MOS Q1, the gate of the MOS is connected to the first ends of the fixed resistors R5-R6, the drain of the MOS is connected to the first end of the fixed resistor R8, and the second end of the capacitor C4, the second ends of the fixed resistors R5-R6, R8, and the second end of the capacitor C2 are grounded.
In one embodiment, the clamp RCD snubber circuit includes a transformer T2, fixed resistors R11-R12, a fixed resistor R19, a capacitor C5, and a diode D6; tap 1 of the transformer T2 is connected with a first end of a fixed resistor R11-R12 and a first end of a capacitor C5 respectively, a second end of the capacitor C5 and a second end of a fixed resistor R11-R12 are both connected with a first end of a fixed resistor R19, a second end of the fixed resistor R19 is connected with a negative electrode of a diode D6, an anode of the diode D6 is connected with a tap 3 of the transformer T2, and a tap 6 of the transformer T2 is grounded.
In one embodiment, the bias supply includes a diode D5 and a capacitor D6; the anode of the diode D5 is connected to the tap 5 of the transformer T2, the cathode of the diode D5 is connected to the first end of the capacitor C6, and the second end of the capacitor 6 is grounded.
In one embodiment, the feedback power supply includes a fixed resistor R9 and a fixed resistor R10; the first end of the fixed resistor R9 is connected with the anode of the diode D5, the second end of the fixed resistor R9 is connected with the first end of the fixed resistor R10, and the second end of the fixed resistor R10 is grounded.
In one embodiment, the driving circuit comprises a fixed resistor R13, a diode D7, a transistor Q2 and an integrated circuit U1; pin 8 of the integrated circuit U1 is connected to the negative electrode of the diode D5 and the first end of the capacitor C6, pin 7 of the integrated circuit U1 is connected to the second end of the fixed resistor R13, the first end of the fixed resistor R13 is connected to the base of the transistor Q2 and the positive electrode of the diode D7, the collector of the transistor Q2 is grounded, and the emitter of the transistor Q2 is connected to the negative electrode of the diode D7.
Furthermore, pin 2 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R9 and the first terminal of the fixed resistor R10, pin 1 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R5, and pin 3 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R4 and the first terminal of the capacitor C1.
In one embodiment, the temperature detection circuit includes a thermistor NTC1 and a capacitor C8; the first terminal of the thermistor NTC1 is connected to the first terminal of the capacitor C8 and the pin 4 of the integrated circuit U1, respectively, and the second terminal of the thermistor NTC1 and the second terminal of the capacitor C8 are both grounded.
Compared with the prior art, the invention has the beneficial effects that by adopting the scheme, the EMI filter is arranged to form the filter circuit to prevent resonance oscillation, the chopper circuit is used as a dimmer to provide dynamic impedance, the flyback converter forms an RCD type primary clamping capacitor, the auxiliary winding simultaneously provides output feedback, and a sensing and electric coupling feedback circuit on the secondary side is eliminated; the dimmer is connected in series with the hot line of the AC line output and the integrated circuit U1 is capable of detecting the dimmer type and detecting the dimmer phase, the circuit operating as if it were when U1 detects that the dimmer is not present and has a high power factor.
Drawings
For a clearer explanation of the embodiments or technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for a person skilled in the art that other drawings can be obtained from the drawings without creative efforts.
FIG. 1 is a schematic block diagram of the present invention;
FIG. 2 is a circuit diagram of the overall structure of the present invention;
fig. 3 is a block diagram of the overall structure module of the present invention.
Detailed Description
In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The use of the terms "fixed," "integrally formed," "left," "right," and the like in this specification is for illustrative purposes only, and elements having similar structures are designated by the same reference numerals in the figures.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As shown in fig. 1-3, one embodiment of the present invention is:
a flyback switching power supply circuit comprises a surge protection circuit, an EMI (electro-magnetic interference) filtering module, a bridge rectifier module, a dimmer detection starting circuit, a chopper circuit, a feedback circuit, a clamp RCD (resistor-capacitor-diode) absorption circuit, a temperature detection circuit, a bias power supply, a driving circuit, an overcurrent detection module, a switching loop circuit, a rectifying circuit and a filtering circuit; the surge protection circuit is connected with the EMI filtering module, the bridge rectifier module, the dimmer detection starting circuit, the chopper circuit, the clamp RCD absorption circuit, the feedback circuit, the bias power supply and the driving circuit in sequence, the driving circuit is respectively connected with the temperature detection circuit and the switch loop circuit, the switch loop circuit is connected with the rectifying circuit, the rectifying circuit is connected with the filtering circuit, and the temperature detection circuit is connected with the overcurrent detection module.
