LED driving circuit applied to two-line programming, LED driving power supply and LED driving system

Abstract

The application relates to an LED driving circuit, an LED driving power supply and an LED driving system applied to two-line programming, which comprises a voltage division circuit, a switch control circuit, a first isolation circuit, a second isolation circuit, a voltage stabilizing circuit and a master control unit; the voltage division circuit generates a detection signal; the switch control circuit wakes up the master control unit, and after being turned on, continuously turns on according to a delay-on signal output by the master control unit and is turned off after reaching a delay time; the master control unit starts working according to a wake-up signal, and judges whether it is an offline state according to the detection signal; if yes, a delay-on signal is sent; if not, no delay-on signal is sent; and the second isolation circuit transmits a power supply signal of an internal auxiliary power supply port to the voltage stabilizing circuit. The application can disconnect the fault driving power supply from the parallel machine network in an abnormal or fault state, avoid problems in the parallel machine use state, and ensure normal use of the two-line programming function.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED driving power supply, and more particularly to an LED driving circuit applied to two-wire programming, an LED driving power supply and an LED driving system. BACKGROUND

[0002] Currently, the programmability of output current and additional functions has become a standard of LED driving power supply, especially intelligent LED driving power supply. In order to facilitate production, debugging and use, offline programming has gradually become the mainstream configuration, and offline two-wire programming is more and more favored by end users because it can realize programming without providing additional power supply. In the two-wire programming mode, the programming line and the dimming line are utilized, that is, the dimming line and the programming line are shared and used in parallel, and all the dimming lines of the LED driving power supply are connected to the controller in parallel after being connected to the controller to realize the control of start-up, shutdown and dimming. The basic working principle of offline two-wire programming is that during offline programming, the MCU circuit directly takes power from the programming signal line, that is, the programming line supplies power to the MCU (power supply circuit 1) at the same time of programming. When the LED driving power supply is normally powered on, the MCU is powered by the auxiliary winding (power supply circuit 2).

[0003] However, the existing two-wire programming circuit has the following defects:

[0004] 1. In the parallel use case, if the power supply circuit 2 of one or several LED driving power supplies is abnormal (such as drive damage, AC input line abnormality), the MCU will take power from the power supply circuit 1, thereby causing the dimming line voltage to be pulled down, the output current of the LED driving power supply to decrease, and the brightness of the lamp to decrease, which is particularly prominent when the controller driving capacity is not enough or when multiple LED driving power supplies are abnormal at the same time;

[0005] 2. In the parallel use case, if the MCU power supply of one or several LED driving power supplies is short-circuited, the faulty LED driving power supply will pull down the dimming line voltage of the entire system to a very low level, thereby causing the entire system to shut down;

[0006] 3. In the parallel use case, if one or several LED driving power supplies work in the hiccup mode (such as output short circuit), the faulty LED driving power supply will intermittently take power from the power supply circuit 1, thereby pulling down the dimming line voltage of the entire system, and causing the entire system to have a lamp flashing problem. SUMMARY

[0007] The technical problem to be solved by the present application is to provide an LED driving circuit applied to two-wire programming, an LED driving power supply and an LED driving system in view of the problems in the prior art.

[0008] The technical scheme adopted by the present application to solve its technical problems is: a LED drive circuit applied to two-line programming is constructed, comprising: a voltage dividing circuit, a switch control circuit, a first isolation circuit, a second isolation circuit, a voltage stabilizing circuit and a master control unit;

[0009] The input end of the voltage dividing circuit is connected with an internal auxiliary power supply port, the output end of the voltage dividing circuit is connected with a detection end of the master control unit, the input end of the switch control circuit is connected with a burning / lighting signal port, the output end of the switch control circuit is connected with the input end of the first isolation circuit, the output end of the first isolation circuit is connected with the input end of the voltage stabilizing circuit, the input end of the second isolation circuit is connected with the internal auxiliary power supply port, the output end of the second isolation circuit is connected with the input end of the voltage stabilizing circuit, the output end of the voltage stabilizing circuit is connected with a power supply end of the master control unit, and the master control unit is further connected with the switch control circuit;

[0010] The voltage dividing circuit is used for detecting the power supply signal of the internal auxiliary power supply port and generating a detection signal;

[0011] The switch control circuit is used for turning on according to the burning signal of the burning / lighting signal port to transmit the wake-up signal to the master control unit through the first isolation circuit and the voltage stabilizing circuit in sequence when burning offline, and continuously turning on according to the delay turn-on signal output by the master control unit after turning on, and turning off after reaching the delay time;

[0012] The master control unit is used for starting work according to the wake-up signal, and judging whether it is offline according to the detection signal after starting work, if yes, sending the delay turn-on signal to the switch control circuit, and if no, not sending the delay turn-on signal;

[0013] The second isolation circuit is used for transmitting the power supply signal of the internal auxiliary power supply port to the voltage stabilizing circuit.

