CN105848349A - A wide input voltage dimming drive circuit - Google Patents

Abstract

The present invention discloses a wide input voltage dimming driving circuit, comprising a rectifier filter circuit, a main control circuit and an output circuit connected in sequence, wherein the main control circuit comprises: a field effect transistor Q1, a field effect transistor Q2, a main control chip U1 and a transformer T1. The wide input voltage dimming driving circuit of the present invention is adapted to a wide input voltage of 100-277Vac. When using the wide input voltage dimming driving circuit, there is no need to worry about the standard selection problem. The wide input voltage dimming driving circuit of the present invention greatly improves the safety of using an LED light source.

Description

A wide input voltage dimming drive circuit

technical field

The invention relates to the technical field of dimming driving, in particular to a wide input voltage dimming driving circuit.

Background technique

At present, LED lighting products have been popularized in a large number, replacing the use of traditional lighting products, but the existence of traditional electronic ballasts and dimmers leads to unsatisfactory advantages and effects after use. One of the reasons is the dimmer. Compatibility issues. There are two systems of low-voltage input (110 volts) and high-voltage input (220 volts) in the existing technology SCR dimming power supply. Users must first select the system when using it. If the selection is not appropriate, the input voltage is not distinguished. Often burn out the drive power, causing safety accidents.

Contents of the invention

The technical problem to be solved by the present invention is to provide a wide input voltage dimming drive circuit for the deficiencies of the prior art, which overcomes the inconvenience caused by the prior art silicon controlled rectifier dimming drive power supply which can only adapt to a single input voltage system And it is easy to cause defects in safety accidents.

The technical scheme that the present invention adopts for solving the problems of the technologies described above is:

A wide input voltage dimming drive circuit includes a rectification and filtering circuit, a main control circuit and an output circuit connected in sequence, wherein the main control circuit includes:

Field effect transistor Q1, field effect transistor Q2, main control chip U1 and transformer T1, the gate of field effect transistor Q2 is connected to capacitor C13, the two ends of resistor R9 are respectively connected to capacitor 13 and capacitor C2, and the drain of field effect transistor Q2 is connected to Capacitor C3, resistor R19 and inductor L4 are connected in parallel, and the two ends are respectively connected to the common terminal of capacitor C2, capacitor C3 and the drain of field effect transistor Q2, and the two ends of resistor R8 are respectively connected to the source of field effect transistor Q2 and capacitor C3, resistor R2 After being connected in series with resistor R3, resistor R2 is connected to the common terminal of capacitor C3 and resistor R19, resistor R3 is connected to pin 1 of main control chip U1, resistor 5 and capacitor C9 are connected in parallel, and both ends are grounded respectively to pin 1 of main control chip U1, capacitor C15, diode D2 and polarized capacitor C4 are connected in parallel, wherein the negative pole of diode D2 is connected to the positive pole of polarized capacitor C4 and then connected to the negative pole of diode D1, and the positive pole of diode D2 is connected to the negative pole of polarized capacitor C4. Afterwards grounding, the anode of diode D1 is connected to the common terminal of resistor R13 and resistor R7, resistor R10 and resistor R11 are connected in series, resistor R10 is connected to pin 6 of main control chip U1 and resistor R11 is grounded, and both ends of capacitor C8 are respectively connected to main control chip U1 Pin 7 and pin 8, capacitor C8 and the common terminal of pin 7 of the main control chip U1 are grounded, the gate of field effect transistor Q1 is connected to resistor R20, the source of field effect transistor Q1 is connected to the anode of diode D7, and diode D4 and After the capacitor C10 is connected in parallel, the anode of the diode D4 is connected to the ground, the cathode of the diode D4 is respectively connected to the cathode of the resistor R14, the resistor R20 and the diode D7, and the two ends of the inductor L6 are respectively connected to the source of the field effect transistor Q1 and pin 5 of the main control chip U1. The anode of the diode D7 is connected to the source of the field effect transistor Q1 and the common terminal of the inductor L6. After the resistor R6 and the diode D3 are connected in parallel, the cathode of the diode D3 is respectively connected to the main control chip U1 pin 2 and the resistor R7, and the anode of the diode D3 is grounded. After resistor R13 and resistor R7 are connected in series, the resistor R13 is connected to the non-identical terminal 5 of the transformer T1, the two ends of the capacitor CY1 are respectively grounded and the analog ground, the terminal 4 of the transformer T1 is connected to the ground, and the anode of the diode D6 is in common with the drain of the field effect transistor Q1. Connect the non-identical terminal 2 of the transformer T1 at the end, the resistor R15 is connected in parallel with the capacitor C12, the two ends of the resistor R15 are respectively connected to the cathode of the diode D6 and the terminal 1 of the same name of the transformer T1, and the two ends of the resistor R12 are respectively connected to the resistor R14, the resistor R15 and the capacitor C12. Common terminal of capacitor C12.

