High-power LED power supply based on gallium nitride

Abstract

The invention relates to a high-power LED power supply based on gallium nitride. The high-power LED power supply comprises an input rectification filter circuit; a transformer; an RCD spike pulse absorption circuit; a master control circuit; a gallium nitride driving circuit; outputting rectification filtering; a CS current sampling circuit; and a feedback circuit. The gallium nitride switching tube is high in critical breakdown voltage and high in electron mobility, so that the switching speed of the gallium nitride switching tube is much higher than that of a traditional silicon-based switching tube, the switching frequency of the power supply can be greatly improved, the power supply can respond to load changes more quickly, the flicker phenomenon of an LED is effectively reduced, and the illumination quality is improved.

Description

Technical Field

[0001] The invention relates to the field of switching power supplies and LED power supplies, and in particular to a high-power LED power supply based on gallium nitride. Background Art

[0002] Traditional LED power supplies and Si-based power supplies have limitations: on the one hand, high-frequency switching is prone to electromagnetic interference (EMI), which causes LED brightness fluctuations, shortens life, and affects the stability of peripheral equipment. On the other hand, limited by the physical limitations of silicon materials, traditional Si-based devices have high switching losses, large output voltage / current ripples, slow dynamic response, and are difficult to significantly improve key indicators such as efficiency and power density, and cannot meet the growing demand for high-power, high-efficiency power supplies. Summary of the invention

[0003] The present invention provides a high-power LED power supply based on gallium nitride, which solves the above technical problems.

[0004] The main technical solution adopted by the present invention is as follows: A high-power LED power supply based on gallium nitride, comprising:

[0005] An input rectifying and filtering circuit is connected to the AC signal and a common ground, and is used to rectify and filter the AC signal to obtain a DC signal;

[0006] A transformer, comprising a primary winding, an auxiliary winding and a secondary winding, wherein one end of the primary winding is connected to the input rectifier filter circuit;

[0007] A gallium nitride switch tube, the gate of which is connected to the driving signal, the drain of which is connected to one end of the primary winding, and the source of which is grounded, and is used to be turned on and off under the action of the driving signal, so that the DC signal passes through the primary winding and the secondary winding of the transformer to generate a coupling signal;

[0008] A high-voltage starting circuit, connected to the input rectifying and filtering circuit, and used to generate a high-voltage starting signal according to the DC signal;

[0009] A main control circuit, connected to the high-voltage starting circuit, used to start working under the action of the high-voltage starting signal and generate a control signal;

[0010] A gallium nitride driving circuit, connected to the main control circuit and the gallium nitride switch tube, and used to generate the driving signal under the action of the control signal, thereby turning the gallium nitride switch tube on and off;

[0011] An output rectification and filtering circuit is connected to the secondary winding, and performs rectification and filtering on the secondary coupling signal generated by the secondary winding to obtain an output signal;

[0012] An RCD peak absorption circuit is connected to both ends of the primary coil and is used to absorb the peak voltage formed in the primary coil due to leakage inductance;

[0013] A CS current sampling circuit, connected to the common ground and the main control circuit, for collecting a source current signal of the GaN switch tube;

[0014] The feedback circuit has one end connected to one end of the auxiliary winding and the other end connected to the FB pin of the control chip U11, and is used to detect the output signal to generate a feedback adjustment signal, thereby maintaining the stability of the output signal.

[0015] The beneficial effects of the present invention are as follows: the present invention is a high-power LED power supply based on gallium nitride, the switching speed of the gallium nitride switch tube used is much faster than that of the traditional silicon-based switch tube, which can reach the MHz level, and can greatly increase the switching frequency of the power supply, so that the power supply can respond to load changes more quickly, effectively reduce the flickering phenomenon of LEDs, and improve the lighting quality; at the same time, the on-resistance of the gallium nitride switch tube is very low, which can significantly reduce the conduction loss, improve the power supply efficiency, reduce heat generation, and thus extend the service life of the power supply and LED lamps; in addition, the gallium nitride switch tube has better voltage resistance than the traditional si, which can meet the needs of high-power LED power supplies under high-voltage input or output conditions, and improve the reliability and stability of the power supply. Finally, the characteristics of the gallium nitride material enable it to achieve high power processing capabilities on a smaller chip area, which helps to reduce the volume and weight of the power supply, realize the miniaturization and lightweight of the power supply, and facilitate integration into various LED lamps. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural block diagram of a high-power LED power supply based on gallium nitride according to the present invention;

