Driving circuit and lamp

Abstract

The invention provides a driving circuit and a lamp, and the driving circuit comprises a rectification module which is used for converting an externally inputted alternating current into a half-wave alternating current; the PFC module is used for boosting and adjusting the half-wave alternating current and outputting direct current of a first voltage, and the PFC module is connected with the rectifier module; the BUCK module is used for reducing the voltage of the direct current of the first voltage output by the PFC module and providing the voltage to a load, and the BUCK module is connected with the output end of the PFC module; and the power supply module is used for supplying power to the BUCK module and the PFC module, the input end of the power supply module is connected with the output end of the rectifier module and is connected with the PFC module, and the output end of the power supply module is connected with the BUCK module and the PFC module. The power supply module supplies power to the PFC module and the BUCK module, so that the power supply loss of the PFC module and the BUCK module is effectively reduced, the operation of a load with relatively high power can be driven while a chip with a small package is used, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of lighting, and in particular to a driving circuit and a lamp. Background Art

[0002] With the improvement of living standards, people have higher and higher demands for lighting in different scenarios. LED has been widely used in the field of lighting due to its advantages of energy saving, environmental protection, long life and high light efficiency. In the process of popularization and application of LED lighting, since LED lamp beads have high requirements for current stability, it is necessary to set up a corresponding driving circuit to drive them.

[0003] To this end, the industry has proposed a variety of solutions, and many LED driving solutions have also appeared in LED lighting. Among them, a high PF (Power Factor) non-isolated two-stage solution is one of the commonly used line architectures, usually a front-stage PFC (Power Factor Correction) architecture and a back-stage BUCK (step-down) architecture.

[0004] In the BUCK architecture, more and more manufacturers integrate power MOS tubes into IC chips for cost considerations. The heat generated by IC chips in the integrated power MOS solution is mainly caused by the heat generated by the internal power supply circuit, built-in MOS and logic control circuit, and small packaged ICs (such as SOP8 or SOP7) are usually unable to drive loads above 30W. For higher power applications, only IC chips with large package built-in MOS solutions, or external MOS solutions, or external heat dissipation measures can be used, which increases the overall cost.

[0005] In view of this, it is indeed necessary to provide a driving circuit and a lamp, which can reduce the manufacturing cost by adopting a BUCK architecture solution with a small package and a built-in MOS. Summary of the invention

[0006] The object of the present invention is to provide a driving circuit and a lamp which can effectively control the amount of heat.

[0007] To achieve the above object, the present invention provides a driving circuit, comprising:

[0008] A rectifier module, used to convert the input AC power into half-wave AC power;

[0009] A PFC module, used for boosting and adjusting the half-wave AC power and outputting DC power of a first voltage, the PFC module being connected to the rectifier module;

[0010] A BUCK module, used for stepping down the direct current of the first voltage output by the PFC module and providing the direct current to a load, wherein the BUCK module is connected to the output end of the PFC module;

[0011] A power supply module is used to supply power to the BUCK module and the PFC module, wherein the input end of the power supply module is connected to the output end of the rectifier module and the PFC module, and the output end of the power supply module is connected to the BUCK module and the PFC module.

[0012] Optionally, the power supply module includes a voltage doubler rectifier circuit and a linear voltage regulator circuit, the voltage doubler rectifier circuit is configured to supply power to the BUCK module, and the linear voltage regulator circuit is configured to supply power to the PFC module.

[0013] Optionally, the voltage doubler rectifier circuit includes a third capacitor, a fourth diode, a second diode and a third electrolytic capacitor, the third capacitor is connected to an auxiliary winding in the PFC module, the positive electrode of the second diode is connected to the third capacitor, the negative electrode of the second diode is connected to the positive electrode of the third electrolytic capacitor, the third electrolytic capacitor is connected to the step-down chip of the BUCK module, the positive electrode of the fourth diode is grounded, and the negative electrode of the fourth diode is connected to the third capacitor.

[0014] Optionally, the linear voltage stabilization circuit includes a ninth resistor, a second transistor, a first voltage stabilizing diode and a fifth capacitor, one end of the ninth resistor is connected to the positive electrode of the third electrolytic capacitor, the other end of the ninth resistor is connected to the base of the second transistor and the negative electrode of the first voltage stabilizing diode, and the emitter of the second transistor is connected to the fifth capacitor.

