A multi-channel dimmable light-off non-afterglow BUCK control circuit

Abstract

A multi-channel dimmable light-off non-afterglow BUCK control circuit comprises a first output end, wherein the positive and negative electrodes of the first output end are respectively connected to the two endpoints of one end of a conduction end of a dual-channel relay K1, the two endpoints of the other end of the conduction end of the dual-channel relay K1 are commonly connected and connected to the drain of a MOS tube Q1, the source of the MOS tube Q1 is grounded, and the gate is connected to the control end of a main control unit U1; further comprising an optical coupler U3, wherein the positive electrode of the light-emitting end is connected to a control signal SW1 through a resistor R15, the negative electrode is grounded, the collector is connected to a voltage VDD, the emitter is grounded, the emitter is also connected to the base of a triode Q3, the collector of the triode Q3 is connected to the voltage VDD, the emitter outputs a voltage VCC1 and is connected to one end of a diode D3, the other end of the diode D3 outputs a first relay control signal and a signal RL1 through a resistor R13; further comprising a second BUCK circuit, wherein the BUCK circuit is connected to the signal RL1 through a diode D5.

Description

Technical Field

[0001] The invention relates to the field of LED power supplies, and in particular to a multi-channel dimming and shut-off non-afterglow BUCK control circuit. Background Art

[0002] At present, the common anode N-way dimming and shut-off BUCK circuit without afterglow is realized by controlling N dual-way relays, which leads to high product cost and low cost performance. Summary of the invention

[0003] In order to solve the above problems, the present technical solution provides a multi-channel dimmable light-off non-afterglow BUCK control circuit.

[0004] To achieve the above purpose, the technical solution is as follows:

[0005] A multi-channel dimmable light-off non-afterglow BUCK control circuit comprises at least a first BUCK circuit and a second BUCK circuit, wherein the first BUCK circuit comprises:

[0006] A first output terminal, wherein the positive and negative electrodes of the first output terminal are respectively connected to two endpoints of one end of the conduction end of the dual-circuit relay K1, and two endpoints of the other end of the conduction end of the dual-circuit relay K1 are commonly connected and connected to the drain of the MOS tube Q1, and the source of the MOS tube Q1 is grounded, and the gate is connected to the control end of the main control unit U1;

[0007] It also includes an optical coupler U3, whose positive electrode of the light-emitting end is connected to the control signal SW1 through a resistor R15, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, whose emitter is also connected to the base of the transistor Q3, whose collector is connected to the voltage VDD, whose emitter outputs the voltage VCC1 and is connected to one end of a diode D3, whose other end outputs the first relay control signal and the signal RL1 through the resistor R13;

[0008] The second BUCK circuit comprises:

[0009] A second output terminal, wherein the positive and negative electrodes of the second output terminal are connected to one end of the conduction terminal of the single-way relay K2, the other end of the conduction terminal of the single-way relay K2 is connected to the drain of the MOS tube Q2, the source of the MOS tube Q2 is grounded, and the gate is connected to the control end of the main control unit U2;

[0010] It also includes an optocoupler U4, whose positive electrode of the light-emitting end is connected to the control signal SW2 through a resistor R16, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, and whose emitter is also connected to the base of a transistor Q4. The collector of the transistor Q4 is connected to the voltage VDD, whose emitter outputs a voltage VCC2 and is connected to one end of a diode D4. The other end of the diode D4 outputs a second relay control signal through a resistor R14, and the other end of the diode D4 is also connected to the signal RL1 through a diode D5.

[0011] In some embodiments, a capacitor EC1 is provided between the positive and negative electrodes of the first output terminal, a voltage HV+, a diode D1 and a transformer T1B are provided between the two ends of the other end of the conduction end of the dual-circuit relay K1, and the source of the MOS tube Q1 is grounded through a resistor R1;

[0012] A capacitor EC1 is provided between the positive and negative electrodes of the second output terminal. The other end of the conduction end of the single-channel relay K2 is connected to the MOS tube Q2 through a transformer T2B. The transformer T2B is also connected to a voltage HV+ through a diode D2. The source of the MOS tube Q2 is grounded through a resistor R2.