[0017] Figure 2 This is a partial circuit schematic diagram of a high-power LED power supply based on gallium nitride according to the present invention; DETAILED DESCRIPTION

[0018] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0019] like Figure 1 As shown, a high-power LED power supply based on gallium nitride includes:

[0020] An input rectifying and filtering circuit 1 is connected to the AC signal and a common ground, and is used to rectify and filter the AC signal to obtain a DC signal;

[0021] Transformer T1, comprising a primary winding, an auxiliary winding and a secondary winding, one end of the primary winding being connected to the input rectifier filter circuit 1;

[0022] A gallium nitride switch tube Q1, with a gate connected to a driving signal, a drain connected to one end of the primary winding, and a source connected to the ground, for switching on and off under the action of the driving signal, so that the DC signal passes through the primary winding and the secondary winding of the transformer T1 to generate a coupling signal;

[0023] A high-voltage starting circuit 2, connected to the input rectifying and filtering circuit 1, for generating a high-voltage starting signal according to the DC signal;

[0024] A main control circuit 3, connected to the high-voltage starting circuit 2, for starting the operation under the action of the high-voltage starting signal and generating a control signal;

[0025] A gallium nitride driving circuit 4 is connected to the main control circuit and the gallium nitride switch tube Q1, and is used to generate the driving signal under the action of the control signal, thereby turning on and off the gallium nitride switch tube Q1;

[0026] An output rectifying and filtering circuit 5 is connected to the secondary winding, and performs rectification and filtering on the secondary coupling signal generated by the secondary winding to obtain an output signal;

[0027] An RCD peak absorption circuit 6, connected to both ends of the primary coil, for absorbing the peak voltage formed in the primary coil due to leakage inductance;

[0028] A CS current sampling circuit 7, connected to the common ground and the main control circuit, for collecting a source current signal of the GaN switch tube;

[0029] The feedback circuit 8 has one end connected to one end of the auxiliary winding and the other end connected to the FB pin of the control chip U11, and is used to detect the output signal to generate a feedback adjustment signal, thereby maintaining the stability of the output signal.

[0030] The beneficial effects of the present invention are as follows: the present invention is a high-power LED power supply based on gallium nitride, the switching speed of the gallium nitride switch tube Q1 used is much faster than that of the traditional silicon-based switch tube, which can reach the MHz level, and can greatly increase the switching frequency of the power supply, so that the power supply can respond to load changes more quickly, effectively reduce the flickering phenomenon of LEDs, and improve the lighting quality; at the same time, the on-resistance of the gallium nitride switch tube Q1 is very low, which can significantly reduce the conduction loss, improve the power supply efficiency, reduce heat generation, and thus extend the service life of the power supply and LED lamps; in addition, the gallium nitride switch tube has better voltage resistance than the traditional si, which can meet the needs of high-power LED power supplies under high-voltage input or output conditions, and improve the reliability and stability of the power supply. Finally, the characteristics of the gallium nitride material enable it to achieve high power processing capabilities on a smaller chip area, which helps to reduce the volume and weight of the power supply, realize the miniaturization and lightweight of the power supply, and facilitate integration into various LED lamps.

[0031] In this embodiment, if Figure 2 As shown, the input rectification and filtering circuit 1 comprises:

[0032] Capacitor C4, connected to the alternating current;

[0033] Common mode inductor U4, a group of ports are connected to the AC power;

[0034] The rectifier bridge D12 has two input terminals connected to the other end of the common mode inductor U4;

[0035] Capacitor C5 is connected to the two output terminals of the rectifier bridge D12 and to the common ground;

[0036] An inductor U1, one end of which is connected to an output end of the rectifier bridge D12;

[0037] Capacitor C6, one end of which is connected to the other end of inductor U1 and the other end is grounded;

[0038] Resistor R2 is connected in parallel to the inductor U1.