[0014] In the LED drive circuit applied to two-line programming, the switch control circuit comprises: an isolation switch, a wake-up circuit and a PWM detection circuit.

[0015] The first end of the isolation switch and the input end of the wake-up circuit are connected with the internal auxiliary power supply port, the second end of the isolation switch is connected with the wake-up circuit, the third end of the isolation switch is connected with the input end of the first isolation circuit, the input end of the PWM detection circuit is connected with the master control unit, and the output end of the PWM detection circuit is connected with the wake-up circuit.

[0016] The wake-up circuit is used to control the isolation switch to be turned on according to the burning signal of the burning / dimming signal port during offline burning, so as to transmit the wake-up signal to the first isolation circuit through the isolation switch; the PWM detection circuit is used to receive the delayed on-signal output by the main control unit, and control the isolation switch to be continuously turned on according to the delayed on-signal, and control the isolation switch to be turned off after the delay time is reached.

[0017] In the LED driving circuit for two-wire programming described in the present invention, the wake-up circuit includes: a unidirectional conduction circuit, a first RC network, a second RC network, a wake-up switch, and a control switch;

[0018] The input end of the unidirectional conduction circuit is connected to the burning / dimming signal port, the output end of the unidirectional conduction circuit is connected to the input end of the first RC network and the input end of the second RC network, the output end of the first RC network is connected to the first end of the wake-up switch, the output end of the second RC network is connected to the second end of the wake-up switch, the third end of the wake-up switch is connected to the input end of the control switch, the output end of the control switch is connected to the second end of the isolation switch, and the control end of the control switch is connected to the PWM detection circuit.

[0019] In the LED driver circuit for two-wire programming according to the present invention, the unidirectional conduction circuit includes: a third diode; the first RC network includes: a second resistor, a third resistor, and a first capacitor; the second RC network includes: a fourth resistor, a fifth resistor, and a second capacitor; the wake-up switch includes: a second MOS transistor; and the control switch includes: a sixth resistor and a third MOS transistor.

[0020] The anode of the third diode is connected to the burning / dimming signal port, the cathode of the third diode is connected to the first end of the second resistor and the first end of the fourth resistor, the second end of the second resistor is connected to the first end of the third resistor, the first end of the first capacitor, and the source of the second MOS transistor, and the second end of the third resistor and the second end of the first capacitor are grounded; the second end of the fourth resistor is connected to the first end of the fifth resistor, the first end of the second capacitor, and the gate of the second MOS transistor, and the second end of the fifth resistor and the second end of the second capacitor are grounded;

[0021] The drain of the second MOS transistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the gate of the third MOS transistor, the gate of the third MOS transistor is also connected to the PWM detection circuit, the drain of the third MOS transistor is connected to the second end of the isolation switch, and the source of the third MOS transistor is grounded.

[0022] In the LED driving circuit applied to two-line programming, the resistance value of the second resistor is the same as that of the fourth resistor, the resistance value of the third resistor is the same as that of the fifth resistor, and the capacitance value of the first capacitor is smaller than that of the second capacitor.

[0023] In the LED driving circuit applied to two-line programming, the PWM detection circuit comprises a seventh resistor, a third capacitor, a fourth capacitor, a fourth diode and a fifth diode.

[0024] The first end of the seventh resistor, the first end of the third capacitor and the cathode of the fourth diode are connected to the gate of the third MOS tube, the second end of the seventh resistor, the second end of the third capacitor and the anode of the fifth diode are grounded, the anode of the fourth diode is connected to the cathode of the fifth diode and the first end of the fourth capacitor, and the second end of the fourth capacitor is connected to the master control unit.

[0025] In the LED driving circuit applied to two-line programming, the voltage dividing circuit comprises a twelfth resistor and a thirteenth resistor.

[0026] The first end of the twelfth resistor is connected to the internal auxiliary power supply port, the second end of the twelfth resistor is connected to the first end of the thirteenth resistor and the detection end of the master control unit, and the second end of the thirteenth resistor is grounded.

[0027] In the LED driving circuit applied to two-line programming, the first isolation circuit comprises a first diode, the second isolation circuit comprises a second diode, and the voltage stabilizing circuit comprises a ninth resistor, a tenth resistor, an eleventh resistor, a reference device, a fifth capacitor and a fourth triode.

[0028] The anode of the first diode is connected to the output end of the switch control circuit, the anode of the first diode is connected to the emitter of the fourth triode and the cathode of the second diode, the anode of the second diode is connected to the internal auxiliary power supply port, the emitter of the fourth triode is connected to the power supply end of the master control unit, the base of the fourth triode is connected to the first end of the fifth capacitor, the second end of the fifth capacitor is connected to the second end of the reference device and the second end of the tenth resistor, and the first end of the tenth resistor is connected to the emitter of the fourth triode.