According to the preferable technical scheme, the surge protection circuit comprises a fuse F1 and a piezoresistor, the first end of the fuse F1 is connected with a live wire, the other end of the fuse F1 is connected with the first end of the piezoresistor, and the second end of the piezoresistor is connected with the live wire.
The EMI filtering module comprises a capacitor CX1, a resistor R1, a fixed resistor R2 and a transformer T1, wherein the first end of the capacitor CX1 is connected with the second end of a fuse F1, the first end of a piezoresistor and a tap 1 of a transformer T1 respectively, the second end of the capacitor CX1 is connected with a tap 3 of the transformer R2 and the second end of the piezoresistor respectively, the first end of the fixed resistor R2 is connected with the tap 3 of the transformer and the second end of the capacitor CX1 respectively, the rectifier bridge circuit comprises a rectifier bridge BR1, a tap 2 of the transformer T1 is connected with a pin 1 of the rectifier bridge BR1, a pin 4 of the rectifier bridge BR1 is grounded, and a pin 3 of the rectifier bridge BR1 is connected with the second end of the fixed resistor R2 and a tap 4 of the transformer T1 respectively.
In a preferred embodiment, the dimmer detection start circuit includes a fixed resistor R3, a fixed resistor R4, and a capacitor C1; the first end of the fixed resistor R3 is connected with pin 2 of a rectifier bridge BR1, the second end of the fixed resistor R3 is connected with the first end of a fixed resistor R4, and the second end of the fixed resistor R4 is connected with the first end of a capacitor C2.
According to the preferable technical scheme, the chopper circuit comprises a diode D1, diodes D3-D4, an MOS tube Q1, an inductor L1, capacitors C2-C4 and fixed resistors R5-R8; the anode of the diode D3 is connected to pin 2 of the rectifier bridge BR1, the first end of the fixed resistor R3, and the anode of the diode D1, the cathode of the diode D1 is connected to the first end of the inductor L1 and the first end of the capacitor C2, the second end of the inductor L1 is connected to the first end of the capacitor C3, the first end of the fixed resistor R7, and the anode of the diode D4, the cathode of the diode D4 is connected to the cathode of the diode D1 and the first end of the capacitor C4, the second end of the capacitor C3 is connected to the second end of the fixed resistor R7 and the source of the MOS Q1, the gate of the MOS is connected to the first ends of the fixed resistors R5-R6, the drain of the MOS is connected to the first end of the fixed resistor R8, and the second end of the capacitor C4, the second ends of the fixed resistors R5-R6, R8, and the second end of the capacitor C2 are grounded.
According to the preferable technical scheme, the clamping RCD absorption circuit comprises a transformer T2, fixed resistors R11-R12, a fixed resistor R19, a capacitor C5 and a diode D6; tap 1 of the transformer T2 is connected with a first end of a fixed resistor R11-R12 and a first end of a capacitor C5 respectively, a second end of the capacitor C5 and a second end of a fixed resistor R11-R12 are both connected with a first end of a fixed resistor R19, a second end of the fixed resistor R19 is connected with a negative electrode of a diode D6, an anode of the diode D6 is connected with a tap 3 of the transformer T2, and a tap 6 of the transformer T2 is grounded.
In a preferred embodiment, the bias power supply includes a diode D5 and a capacitor D6; the anode of the diode D5 is connected to the tap 5 of the transformer T2, the cathode of the diode D5 is connected to the first end of the capacitor C6, and the second end of the capacitor 6 is grounded.
According to the preferred technical scheme, the feedback power supply comprises a fixed resistor R9 and a fixed resistor R10; the first end of the fixed resistor R9 is connected with the anode of the diode D5, the second end of the fixed resistor R9 is connected with the first end of the fixed resistor R10, and the second end of the fixed resistor R10 is grounded.