[0039] Specifically, in the input rectifier filter circuit 1, 220V AC is connected between the live wire L and the neutral wire N; a fuse F1 is also connected in series between the live wire L and the common mode inductor U4. The EM I filter circuit composed of the common mode inductor U4 and the capacitor C4 filters out high-frequency noise in the power grid to prevent interference to the system and converts the input 220V AC into DC; the capacitor C5, the inductor U1, the capacitor C6, and the resistor R22 form a π-type filter circuit to change the half-wave passing through the rectifier bridge D12 into a relatively stable DC.

[0040] In this embodiment, if Figure 2 As shown, the main control circuit 3 includes:

[0041] The main control chip U11 is provided with a VDD pin, an FB pin, an HV pin, a GATE pin, a GND pin, a CS pin and a COMP pin.

[0042] In this embodiment, if Figure 2 As shown, the high voltage starting circuit 2 includes:

[0043] The resistor R8 has one end connected to the HV pin of the control chip U11 and the other end connected to the input filter rectifier circuit to access the DC signal.

[0044] In this embodiment, if Figure 2 As shown, the gallium nitride driving circuit 4 includes:

[0045] A resistor R15, one end of which is connected to the GATE pin of the control chip U11;

[0046] The cathode of diode D9 is connected to the other end of resistor R15;

[0047] A resistor R16, one end of which is connected to the anode of the diode D9, and the other end of which is connected to the GATE terminal of the control chip U11;

[0048] A resistor R14, one end of which is connected to the anode of the diode D9, and the other end of which is connected to the gate of the gallium nitride switch tube;

[0049] Capacitor C8, connected in parallel to the resistor R14;

[0050] The voltage regulator tube ZD1, the cathode of which is connected to the gate of the gallium nitride switch tube;

[0051] The voltage regulator tube ZD2 has a negative electrode connected to the gate of the gallium nitride switch tube, and a positive electrode connected to the positive electrode of the voltage regulator tube ZD1.

[0052] Specifically, in the initial stage of power-on, the DC signal passing through the input rectifier filter circuit 1 is cut off when it reaches the drain of the gallium nitride switch tube Q1 through the primary winding. At the same time, the DC also reaches the HV pin of the control chip U12 through the resistor R13 of the high-voltage starting circuit to charge the VDD capacitor on the control chip. When VDD reaches the start-up voltage, the control chip U11 starts, and the high-voltage starting circuit outputs a control signal to the GATE pin of the control chip U11, which drives the gallium nitride switch tube Q1 to turn on through the gallium nitride driving circuit 4.

[0053] In this embodiment, if Figure 2 As shown, the RCD peak pulse absorption circuit 6 includes:

[0054] A heat dissipation resistor U23, one end of which is connected to one end of the primary coil;

[0055] A heat dissipation resistor U24, one end of which is connected to one end of the primary coil;

[0056] A capacitor C3, one end of which is connected to one end of the primary coil;

[0057] A resistor R34, one end of which is connected to the other end of the heat dissipation resistor U23, the other end of the heat dissipation resistor U24, and the other end of the capacitor C3;

[0058] A resistor R35, one end of which is connected to the other end of the heat dissipation resistor U23, the other end of the heat dissipation resistor U24, and the other end of the capacitor C3;

[0059] A voltage regulator tube D14, a negative electrode of which is connected to the other end of the resistor R34 and the other end of the resistor R35, and a positive electrode of which is connected to the other end of the primary coil;

[0060] A voltage regulator tube D13, a negative electrode of which is connected to the other end of the resistor R34 and the other end of the resistor R35, and a positive electrode of which is connected to the other end of the primary coil;

[0061] Specifically, the RCD peak absorption circuit is used to absorb the peak generated by the leakage inductance of the transformer T1 to prevent the peak high voltage from having an adverse effect on the gallium nitride switch tube Q1.

[0062] In this embodiment, if Figure 2 As shown, the CS current sampling circuit 7 includes:

[0063] A resistor R21, one end of which is connected to the CS pin of the control chip U11, and the other end of which is connected to the source of the GaN switch tube;

[0064] Specifically, the CS current sampling circuit is used to collect the current information of the source of the GaN switch tube Q1. If the current is overcurrent, the control chip U11 will perform overcurrent protection and cut off the GaN switch tube Q1 to prevent overcurrent from damaging the control chip U11 and the GaN switch tube Q1.