[0029] The first end of the ninth resistor is connected to the collector of the fourth triode, the second end of the ninth resistor is connected to the base of the fourth triode and the first end of the reference device, the third end of the reference device and the second end of the eleventh resistor are grounded, and the second end of the tenth resistor is connected to the first end of the eleventh resistor.

[0030] The application also provides an LED driving power supply, comprising the LED driving circuit for two-line programming.

[0031] The application also provides an LED driving system, comprising a plurality of LED driving power supplies used in parallel, each of the LED driving power supplies comprising the LED driving circuit for two-line programming.

[0032] The LED driving circuit for two-line programming, the LED driving power supply and the LED driving system have the following beneficial effects: comprising a voltage dividing circuit, a switch control circuit, a first isolation circuit, a second isolation circuit, a voltage stabilizing circuit and a master control unit; the voltage dividing circuit generates a detection signal; the switch control circuit wakes up the master control unit and, after being turned on, continues to be turned on according to a delay-on signal output by the master control unit and is turned off after a delay time is reached; the master control unit starts working according to a wake-up signal and judges whether it is in an offline state according to the detection signal, if yes, sends the delay-on signal, and if no, does not send the delay-on signal; the second isolation circuit transmits a power supply signal of an internal auxiliary power supply port to the voltage stabilizing circuit. The application can disconnect the faulty driving power supply from the parallel network in an abnormal or faulty state, avoid problems in parallel use, and ensure normal use of the two-line programming function. BRIEF DESCRIPTION OF DRAWINGS

[0033] The application will be further described below in combination with the drawings and examples, in which:

[0034] Figure 1 is a principle block diagram of the LED driving circuit for two-line programming provided by the application;

[0035] Figure 2 is a circuit principle diagram of the LED driving circuit for two-line programming provided by the application;

[0036] Figure 3 is a voltage waveform diagram of the gate, the source and the VCC voltage of the wake-up switch when DIM+ is powered on;

[0037] Figure 4 is a voltage waveform diagram of the gate, the source of the wake-up switch when a PWM dimming signal is applied to DIM+;

[0038] Figure 5 is a gate voltage waveform diagram of the third MOS tube when a PWM dimming signal is applied to V-G;

[0039] Figure 6 is a gate voltage waveform diagram of the third MOS tube when a high or low level is applied to V-G;

[0040] Figure 7 This is the complete power-on programming process provided by the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] The present invention provides a switch control circuit in a driving power supply for two-wire programming (i.e., two-wire burning). When an LED driving power supply fails, the dimming line of the failed LED driving power supply can be promptly and effectively disconnected from the parallel network, thereby achieving the purpose of not affecting the normal operation of other grid-connected LED driving power supplies and ensuring the normal use of the two-wire burning function.

[0043] refer to Figure 1 , Figure 1 This is a principle block diagram of a preferred embodiment of an LED driving circuit for two-wire programming provided by the present invention.

[0044] Specifically, such as Figure 1 As shown, in this embodiment, the LED driving circuit applied to two-wire programming includes: a voltage divider circuit 11, a switch control circuit 12, a first isolation circuit 13, a second isolation circuit 14, a voltage stabilizing circuit 15 and a main control unit 16.

[0045] The input end of the voltage divider circuit 11 is connected to the internal auxiliary power supply port, the output end of the voltage divider circuit 11 is connected to the detection end of the main control unit 16, the input end of the switch control circuit 12 is connected to the burning / dimming signal port, the output end of the switch control circuit 12 is connected to the input end of the first isolation circuit 13, the output end of the first isolation circuit 13 is connected to the input end of the voltage stabilizing circuit 15, the input end of the second isolation circuit 14 is connected to the internal auxiliary power supply port, the output end of the second isolation circuit 14 is connected to the input end of the voltage stabilizing circuit 15, the output end of the voltage stabilizing circuit 15 is connected to the power supply end of the main control unit 16, and the main control unit 16 is also connected to the switch control circuit 12.

[0046] The voltage dividing circuit 11 is configured to detect the power signal of the internal auxiliary power port and generate a detection signal; the switch control circuit 12 is configured to be turned on according to the programming signal of the programming / dimming signal port when offline programming, so as to transmit the wake-up signal to the main control unit 16 through the first isolation circuit 13 and the voltage stabilizing circuit 15 in sequence, and after being turned on, the switch control circuit 12 is configured to be continuously turned on according to the delay-on signal output by the main control unit 16, and be turned off after the delay time is reached; the main control unit 16 is configured to start working according to the wake-up signal, and after starting working, the main control unit 16 is configured to judge whether it is offline according to the detection signal, if yes, the main control unit 16 is configured to send the delay-on signal to the switch control circuit 12, if not, the main control unit 16 is configured to not send the delay-on signal; and the second isolation circuit 14 is configured to transmit the power signal of the internal auxiliary power port to the voltage stabilizing circuit 15.