According to an embodiment of the present invention, the rectification and filtering circuit includes:

Transformer L1, bidirectional trigger diode ZNR1 and rectifier bridge DB1, the first end of the same name of the transformer L1 is connected to the resistor R1, the second end of the same name of the transformer L1 is connected to the fuse F1, the resistor R17 is connected in parallel with the inductor L3, and the two ends are respectively connected to the mutual inductance The first non-identical end of the transformer L1 and one end of the bidirectional trigger diode ZNR1, the resistor R18 and the inductance L2 are connected in parallel, and the two ends are respectively connected to the second non-identical end of the transformer L1 and the other end of the bidirectional trigger diode ZNR1, and the two ends of the capacitor C1 Connect the resistor R18 and the terminal 1 of the rectifier bridge DB1 respectively, the terminal 4 of the rectifier bridge DB1 is connected to the common pole of the resistor R9 and grounded, the terminal 3 of the rectifier bridge DB1 is connected to the common terminal of the capacitor C1 and the resistor R18, and the terminal 2 of the rectifier bridge DB1 is connected to the capacitor The common terminal of C2 and resistor R19.

According to an embodiment of the present invention, the output circuit includes:

Transformer L5, after polarized capacitor C6, polarized capacitor C7 and resistor R16 are connected in parallel, the positive poles of polarized capacitor C6 and polarized capacitor C7 are connected to the first end of the transformer L5 with the same name, and polarized capacitor C6 and The negative pole of the polarized capacitor C7 is connected to the second end of the same name of the transformer L5, the common pole of the same name end G of the secondary side of the transformer T1 and the negative pole of the polarized capacitor C6 are connected to the analog ground, and the positive pole of the diode D5 is connected to the second end of the transformer T1 The non-identical terminal of the secondary side, the negative pole of the diode D5 is connected to the positive pole of the polarized capacitor C6, after the capacitor C11 is connected in series with the resistor R4, the capacitor C11 is connected to the positive pole of the diode D5 and the secondary side non-identical terminal of the transformer T1, and the resistor R4 is connected to the diode D5 the negative pole.

Implementing the technical solution of the present invention has the following beneficial effects: the wide input voltage dimming driving circuit of the present invention is suitable for wide input voltage of 100-277Vac, and the wide input voltage dimming driving circuit can be used without worrying about the problem of input voltage selection. The input voltage dimming drive circuit greatly improves the safety of using LED light sources.

Description of drawings

The advantages and implementation methods of the present invention will be more obvious by referring to the accompanying drawings and describing the present invention in conjunction with examples below, wherein the content shown in the accompanying drawings is only used for explaining the present invention, and does not constitute any sense of the present invention The constraints, in the attached image:

Fig. 1 is a wide input voltage dimming driving circuit diagram of the present invention.