[0015] Optionally, the power supply module also includes an eighth resistor and a fourth electrolytic capacitor, one end of the eighth resistor is connected to the output end of the rectifier module, and the other end of the eighth resistor is connected to the positive electrode of the fourth electrolytic capacitor. At the same time, the positive electrode of the fourth electrolytic capacitor is connected to the VCC pin of the PFC control chip of the PFC module. The half-wave alternating current output by the rectifier module charges the fourth electrolytic capacitor after passing through the eighth resistor. When the voltage on the fourth electrolytic capacitor reaches the driving voltage of the PFC control chip, the PFC control chip starts working and outputs a PWM signal.

[0016] Optionally, the power supply module includes a third diode, an anode of the third diode is connected to the fifth capacitor, and a cathode of the third diode is connected to the VCC pin of the PFC control chip.

[0017] Optionally, the PFC module includes an auxiliary winding, which is connected to the output end of the rectifier module to supply power to the drive circuit.

[0018] Optionally, the BUCK module includes a buck chip, the buck chip is used to supply high voltage to an internal HV pin, and the HV pin of the buck chip is connected to the output end of the power supply module.

[0019] Optionally, the step-down chip has a built-in power MOS, and the BUCK module operates in a BUCK topology.

[0020] Another object of the present invention is to provide a lamp having the above driving circuit.

[0021] To achieve the above object, the present invention provides a lamp, comprising the above driving circuit and a load, wherein the load is connected to the driving circuit.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: the LED driving circuit of the present invention supplies power to the PFC module and the BUCK module through the power supply module provided, and the power supply module takes power from the auxiliary winding of the PFC module and provides it to the PFC module and the BUCK module respectively after processing, which is beneficial to reducing the power supply loss of the PFC module and the BUCK module, reducing heat generation, and realizing that the PFC module and the BUCK module can drive a large power load while using a small package chip, effectively reducing the manufacturing cost, and at the same time, through the design of the line structure of the power supply module, it also has a lightning protection function, and has good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a principle block diagram of a driving circuit according to an embodiment of the present invention;

[0024] Figure 2 yes Figure 1 Circuit diagram of the .

[0025] 100- driving circuit;

[0026] 10-rectifier circuit, 20-PFC module, 30-BUCK module, 40-power supply module. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] It should be noted here that in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0029] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0030] See also Figures 1-2 FIG. 1 is a driving circuit 100 according to a preferred embodiment of the present invention, comprising:

[0031] The rectifier module 10 is connected to the mains and is used to convert the external input AC power into half-wave AC power;

[0032] The PFC module 20 is connected to the rectifier module 10 and performs voltage boosting and adjustment on the half-wave AC power to output a first voltage DC power;

[0033] The BUCK module 30 is connected to the output end of the PFC module 20, and provides the first voltage DC power output by the PFC module 20 to the load after voltage adjustment.

[0034] A power supply module 40, wherein the input end of the power supply module 40 is connected to the output end of the rectifier module 10 and the PFC module 20, and the output end of the power supply module 40 is connected to the BUCK module 30 and the PFC module 20 to supply power to the BUCK module 30 and the PFC module 20.

[0035] The heat generated by the BUCK module 30 is mainly caused by the loss of the HV power supply part of the buck chip U2 in the BUCK module 30, the loss of the built-in power MOS, and the loss of the logic control circuit. The loss of the built-in power MOS and the loss of the logic control circuit have been finalized and cannot be changed. The loss calculation formula of the HV power supply part of the buck chip U2 is P_loss=(Vin-V_cc)*I_cc, where V_cc is the internal operating voltage of the buck chip U2, I_cc is the operating current of the buck chip U2, and Vin is the input voltage of the HV pin of the buck chip U2. It can be seen that the lower the input voltage of the HV pin of the buck chip U2, the lower the power supply loss of the buck chip U2.

[0036] By setting up a power supply module 40, power is taken from behind the rectifier module 10 and before the PFC module 20 and then provided to the BUCK module 30 and the PFC module 20. Compared with the BUCK module 30 directly taking power from the electrolytic capacitor after the PFC module 20 is boosted, the input voltage of the buck chip U2 of the BUCK module 30 can be effectively reduced, thereby reducing the power supply loss of the buck chip U2, optimizing the loss and heat generation of the BUCK module 30, and also reducing the power consumption of the PFC module 20, thereby better controlling the overall power consumption of the driving circuit 100.

