CN209949483U

CN209949483U - Single-pole multi-mode wide-range input voltage electrolytic-capacitor-free LED driver

Info

Publication number: CN209949483U
Application number: CN201920293662.0U
Authority: CN
Inventors: 曾君; 刘锋; 刘俊峰
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-03-07
Filing date: 2019-03-07
Publication date: 2020-01-14
Anticipated expiration: 2029-03-07

Abstract

The utility model discloses a single-pole multi-mode wide range input voltage does not have electrolytic capacitor LED driver, including alternating current power supply, filter inductance, filter capacitance, 4 rectifier diode, 4 switch tubes, 2 input capacitance, 2 diode that steps up, the inductance that steps up, 2 output diode, 2 LED loads, output inductance, 2 output capacitance, wherein 2 switch tubes constitute two-way switch. When the input voltage is 220V, the bidirectional switch is switched off, and the LED driver works in a half-voltage input mode, so that low bus voltage and high efficiency can be realized; when the input voltage is 110V, the bidirectional switch is conducted, the LED driver works in a full-voltage input mode, the conduction loss of the bridge rectifier diode and the other 2 switching tubes is reduced, and the efficiency of the system under the condition of low input voltage is improved. The utility model has the advantages of high efficiency, wide voltage input, low bus voltage, no electrolytic capacitor, etc.

Description

Single-pole multi-mode wide-range input voltage electrolytic-capacitor-free LED driver

Technical Field

The invention relates to the technical field of LED driving, in particular to a single-pole multi-mode wide-range input voltage electrolytic-capacitor-free LED driver.

Background

The traditional LED driver topology consists of a two-stage structure: a Power Factor Correction (PFC) stage and a half-bridge DC/DC converter stage. While the independence of the two-stage architecture simplifies the design, the control complexity and system cost increases accordingly. At the same time, the efficiency is relatively low due to the need for more control circuits and switching devices. Therefore, a single-pole LED driver that shares the control circuit and the switching device is widely used. The traditional unipolar bridgeless boost PFC LED driver has the advantages of high efficiency, high power factor and the like, but the bus voltage is overhigh due to the fact that the LED driver works in a DCM mode, and V is usually the voltage of a bus_Bus>2V_in(V_inInput voltage magnitude). This not only places higher demands on the withstand voltage of the bus capacitor, but also subjects the switching tube to greater voltage stresses. When the input voltage has an effective value of 220V, V_BusMay reach over 600V. Therefore, the unipolar bridgeless boost PFC LED driver is usually used in the low input voltage occasions, and the application range of the unipolar bridgeless PFC LED driver is limited. Although the bridge boost PFC LED driver can effectively reduce the bus voltage, it includes a full bridge rectification structure, which causes high conduction loss at low input voltage and thus has low system efficiency.

Disclosure of Invention

The invention aims to overcome the defect that the traditional LED driver can not consider the application occasions of high input voltage and low input voltage, provides a single-pole multi-mode wide-range input voltage electrolytic-capacitor-free LED driver capable of working in wide-range input voltage, and can realize high efficiency and optimized bus voltage.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: the single-pole multi-mode wide-range input voltage electrolytic-capacitor-free LED driver comprises an alternating current power supply, a filter inductor, a filter capacitor, a first rectifier diode, a second rectifier diode, a third rectifier diode, a fourth rectifier diode, a first switch tube, a second switch tube, a first input capacitor, a second input capacitor, a first boost diode, a second boost diode, a boost inductor, a third switch tube, a fourth switch tube, a first output diode, a second output diode, a first LED load, a second LED load, an output inductor, a first output capacitor and a second output capacitor; one end of the alternating current power supply is connected with the anode of the first rectifying diode, the cathode of the second rectifying diode and one end of the filter capacitor, and the other end of the alternating current power supply is connected with one end of the filter inductor; the other end of the filter inductor is connected with the anode of the third rectifier diode, the cathode of the fourth rectifier diode, the other end of the filter capacitor and the drain electrode of the first switch tube; the source electrode of the first switch tube is connected with the source electrode of the second switch tube to form a bidirectional switch; the drain electrode of the second switching tube is connected with the cathode of the first input capacitor, the anode of the second input capacitor and one end of the boost inductor; the anode of the first input capacitor is connected with the cathode of the first rectifier diode, the cathode of the third rectifier diode and the anode of the first boost diode; the cathode of the second input capacitor is connected with the anode of the second rectifier diode, the anode of the fourth rectifier diode and the cathode of the second boost diode; the other end of the boosting inductor is connected with a source electrode of the third switching tube, a drain electrode of the fourth switching tube, an anode of the first output diode and a cathode of the second LED load; the drain electrode of the third switching tube is connected with the cathode of the first boost diode and the anode of the first output capacitor; the source electrode of the fourth switching tube is connected with the anode of the second boost diode and the cathode of the second output capacitor; the cathode of the first output diode is connected with the anode of the first LED load; the anode of the second LED load is connected with the cathode of the second output diode; the cathode of the first LED load is connected with the anode of the second output diode and one end of the output inductor; the other end of the output inductor is connected with the cathode of the first output capacitor and the anode of the second output capacitor.