[0065] In this embodiment, if Figure 2 As shown, the output rectification and filtering circuit 5 includes:

[0066] A diode U6, the anode of which is connected to one end of the secondary winding;

[0067] An electrolytic capacitor C18, with a positive electrode connected to the negative electrode of the diode U6 and a negative electrode connected to the other end of the secondary winding;

[0068] One end of capacitor C1 is connected to the positive electrode of diode U6;

[0069] A resistor R1, one end of which is connected to the other end of the capacitor C1, and the other end of which is connected to the cathode of the diode U6;

[0070] Electrolytic capacitor C17 is connected in parallel with electrolytic capacitor C18;

[0071] The resistor R7 is connected in parallel to the electrolytic capacitor C17;

[0072] Common mode inductor L1, one group of ports connected to resistor R7, another group of ports outputs the output signal and is connected to analog ground;

[0073] Specifically, in the rectifier filter circuit 5, the negative half voltage outputted from the secondary winding can be eliminated by the diode U6, and then the high-frequency noise is removed and interference is reduced by the filter circuit composed of the electrolytic capacitor C18, the electrolytic capacitor C17 and the common-mode inductor L1.

[0074] In this embodiment, if Figure 2 As shown, the feedback circuit 8 includes:

[0075] A resistor R19, one end of which is connected to one end of the auxiliary winding, and the other end of which is connected to the FB pin of the control chip U11;

[0076] A resistor R20 connected in parallel to the resistor R19;

[0077] A resistor R22, one end of which is connected to the FB pin of the control chip U11, and the other end of which is connected to the common ground;

[0078] A resistor R23, one end of which is connected to the FB pin of the control chip U11, and the other end of which is connected to the common ground;

[0079] One end of the capacitor C10 is connected to the FB pin of the control chip U11, and the other end is connected to the common ground.

[0080] Specifically, in the feedback circuit 8, the voltage at one end of the auxiliary winding of the transformer TI passes through resistors R19, R20, R22 and R23, and reaches the FB pin of the control chip U11 to collect the output voltage, which is then compared with the internal reference voltage of the control chip U11 to maintain a constant voltage; in addition, if the output voltage collected by the feedback circuit is greater than the internal reference voltage of the control chip U11, the control chip U11 will be triggered to start overvoltage protection.

[0081] The above description is only a preferred embodiment of the present invention and should not be construed as a limitation of the present invention. Within the scope of the present invention, ordinary technicians may modify, replace, and improve the above examples.

Claims

1. A high-power LED power supply based on gallium nitride, characterized in that: include: An input rectifying and filtering circuit is connected to the AC signal and a common ground, and is used to rectify and filter the AC signal to obtain a DC signal; A transformer, comprising a primary winding, an auxiliary winding and a secondary winding, wherein one end of the primary winding is connected to the input rectifying and filtering circuit; A gallium nitride switch tube, the gate of which is connected to the driving signal, the drain of which is connected to one end of the primary winding, and the source of which is grounded, and is used to be turned on and off under the action of the driving signal, so that the DC signal passes through the primary winding and the secondary winding of the transformer to generate a coupling signal; A high-voltage starting circuit, connected to the input rectifying and filtering circuit, and used for generating a high-voltage starting signal according to the DC signal; A main control circuit, connected to the high-voltage starting circuit, used to start working under the action of the high-voltage starting signal and generate a control signal; A gallium nitride driving circuit, connected to the main control circuit and the gallium nitride switch tube, and used to generate the driving signal under the action of the control signal, thereby turning the gallium nitride switch tube on and off; An output rectification and filtering circuit is connected to the secondary winding, and performs rectification and filtering on the secondary coupling signal generated by the secondary winding to obtain an output signal; An RCD peak absorption circuit is connected to both ends of the primary coil and is used to absorb the peak voltage formed in the primary coil due to leakage inductance; A CS current sampling circuit, connected to the common ground and the main control circuit, for collecting a source current signal of the GaN switch tube; The feedback circuit has one end connected to one end of the auxiliary winding and the other end connected to the FB pin of the control chip U11, and is used to detect the output signal to generate a feedback adjustment signal, thereby maintaining the stability of the output signal.

2. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The input filtering and rectifying circuit comprises: Capacitor C4, connected to the alternating current; A common mode inductor U4, a group of ports connected to the AC power; The rectifier bridge D12 has two input terminals connected to the other end of the common mode inductor U4; Capacitor C5 is connected to the two output terminals of the rectifier bridge D12 and to the common ground; An inductor U1, one end of which is connected to an output end of a rectifier bridge D12; Capacitor C6, one end of which is connected to the other end of inductor U1 and the other end is grounded; The resistor R2 is connected in parallel to the inductor U1.

3. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The main control circuit includes a control chip U11, and a GATE pin is provided in the control chip U11; the gallium nitride driving circuit includes: A resistor R15, one end of which is connected to the GATE pin of the control chip U11; The cathode of diode D9 is connected to the other end of resistor R15; A resistor R16, one end of which is connected to the anode of the diode D9, and the other end of which is connected to the GATE terminal of the control chip U11; A resistor R14, one end of which is connected to the anode of the diode D9, and the other end of which is connected to the gate of the gallium nitride switch tube; Capacitor C8, connected in parallel to the resistor R14; The voltage regulator tube ZD1, the cathode of which is connected to the gate of the gallium nitride switch tube; The voltage regulator tube ZD2 has a negative electrode connected to the gate of the gallium nitride switch tube, and a positive electrode connected to the positive electrode of the voltage regulator tube ZD1.

4. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The main control circuit includes: a control chip U11, in which a HV pin is provided; the high-voltage startup circuit includes: The resistor R8 has one end connected to the HV pin of the control chip U11 and the other end connected to the input filter rectifier circuit to access the DC signal.

5. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The output rectification and filtering circuit comprises: A diode U6, the anode of which is connected to one end of the secondary winding; An electrolytic capacitor C18, with a positive electrode connected to the negative electrode of the diode U6 and a negative electrode connected to the other end of the secondary winding; One end of capacitor C1 is connected to the positive electrode of diode U6; A resistor R1, one end of which is connected to the other end of the capacitor C1, and the other end of which is connected to the cathode of the diode U6; Electrolytic capacitor C17 is connected in parallel with electrolytic capacitor C18; The resistor R7 is connected in parallel to the electrolytic capacitor C17; The common mode inductor L1 has one group of ports connected to the resistor R7, and another group of ports outputs the output signal and is connected to the analog ground.

6. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The RCD peak pulse absorption circuit comprises: A heat dissipation resistor U23, one end of which is connected to one end of the primary coil; A heat dissipation resistor U24, one end of which is connected to one end of the primary coil; A capacitor C3, one end of which is connected to one end of the primary coil; A resistor R34, one end of which is connected to the other end of the heat dissipation resistor U23, the other end of the heat dissipation resistor U24, and the other end of the capacitor C3; A resistor R35, one end of which is connected to the other end of the heat dissipation resistor U23, the other end of the heat dissipation resistor U24, and the other end of the capacitor C3; A voltage regulator tube D14, a negative electrode of which is connected to the other end of the resistor R34 and the other end of the resistor R35, and a positive electrode of which is connected to the other end of the primary coil; The voltage regulator D13 has a negative electrode connected to the other end of the resistor R34 and the other end of the resistor R35, and a positive electrode connected to the other end of the primary coil.

7. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The CS current sampling circuit comprises: The resistor R21 has one end connected to the CS pin of the control chip U11 and the other end connected to the source of the GaN switch tube.

8. The gallium nitride-based high-power LED power supply according to claim 1, characterized in that: The feedback circuit comprises: A resistor R19, one end of which is connected to one end of the auxiliary winding, and the other end of which is connected to the FB pin of the control chip U11; A resistor R20 connected in parallel to the resistor R19; A resistor R22, one end of which is connected to the FB pin of the control chip U11, and the other end of which is connected to the common ground; A resistor R23, one end of which is connected to the FB pin of the control chip U11, and the other end of which is connected to the common ground; One end of the capacitor C10 is connected to the FB pin of the control chip U11, and the other end is connected to the common ground.

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