[0047] Specifically, through the switch control circuit 12, when offline programming, the switch control circuit 12 can be turned on according to the programming signal, and then the wake-up signal (which is the programming signal) is transmitted through the first isolation circuit 13 and the voltage stabilizing circuit 15 in sequence, so as to provide a power supply voltage to the main control unit 16, so as to wake up the main control unit 16. After the main control unit 16 is woken up, the power signal output by the internal auxiliary power port is detected by the voltage dividing circuit 11 to generate a corresponding detection signal, so that the main control unit 16 can judge whether the current state of the LED driving power supply is offline or online based on the detection signal. If it is judged that the current state of the LED driving power supply is online, the main control unit 16 controls the switch control circuit 12 to be cut off; if it is judged that the current state of the LED driving power supply is offline, the main control unit 16 sends a delay-on signal to the switch control circuit 12, so that the switch control circuit 12 is continuously turned on through the delay-on signal, and is turned off after the delay time is reached, so as to disconnect the power supply loop 1 from the dimming / programming line.

[0048] Optionally, in the embodiment of the present application, the switch control circuit 12 comprises an isolation switch 121, a wake-up circuit 122 and a PWM detection circuit 123.

[0049] The first end of the isolating switch 121 and the input end of the wake-up circuit 122 are connected with the internal auxiliary power supply port, the second end of the isolating switch 121 is connected with the wake-up circuit 122, the third end of the isolating switch 121 is connected with the input end of the first isolation circuit 13, the input end of the PWM detection circuit 123 is connected with the main control unit 16, and the output end of the PWM detection circuit 123 is connected with the wake-up circuit 122; the wake-up circuit 122 is used for controlling the isolating switch 121 to be turned on according to the programming signal of the programming / dimming signal port when offline programming, so as to transmit the wake-up signal to the first isolation circuit 13 through the isolating switch 121; and the PWM detection circuit 123 is used for receiving the delay-on signal output by the main control unit 16, and controlling the isolating switch 121 to be continuously turned on according to the delay-on signal, and controlling the isolating switch 121 to be turned off after the delay time is reached.

[0050] The wake-up circuit 122 comprises a one-way conduction circuit, a first RC network, a second RC network, a wake-up switch and a control switch; the input end of the one-way conduction circuit is connected with the programming / dimming signal port, the output end of the one-way conduction circuit is connected with the input end of the first RC network and the input end of the second RC network, the output end of the first RC network is connected with the first end of the wake-up switch, the output end of the second RC network is connected with the second end of the wake-up switch, the third end of the wake-up switch is connected with the input end of the control switch, the output end of the control switch is connected with the second end of the isolating switch 121, and the control end of the control switch is connected with the PWM detection circuit 123. Specifically, the delay-on signal sent by the main control unit 16 to the PWM detection circuit 123 is a fixed-frequency PWM signal, and the PWM detection circuit 123 controls the isolating switch 121 to be kept turned on only when the fixed-frequency PWM signal is received. Since the main control unit 16 stops sending the fixed-frequency PWM signal to the PWM detection circuit 123 after a preset delay time (wherein the delay time needs to ensure that a normal programming is completed), the PWM detection circuit 123 no longer controls the isolating switch 121 to be kept turned on, that is, the isolating switch 121 is controlled to be turned off, so that the power supply circuit 1 is disconnected from the dimming / programming line.

[0051] The principles of the application are described below with reference to a specific embodiment.

[0052] Reference Figure 2 , Figure 2 The circuit principle diagram of the LED driving circuit for two-wire programming provided by the application is shown in the following preferred embodiment.

[0053] As Figure 2As shown, in this embodiment, Q1 is an isolation switch 121. The unidirectional conduction circuit includes: a third diode D3; a first RC network including: a second resistor R2, a third resistor R3, and a first capacitor C1; a second RC network including: a fourth resistor R4, a fifth resistor R5, and a second capacitor C2; a wake-up switch Q2 including: a second MOS transistor; and a control switch including: a sixth resistor R6 and a third MOS transistor Q3.