[0013] In some embodiments, the emitter of the optical coupler U3 is connected to one end of the resistor R10, the other end of the resistor R10 is grounded through the resistor R5 and the diode ZD5, and the other end of the resistor R10 is also connected to the transistor Q3;

[0014] The emitter of the optical coupler U4 is connected to one end of the resistor R11 , and the other end of the resistor R11 is grounded through the resistor R7 and the diode ZD6 , respectively. The other end of the resistor R11 is also connected to the transistor Q4 .

[0015] In some embodiments, the emitter of the transistor Q3 is grounded via an electrolytic capacitor EC3, and the emitter of the transistor Q4 is grounded via an electrolytic capacitor EC4.

[0016] The beneficial effects of this application are:

[0017] The present application adopts a dual-channel relay and N-1 single-channel relays to expand the realization of a common anode N-channel dimming and shutting down BUCK circuit without afterglow, which is low in cost, greatly improves the cost performance of the product, and improves the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below.

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] Please refer to Figure 1 As shown, a multi-channel dimmable light-off non-afterglow BUCK control circuit comprises at least a first BUCK circuit and a second BUCK circuit, wherein the first BUCK circuit comprises:

[0022] A first output terminal, wherein the positive and negative electrodes of the first output terminal are respectively connected to two endpoints of one end of the conduction end of the dual-circuit relay K1, and two endpoints of the other end of the conduction end of the dual-circuit relay K1 are commonly connected and connected to the drain of the MOS tube Q1, and the source of the MOS tube Q1 is grounded, and the gate is connected to the control end of the main control unit U1;

[0023] It also includes an optical coupler U3, whose positive electrode of the light-emitting end is connected to the control signal SW1 through a resistor R15, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, whose emitter is also connected to the base of the transistor Q3, whose collector is connected to the voltage VDD, whose emitter outputs the voltage VCC1 and is connected to one end of a diode D3, whose other end outputs the first relay control signal and the signal RL1 through the resistor R13;

[0024] The second BUCK circuit comprises:

[0025] A second output terminal, wherein the positive and negative electrodes of the second output terminal are connected to one end of the conduction terminal of the single-way relay K2, the other end of the conduction terminal of the single-way relay K2 is connected to the drain of the MOS tube Q2, the source of the MOS tube Q2 is grounded, and the gate is connected to the control end of the main control unit U2;

[0026] It also includes an optocoupler U4, whose positive electrode of the light-emitting end is connected to the control signal SW2 through a resistor R16, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, and whose emitter is also connected to the base of a transistor Q4. The collector of the transistor Q4 is connected to the voltage VDD, whose emitter outputs a voltage VCC2 and is connected to one end of a diode D4. The other end of the diode D4 outputs a second relay control signal through a resistor R14, and the other end of the diode D4 is also connected to the signal RL1 through a diode D5.

[0027] In this embodiment, a capacitor EC1 is provided between the positive and negative electrodes of the first output terminal, a voltage HV+, a diode D1 and a transformer T1B are provided between the two ends of the other end of the conducting end of the dual-circuit relay K1, and the source of the MOS tube Q1 is grounded through a resistor R1;

[0028] A capacitor EC1 is provided between the positive and negative electrodes of the second output terminal. The other end of the conduction end of the single-channel relay K2 is connected to the MOS tube Q2 through a transformer T2B. The transformer T2B is also connected to a voltage HV+ through a diode D2. The source of the MOS tube Q2 is grounded through a resistor R2.

[0029] In this embodiment, the emitter of the optical coupler U3 is connected to one end of the resistor R10, the other end of the resistor R10 is grounded through the resistor R5 and the diode ZD5, and the other end of the resistor R10 is also connected to the transistor Q3;

[0030] The emitter of the optical coupler U4 is connected to one end of the resistor R11 , and the other end of the resistor R11 is grounded through the resistor R7 and the diode ZD6 , respectively. The other end of the resistor R11 is also connected to the transistor Q4 .

