Single-stage high-power-factor LED driving power supply

Abstract

The invention discloses a single-stage high-power-factor LED driving power supply, and relates to the technical field of power supply systems. The circuit comprises a bridgeless Boost power factor correction (PFC) circuit and an LCC half-bridge resonant converter. The bridgeless Boost power factor correction (PFC) circuit comprises vin, Lf, Cb, two diodes D1 and D2 and two metal oxide semiconductor (MOS) switch tubes S1 and S2. The LCC half-bridge resonant converter comprises two MOS switch tubes S1 and S2, two diodes D3 and D4, a series resonant capacitor Cr, a parallel resonant capacitor Cp and a series resonant inductor Ls. Vin is an alternating current mains supply input voltage of the bridgeless Boost power factor correction PFC circuit; according to the LED driving power supply circuit, the bridgeless Boost power factor correction (PFC) circuit and the LCC half-bridge resonant conversion circuit are integrated together through the switching tube sharing technology, and the LED driving power supply circuit has the advantages that only one set of controller is needed, the control logic is simple, the number of used electronic components is small, the cost is low, and the reliability is high.

Description

Technical Field

[0001] The invention relates to the technical field of power supply systems, and in particular to a single-stage high power factor LED driving power supply. Background Art

[0002] LED lighting technology combines the working principle of traditional light sources with microelectronic chip technology, and replaces traditional lighting devices with semiconductor light emitting diode (LED) light sources. LED driver power supply is an important component of LED lighting equipment. Its performance, safety, reliability and life directly determine the use of LED lighting equipment. Commonly used LED driver power supply circuit topologies include two-stage and single-stage.

[0003] The two-stage LED driver consists of a power factor correction PFC circuit and a DC-DC conversion circuit, and requires two controllers;

[0004] The single-stage LED drive power supply circuit integrates the power factor correction PFC circuit and the DC-DC conversion circuit together through the switch tube sharing technology, and only requires one controller;

[0005] The front-stage PFC circuit of the two-stage LED driver power supply generally uses basic circuits such as Boost, Cuk, Buck-Boost, Sepic, etc. Among them, the Boost PFC circuit is widely used in switching power supply products in actual engineering due to its simple topology, high efficiency, continuous input current, low EMI interference, easy driving and other advantages. The basic bridgeless PFC circuit was proposed by Rockwell Corporation in the United States in 1983. Compared with the traditional bridge-type Boost PFC, the number of semiconductor devices used is significantly reduced. Only two semiconductor devices are turned on in any working state, which greatly reduces the conduction loss;

[0006] Usually, LED driver power supply consists of two-stage circuits, including a front-stage PFC circuit and a rear-stage DC-DC circuit. The front-stage mainly realizes power factor correction and provides a stable DC bus voltage for the rear-stage. The rear-stage converts the bus voltage into the actual required output voltage value to meet different needs. Although the traditional two-stage LED driver power supply has good grid-side characteristics and smooth output characteristics, it requires two sets of control systems, which increases the complexity of control. In addition, it also has the disadvantages of large size, large number of components, and low efficiency.

[0007] In view of the above problems, the inventor proposes a single-stage high power factor LED driving power supply to solve the above problems. Summary of the invention

[0008] In order to solve the problem that a two-stage AC-DC LED driving power supply requires two sets of control circuit units; the object of the present invention is to provide a single-stage high power factor LED driving power supply.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions: a single-stage high power factor LED driving power supply, the circuit of the LED driving power supply includes a bridgeless Boost power factor correction PFC circuit and an LCC half-bridge resonant converter;

[0010] The bridgeless Boost power factor correction PFC circuit includes v in , L f , C b , two diodes D1 and D2 and two MOS switches S1 and S2;

[0011] The LCC half-bridge resonant converter includes two MOS switch tubes S1 and S2, two diodes D3 and D4, and a series resonant capacitor C r , parallel resonant capacitor C p And the series resonant inductor L s .

[0012] Preferably, the v in is the AC mains input voltage of the bridgeless Boost power factor correction PFC circuit, the L f The C is the energy storage inductor of the bridgeless Boost power factor correction PFC circuit. b It is the output filter energy storage capacitor of the bridgeless Boost power factor correction (PFC) circuit.

[0013] Preferably, the two MOS switch tubes S1 and S2 are common switch tubes for the bridgeless Boost power factor correction PFC circuit and the LCC half-bridge resonant converter.

[0014] Preferably, a T is provided on the LCC half-bridge resonant converter, and the T is a high-frequency integrated transformer with a primary-to-secondary turns ratio of n of the LCC half-bridge resonant converter.

[0015] Preferably, the two diodes D3 and D4 form a center-tapped rectifier circuit on the secondary side of T.

[0016] Preferably, the LCC half-bridge resonant converter is provided with a C o , the C o is the output filter capacitor.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the present invention, an LED driving power supply circuit is set up, which integrates a bridgeless Boost power factor correction (Power Factor Correction, PFC) circuit and an LCC half-bridge resonant conversion together through a switch tube sharing technology. The proposed LED driving power supply circuit has the advantages of only requiring one set of controllers, simple control logic, using fewer electronic components, low cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 The single-stage LED driving circuit diagram of the bridgeless PFC and LCC resonant converter of the present invention.