[0037] The power supply module 40 includes a voltage doubling rectifier circuit and a linear voltage stabilizing circuit. The voltage doubling rectifier circuit is configured to supply power to the BUCK module 30, and the linear voltage stabilizing circuit is configured to supply power to the PFC module 20. The voltage doubling rectifier circuit converts the half-wave AC power provided by the auxiliary winding T1 into DC power, and supplies part of the DC power to the buck chip U2 of the BUCK module 30, and the other part flows into the linear voltage stabilizing circuit, which steps down the DC power and supplies it to the PFC control chip U1.

[0038] The voltage doubling rectification circuit includes a third capacitor C3, a fourth diode D4, a second diode D2 and a third electrolytic capacitor EC3. The third capacitor C3 is connected to the auxiliary winding T1 in the PFC module 20. The positive electrode of the second diode D2 is connected to the third capacitor C3, the negative electrode of the second diode D2 is connected to the positive electrode of the third electrolytic capacitor EC3, the third electrolytic capacitor EC3 is connected to the buck chip U2 of the BUCK module 30, the positive electrode of the fourth diode D4 is grounded, and the negative electrode of the fourth diode D4 is connected to the third capacitor C3. The alternating current provided by the auxiliary winding T1 is converted into direct current through the voltage doubling rectification circuit and then provided to the BUCK module 30.

[0039] The linear voltage stabilization circuit includes a ninth resistor R9, a second triode Q2, a first voltage stabilization diode ZD1 and a fifth capacitor C5, one end of the ninth resistor R9 is connected to the positive electrode of the third electrolytic capacitor EC3, the other end is connected to the base of the second triode Q2 and the negative electrode of the first voltage stabilization diode ZD1, and the emitter of the second triode Q2 is connected to the fifth capacitor C5. Through the linear voltage stabilization circuit, the direct current on the third electrolytic capacitor EC3 is stepped down and then output to the PFC control chip U1, thereby reducing the power supply loss of the PFC control chip U1 and keeping it in working state.

[0040] The PFC module 20 includes an auxiliary winding T1 , which is connected to the output end of the rectifier module 10 to supply power to the drive circuit 100 .

[0041] The power supply module 40 also includes an eighth resistor R8 and a fourth electrolytic capacitor EC4. The power supply module 40 is connected to the output end of the rectifier module 10 through the eighth resistor R8. One end of the eighth resistor R8 is connected to the output end of the rectifier module 10, and the other end of the eighth resistor R8 is connected to the positive electrode of the fourth electrolytic capacitor EC4. At the same time, the positive electrode of the fourth electrolytic capacitor EC4 is connected to the VCC pin of the PFC control chip U1 of the PFC module 20. The half-wave alternating current output by the rectifier module 10 charges the fourth electrolytic capacitor EC4 after passing through the eighth resistor R8. When the voltage on the fourth electrolytic capacitor EC4 reaches the driving voltage of the PFC control chip U1, the PFC control chip U1 starts to work and outputs a PWM signal. The eighth resistor R8 is used as a starting resistor to charge the fourth electrolytic capacitor EC4 to start the PFC control chip U1.

[0042] The third electrolytic capacitor EC3 and the fourth electrolytic capacitor EC4 can be aluminum electrolytic capacitors with relatively large capacity, so as to improve the lightning surge protection capability of the driving circuit 100 and improve the overall safety of the circuit.

[0043] The power supply module 40 includes a third diode D3, the anode of the third diode D3 is connected to the fifth capacitor C5, and the cathode of the third diode D3 is connected to the VCC pin of the PFC control chip U1. The third diode D3 has a reverse unidirectional conduction function to prevent the circuit components on the left side of EC4 from affecting the charging of EC4 during startup.