[0054] The anode of the third diode D3 is connected to the burning / dimming signal port, the cathode of the third diode D3 is connected to the first end of the second resistor R2 and the first end of the fourth resistor R4, the second end of the second resistor R2 is connected to the first end of the third resistor R3, the first end of the first capacitor C1, and the source of the second MOS transistor, and the second end of the third resistor R3 and the second end of the first capacitor C1 are grounded; the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5, the first end of the second capacitor C2, and the gate of the second MOS transistor, and the second end of the fifth resistor R5 and the second end of the second capacitor C2 are grounded; the drain of the second MOS transistor is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the gate of the third MOS transistor Q3, the gate of the third MOS transistor Q3 is also connected to the PWM detection circuit 123, the drain of the third MOS transistor Q3 is connected to the second end of the isolation switch 121, and the source of the third MOS transistor Q3 is grounded.

[0055] In the embodiment of the present invention, the resistance of the second resistor R2 is the same as that of the fourth resistor R4, the resistance of the third resistor R3 is the same as that of the fifth resistor R5, and the capacitance of the first capacitor C1 is smaller than that of the second capacitor C2.

[0056] like Figure 2 As shown, in this embodiment, the PWM detection circuit 123 includes: a seventh resistor R7, a third capacitor C3, a fourth capacitor C4, a fourth diode D4 and a fifth diode D5.

[0057] A first end of the seventh resistor R7, a first end of the third capacitor C3, and a cathode of the fourth diode D4 are connected to the gate of the third MOS transistor Q3. A second end of the seventh resistor R7, a second end of the third capacitor C3, and an anode of the fifth diode D5 are grounded. An anode of the fourth diode D4 is connected to the cathode of the fifth diode D5 and the first end of the fourth capacitor C4. A second end of the fourth capacitor C4 is connected to the main control unit 16.

[0058] like Figure 2 As shown, in this embodiment, the voltage divider circuit 11 includes: a twelfth resistor R12 and a thirteenth resistor R13; the first end of the twelfth resistor R12 is connected to the internal auxiliary power supply port, the second end of the twelfth resistor R12 is connected to the first end of the thirteenth resistor R13 and the detection end of the main control unit 16, and the second end of the thirteenth resistor R13 is grounded.

[0059] like Figure 2 As shown, in this embodiment, the first isolation circuit 13 includes: a first diode D1; the second isolation circuit 14 includes: a second diode D2; the voltage stabilizing circuit 15 includes: a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a reference device U1, a fifth capacitor C5 and a fourth transistor Q4.

[0060] Among them, the anode of the first diode D1 is connected to the output end of the switch control circuit 12, the anode of the first diode D1 is connected to the emitter of the fourth transistor Q4 and the cathode of the second diode D2, the anode of the second diode D2 is connected to the internal auxiliary power supply port, the emitter of the fourth transistor Q4 is connected to the power supply end of the main control unit 16, the base of the fourth transistor Q4 is connected to the first end of the fifth capacitor C5, the second end of the fifth capacitor C5 is connected to the second end of the reference U1 and the second end of the tenth resistor R10, the first end of the tenth resistor R10 is connected to the emitter of the fourth transistor Q4; the first end of the ninth resistor R9 is connected to the collector of the fourth transistor Q4, the second end of the ninth resistor R9 is connected to the base of the fourth transistor Q4 and the first end of the reference U1, the third end of the reference U1 and the second end of the eleventh resistor R11 are grounded, and the second end of the tenth resistor R10 is connected to the first end of the eleventh resistor R11.

[0061] like Figure 2 As shown, V-AUX is the internal auxiliary power supply port of the LED driver power supply (i.e., the power supply signal interface provided by the auxiliary winding), and DIM+ is the burning / dimming signal port. Among them, the voltage divider circuit 11 composed of the twelfth resistor R12 and the thirteenth resistor R13 is used to supply the main control unit 16 (MCU, wherein the MCU is Figure 2 (not shown in the figure) to detect whether the current state is offline programming.

[0062] like Figure 2As shown, during offline programming, DIM+ and GND will be connected to the programmer. When connected, DIM+ outputs a step level (i.e., the programming signal). This step level is sent to the source of the wake-up switch Q2 (wherein the wake-up switch Q2 is a P-type MOS transistor) through the first RC network composed of the second resistor R2, the third resistor R3, and the first capacitor C1. At the same time, the step level is also sent to the gate of the wake-up switch Q2 through the second RC network composed of the fourth resistor R4, the fifth resistor R5, and the second capacitor C2. When connected to a programmer, the voltage output by DIM+ charges the first capacitor C1 through the second resistor R2 and the second capacitor C2 through the fourth resistor R4. Since the resistance of the second resistor R2 is the same as that of the fourth resistor R4, and the capacitance of the first capacitor C1 is smaller than that of the second capacitor C2, the first voltage rises faster than the voltage of the second capacitor C2. In other words, the source voltage of the wake-up switch Q2 rises faster than the gate voltage. When the difference between the source voltage and the gate voltage of the wake-up switch Q2 is greater than the Vgs(th) of the wake-up switch Q2, the wake-up switch Q2 turns on, thereby driving the third MOS transistor Q3 to turn on. The third MOS transistor Q3 then controls the isolation switch 121 to turn on. At this time, the voltage output by DIM+ is sent to the voltage regulator circuit 15 through the isolation switch 121 and the first diode D1 to power the MCU, and the MCU starts working, that is, the MCU is awakened.