[0021] Figure 2 It is the equivalent circuit diagram of each mode in a single switching cycle of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example: Figure 1-2 As shown, the present invention provides a single-stage high power factor LED driving power supply, the circuit of the LED driving power supply includes a bridgeless Boost power factor correction PFC circuit and an LCC half-bridge resonant converter;

[0024] The bridgeless Boost power factor correction PFC circuit includes v in , L f , C b , two diodes D1 and D2 and two MOS switches S1 and S2;

[0025] The LCC half-bridge resonant converter includes two MOS switches S1 and S2, two diodes D3 and D4, and a series resonant capacitor C r , parallel resonant capacitor C p And the series resonant inductor L s .

[0026] v in is the AC mains input voltage of the bridgeless Boost power factor correction PFC circuit, L f is the energy storage inductor of the bridgeless Boost power factor correction PFC circuit, C b It is the output filter energy storage capacitor of the bridgeless Boost power factor correction (PFC) circuit.

[0027] The two MOS switch tubes S1 and S2 are common switch tubes for the bridgeless Boost power factor correction PFC circuit and the LCC half-bridge resonant converter.

[0028] The LCC half-bridge resonant converter is provided with T, where T is a high-frequency integrated transformer with a primary-to-secondary turns ratio of n of the LCC half-bridge resonant converter.

[0029] The two diodes D3 and D4 form a center-tapped rectifier circuit on the secondary side of T.

[0030] The LCC half-bridge resonant converter is equipped with a C o , C o is the output filter capacitor.

[0031] By v in , L f , C b The bridgeless Boost power factor correction PFC circuit is composed of two diodes D1 and D2 and two MOS switch tubes S1 and S2. In the positive half cycle, the switch tube S1 is turned on, the inductor L stores energy, the inductor current i(L) rises linearly, the freewheeling diode D2 is turned off, and the capacitor C1 voltage drops to release energy; in the negative half cycle, the switch tube S1 is turned off, the inductor L releases energy, the inductor current i(L) drops linearly, the freewheeling diode D2 is turned on, and the capacitor C1 voltage rises to store energy. The bridgeless Boost power factor correction PFC circuit works in the DCM state and has the functions of power factor correction and boost.

[0032] Through two MOS switch tubes S1, S2, two diodes D3 and D4, and a series resonant capacitor C r , parallel resonant capacitor C p And the series resonant inductor L s The LCC half-bridge resonant converter constitutes a half-bridge resonant circuit to convert the high-voltage DC output of the bridgeless Boost power factor correction PFC circuit into Cb The high-frequency transformer T with the primary-secondary turns ratio n has the functions of electrical isolation and energy transfer. The rectifier circuit composed of two diodes D3 and D4 at the middle tap of the secondary side of the high-frequency integrated transformer T converts the high-frequency AC square wave into high-frequency pulsating DC. o Then the DC power that meets the requirements is supplied to the LED load;

[0033] The LED driver circuit has 7 operating modes in one switching cycle. The equivalent circuits of each mode are as follows: Figure 2 As shown in (a)-(g) in .

[0034] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A single-stage high power factor LED driver power supply, characterized in that: The circuit of the LED driving power supply includes a bridgeless Boost power factor correction PFC circuit and an LCC half-bridge resonant converter; The bridgeless Boost power factor correction PFC circuit includes v in , L f , C b , two diodes D1 and D2 and two MOS switches S1 and S2; The LCC half-bridge resonant converter includes two MOS switch tubes S1 and S2, two diodes D3 and D4, and a series resonant capacitor C r , parallel resonant capacitor C p And the series resonant inductor L s .

2. A single-stage high power factor LED driving power supply as claimed in claim 1, characterized in that: The v in is the AC mains input voltage of the bridgeless Boost power factor correction PFC circuit, the L f The C is the energy storage inductor of the bridgeless Boost power factor correction PFC circuit. b It is the output filter energy storage capacitor of the bridgeless Boost power factor correction (PFC) circuit.

3. A single-stage high power factor LED driving power supply as claimed in claim 1, characterized in that: The two MOS switch tubes S1 and S2 are common switch tubes for the bridgeless Boost power factor correction PFC circuit and the LCC half-bridge resonant converter.

4. A single-stage high power factor LED driving power supply as claimed in claim 1, characterized in that: The LCC half-bridge resonant converter is provided with T, which is a high-frequency integrated transformer with a primary-to-secondary turns ratio of n of the LCC half-bridge resonant converter.

5. A single-stage high power factor LED driving power supply as claimed in claim 4, characterized in that: The two diodes D3 and D4 form a center-tapped rectifier circuit on the secondary side of T.

6. A single-stage high power factor LED driving power supply as claimed in claim 1, characterized in that: The LCC half-bridge resonant converter is provided with a C o , the C o is the output filter capacitor.

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