[0044] The BUCK module 30 includes a buck chip U2, which is a high voltage power supply for the internal HV pin, and the HV pin of the buck chip U2 is connected to the output end of the power supply module 40. The BUCK module 30 converts the high voltage DC power on the first electrolytic capacitor EC1 into a DC power with a lower voltage on the second electrolytic capacitor EC2, and the output terminals LED+ and LED- are respectively connected to the positive and negative terminals of the second electrolytic capacitor EC2. The buck chip U2 is a SOP8 package and is widely used in designs below 30W.

[0045] The buck chip U2 has a built-in power MOS, and the BUCK module 30 works in a BUCK topology structure, with fewer circuit components and relatively simple circuits, while also achieving higher conversion efficiency and lower electromagnetic interference.

[0046] In some embodiments, the working topology of the PFC module 20 is a BOOST structure.

[0047] The output end of the BUCK module 30 includes LED+ and LED-, which are used to be connected to a load to provide a voltage required for the load to work.

[0048] The present invention further provides a lamp, comprising the above-mentioned driving circuit 100 and a load, wherein the load and the driving circuit 100 are connected to drive a load with relatively high power while the overall volume of the driving circuit 100 is relatively small.

[0049] The working process of the driving circuit 100 is as follows:

[0050] When the input terminals L and N of the driving circuit 100 flow into the mains, the mains is converted into high-voltage half-wave AC by the rectifier module 10. At this time, the high-voltage half-wave AC flows into the fourth electrolytic capacitor EC4 through the starting resistor. When the voltage on the fourth electrolytic capacitor EC4 reaches the VCC starting voltage of the PFC control chip U1, the PFC control chip U1 starts to work and outputs a PWM signal, and the PFC module 20 works to increase the voltage on the first electrolytic capacitor to 400V. Since the PFC module 20 works in the PWM switching state, the auxiliary winding T1 of the transformer is coupled to the PWM signal on the main winding, and the ZCD point of the auxiliary winding T1 is in the PWM state of 40V. The voltage doubling rectifier circuit composed of the third capacitor C3, the fourth diode D4, the second diode D2, and the third electrolytic capacitor EC3 converts the 40V PWM into 40V DC to the third electrolytic capacitor EC3. The third electrolytic capacitor EC3 is connected to the HV pin of the buck chip U2. At this time, the voltage is greater than the minimum working voltage of the buck chip U2, 30V. The buck chip U2 starts to work, and the circuit of the BUCK module 30 topology converts the 400V DC on the first electrolytic capacitor into DC that can work on the LED. The 40V DC on the third electrolytic capacitor EC3 is higher than the maximum working voltage of the VCC of the PFC control chip U1. It is converted into about 20V DC through the linear voltage stabilization circuit ninth resistor R9, the second triode Q2, the first voltage stabilization diode ZD1, and the fifth capacitor C5, and then through the third diode D3, the fourth electrolytic capacitor EC4 through the VCC pin of the PFC control chip U1 to power the PFC control chip U1. The third diode D3 has a unidirectional conduction function for preventing backflow, so as to prevent the circuit components on the left side of the fourth electrolytic capacitor EC4 from affecting the charging of the fourth electrolytic capacitor EC4 during startup.

[0051] The 40V DC power on the third electrolytic capacitor EC3 is directly provided to the buck chip U2. The power supply loss of the buck chip U2 is P_loss = (Vin-V_cc)*I_cc. Vin is only 40V, and the voltage on the first electrolytic capacitor is 400V. Compared with directly supplying power to the buck chip U2 from the first electrolytic capacitor, the power supply loss is 1 / 10 of the original.

[0052] At the same time, the linear voltage stabilization circuit on the power supply module 40 supplies power to the PFC control chip U1 , which can also reduce the loss of the PFC control chip U1 and better control the heating of the drive circuit 100 .

[0053] In summary, the driving circuit 100 of the present invention supplies power to the PFC module 20 and the BUCK module 30 through the power supply module 40. The power supply module 40 draws power from the auxiliary winding T1 of the PFC module 20. Compared with directly drawing power from the first electrolytic capacitor EC1 after boosting, the power supply loss of the PFC module 20 and the BUCK module 30 is greatly reduced, and it is possible to drive a large power load while using a small package chip, thereby effectively reducing the manufacturing cost. At the same time, the third electrolytic capacitor EC3 and the fourth electrolytic capacitor EC4 in the power supply module 40 can also prevent lightning surges and improve safety. The driving circuit 100 has a simple overall structure and is highly practical.