[0031] In this embodiment, the emitter of the transistor Q3 is grounded via an electrolytic capacitor EC3, and the emitter of the transistor Q4 is grounded via an electrolytic capacitor EC4.

[0032] When the potentials at SW1 and SW2 are both low, the optocouplers U3 and U4 are turned off through the control of resistors R15 and R16, and then the NPN transistors Q3 and Q4 are turned off through the control of resistors R10, R5, R11, R7 and the voltage regulators ZD5 and ZD6, so that the potentials of VCC1 and VCC2 are both low, and the BUCK chips U1 and U2 stop working, realizing the The BUCK chip dimming shutdown function, at the same time, the potentials through D3, D4 diodes, R13, R14 resistors to 12V1, 12V2 are low, and then the K1 dual-channel relay and the K2 single-channel relay are in the disconnected state, and the relay contacts are in the normally open state, realizing the two-channel BUCK output LED1+, LED1-, LED2+, LED2-no afterglow function. Similarly, when the potentials at SW1 and SW2 are both high, the potentials at VCC1, VCC2, 12V1, 12V2 are all high, and the two-channel BUCK chips U1, U2 work normally, realizing the normal output of the LED1+, LED1-, LED2+, LED2- ports of the two-channel BUCK.

[0033] When SW1 is at a high potential, U3 optocoupler and Q3 transistor are turned on, and SW2 is at a low potential, U4 optocoupler and Q4 transistor are not turned on, the internal auxiliary source supplies power to VDD, which is turned on by Q3 transistor, VCC1 is at a high potential, and then through D3 diode and R13 resistor, the potential at 12V1 is also at a high potential, so that K1 dual-channel relay is turned on, and the BUCK circuit controlled by U1 also works normally and outputs to LED1+ and LED1- ports. Due to the reverse non-conduction of D5 diode and the non-conduction of U4 optocoupler and Q4 transistor, the potential at RL2 and VCC2 is zero, K2 relay and U2 BUCK chip do not work, and the BUCK controlled by U2 has no output, while the BUCK controlled by U1 can output normally.

[0034] When SW1 is at a low potential, U3 optocoupler and Q3 transistor are turned off, and SW2 is at a high potential, U4 optocoupler and Q4 transistor are turned on, the internal auxiliary source supplies power to VDD, Q4 transistor is turned on, and then D4, D5 diodes, R14, R13 are turned on, 12V1, 12V2, VCC2 are at a high potential, so that K1 dual-channel relay and K2 single-channel relay are both in the on state, and the BUCK circuit controlled by U2 also works normally and outputs to LED2+ and LED2- ports. Due to the reverse non-conduction of D3 diode and non-conduction of Q3 in the patented circuit, the potential at VCC1 is zero, and the U1 BUCK chip is in the off state, which normally realizes that the BUCK controlled by U1 has no output, and the BUCK controlled by U2 can output normally.

[0035] Through the action of the D5 diode, not only can the RL2 power supply of the K2 single-channel relay be unidirectionally provided to the RL1 power supply of the K1 dual-channel relay in the main circuit, effectively ensuring that the BUCK circuit controlled by U2 is output to the LED2+, LED2- ports through the K1 and K2 relays, but it can also prevent the RL1 power supply of the dual-channel relay in the main circuit from being provided to the single-channel relays in all the extension circuits, thereby preventing the main circuit Q3 linear step-down transistor from overheating and burning. In addition, due to the unidirectional action of the D3 and D4 diodes in the patent, the power supply VCC1 potential of the U1BUCK chip is only controlled by the SW1 potential, and the power supply VCC2 potential of the U2 BUCK chip is only controlled by the SW2 potential, ensuring that each BUCK topology can be turned on and off independently without affecting each other, and correctly realizing the dimming and shutoff function of each BUCK.

