CN112040604A - Overload non-output driving power supply circuit - Google Patents
Overload non-output driving power supply circuit Download PDFInfo
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- CN112040604A CN112040604A CN202011147735.9A CN202011147735A CN112040604A CN 112040604 A CN112040604 A CN 112040604A CN 202011147735 A CN202011147735 A CN 202011147735A CN 112040604 A CN112040604 A CN 112040604A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/34—Voltage stabilisation; Maintaining constant voltage
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/32—Pulse-control circuits
- H05B45/325—Pulse-width modulation [PWM]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/345—Current stabilisation; Maintaining constant current
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
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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]
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Abstract
The invention discloses an overload non-output driving power supply circuit which comprises an EMI circuit, a rectifying filter circuit, a PFC booster circuit, a PWM pulse width modulation circuit, a voltage transformation circuit, an output synchronous rectifying circuit, a constant current and constant voltage loop, a dimming control circuit, a temperature control protection circuit and an overload/short circuit protection circuit. The invention has simple circuit, reliable performance and wide applicability. The ultra-low safety low voltage, the safety is higher, the multiple sensitive protection circuit is used by the user more safely and more securely. The output overload and short-circuit protection and the design of switching off the output after overload and short circuit are realized.
Description
Technical Field
The invention relates to the technical field of LED lamp driving circuits, in particular to an overload non-output driving power supply circuit.
Background
When the output overload phenomenon appears in the drive circuit of the current LED drive circuit, the drive circuit still keeps the voltage output due to the lack of the protection circuit, and the potential safety hazard of the circuit is easily caused.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art, and provides an overload non-output driving power supply circuit, which provides safer guarantee for the circuit when preventing load abnormality and prevents accidents.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: an overload non-output driving power supply circuit comprises an EMI circuit, a rectifying and filtering circuit, a PFC booster circuit, a PWM pulse width modulation circuit, a voltage transformation circuit, an output synchronous rectifying circuit, a constant-current constant-voltage loop, a dimming control circuit, a temperature control protection circuit and an overload/short circuit protection circuit; the mains supply outputs direct current pulse voltage VIN + through an EMI circuit and a rectifying and filtering circuit, the direct current pulse voltage VIN + outputs boosted direct current voltage HV after a PFC booster circuit corrects a power factor, the direct current voltage HV outputs voltage transformation from a main primary side to a main secondary side of a voltage transformation circuit after passing through a temperature control protection circuit, the main secondary side of the voltage transformation circuit outputs load working voltage to a load through an output synchronous rectification circuit, a PWM (pulse width modulation) circuit controls the on-off of a main primary side loop of the voltage transformation circuit through a switching tube Q2, a secondary primary side loop of the voltage transformation circuit provides starting voltage for the PWM pulse width modulation circuit, and the PWM pulse width modulation circuit provides starting voltage PFC VCC to a PFC chip in the PFC booster circuit; the constant-current constant-voltage loop is used for sampling and comparing a load loop in the output synchronous rectification circuit and feeding back the load loop to the PWM circuit through the optical coupler, and the PWM circuit controls the output of the transformation circuit and the output synchronous rectification circuit according to the feedback and modulates the load through a switching circuit based on a switching tube group; the overload/short circuit protection circuit samples and detects the current of a load loop and controls the on-off of the output synchronous rectification circuit to the load output through the switch circuit, and the overload/short circuit protection circuit feeds back the on-off information of the load output to the PWM circuit through the optical coupler so as to control the output of the voltage transformation circuit.
In the above technical solution, the constant current and constant voltage loop includes an operational amplifier U6A and an operational amplifier U6B to respectively implement voltage feedback and current feedback on the load loop.
In the above technical solution, the output end of the operational amplifier U6A is connected with the diode D21 and the pull-up resistor R61 in reverse, and the output end of the operational amplifier U6B is connected with the diode D22 and the pull-up resistor R59 in reverse, which respectively form a voltage follower and a current follower.