detailed description

As shown in Figure 1, the wide input voltage dimming drive circuit of the present invention includes a rectification filter circuit, a main control circuit and an output circuit connected in sequence, wherein the main control circuit includes: field effect transistor Q1, field effect transistor Q2, main control chip U1 and transformer T1, the gate of field effect transistor Q2 is connected to capacitor C13, the two ends of resistor R9 are respectively connected to capacitor 13 and capacitor C2, the drain of field effect transistor Q2 is connected to capacitor C3, and the two ends of resistor R19 and inductor L4 are connected in parallel. Connect capacitor C2, capacitor C3 and the common terminal of the drain of field effect transistor Q2, and connect the two ends of resistor R8 to the source of field effect transistor Q2 and capacitor C3 respectively. After resistor R2 and resistor R3 are connected in series, resistor R2 is connected to capacitor C3 and resistor The common terminal of R19, the resistor R3 is connected to the pin 1 of the main control chip U1, the two ends of the resistor 5 and the capacitor C9 are connected in parallel to ground respectively to the pin 1 of the main control chip U1, the capacitor C15, the diode D2 and the polarized capacitor C4 are connected in parallel, among which The negative pole of diode D2 is connected to the positive pole of polarized capacitor C4 and then connected to the negative pole of diode D1, the positive pole of diode D2 is connected to the negative pole of polarized capacitor C4 and grounded, and the positive pole of diode D1 is connected to resistor R13 and resistor R7 After resistor R10 and resistor R11 are connected in series, resistor R10 is connected to pin 6 of the main control chip U1 and resistor R11 is grounded. The two ends of capacitor C8 are respectively connected to pin 7 and pin 8 of the main control chip U1. The common end of pin 7 of the chip U1 is grounded, the gate of the field effect transistor Q1 is connected to the resistor R20, the source of the field effect transistor Q1 is connected to the anode of the diode D7, the diode D4 is connected in parallel with the capacitor C10, and the anode of the diode D4 is connected to the ground, and the diode D4 The negative poles are respectively connected to the negative poles of the resistor R14, the resistor R20 and the diode D7, the two ends of the inductor L6 are respectively connected to the source of the field effect transistor Q1 and pin 5 of the main control chip U1, and the positive pole of the diode D7 is connected to the source of the field effect transistor Q1 and The common terminal of the inductor L6, the resistor R6 and the diode D3 are connected in parallel, the cathode of the diode D3 is respectively connected to the main control chip U1 pin 2 and the resistor R7, the anode of the diode D3 is grounded, and the resistor R13 and the resistor R7 are connected in series, and the resistor R13 is connected to the transformer T1 The non-identical terminal 5, the two ends of the capacitor CY1 are respectively grounded and the analog ground, the homonymous terminal 4 of the transformer T1 is grounded, the anode of the diode D6 is connected to the non-identical terminal 2 of the transformer T1 after the drain of the field effect transistor Q1 is common, and the resistor R15 It is connected in parallel with the capacitor C12, the two ends of the resistor R15 are respectively connected to the cathode of the diode D6 and the terminal 1 of the transformer T1 with the same name, and the two ends of the resistor R12 are respectively connected to the common terminals of the resistor R14, the resistor R15 and the capacitor C12. The rectification and filtering circuit includes: transformer L1, bidirectional trigger diode ZNR1 and rectifier bridge DB1, the first end of the same name of the transformer L1 is connected to the resistor R1, the second end of the same name of the transformer L1 is connected to the fuse F1, and the resistor R17 is connected in parallel with the inductance L3 The two ends are respectively connected to the first non-identical end of the transformer L1 and one end of the bidirectional trigger diode ZNR1, and the resistor R18 is connected in parallel with the inductance L2. After the two ends are respectively connected to the second non-identical end of the transformer L1 and the other end of the bidirectional trigger diode ZNR1, The two ends of the capacitor C1 are respectively connected to the resistor R18 and the terminal 1 of the rectifier bridge DB1. The terminal 4 of the rectifier bridge DB1 is connected to the common pole of the resistor R9 and then grounded. The terminal 3 of the rectifier bridge DB1 is connected to the common terminal of the capacitor C1 and the resistor R18. The rectifier bridge DB1 The terminal 2 of the capacitor C2 is connected with the common terminal of the resistor R19. The output circuit includes: a transformer L5, after the polarized capacitor C6, the polarized capacitor C7 and the resistor R16 are connected in parallel, the positive poles of the polarized capacitor C6 and the polarized capacitor C7 are connected to the first end of the same name of the transformer L5, and the polarized The negative poles of polarized capacitor C6 and polarized capacitor C7 are connected to the second terminal of the same name of the transformer L5, the common pole of the secondary side of the transformer T1 with the same name and the negative pole of the polarized capacitor C6 are connected to the analog ground, and the positive pole of the diode D5 is connected to The secondary side of the transformer T1 is not the terminal of the same name, and the negative pole of the diode D5 is connected to the positive pole of the polarized capacitor C6. After the capacitor C11 is connected in series with the resistor R4, the capacitor C11 is connected to the positive pole of the diode D5 and the secondary side of the transformer T1. R4 is connected to the cathode of diode D5.