[0063] After the MUC wakes up, the MCU detects whether the detection signal (VSENS) obtained by dividing the power supply signal output by the twelfth resistor R12 and the thirteenth resistor R13 is a low level (if VSENS is low, it means that it is currently in an offline state). If so, the MCU sends a fixed-frequency PWM signal to the VG port of the PWM detection circuit 123. After the PWM detection circuit 123 detects the PWM signal sent by the MCU, it will generate a high level at the gate of the third MOS tube Q3. At the same time, the voltage difference between the source level and the gate level of the wake-up switch Q2 gradually decreases. When the voltage Vgs(th) decreases to less than the Vgs(th) of the wake-up switch Q2, Q2 is turned off. At this time, the PWM detection circuit 123 generates a high level at the gate of the third MOS transistor Q3, so that the third MOS transistor Q3 can continue to be turned on, thereby ensuring that DIM+ continues to power the MCU. After a preset delay time, the MCU stops sending the PWM signal to the VG port. At this time, the PWM detection circuit 123 no longer generates a high level at the gate of the third MOS transistor Q3, and the third MOS transistor Q3 is turned off, thereby controlling the isolation switch 121 to be turned off, thereby disconnecting the power supply circuit 1 from the dimming / programming line.

[0064] Based on the above principles, it can be seen that the present invention utilizes the time constant difference between the first and second RC networks to provide a short pulse drive to the wake-up switch Q2 during offline programming to wake up the MCU. The MCU then determines whether to turn on the isolation switch 121 by detecting whether it is currently in an offline state. When DIM+ is a PWM dimming signal, since the resistance values ​​of the second resistor R2 and the fourth resistor R4 are the same, and the resistance values ​​of the third resistor R3 and the fifth resistor R5 are the same, the gate-source voltage difference of the wake-up switch Q2 is zero, and the wake-up switch Q2 remains off. Therefore, the MCU will not be repeatedly woken up, and the voltage of the parallel circuit will not be affected.

[0065] Furthermore, due to the PWM detection circuit 123, if the MCU experiences an abnormality or fails to properly send a PWM signal to the VG port, the third MOS transistor can be promptly shut down after the wake-up process is complete, even in the offline programming state. This is because the PWM detection circuit 123 only generates a high level at the gate of the third MOS transistor to maintain the conduction of the third MOS transistor Q3 when receiving a PWM signal. If the VG port receives a continuous high or low level, the gate of the third MOS transistor Q3 remains at a low level, and the third MOS transistor Q3 remains in the off state, thereby keeping the isolation switch 121 in the off state.

[0066] Through the present invention, when used in parallel, if the LED driver power supply circuit 2 is abnormal (such as LED driver damage, AC input line abnormality, etc.), because Q1 is cut off, the MCU will not draw power from the power supply circuit 1, the dimming bar voltage will not be pulled down, and the normal operation of other LED drivers connected to the grid will not be affected. When used in parallel, if the MCU power supply of the LED driver power supply is short-circuited, because Q1 is cut off, the MCU will not draw power from the power supply circuit 1, the dimming bar voltage will not be pulled down, and the normal operation of other LED drivers connected to the grid will not be affected. When used in parallel, if the LED driver power supply operates in hiccup mode due to a fault (such as output short circuit), the VSENS port will generate a high level, the MCU will determine that the current mode is non-offline, and will not send a PWM signal to the VG network. Q1 will remain cut off, and the faulty LED driver power supply will not draw power from the power supply circuit 1, and the normal operation of other LED drivers connected to the grid will not be affected.

[0067] like Figure 3 As shown, channel 1 is the voltage waveform of DIM+ output, channel 2 is the source voltage waveform of the wake-up switch Q2, channel 3 is the gate voltage waveform of the wake-up switch Q2, and channel 4 is the VCC voltage waveform. Figure 3It can be seen that the source voltage of the wake-up switch Q2 rises faster than the gate voltage when power is turned on, and the gate-source voltage difference is sufficient to turn on the wake-up switch Q2, after the wake-up switch Q2 is turned on, the isolation switch 121 is turned on, and the VCC output 5V is supplied to the MCU, when the gate-source voltage difference of the wake-up switch Q2 gradually decreases to the off voltage, the wake-up switch Q2 is turned off, after the wake-up switch Q2 is turned off, the isolation switch 121 is also turned off accordingly, and the VCC voltage decreases, which is the MCU wake-up process.