In the above technical solution, the overload/short-circuit protection circuit includes a comparator, the comparator performs current sampling on the load loop and compares the sampled current with a reference current, an output terminal HP of the comparator outputs a detection voltage for detecting whether the load loop is overloaded/short-circuited, the detection voltage controls on/off of the switching circuit, and meanwhile, the detection voltage is fed back to the PWM pulse width modulation circuit through the photoelectric coupler.
In the above technical solution, the switching circuit includes a switching tube Q10, a switching tube Q9, a switching tube Q7, a switching tube Q6 and a switching tube Q4, the switching circuit obtains a working voltage AUX from an output end of the transformer circuit, the working voltage AUX is electrically connected to a negative electrode of a load through a series resistor R101 and a resistor R63, the other circuit is electrically connected to a control end of a switching tube Q7, an input end of the switching tube Q7 is electrically connected to a control end of the switching tube Q6, an output end of a switching tube Q6 is electrically connected to a control end of the switching tube Q4, an output end of the switching tube Q4 is used as a voltage output end VCOM + of the load, and input ends of the switching tube Q7, the switching tube Q6 and the switching tube Q4 are electrically connected to an output end OP + of the output synchronous rectification circuit; the control end of the switching tube Q10 is electrically connected with the output end HP of the comparator, one path of the input end of the switching tube Q10 is electrically connected with the node CT between the resistor R100 and the resistor R63, the other path of the input end of the switching tube Q10 is electrically connected with the control end of the switching tube Q9, and the input end of the switching tube Q9 is electrically connected with the node CT.
In the above technical solution, the output end HP of the comparator changes the on-off loop of the optocoupler by controlling the on-off of the switching tube Q8, so as to realize that the detected voltage condition of the output end HP is fed back to the PWM circuit.
In the above technical solution, the dimming control circuit outputs a PWM control signal to control the switching circuit through the switching tube Q5 to realize dimming.
In the above technical solution, the output synchronous rectification circuit includes a synchronous rectification chip U4 and a switching tube Q3, an input end VS of the switching tube Q3 is electrically connected with an output end of the transformed voltage, an output end VD of the switching tube Q3 is used as an output end OP + of the output synchronous rectification circuit, and the synchronous rectification chip U4 performs output rectification by using the input end VS and the output end VD of the switching tube Q3 as sampling points.
In the above technical solution, a connection terminal VSTART is provided in the EMI circuit and electrically connected to the start terminal of the control chip U2 of the PWM pulse width modulation circuit.
In the above technical solution, the PFC boost circuit includes a PFC chip U1, an inductor T1 and a switching tube Q1, one input end of the inductor T1 is electrically connected to a dc pulse voltage VIN +, the other input end is electrically connected to an output end of the PFC chip U1, the dc pulse voltage VIN + is electrically connected to an input end of the PFC chip U1, a control end of the switching tube Q1 is electrically connected to a control output end of the PFC chip U1, and an output end of the switching tube Q1 is electrically connected to a control end of the PFC chip U1; one path of the output end of the inductor T1 is grounded, and the other path of the output end is connected with the diode D4 and the magnetic bead FB3 in series and then outputs the direct-current voltage HV.
The invention has the beneficial effects that:
1. the circuit is simple, the performance is reliable, and the applicability is wide.
2. The ultra-low safety low voltage, the safety is higher, the multiple sensitive protection circuit is used by the user more safely and more securely.
3. The output overload and short-circuit protection and the design of switching off the output after overload and short circuit are realized.
Drawings
Fig. 1 is a schematic circuit diagram of a driving power supply circuit of the present invention.
FIG. 2 is a schematic circuit diagram of an EMI circuit, a rectifying and filtering circuit, and a temperature control protection circuit according to the present invention.
Fig. 3 is a schematic circuit diagram of the PFC boost circuit and the PWM pulse width modulation circuit according to the present invention.
Fig. 4 is a schematic diagram of the circuit principle of the transformer circuit, the output synchronous rectification circuit, the constant current and constant voltage loop and the switch circuit of the invention.