[0036] This description only shows an example of adding one BUCK. Similarly, the application circuit can be expanded to add more than two BUCKs.

[0037] After adopting this circuit, the common anode N-way dimmable turn-off no-afterglow BUCK circuit does not need N dual-way relays to control, but only needs one dual-way relay and N-1 single-way relays to control, which greatly saves product cost and improves the cost performance and competitiveness of the product.

[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application. Other principles and basic structures that are the same or similar to those of the present application are within the protection scope of the present application.

Claims

1. A multi-channel dimmable light-off non-afterglow BUCK control circuit, characterized in that: At least includes a first BUCK circuit and a second BUCK circuit, wherein the first BUCK circuit includes: A first output terminal, wherein the positive and negative electrodes of the first output terminal are respectively connected to two endpoints of one end of the conduction end of the dual-circuit relay K1, and two endpoints of the other end of the conduction end of the dual-circuit relay K1 are commonly connected and connected to the drain of the MOS tube Q1, and the source of the MOS tube Q1 is grounded, and the gate is connected to the control end of the main control unit U1; It also includes an optical coupler U3, whose positive electrode of the light-emitting end is connected to the control signal SW1 through a resistor R15, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, and whose emitter is also connected to the base of a transistor Q3, whose collector is connected to the voltage VDD, whose emitter outputs a voltage VCC1 and is connected to one end of a diode D3, whose other end outputs a first relay control signal through a resistor R13, and whose other end also outputs a signal RL1; The second BUCK circuit comprises: A second output terminal, wherein the positive and negative electrodes of the second output terminal are connected to one end of the conduction terminal of the single-way relay K2, the other end of the conduction terminal of the single-way relay K2 is connected to the drain of the MOS tube Q2, the source of the MOS tube Q2 is grounded, and the gate is connected to the control end of the main control unit U2; It also includes an optical coupler U4, whose positive electrode of the light-emitting end is connected to the control signal SW2 through a resistor R16, whose negative electrode is grounded, whose collector is connected to the voltage VDD, whose emitter is grounded, and whose emitter is also connected to the base of a transistor Q4, whose collector is connected to the voltage VDD, whose emitter outputs a voltage VCC2 and is connected to one end of a diode D4, whose other end outputs a second relay control signal through a resistor R14, and whose other end is also connected to a signal RL1 through a diode D5; The voltage VCC1 is used to supply power to the VCC terminal of the main control unit U1 , and the voltage VCC2 is used to supply power to the VCC terminal of the main control unit U2 .

2. The multi-channel dimmable light-off non-afterglow BUCK control circuit according to claim 1, characterized in that: A capacitor EC1 is provided between the positive and negative electrodes of the first output terminal, a voltage HV+, a diode D1 and a transformer T1B are provided between the two ends of the other end of the conduction end of the dual-circuit relay K1, and the source of the MOS tube Q1 is grounded through a resistor R1; A capacitor EC2 is provided between the positive and negative electrodes of the second output terminal. The other end of the conduction end of the single-channel relay K2 is connected to the MOS tube Q2 through a transformer T2B. The transformer T2B is also connected to a voltage HV+ through a diode D2. The source of the MOS tube Q2 is grounded through a resistor R2.

3. The multi-channel dimmable light-off non-afterglow BUCK control circuit according to claim 1, characterized in that: The emitter of the optical coupler U3 is connected to one end of the resistor R10, the other end of the resistor R10 is grounded through the resistor R5 and the diode ZD5, and the other end of the resistor R10 is also connected to the transistor Q3; The emitter of the optical coupler U4 is connected to one end of the resistor R11 , and the other end of the resistor R11 is grounded through the resistor R7 and the diode ZD6 , respectively. The other end of the resistor R11 is also connected to the transistor Q4 .

4. The multi-channel dimmable light-off non-afterglow BUCK control circuit according to claim 3, characterized in that: The emitter of the transistor Q3 is grounded via an electrolytic capacitor EC3, and the emitter of the transistor Q4 is grounded via an electrolytic capacitor EC4.

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