[0068] As shown in the figure, the gate and source voltage waveforms of Q2 when the PWM dimming signal is applied to DIM+ after the wake-up process is completed. Figure 4 Figure 4 As shown in the figure, the gate and source voltage waveforms of Q2 when the PWM dimming signal is applied to DIM+ after the wake-up process is completed. Figure 4 As can be seen, when different duty cycles of PWM waveforms are applied to the DIM+ end, the gate and source voltages of the wake-up switch Q2 will change accordingly, but the gate and source voltage difference is very small, which is not enough to turn on the wake-up switch Q2, that is, the PWM signal on the dimming bus will not generate a wake-up signal for the faulty LED drive power supply during normal operation.

[0069] As shown in the figure, Figure 5 Figure 5 As shown in the figure, the gate and source voltage waveforms of Q2 when the PWM dimming signal is applied to DIM+ after the wake-up process is completed. Figure 5 As can be seen, when the PWM signal is applied to the V-G network, the gate of the third MOS tube Q3 will generate a corresponding high level.

[0070] Figure 6 As shown in the figure, the gate and source voltage waveforms of Q2 when the PWM dimming signal is applied to DIM+ after the wake-up process is completed. Figure 6 As can be seen, when high and low levels are applied to the V-G network, the gate of the third MOS tube Q3 always maintains a low level.

[0071] Figure 7 As shown in the figure, the gate and source voltage waveforms of Q2 when the PWM dimming signal is applied to DIM+ after the wake-up process is completed. Figure 7 As can be seen, after the DIM+ end is powered on, the VCC outputs 5V to wake up the MCU, and after the MCU is woken up and works, the PWM signal is output to the V-G network to maintain continuous power supply of VCC.

[0072] The application also provides an LED drive power supply, which comprises the LED drive circuit applied to two-wire programming disclosed in the embodiments of the application.

[0073] ​​The present invention also provides an LED driver system comprising: a plurality of LED driver power supplies for parallel operation. Specifically, the plurality of LED driver power supplies are connected in parallel to form a parallel network. Each LED driver power supply is equipped with an LED driver circuit for two-wire programming disclosed in an embodiment of the present invention.

[0074] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0075] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0076] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0077] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent variations and modifications within the scope of the claims of the present invention are intended to be covered by the claims of the present invention.

Claims

1. An LED driver circuit for two-wire programming, characterized in that: include: A voltage dividing circuit, a switch control circuit, a first isolation circuit, a second isolation circuit, a voltage stabilizing circuit and a main control unit; The input end of the voltage divider circuit is connected to the internal auxiliary power supply port, the output end of the voltage divider circuit is connected to the detection end of the main control unit, the input end of the switch control circuit is connected to the burning / dimming signal port, the output end of the switch control circuit is connected to the input end of the first isolation circuit, the output end of the first isolation circuit is connected to the input end of the voltage stabilizing circuit, the input end of the second isolation circuit is connected to the internal auxiliary power supply port, the output end of the second isolation circuit is connected to the input end of the voltage stabilizing circuit, the output end of the voltage stabilizing circuit is connected to the power supply end of the main control unit, and the main control unit is further connected to the switch control circuit; The voltage divider circuit is used to detect the power supply signal of the internal auxiliary power supply port and generate a detection signal; The switch control circuit is configured to be turned on according to the programming signal of the programming / dimming signal port during offline programming so as to transmit the wake-up signal to the main control unit through the first isolation circuit and the voltage stabilizing circuit in sequence, and to be continuously turned on according to the delayed turn-on signal output by the main control unit after being turned on, and to be turned off after the delay time expires; The main control unit is used to start working according to the wake-up signal, and after starting working, determine whether it is in an offline state according to the detection signal, and if so, send the delayed conduction signal to the switch control circuit; if not, do not send the delayed conduction signal; The second isolation circuit is used to transmit the power supply signal of the internal auxiliary power supply port to the voltage stabilizing circuit.

2. The LED driving circuit for two-wire programming according to claim 1, characterized in that: The switch control circuit includes: an isolation switch, a wake-up circuit and a PWM detection circuit; The first end of the isolation switch and the input end of the wake-up circuit are connected to the internal auxiliary power supply port, the second end of the isolation switch is connected to the wake-up circuit, the third end of the isolation switch is connected to the input end of the first isolation circuit, the input end of the PWM detection circuit is connected to the main control unit, and the output end of the PWM detection circuit is connected to the wake-up circuit; The wake-up circuit is used to control the isolation switch to be turned on according to the burning signal of the burning / dimming signal port during offline burning, so as to transmit the wake-up signal to the first isolation circuit through the isolation switch; the PWM detection circuit is used to receive the delayed on-signal output by the main control unit, and control the isolation switch to be continuously turned on according to the delayed on-signal, and control the isolation switch to be turned off after the delay time is reached.