Fig. 5 is a schematic circuit diagram of the overload/short-circuit protection circuit of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1 to 5, an overload no-output driving power supply circuit includes an EMI circuit 1, a rectifying and filtering circuit 2, a PFC boost circuit 3, a PWM pulse width modulation circuit 4, a transformer circuit 5, an output synchronous rectification circuit 6, a constant current and constant voltage loop 7, a dimming control circuit 10, a temperature control protection circuit 8, and an overload/short circuit protection circuit 9. The mains supply outputs direct current pulse voltage VIN + through an EMI circuit and a rectifying and filtering circuit, the direct current pulse voltage VIN + outputs boosted direct current voltage HV after a PFC booster circuit corrects a power factor, the direct current voltage HV outputs voltage transformation from a main primary side to a main secondary side of a voltage transformation circuit after passing through a temperature control protection circuit, the main secondary side of the voltage transformation circuit outputs load working voltage to a load through an output synchronous rectification circuit, a PWM (pulse width modulation) circuit controls the on-off of a main primary side loop of the voltage transformation circuit through a switching tube Q2, a secondary primary side loop of the voltage transformation circuit provides starting voltage for the PWM pulse width modulation circuit, and the PWM pulse width modulation circuit provides starting voltage PFC VCC to a PFC chip in the PFC booster circuit; the constant current and constant voltage loop is used for sampling and comparing a load loop in the output synchronous rectification circuit and feeding back the load loop to the PWM circuit through the optical coupler, and the PWM circuit controls the output of the transformation circuit and the output synchronous rectification circuit according to the feedback and modulates the load through a switch circuit 10 based on a switch tube group; the overload/short circuit protection circuit samples and detects the current of a load loop and controls the on-off of the output synchronous rectification circuit to the load output through the switch circuit, and the overload/short circuit protection circuit feeds back the on-off information of the load output to the PWM circuit through the optical coupler so as to control the output of the voltage transformation circuit.
Specifically, the EMI circuit 1 is configured to filter interference of a high-frequency pulse of an external power grid to a power supply, and also reduce electromagnetic interference of the switching power supply itself to the outside. The EMI circuit comprises a fuse F1 connected in series, a voltage dependent resistor VR1 connected in parallel, a capacitor C3 connected in parallel, a common mode inductor LF1 and a common mode inductor LF2 connected in series, a resistor R10 and a resistor R11 connected in parallel, and a common mode inductor LF4 connected in series, wherein a diode D2 is connected in parallel in the forward direction of the resistor R10, a diode D3 is connected in parallel in the reverse direction of the resistor R11, and a node between the resistor R10 and the resistor R11 serves as a connecting end VSTSRT. A connection terminal VSTART is provided in the EMI circuit and is electrically connected with the starting terminal of a control chip U2 of the PWM circuit.
Specifically, the rectifying and filtering circuit 2 is used for stepping down, rectifying, and filtering the ac power supply into a suitable dc voltage. The rectification filter circuit comprises a rectifier BD1, an inductor L1, a capacitor C10, a capacitor C11 and a resistor R9, wherein the output end of the rectifier BD1 is connected in series with an inductor L1 and then outputs a direct-current pulse voltage VIN +, the input end of the inductor L1 is connected in series with the capacitor C10 and then is grounded, the output end of the inductor L1 is connected in series with the capacitor C11 and then is grounded, and the two ends of the inductor L1 are connected in parallel with the resistor R9.