AC mains (100-277Vac) is rectified and filtered by F1, R1, L1, L2, L3, R17, R18, ZNR1, C1, BD1, among which R1 resistor damps the inrush current generated by the rapid charge and discharge of capacitor C1 when dimming is triggered , to prevent the current oscillation caused by the current peak of the surge current; because the current in the oscillation is lower than the negative current of the maintenance current, it will cause flicker, especially although C1 suppresses the low-frequency interference in the circuit, its value cannot be too high Large, its value cannot be greater than 47NF, otherwise it will cause the dimming circuit to work abnormally, resulting in flickering, R17 and R18 eliminate the oscillation for the inductance L3 and L2, C2 and R9 constitute a passive discharge circuit, the passive discharge circuit is used for Provide the maintenance current of the field effect tube; the capacity of C2 should not be too large or too small, the value is generally determined according to the wattage, the general value is 100-220NF, if it is too small, the trigger current provided is less than the maintenance current, and it will also cause flickering , if it is too large, it will reduce the power factor value of the circuit and the resistance loss of R9; to increase the heat generation, the resistance value of R9 should not be too large or too small, if the resistance of R9 is too small, the damping will be insufficient, causing oscillation, if it is too large will get bigger. The main control chip U1 can choose the MP4056 of American Xinyuan Company (MPS). The main control chip U1 has 8 pins. The main control chip U1 uses source output to control the external high-voltage MOS. There is a 40V low-voltage MOS inside U1. Through Its D pole (pin 5) is connected in series with the external high-voltage MOS Q1 for high-frequency switching, which can achieve a better dimming effect, while the low-voltage MOS has a very low gate turn-on voltage, and the turn-on voltage is greater than or equal to 1.5 V is fine, so that even when the output voltage is low (the LED is dark), because the output voltage is proportional to the power supply feedback voltage of U1, there will be a normal high-frequency switching signal output control when the feedback voltage of U1 is lower than 5V, so that It ensures the stable state of the circuit, so that the LED light will not flicker; at the same time, U1 works in the real-time current control mode of the primary side, and it works in the discontinuous mode at any input voltage, through the feedback winding of the transformer T1 and R13 and The pin 2 detection of U1 realizes the valley switch, that is, the quasi-resonant mode, which can make the switching loss of the MOS very low, and at the same time, the output diode has no reverse recovery loss, which has the effect of high efficiency and low electromagnetic interference. The most important thing is It can guarantee the constant output current, whether it is input high voltage or low voltage, the inductance of transformer T1 is fixed, and the current setting resistor of pin 6 of U1 is also fixed, so the output current is: I=VREF/(R10+ R11), at the same time VREF=0.414V is the fixed reference voltage inside U1, so the output current is constant under any conditions, so as to meet the requirements of wide input voltage. Now the dimming power supply in the market does not work in the constant current state, the input When the voltage is low, the current becomes low, and when the input voltage is high, the current becomes large, which will cause harm to the use of LED lights, because in some places the grid voltage fluctuates greatly. U1 pin 1 has multiple functions of phase detection and input voltage detection, U1 pin 2 is the input pin of feedback degaussing circuit and primary voltage setting, the feedback function is realized by R7, R6, R3, U1 pin 3 is VCC power supply It is realized by R13, D1, D2, C15, and C4. U1 pin 4 adjusts the conduction degree of Q2 according to the input signal. Q2 is connected in series with the damping resistor R8 to achieve the best dimming effect and efficiency. U1 pin 5 is Source output, connected in series with high-voltage MOS Q1 for high-frequency switching, U1 pin 6 is the current adjustment pin, current adjustment is realized through R10 and R11, U1 pin 7 is the ground pin, U1 pin 8 is connected to C8 for loop compensation, R12, R14, D4, C10, R20 and D7 constitute the gate power supply circuit of Q1. D7 discharges the internal MOS junction capacitance of U1 for protection. The voltage of D4 should not exceed 16V, preferably 15V. D6, R15 and C12 constitute the degaussing circuit of transformer T1. The output winding of transformer T1 is rectified and filtered by D5, C6, C7 and L5 to provide output power for LED. C11, R4 and L5 are used to suppress EMI.

Those skilled in the art do not depart from the essence and spirit of the present invention, there can be many variants to realize the present invention, the above is only a preferred and feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. The equivalent structural changes made in the description of the invention and the accompanying drawings are all included in the scope of rights of the present invention.

Claims (3)