[0054] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A driving circuit, characterized in that: include: A rectifier module (10), used for converting externally input alternating current into half-wave alternating current; A PFC module (20) is used to step up and adjust the half-wave alternating current and output direct current of a first voltage, the PFC module (20) being connected to the rectifier module (10); A BUCK module (30) is used to step down the direct current of the first voltage output by the PFC module (20) and provide it to a load, the BUCK module (30) being connected to the output end of the PFC module (20); A power supply module (40) is used to supply power to the BUCK module (30) and the PFC module (20), wherein an input end of the power supply module (40) is connected to an output end of the rectifier module (10) and to the PFC module (20), and an output end of the power supply module (40) is connected to the BUCK module (30) and the PFC module (20).

2. The driving circuit according to claim 1, characterized in that: The power supply module (40) comprises a voltage doubling rectification circuit and a linear voltage stabilization circuit, the voltage doubling rectification circuit is configured to supply power to the BUCK module (30), and the linear voltage stabilization circuit is configured to supply power to the PFC module (20).

3. The driving circuit according to claim 2, characterized in that: The voltage doubling rectifier circuit comprises a third capacitor (C3), a fourth diode (D4), a second diode (D2) and a third electrolytic capacitor (EC3); the third capacitor (C3) is connected to an auxiliary winding (T1) in a PFC module (20); the positive electrode of the second diode (D2) is connected to the third capacitor (C3); the negative electrode of the second diode (D2) is connected to the positive electrode of the third electrolytic capacitor (EC3); the third electrolytic capacitor (EC3) is connected to a step-down chip (U2) of the BUCK module (30); the positive electrode of the fourth diode (D4) is grounded; and the negative electrode of the fourth diode (D4) is connected to the third capacitor (C3).

4. The driving circuit according to claim 3, characterized in that: The linear voltage stabilization circuit comprises a ninth resistor (R9), a second transistor (Q2), a first voltage stabilization diode (ZD1) and a fifth capacitor (C5), one end of the ninth resistor (R9) is connected to the positive electrode of the third electrolytic capacitor (EC3), the other end of the ninth resistor (R9) is connected to the base of the second transistor (Q2) and the negative electrode of the first voltage stabilization diode (ZD1), and the emitter of the second transistor (Q2) is connected to the fifth capacitor (C5).

5. The driving circuit according to any one of claims 1 to 4, characterized in that: The power supply module (40) further comprises an eighth resistor (R8) and a fourth electrolytic capacitor (EC4), one end of the eighth resistor (R8) being connected to the output end of the rectifier module (10), and the other end of the eighth resistor (R8) being connected to the positive electrode of the fourth electrolytic capacitor (EC4); at the same time, the positive electrode of the fourth electrolytic capacitor (EC4) is connected to the VCC pin of the PFC control chip (U1) of the PFC module (20); the half-wave alternating current output by the rectifier module (10) charges the fourth electrolytic capacitor (EC4) after passing through the eighth resistor (R8); and when the voltage on the fourth electrolytic capacitor (EC4) reaches the driving voltage of the PFC control chip (U1), the PFC control chip (U1) starts to work and outputs a PWM signal.

6. The driving circuit according to claim 5, characterized in that: The power supply module (40) further comprises: a third diode (D3), the anode of the third diode (D3) being connected to the fifth capacitor (C5), and the cathode of the third diode (D3) being connected to the VCC pin of the PFC control chip (U1).

7. The driving circuit according to claim 1, characterized in that: The PFC module (20) comprises an auxiliary winding (T1), and the auxiliary winding (T1) is connected to the output end of the rectifier module (10) to supply power to the drive circuit.

8. The driving circuit according to claim 1, characterized in that: The BUCK module (30) comprises a buck chip (U2), the buck chip (U2) supplies high voltage to an internal HV pin, and the HV pin of the buck chip (U2) is connected to the output end of the power supply module (40).

9. The driving circuit according to claim 8, characterized in that: The buck chip (U2) has a built-in power MOS, and the BUCK module (30) operates in a BUCK topology structure.

10. A lamp, characterized in that: The invention comprises the driving circuit and a load according to any one of claims 1 to 9, wherein the load is connected to the driving circuit.

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