According to the preferable technical scheme, the driving circuit comprises a fixed resistor R13, a diode D7, a triode Q2 and an integrated circuit U1; pin 8 of the integrated circuit U1 is connected to the negative electrode of the diode D5 and the first end of the capacitor C6, pin 7 of the integrated circuit U1 is connected to the second end of the fixed resistor R13, the first end of the fixed resistor R13 is connected to the base of the transistor Q2 and the positive electrode of the diode D7, the collector of the transistor Q2 is grounded, and the emitter of the transistor Q2 is connected to the negative electrode of the diode D7.
Furthermore, pin 2 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R9 and the first terminal of the fixed resistor R10, pin 1 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R5, and pin 3 of the integrated circuit U1 is connected to the second terminal of the fixed resistor R4 and the first terminal of the capacitor C1.
According to a preferred technical scheme, the temperature detection circuit comprises a thermistor NTC1 and a capacitor C8; the first terminal of the thermistor NTC1 is connected to the first terminal of the capacitor C8 and the pin 4 of the integrated circuit U1, respectively, and the second terminal of the thermistor NTC1 and the second terminal of the capacitor C8 are both grounded.
Further, the switch loop circuit comprises a MOS transistor Q3, a gate of the MOS transistor Q3 is connected to an emitter of the transistor Q2 and a cathode of the diode D7, respectively, and a source of the MOS transistor is connected to the tap 3 of the transformer T2 and the anode of the diode D6, respectively.
Further, the over-current detection circuit comprises a fixed resistor R15 and a fixed resistor R16; the first end of the fixed resistor R15 is respectively connected with the first end of the fixed resistor R16 and the pin 6 of the integrated circuit U1, the second ends of the fixed resistors R15-R16 are all grounded, and the pin 5 of the integrated circuit U1 is grounded.
Further, the rectifying circuit and the filter circuit comprise a diode D2, a capacitor C7 and a fixed resistor R14; the anode of the diode D2 is connected with a tap 7 of a transformer T2, the cathode of the diode D2 is connected with the first end of a fixed resistor R14 and the first end of a capacitor C7, and the first end of the fixed resistor R14 is connected with a power supply VCC; the second end of the capacitor C7 is connected with the tap 8 of the transformer T2, and the second end of the capacitor C7 and the second end of the fixed resistor R14 are both grounded.
The working principle is as follows:
after the AC power is turned on, the rectified DC high voltage charges the capacitor C6 through the diode between the internal connection pins of the resistors R3, R4 and U1, the U1 enters a normal operation mode, the constant current circuit enables the output voltage to start rising during the first 3 AC half cycles, and the U1 starts operating in the constant current mode when the output voltage is higher than the total voltage across the LED string;
the dimming detection is divided into two steps, the first step is to determine whether a dimmer exists, the second step is to detect the type of the dimmer under the condition that the dimmer exists, the dimmer detection is carried out in the third period after the system is started, when the time that the voltage VIN 1 on the pin of U1 is less than 0.1V exceeds 600us, the U1 determines that the dimmer is not connected, and the U1 sets the type of the dimmer to be in a 'no dimmer'; if VIN <0.1V time exceeds 600us, U1 determines the presence of a dimmer, and if a dimmer is present, U1 will detect the dimmer type. During the detection of the dimmer, a U1 pin 1 outputs a high level, and an MOS (metal oxide semiconductor) tube in the chopper circuit is conducted, so that a pure resistance load is generated for dimming; the VIN period is detected and the standby is locked in the second period in which the dimmer is found to be present. When VIN exceeds 0.1V and the input voltage is counted for sampling, the phase of the dimmer is measured, if the conduction time of the controlled silicon is ton, the dimming cycle is t, and the phase of the dimmer is ton/t, the larger the conduction angle of the controlled silicon in the dimmer is, the larger the power output power of the power supply is, and the brighter the LED is, otherwise, the smaller the conduction angle of the dimmer is, the darker the LED brightness is;
the chopper circuit functions to provide dynamic impedance to the dimmer and to build power to the flyback converter, and during constant current output operation, U1 uses valley switching, i.e., switching at the lowest point of the drain-to-pole resonant voltage, with minimal switching losses and EMI.