3. The LED driving circuit for two-wire programming according to claim 2, characterized in that: The wake-up circuit includes: a unidirectional conduction circuit, a first RC network, a second RC network, a wake-up switch and a control switch; The input end of the unidirectional conduction circuit is connected to the burning / dimming signal port, the output end of the unidirectional conduction circuit is connected to the input end of the first RC network and the input end of the second RC network, the output end of the first RC network is connected to the first end of the wake-up switch, the output end of the second RC network is connected to the second end of the wake-up switch, the third end of the wake-up switch is connected to the input end of the control switch, the output end of the control switch is connected to the second end of the isolation switch, and the control end of the control switch is connected to the PWM detection circuit.

4. The LED driving circuit for two-wire programming according to claim 3, characterized in that: The unidirectional conduction circuit includes: a third diode; the first RC network includes: a second resistor, a third resistor and a first capacitor; the second RC network includes: a fourth resistor, a fifth resistor and a second capacitor; the wake-up switch includes: a second MOS transistor; the control switch includes: a sixth resistor and a third MOS transistor; The anode of the third diode is connected to the burning / dimming signal port, the cathode of the third diode is connected to the first end of the second resistor and the first end of the fourth resistor, the second end of the second resistor is connected to the first end of the third resistor, the first end of the first capacitor, and the source of the second MOS transistor, and the second end of the third resistor and the second end of the first capacitor are grounded; the second end of the fourth resistor is connected to the first end of the fifth resistor, the first end of the second capacitor, and the gate of the second MOS transistor, and the second end of the fifth resistor and the second end of the second capacitor are grounded; The drain of the second MOS transistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the gate of the third MOS transistor, the gate of the third MOS transistor is also connected to the PWM detection circuit, the drain of the third MOS transistor is connected to the second end of the isolation switch, and the source of the third MOS transistor is grounded.

5. The LED driving circuit for two-wire programming according to claim 4, characterized in that: The resistance value of the second resistor is the same as the resistance value of the fourth resistor, the resistance value of the third resistor is the same as the resistance value of the fifth resistor, and the capacitance value of the first capacitor is smaller than the capacitance value of the second capacitor.

6. The LED driving circuit for two-wire programming according to claim 5, characterized in that: The PWM detection circuit includes: a seventh resistor, a third capacitor, a fourth capacitor, a fourth diode and a fifth diode; The first end of the seventh resistor, the first end of the third capacitor, and the cathode of the fourth diode are connected to the gate of the third MOS tube, the second end of the seventh resistor, the second end of the third capacitor, and the anode of the fifth diode are grounded, the anode of the fourth diode is connected to the cathode of the fifth diode and the first end of the fourth capacitor, and the second end of the fourth capacitor is connected to the main control unit.

7. The LED driving circuit for two-wire programming according to claim 1, characterized in that: The voltage divider circuit includes: a twelfth resistor and a thirteenth resistor; The first end of the twelfth resistor is connected to the internal auxiliary power supply port, the second end of the twelfth resistor is connected to the first end of the thirteenth resistor and the detection end of the main control unit, and the second end of the thirteenth resistor is grounded.

8. The LED driving circuit for two-wire programming according to claim 1, characterized in that: The first isolation circuit includes: a first diode; the second isolation circuit includes: a second diode; the voltage stabilizing circuit includes: a ninth resistor, a tenth resistor, an eleventh resistor, a reference, a fifth capacitor, and a fourth transistor; The anode of the first diode is connected to the output end of the switch control circuit, the anode of the first diode is connected to the emitter of the fourth transistor and the cathode of the second diode, the anode of the second diode is connected to the internal auxiliary power supply port, the emitter of the fourth transistor is connected to the power supply end of the main control unit, the base of the fourth transistor is connected to the first end of the fifth capacitor, the second end of the fifth capacitor is connected to the second end of the reference device and the second end of the tenth resistor, and the first end of the tenth resistor is connected to the emitter of the fourth transistor; The first end of the ninth resistor is connected to the collector of the fourth transistor, the second end of the ninth resistor is connected to the base of the fourth transistor and the first end of the reference device, the third end of the reference device and the second end of the eleventh resistor are grounded, and the second end of the tenth resistor is connected to the first end of the eleventh resistor.

9. An LED driving power supply, characterized in that: include: An LED driving circuit for two-wire programming according to any one of claims 1 to 8.

10. An LED driving system, characterized in that: include: A plurality of LED driving power supplies used in parallel, each of the LED driving power supplies comprising the LED driving circuit for two-wire programming according to any one of claims 1 to 8.

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