Specifically, the PFC boost circuit 3 is configured to perform power factor correction boost on the dc pulse voltage VIN + output by the rectifying and filtering circuit to output a stable and reliable dc voltage HV. The PFC boost circuit comprises a PFC chip U1, an inductor T1 and a switching tube Q1, wherein one input end of the inductor T1 is electrically connected with a direct-current pulse voltage VIN +, the other input end of the inductor T1 is electrically connected with the output end of the PFC chip U1, the direct-current pulse voltage VIN + is electrically connected with the input end of the PFC chip U1, the control end of the switching tube Q1 is electrically connected with the control output end of the PFC chip U1, and the output end of the switching tube Q1 is electrically connected with the control end of the PFC chip U1; one path of the output end of the inductor T1 is grounded, and the other path of the output end is connected with the diode D4 and the magnetic bead FB3 in series and then outputs the direct-current voltage HV. The direct-current pulse voltage VIN + series resistor R2 and the resistor R4 are electrically connected with the MULT end of the PFC chip U1. The switch tube Q1 is an MOS tube, a control end of the switch tube Q1 is connected with a resistor R3 and a resistor R49 in series and then is electrically connected with a control output end of a PFC chip U1, the resistor R3 is connected with a diode D1 in parallel, an output end of the switch tube Q1 is connected with a magnetic bead FB1 in series and then is connected with resistors R20, R21 and R22 in series and then is grounded, the resistors R20, R21 and R22 are connected in parallel, and the resistors R20, R21 and R22 are connected with a diode D16 and a diode D19 in parallel.
Specifically, the PWM pulse width modulation circuit 4 is configured to control the input and output of the transformer circuit according to the feedback signal collected by the feedback terminal. The PWM circuit comprises a control chip U2, a control output end of the control chip U2 is electrically connected with a series resistor R27 and a control end of a switch tube Q2 after being connected with a resistor R39 in series, a diode D6 is connected in parallel in reverse direction with a resistor R27, an output end of the switch tube Q2 is connected with a magnetic bead FB2 in series and then connected with resistors R47, R46, R99, R45 and R44 in series and then connected with the ground, the resistors R47, R46, R99, R45 and R44 are in parallel connection, and the resistors R47, R46, R99, R45 and R44 are also connected with a diode D17 and a diode D20 in series in parallel connection; the control end and the output end of the switching tube Q2 are connected with a resistor R40 in parallel. The feedback end of the control chip U2 is electrically connected with an optocoupler receiving end U3B of the optocoupler, and the input and output ends of the optocoupler receiving end U3B are connected with a capacitor C24 in parallel. A secondary primary side loop of the transformation circuit is connected in series with a diode D7, a resistor R13, a diode D5 and a polar capacitor C15 and then grounded, and the cathode end of the diode D5 is electrically connected with a starting end VCC of a control chip U2.
Specifically, the transforming circuit 5 is configured to transform the dc voltage HV output by the PFC boost circuit into an operating voltage output required by the load. The transformer circuit comprises a transformer T2, the input end of which has a primary side and a secondary side, and the output end of which has a primary side and a secondary side. The secondary primary side loop is connected with a capacitor C12 in parallel, and the secondary primary side loop and the main secondary side loop are connected with a capacitor C19 in parallel.
Specifically, the output synchronous rectification circuit 6 is used for a power MOSFET with extremely low on-state resistance to replace a rectifier diode, so that the loss of the rectifier can be greatly reduced, the efficiency of the DC/DC converter is improved, and the requirements of low-voltage and large-current rectification are met. The output synchronous rectification circuit comprises a switching tube Q3, polar capacitors C28, C20, C29, a capacitor C26 and a common-mode inductor LF3, wherein the input end of the common-mode inductor LF3 is connected with a resistor R83 in parallel and is connected with the resistor R51 in series to serve as an output voltage sampling point VD of a synchronous rectification chip U4, the output point of the common-mode inductor LF3 is connected with a resistor R78 and a light-emitting diode LED1 in parallel from C1, and the output end of the common-mode inductor LF3 serves as an output end OP + of the output synchronous rectification circuit. A series capacitor C27 and a resistor R37 are connected in parallel between the input end and the output end of the switching tube Q3, and a resistor R38 is connected in parallel with the resistor R37. The input end VS of the switch tube Q3 is electrically connected with the output end of the transformation voltage, the output end VD of the switch tube Q3 is used as the output end OP + of the output synchronous rectification circuit, and the synchronous rectification chip U4 carries out output rectification by taking the input end VS and the output end VD of the switch tube Q3 as sampling points. The synchronous rectification chip U4 is provided with a starting voltage by a secondary side SB series diode D8 of the voltage transformation circuit.