Compared with the prior art, the invention has the beneficial effects that by adopting the scheme, the EMI filter is arranged to form the filter circuit to prevent resonance oscillation, the chopper circuit is used as a dimmer to provide dynamic impedance, the flyback converter forms an RCD type primary clamping capacitor, the auxiliary winding simultaneously provides output feedback, and a sensing and electric coupling feedback circuit on the secondary side is eliminated; the dimmer is connected in series with the hot line of the AC line output and the integrated circuit U1 is capable of detecting the dimmer type and detecting the dimmer phase, the circuit operating as if it were when U1 detects that the dimmer is not present and has a high power factor.
The technical features mentioned above are combined with each other to form various embodiments which are not listed above, and all of them are regarded as the scope of the present invention described in the specification; also, modifications and variations may be suggested to those skilled in the art in light of the above teachings, and it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A flyback switching power supply circuit is characterized by comprising a surge protection circuit, an EMI filtering module, a bridge rectifier module, a dimmer detection starting circuit, a chopper circuit, a feedback circuit, a clamp RCD absorption circuit, a temperature detection circuit, a bias power supply, a driving circuit, an overcurrent detection module, a switching loop circuit, a rectifying circuit and a filtering circuit; the surge protection circuit is connected with the EMI filtering module, the bridge rectifier module, the dimmer detection starting circuit, the chopper circuit, the clamp RCD absorption circuit, the feedback circuit, the bias power supply and the driving circuit in sequence, the driving circuit is respectively connected with the temperature detection circuit and the switch loop circuit, the switch loop circuit is connected with the rectifying circuit, the rectifying circuit is connected with the filtering circuit, and the temperature detection circuit is connected with the overcurrent detection module.
2. The flyback switching power supply circuit of claim 1, wherein the surge protection circuit comprises a fuse F1 and a varistor, a first terminal of the fuse F1 is connected to the live wire, another terminal of the fuse F1 is connected to a first terminal of the varistor, and a second terminal of the varistor is connected to the live wire.
3. The flyback switching power supply circuit of claim 2, wherein the EMI filter module comprises a capacitor CX1, a resistor R1, a fixed resistor R2 and a transformer T1, a first end of the capacitor CX1 is connected to a second end of the fuse F1, a first end of the varistor and a tap 1 of the transformer T1, a second end of the capacitor CX1 is connected to a tap 3 of the transformer R2 and a second end of the varistor, a first end of the fixed resistor R2 is connected to a tap 3 of the transformer and a second end of the capacitor CX1, the rectifier bridge circuit comprises a rectifier bridge BR1, a pin 1 of the rectifier bridge BR1 is connected to a tap 2 of the transformer T1, a pin 4 of the rectifier bridge BR1 is grounded, and a pin 3 of the rectifier bridge BR1 is connected to a second end of the fixed resistor R2 and a tap 4 of the transformer T1.
4. The flyback switching power supply circuit of claim 1 wherein the dimmer detection start-up circuit comprises a fixed resistor R3, a fixed resistor R4, and a capacitor C1; the first end of the fixed resistor R3 is connected with pin 2 of a rectifier bridge BR1, the second end of the fixed resistor R3 is connected with the first end of a fixed resistor R4, and the second end of the fixed resistor R4 is connected with the first end of a capacitor C2.
5. The flyback switching power supply circuit of claim 4, wherein the chopper circuit comprises a diode D1, diodes D3-D4, a MOS transistor Q1, an inductor L1, capacitors C2-C4 and fixed resistors R5-R8; the anode of the diode D3 is connected to pin 2 of the rectifier bridge BR1, the first end of the fixed resistor R3, and the anode of the diode D1, the cathode of the diode D1 is connected to the first end of the inductor L1 and the first end of the capacitor C2, the second end of the inductor L1 is connected to the first end of the capacitor C3, the first end of the fixed resistor R7, and the anode of the diode D4, the cathode of the diode D4 is connected to the cathode of the diode D1 and the first end of the capacitor C4, the second end of the capacitor C3 is connected to the second end of the fixed resistor R7 and the source of the MOS Q1, the gate of the MOS is connected to the first ends of the fixed resistors R5-R6, the drain of the MOS is connected to the first end of the fixed resistor R8, and the second end of the capacitor C4, the second ends of the fixed resistors R5-R6, R8, and the second end of the capacitor C2 are grounded.