1. A wide input voltage dimming drive circuit, characterized in that it comprises a rectification filter circuit, a main control circuit and an output circuit connected in sequence, wherein the main control circuit includes: Field effect transistor Q1, field effect transistor Q2, main control chip U1 and transformer T1, the gate of field effect transistor Q2 is connected to capacitor C13, the two ends of resistor R9 are respectively connected to capacitor 13 and capacitor C2, and the drain of field effect transistor Q2 is connected to Capacitor C3, resistor R19 and inductor L4 are connected in parallel, and the two ends are respectively connected to the common terminal of capacitor C2, capacitor C3 and the drain of field effect transistor Q2, and the two ends of resistor R8 are respectively connected to the source of field effect transistor Q2 and capacitor C3, resistor R2 After being connected in series with resistor R3, resistor R2 is connected to the common terminal of capacitor C3 and resistor R19, resistor R3 is connected to pin 1 of main control chip U1, resistor 5 and capacitor C9 are connected in parallel, and both ends are grounded respectively to pin 1 of main control chip U1, capacitor C15, diode D2 and polarized capacitor C4 are connected in parallel, wherein the negative pole of diode D2 is connected to the positive pole of polarized capacitor C4 and then connected to the negative pole of diode D1, and the positive pole of diode D2 is connected to the negative pole of polarized capacitor C4. Afterwards grounding, the anode of diode D1 is connected to the common terminal of resistor R13 and resistor R7, resistor R10 and resistor R11 are connected in series, resistor R10 is connected to pin 6 of main control chip U1 and resistor R11 is grounded, and both ends of capacitor C8 are respectively connected to main control chip U1 Pin 7 and pin 8, capacitor C8 and the common terminal of pin 7 of the main control chip U1 are grounded, the gate of field effect transistor Q1 is connected to resistor R20, the source of field effect transistor Q1 is connected to the anode of diode D7, and diode D4 and After the capacitor C10 is connected in parallel, the anode of the diode D4 is connected to the ground, the cathode of the diode D4 is respectively connected to the cathode of the resistor R14, the resistor R20 and the diode D7, and the two ends of the inductor L6 are respectively connected to the source of the field effect transistor Q1 and pin 5 of the main control chip U1. The anode of the diode D7 is connected to the source of the field effect transistor Q1 and the common terminal of the inductor L6. After the resistor R6 and the diode D3 are connected in parallel, the cathode of the diode D3 is respectively connected to the main control chip U1 pin 2 and the resistor R7, and the anode of the diode D3 is grounded. After resistor R13 and resistor R7 are connected in series, the resistor R13 is connected to the non-identical terminal 5 of the transformer T1, the two ends of the capacitor CY1 are respectively grounded and the analog ground, the terminal 4 of the transformer T1 is connected to the ground, and the anode of the diode D6 is in common with the drain of the field effect transistor Q1. Connect the non-identical terminal 2 of the transformer T1 at the end, the resistor R15 is connected in parallel with the capacitor C12, the two ends of the resistor R15 are respectively connected to the cathode of the diode D6 and the terminal 1 of the same name of the transformer T1, and the two ends of the resistor R12 are respectively connected to the resistor R14, the resistor R15 and the capacitor C12. Common terminal of capacitor C12. 2. The wide input voltage dimming drive circuit according to claim 1, wherein the rectification and filtering circuit comprises: Transformer L1, bidirectional trigger diode ZNR1 and rectifier bridge DB1, the first end of the same name of the transformer L1 is connected to the resistor R1, the second end of the same name of the transformer L1 is connected to the fuse F1, the resistor R17 is connected in parallel with the inductor L3, and the two ends are respectively connected to the mutual inductance The first non-identical end of the transformer L1 and one end of the bidirectional trigger diode ZNR1, the resistor R18 and the inductance L2 are connected in parallel, and the two ends are respectively connected to the second non-identical end of the transformer L1 and the other end of the bidirectional trigger diode ZNR1, and the two ends of the capacitor C1 Connect the resistor R18 and the terminal 1 of the rectifier bridge DB1 respectively, the terminal 4 of the rectifier bridge DB1 is connected to the common pole of the resistor R9 and grounded, the terminal 3 of the rectifier bridge DB1 is connected to the common terminal of the capacitor C1 and the resistor R18, and the terminal 2 of the rectifier bridge DB1 is connected to the capacitor The common terminal of C2 and resistor R19. 3. The wide input voltage dimming drive circuit according to claim 2, characterized in that: the output circuit comprises: Transformer L5, after polarized capacitor C6, polarized capacitor C7 and resistor R16 are connected in parallel, the positive poles of polarized capacitor C6 and polarized capacitor C7 are connected to the first end of the transformer L5 with the same name, and polarized capacitor C6 and The negative pole of the polarized capacitor C7 is connected to the second end of the same name of the transformer L5, the common pole of the same name end G of the secondary side of the transformer T1 and the negative pole of the polarized capacitor C6 are connected to the analog ground, and the positive pole of the diode D5 is connected to the second end of the transformer T1 The non-identical terminal of the secondary side, the negative pole of the diode D5 is connected to the positive pole of the polarized capacitor C6, after the capacitor C11 is connected in series with the resistor R4, the capacitor C11 is connected to the positive pole of the diode D5 and the secondary side non-identical terminal of the transformer T1, and the resistor R4 is connected to the diode D5 the negative pole.