Specifically, the constant current and constant voltage loop 7 is used for sampling current and voltage signals output from the synchronous trimming circuit and feeding the current and voltage signals back to the PWM circuit so as to adjust the constant current and the constant voltage. The constant-current constant-voltage loop comprises an operational amplifier U6A and an operational amplifier U6B, and voltage feedback and current feedback of a load loop are achieved respectively. The output end of the operational amplifier U6A is connected with a diode D21 and a pull-up resistor R61 in an opposite mode, and the output end of the operational amplifier U6B is connected with a diode D22 and a pull-up resistor R59 in an opposite mode, so that a voltage follower and a current follower are formed respectively. The V0 end of the output synchronous rectification circuit is connected in series with the resistor 58, the resistor R67 and the resistor R42 and then grounded, and the voltage of a node between the resistor R58 and the resistor R67 is used as a reference voltage source 2.5V for a subsequent comparator.
Specifically, the temperature control protection circuit 8 is used for protecting the temperature of the input end of the transformer. The temperature control protection circuit is electrically connected to a main primary circuit of the transformer and comprises resistors R24, R23, R25, R32, R33, R34, R35, R36, a fuse F2, a diode D9 and a capacitor C21. The system has the advantages of overload output and short-circuit protection, the output design is switched off after overload and short circuit, after overload or short circuit, the mains supply is switched off and the fault is relieved, the time is about 10 seconds, then the mains supply is switched on again, normal output can be realized, and the short-circuit power is ultralow. When the working temperature of F2 reaches 110 +/-5 ℃, the circuit immediately cuts off the output; when the working temperature of F2 drops by 75 +/-15 ℃, the circuit automatically restores the output. From this, the purpose of excess temperature protection has been realized.
Specifically, the overload/short-circuit protection circuit 9 is used to protect the circuit when an overload/short-circuit phenomenon occurs in the output. The overload/short circuit protection circuit comprises a comparator, the comparator samples current of the load loop and compares the current with reference current, the output end HP of the comparator outputs detection voltage whether the load loop is overloaded/short-circuited, the detection voltage controls the on-off of the switch circuit, and meanwhile, the detection voltage is fed back to the PWM circuit through a photoelectric coupler. The switching circuit 10 comprises a switching tube Q10, a switching tube Q9, a switching tube Q7, a switching tube Q6 and a switching tube Q4, the switching circuit obtains a working voltage AUX from the output end of the transformer circuit, one path of series resistor R101 behind the working voltage AUX series resistor R100 and the resistor R63 is electrically connected with the negative electrode of a load, the other path of series resistor R101 is electrically connected with the control end of a switching tube Q7, the input end of the switching tube Q7 is electrically connected with the control end of the switching tube Q6, the output end of the switching tube Q6 is electrically connected with the control end of the switching tube Q4, the output end of the switching tube Q4 is used as the voltage output end VCOM + of the load, and the input ends of the switching tube Q7, the switching tube Q6 and the switching tube Q4 are electrically connected with the output end OP + of the; the control end of the switching tube Q10 is electrically connected with the output end HP of the comparator, one path of the input end of the switching tube Q10 is electrically connected with the node CT between the resistor R100 and the resistor R63, the other path of the input end of the switching tube Q10 is electrically connected with the control end of the switching tube Q9, and the input end of the switching tube Q9 is electrically connected with the node CT. The output end HP of the comparator is switched on and off by controlling a switching tube Q8 to change the on-off loop of the optical coupler so as to realize that the detection voltage condition of the output end HP is fed back to the PWM circuit.
Specifically, the dimming control circuit 10 is a control circuit that outputs a dimming signal PWM. The dimming control circuit outputs a PWM control signal to control the switching circuit through a switching tube Q5 to realize dimming.