The LED driver works in different modes to obtain high efficiency and low bus voltage through the connection and disconnection of the first switching tube and the second switching tube under the condition of different input voltages; when the input voltage is in the range of 220-240Vrms, the first switch tube and the second switch tube are turned off, the LED driver works in a half-voltage input mode to obtain low bus voltage and reduce the switching stress of the device, the high input voltage in the half-voltage input mode is equally divided by the first input capacitor and the second input capacitor, and the boost inductor works in a critical conduction mode; when the input voltage is within the range of 100-120Vrms, the first switching tube and the second switching tube are conducted, the LED driver works in a full-voltage input mode, the diode conduction loss is reduced, and the system efficiency is improved.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. under the condition of high input voltage, the bus voltage is reduced by turning off the first switching tube and the second switching tube, and the voltage stress of a bus capacitor and a switching device is reduced.

2. Under the condition of low input voltage, the loss of a rectifier diode and an open light tube is reduced by opening a first switch tube and a second switch tube, and the system efficiency is improved.

3. No electrolytic capacitor and long service life.

In a word, the invention can work in different modes according to different input voltages, realizes low bus voltage at high input voltage and high efficiency at low input voltage, has simple structure and flexible control, has good application prospect and is worthy of popularization.

Drawings

Fig. 1 is a circuit diagram of a unipolar multimode wide-range input voltage electrolytic-capacitor-less LED driver of the present invention.

FIG. 2a is an equivalent circuit diagram of the present invention operating in the half-voltage input mode.

FIG. 2b is an equivalent circuit diagram of the present invention operating in the full-voltage input mode.

Detailed Description

The present invention will be further described with reference to the following embodiments.

As shown in fig. 1, the unipolar multimode wide-range input voltage electrolytic-capacitor-less LED driver provided in this embodiment includes an ac power source V_inFilter inductor L_fFilter capacitor C_fA first rectifying diode D₁A second rectifying diode D₂A third rectifying diode D₃A fourth rectifying diode D₄A first switch tube S₁A second switch tube S₂A first input capacitor C₁A second input capacitor C₂A first boost diode D₅A second boost diode D₆Boost inductor L_bA third switch tube S₃And a fourth switching tube S₄A first output diode D₇A second output diode D₈A first LED load LED₁A second LED load LED₂An output inductor L_rA first output capacitor C_b1A second output capacitor C_b2(ii) a The AC power supply V_inAnd a first rectifying diode D₁Anode of (2), second rectifying diode D₂Cathode and filter capacitor C_fIs connected with one end of the filter inductor L and the other end of the filter inductor L_fOne end of the two ends are connected; the filter inductor L_fAnd the other end of the third rectifying diode D₃Anode of (2), fourth rectifying diode D₄Cathode and filter capacitor C_fAnother end of the first switch tube S₁The drain electrodes of the two electrodes are connected; the first switch tube S₁Source electrode of and the second switch tube S₂The source electrodes of the two-way switch are connected to form a two-way switch; the second switch tube S₂Drain electrode of and the first input capacitor C₁Negative pole of (1), second input capacitance C₂Positive electrode, boost inductor L_bOne end of the two ends are connected; the first input capacitor C₁Anode and first rectifying diode D₁Cathode of (2), third rectifying diode D₃Cathode of (1), first boost diode D₅The anodes of the anode groups are connected; the second input capacitor C₂And a second rectifying diode D₂Anode of (2), fourth rectifying diode D₄Anode of (2), second boost diode D₆The cathodes of the two electrodes are connected; the boost inductor L_bThe other end of the first switch tube and the third switch tube S₃Source electrode and fourth switching tube S₄Drain electrode of (1), first output diode D₇Anode of, second LED load LED₂The cathodes of the two electrodes are connected; the third switch tube S₃And the first boost diode D₅Cathode and first output capacitor C_b1The positive electrodes of the two electrodes are connected; the fourth switch tube S₄Source and second boost diode D₆Anode of, a second output capacitor C_b2The negative electrodes are connected; the first output diode D₇And the first LED load LED₁The anodes of the anode groups are connected; the second LED load LED₂Anode of and a second output diode D₈The cathodes of the two electrodes are connected; the first LED load LED₁Cathode of and a second output diode D₈Anode and output inductor L_rOne end of the two ends are connected; the output inductor L_rAnd the other end of the first output capacitor C_b1Negative electrode of (1), and second output capacitor C_b2The positive electrodes of (a) and (b) are connected.