6. The flyback switching power supply circuit of claim 1, wherein the clamp RCD snubber circuit comprises a transformer T2, fixed resistors R11-R12, a fixed resistor R19, a capacitor C5, and a diode D6; tap 1 of the transformer T2 is connected with a first end of a fixed resistor R11-R12 and a first end of a capacitor C5 respectively, a second end of the capacitor C5 and a second end of a fixed resistor R11-R12 are both connected with a first end of a fixed resistor R19, a second end of the fixed resistor R19 is connected with a negative electrode of a diode D6, an anode of the diode D6 is connected with a tap 3 of the transformer T2, and a tap 6 of the transformer T2 is grounded.
7. The flyback switching power supply circuit of claim 6, wherein the bias power supply comprises a diode D5 and a capacitor D6; the anode of the diode D5 is connected to the tap 5 of the transformer T2, the cathode of the diode D5 is connected to the first end of the capacitor C6, and the second end of the capacitor 6 is grounded.
8. The flyback switching power supply circuit of claim 7, wherein the feedback power supply comprises a fixed resistor R9 and a fixed resistor R10; the first end of the fixed resistor R9 is connected with the anode of the diode D5, the second end of the fixed resistor R9 is connected with the first end of the fixed resistor R10, and the second end of the fixed resistor R10 is grounded.
9. The flyback switching power supply circuit of claim 8, wherein the driving circuit comprises a fixed resistor R13, a diode D7, a transistor Q2, and an integrated circuit U1; pin 8 of the integrated circuit U1 is connected to the negative electrode of the diode D5 and the first end of the capacitor C6, pin 7 of the integrated circuit U1 is connected to the second end of the fixed resistor R13, the first end of the fixed resistor R13 is connected to the base of the transistor Q2 and the positive electrode of the diode D7, the collector of the transistor Q2 is grounded, and the emitter of the transistor Q2 is connected to the negative electrode of the diode D7.
10. The flyback switching power supply circuit of claim 9, wherein the temperature sensing circuit comprises a thermistor NTC1 and a capacitor C8; the first terminal of the thermistor NTC1 is connected to the first terminal of the capacitor C8 and the pin 4 of the integrated circuit U1, respectively, and the second terminal of the thermistor NTC1 and the second terminal of the capacitor C8 are both grounded.
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| CN201911304634.5A CN110881232A (en) | 2019-12-17 | 2019-12-17 | Flyback switching power supply circuit |
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| CN201911304634.5A CN110881232A (en) | 2019-12-17 | 2019-12-17 | Flyback switching power supply circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113056061A (en) * | 2021-02-21 | 2021-06-29 | 厦门普为光电科技有限公司 | Lamp tube with electric shock protection and compatible multiple power supply modes |
| CN113473672A (en) * | 2021-05-31 | 2021-10-01 | 厦门普为光电科技有限公司 | Lamp tube with electric shock protection and compatible multiple current stable power supply modes |
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| CN203788516U (en) * | 2014-03-17 | 2014-08-20 | 无锡汉咏微电子股份有限公司 | Intelligent dimming efficient constant-current LED driving chip |
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| CN206775775U (en) * | 2017-04-25 | 2017-12-19 | 西安工业大学 | A kind of driving testing circuit of LED |
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| CN113056061A (en) * | 2021-02-21 | 2021-06-29 | 厦门普为光电科技有限公司 | Lamp tube with electric shock protection and compatible multiple power supply modes |
| CN113056061B (en) * | 2021-02-21 | 2023-11-14 | 厦门普为光电科技有限公司 | Lamp tube with electric shock protection and compatibility of various power supply modes |
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| CN113473672B (en) * | 2021-05-31 | 2023-11-14 | 厦门普为光电科技有限公司 | Lamp tube with electric shock protection and compatible multiple current stable power supply modes |
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