The working principle of the invention is as follows: emphasis is placed on overload protection. When the output end is overloaded or short-circuited, the circuit respectively pulls the potentials of the pins 3, 5, 10 and 12 of the comparators U8 and U9 to 0 potential through the sampling resistors R66, R70, R72, R74 and R82, at this time, the pins 1, 7, 8 and 14 of the comparators U8 and U9 output a high level of about 0.7V, and simultaneously, a capacitor C34 continuously provides a high level for the base of the switching tube Q9 and the collector of the switching tube Q10 through a resistor R100, at this time, the switching tubes Q9 and Q10 are turned on, the switching tube Q9 outputs a high level, the base of the switching tube Q7 obtains a high level after voltage division is carried out through the resistor R63 and the resistor R101, the switching tube Q7 is turned on, the switching tube Q7 turns on, the resistor R64 provides a high level for the base of the switching tube Q6, the switching tube Q6 is turned on, and the gate QP 58 is turned off, so that the overload protection of the switching tube Q6 and the output of the short-off are realized. .
The above examples are intended to illustrate rather than to limit the invention, and all equivalent changes and modifications made by the methods described in the claims of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. An overload no-output driving power supply circuit, characterized in that: the power supply circuit comprises an EMI circuit, a rectifying and filtering circuit, a PFC booster circuit, a PWM pulse width modulation circuit, a voltage transformation circuit, an output synchronous rectification circuit, a constant current and constant voltage loop, a dimming control circuit, a temperature control protection circuit and an overload/short circuit protection circuit; the mains supply outputs direct current pulse voltage VIN + through an EMI circuit and a rectifying and filtering circuit, the direct current pulse voltage VIN + outputs boosted direct current voltage HV after a PFC booster circuit corrects a power factor, the direct current voltage HV outputs voltage transformation from a main primary side to a main secondary side of a voltage transformation circuit after passing through a temperature control protection circuit, the main secondary side of the voltage transformation circuit outputs load working voltage to a load through an output synchronous rectification circuit, a PWM (pulse width modulation) circuit controls the on-off of a main primary side loop of the voltage transformation circuit through a switching tube Q2, a secondary primary side loop of the voltage transformation circuit provides starting voltage for the PWM pulse width modulation circuit, and the PWM pulse width modulation circuit provides starting voltage PFC VCC to a PFC chip in the PFC booster circuit; the constant-current constant-voltage loop is used for sampling and comparing a load loop in the output synchronous rectification circuit and feeding back the load loop to the PWM circuit through the optical coupler, and the PWM circuit controls the output of the transformation circuit and the output synchronous rectification circuit according to the feedback and modulates the load through a switching circuit based on a switching tube group; the overload/short circuit protection circuit samples and detects the current of a load loop and controls the on-off of the output synchronous rectification circuit to the load output through the switch circuit, and the overload/short circuit protection circuit feeds back the on-off information of the load output to the PWM circuit through the optical coupler so as to control the output of the voltage transformation circuit.
2. An overload no-output driving power supply circuit according to claim 1, wherein: the constant-current constant-voltage loop comprises an operational amplifier U6A and an operational amplifier U6B, and voltage feedback and current feedback of a load loop are achieved respectively.
3. An overload no-output driving power supply circuit according to claim 2, wherein: the output end of the operational amplifier U6A is connected with a diode D21 and a pull-up resistor R61 in an opposite mode, and the output end of the operational amplifier U6B is connected with a diode D22 and a pull-up resistor R59 in an opposite mode, so that a voltage follower and a current follower are formed respectively.
4. An overload no-output driving power supply circuit according to claim 1, wherein: the overload/short circuit protection circuit comprises a comparator, the comparator samples current of the load loop and compares the current with reference current, the output end HP of the comparator outputs detection voltage whether the load loop is overloaded/short-circuited, the detection voltage controls the on-off of the switch circuit, and meanwhile, the detection voltage is fed back to the PWM circuit through a photoelectric coupler.