The working principle of the unipolar multimode wide-range input voltage electrolytic-capacitor-free LED driver in the embodiment is as follows: when the input voltage V_inIn the range of 220-240Vrms, the first switch tube S₁And a second switching tube S₂And is turned off, at which time the proposed LED driver operates in a half-voltage input mode, and the equivalent circuit is as shown in fig. 2 a. In half-voltage input mode, high input voltage is supplied from the first input capacitor C₁And a second input capacitance C₂And the low bus voltage is realized by sharing. In addition, the boost inductor L_rOperating in critical conduction mode to achieve high power factor. When the input voltage V_inWithin the range of 100-120Vrms, the first switch tube S₁And a second switching tube S₂And when the LED driver is switched on, the LED driver works in a full-voltage input mode. In the full-voltage input mode, because of the first input capacitor C₁And a second input capacitance C₂Is non-negative, and a third rectifying diode D₃And a fourth rectifying diode D₄Off and the equivalent circuit is shown in figure 2 b. In the positive half period of the input voltage, the first input capacitor C₁Is equal to the input voltage, secondTwo-input capacitor C₂The voltage of (d) is kept at zero; in the negative half-cycle of the input voltage, the second input capacitance C₂Is equal to the input voltage, a first input capacitor C₁The voltage of (c) is kept at zero. The full-voltage input mode reduces the loss of the diode and the switching device and improves the system efficiency. In addition, the boost inductor L_rOperating in discontinuous conduction mode to ensure high power factor.

In conclusion, the unipolar multimode wide-range input voltage electrolytic capacitor-free LED driver realizes optimization of bus voltage, effectively reduces voltage stress of a bus capacitor and a switching device under the condition of high input voltage, reduces loss of a system under the condition of low input voltage, and improves system efficiency. In addition, the LED driver of the invention realizes no electrolytic capacitor, and effectively improves the service life and reliability of the system.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, so that variations based on the shape and principle of the present invention should be covered within the scope of the present invention.

Claims

1. Unipolar multimode wide-range input voltage electrolytic capacitor-free LED driver is characterized in that: the LED driver comprises an alternating current power supply, a filter inductor, a filter capacitor, a first rectifier diode, a second rectifier diode, a third rectifier diode, a fourth rectifier diode, a first switch tube, a second switch tube, a first input capacitor, a second input capacitor, a first boost diode, a second boost diode, a boost inductor, a third switch tube, a fourth switch tube, a first output diode, a second output diode, a first LED load, a second LED load, an output inductor, a first output capacitor and a second output capacitor; one end of the alternating current power supply is connected with the anode of the first rectifying diode, the cathode of the second rectifying diode and one end of the filter capacitor, and the other end of the alternating current power supply is connected with one end of the filter inductor; the other end of the filter inductor is connected with the anode of the third rectifier diode, the cathode of the fourth rectifier diode, the other end of the filter capacitor and the drain electrode of the first switch tube; the source electrode of the first switch tube is connected with the source electrode of the second switch tube to form a bidirectional switch; the drain electrode of the second switching tube is connected with the cathode of the first input capacitor, the anode of the second input capacitor and one end of the boost inductor; the anode of the first input capacitor is connected with the cathode of the first rectifier diode, the cathode of the third rectifier diode and the anode of the first boost diode; the cathode of the second input capacitor is connected with the anode of the second rectifier diode, the anode of the fourth rectifier diode and the cathode of the second boost diode; the other end of the boosting inductor is connected with a source electrode of the third switching tube, a drain electrode of the fourth switching tube, an anode of the first output diode and a cathode of the second LED load; the drain electrode of the third switching tube is connected with the cathode of the first boost diode and the anode of the first output capacitor; the source electrode of the fourth switching tube is connected with the anode of the second boost diode and the cathode of the second output capacitor; the cathode of the first output diode is connected with the anode of the first LED load; the anode of the second LED load is connected with the cathode of the second output diode; the cathode of the first LED load is connected with the anode of the second output diode and one end of the output inductor; the other end of the output inductor is connected with the cathode of the first output capacitor and the anode of the second output capacitor.