5. The power supply circuit according to claim 4, wherein: the switching circuit comprises a switching tube Q10, a switching tube Q9, a switching tube Q7, a switching tube Q6 and a switching tube Q4, the switching circuit obtains a working voltage AUX from the output end of the transformer circuit, one path of series resistor R101 behind the working voltage AUX series resistor R100 and the resistor R63 is electrically connected with the negative electrode of a load, the other path of series resistor R101 is electrically connected with the control end of a switching tube Q7, the input end of the switching tube Q7 is electrically connected with the control end of the switching tube Q6, the output end of the switching tube Q6 is electrically connected with the control end of the switching tube Q4, the output end of the switching tube Q4 is used as the voltage output end VCOM + of the load, and the input ends of the switching tube Q7, the switching tube Q6 and the switching tube Q4 are electrically connected with the output end OP + of; the control end of the switching tube Q10 is electrically connected with the output end HP of the comparator, one path of the input end of the switching tube Q10 is electrically connected with the node CT between the resistor R100 and the resistor R63, the other path of the input end of the switching tube Q10 is electrically connected with the control end of the switching tube Q9, and the input end of the switching tube Q9 is electrically connected with the node CT.
6. The power supply circuit according to claim 4, wherein: the output end HP of the comparator is switched on and off by controlling a switching tube Q8 to change the on-off loop of the optical coupler so as to realize that the detection voltage condition of the output end HP is fed back to the PWM circuit.
7. An overload no-output driving power supply circuit according to claim 1, wherein: the dimming control circuit outputs a PWM control signal to control the switching circuit through a switching tube Q5 to realize dimming.
8. An overload no-output driving power supply circuit according to claim 1, wherein: the output synchronous rectification circuit comprises a synchronous rectification chip U4 and a switching tube Q3, wherein the input end VS of the switching tube Q3 is electrically connected with the output end of the variable voltage, the output end VD of the switching tube Q3 is used as the output end OP + of the output synchronous rectification circuit, and the synchronous rectification chip U4 carries out output rectification by taking the input end VS of the switching tube Q3 and the output end VD as sampling points.
9. An overload no-output driving power supply circuit according to claim 1, wherein: a connection terminal VSTART is provided in the EMI circuit and is electrically connected with the starting terminal of a control chip U2 of the PWM circuit.
10. An overload no-output driving power supply circuit according to claim 1, wherein: the PFC boost circuit comprises a PFC chip U1, an inductor T1 and a switching tube Q1, wherein one input end of the inductor T1 is electrically connected with a direct-current pulse voltage VIN +, the other input end of the inductor T1 is electrically connected with the output end of the PFC chip U1, the direct-current pulse voltage VIN + is electrically connected with the input end of the PFC chip U1, the control end of the switching tube Q1 is electrically connected with the control output end of the PFC chip U1, and the output end of the switching tube Q1 is electrically connected with the control end of the PFC chip U1; one path of the output end of the inductor T1 is grounded, and the other path of the output end is connected with the diode D4 and the magnetic bead FB3 in series and then outputs the direct-current voltage HV.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011147735.9A CN112040604A (en) | 2020-10-23 | 2020-10-23 | Overload non-output driving power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011147735.9A CN112040604A (en) | 2020-10-23 | 2020-10-23 | Overload non-output driving power supply circuit |
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| Publication Number | Publication Date |
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| CN112040604A true CN112040604A (en) | 2020-12-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011147735.9A Pending CN112040604A (en) | 2020-10-23 | 2020-10-23 | Overload non-output driving power supply circuit |
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| Country | Link |
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| CN (1) | CN112040604A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114465197A (en) * | 2022-01-21 | 2022-05-10 | 深圳市鸿远微思电子有限公司 | Novel short-circuit protection BRCT clamping absorption circuit |
-
2020
- 2020-10-23 CN CN202011147735.9A patent/CN112040604A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114465197A (en) * | 2022-01-21 | 2022-05-10 | 深圳市鸿远微思电子有限公司 | Novel short-circuit protection BRCT clamping absorption circuit |
| WO2023138056A1 (en) * | 2022-01-21 | 2023-07-27 | 深圳市鸿远微思电子有限公司 | Novel short circuit protection brct clamping and absorption circuit |
| CN114465197B (en) * | 2022-01-21 | 2024-05-03 | 深圳市鸿远微思电子有限公司 | Clamp absorption circuit for short-circuit protection BRCT |
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