CN110809347A

CN110809347A - Alternating current driving circuit of LED lamp tube

Info

Publication number: CN110809347A
Application number: CN201911119006.XA
Authority: CN
Inventors: 程雅文; 侯启杭
Original assignee: Guyuan Photoelectric Technology (shanghai) Co Ltd
Current assignee: Guyuan Photoelectric Technology (shanghai) Co Ltd
Priority date: 2019-11-15
Filing date: 2019-11-15
Publication date: 2020-02-18

Abstract

The invention provides an alternating current driving circuit of an LED Lamp tube, wherein two switching tubes Q1 and Q2 are connected in series, two capacitors C1 and C2 are connected in series between the drain of a switching tube Q1 and the source of the switching tube Q2, a choke coil L1 and a Lamp1 which are connected in series are connected in parallel between a node a connected with the switching tubes Q1 and Q2 and a connecting node b connected with the capacitors C1 and C2, the choke coils L3945 and Q1 which are connected in series are controlled by signals to be alternately switched on and off, so that the capacitors C1 and C2 discharge the Lamp lamps Lamp1 and Lamp2 in series, and LED lamps of the Lamp lamps 686 1 and Lamp2 are lighted. The invention has the advantages that due to the existence of the choke coil L2, a complete output alternating current loop can be always kept in the working process, and the abnormal work of a product caused by the damage of an LED load or an open circuit state in poor contact can be avoided. The design avoids the interference of the external environment as much as possible and ensures the normal operation of the LED lighting system.

Description

Alternating current driving circuit of LED lamp tube

Technical Field

The present invention relates to a driving power supply for an LED lamp, and more particularly to an ac driving power supply circuit for an LED lamp.

Background

The LED has the characteristics of energy and power saving, environmental protection, long service life, small volume, rich colors, flexible combination, strong anti-vibration capability, no noise and the like. LED lamps are currently among the accepted green light sources and have penetrated the market completely. With the popularization of LED technology, the LED lamp greatly enriches the lamp market, so that the functions of the lamp are diversified, and LED lamp tubes driven by electronic ballasts are common in the market.

Stable operation of LED lighting systems is becoming more and more important. If we are installed the LED lamp (driver and LED load) because of human misoperation, the LED load is not firmly contacted with the driver or because it is installed in a specific use environment and place (garage, etc. where vibration is easy to occur), in such abnormal working environment, the driving circuit capable of ensuring normal and stable operation of the LED lighting system will be very important.

When the existing LED lighting driving product meets the special condition that an LED load lamp tube is damaged or is in poor contact, the product can enter an abnormal working state and even cause the product to lose efficacy.

Disclosure of Invention

The technical scheme includes that two switching tubes Q1 and Q2 are connected in series, two capacitors C1 and C2 are connected in series between the drain of a switching tube Q1 and the source of the switching tube Q2, the connection point of the drain of a switching tube Q1 and the capacitor C1 is connected with the positive electrode of direct-current voltage, an LED lamp tube and a choke coil are connected in parallel between a node a of the switching tube Q1 and the switching tube Q2 which are connected in series and a node b of the capacitors C1 and C2 which are connected in series, the LED lamp tubes connected in parallel are connected in series with the choke coil, the grids of the switching tubes Q1 and Q2 are controlled by control signals and are alternately switched on and switched off, so that the capacitors C1 and C2 alternately discharge to the LED lamp tubes, and alternating current driving of the LED lamp is achieved.

The number of the LED lamp tubes connected with the choking coils in series is at least more than two.

The invention has the advantages that due to the existence of the parallel choke coils, a complete output alternating current loop can be always kept in the working process, and the abnormal work of a product caused by the damage of an LED load or an open circuit state when the contact is poor can be avoided. The design avoids the interference of the external environment as much as possible and ensures the normal operation of the LED lighting system.

Drawings

FIG. 1 is a block diagram of the present invention with two LED tubes

FIG. 2 is a block diagram of the present invention with four LED tubes

FIG. 3 is a diagram of an embodiment of a switch tube controlled by a chip IC

The reference numbers in the figures illustrate:

1-input signal (i.e. AC/DC conversion circuit); 2-half bridge driving circuit.

Detailed Description

Referring to fig. 1, 2 and 3, two switching tubes Q1 and Q2 of the invention are connected in series, a connection point between a drain of a switching tube Q1 and a source of the switching tube Q2 is connected in series with two capacitors C1 and C2, a drain of a switching tube Q1 and a capacitor C1 is connected with a positive electrode Vin + of a direct current voltage, a node a between the series connection of the switching tubes Q1 and Q2 and a node b between the series connection of the capacitors C1 and C2 are connected in parallel with two LED lamps Lamp tubes Lamp1 and Lamp2 and a choke coil L2, the parallel LED lamps Lamp tubes Lamp1 and Lamp2 are connected in series with the choke coils L1 and L3, gates of the switching tubes Q1 and Q2 are controlled by a chip IC control signal to be turned on and off in turn, so that the capacitors C1 and C2 discharge to the LED lamps in turn, thereby performing alternating current driving of the LED lamps.

When the Q1 tube is turned on and the Q2 is turned off, the current flowing process is as follows: vin + ➡ Q1 ➡ a ➡ L1, Lamp1, L3, Lamp2, L2 ➡ C2- (ground).

When Q2 is turned on and Q1 is turned off, the current flow process is as follows: c2 ➡ Lamp1, L1, Lamp2, L3, L2 ➡ a ➡ Q2 source ➡ (ground).

During the above operation, the current flows in the opposite direction. When Q1 and Q2 are respectively conducted for a half period, when Q1 is conducted, energy on a capacitor C1 is released to loads Lamp1 and Lamp2, and when Q2 is conducted, energy on a capacitor C2 is released to loads Lamp1 and Lamp2, so that alternating current power is obtained at two ends of the loads when Q1 and Q2 are conducted in turn. By changing the switching frequency of the switching tube, the desired output ac frequency can be obtained. In the whole operation process of the product, the choke coil L2 always participates in the operation, namely even if the Lamp1 or Lamp2 is replaced due to application requirements, the open circuit is not possible, so that a complete alternating current loop can be always maintained, and the normal working state of the LED lighting system is ensured. Referring to fig. 2, four LED lamps Lamp1, Lamp2, Lamp3, Lamp4 and a choke coil L5 are connected in parallel, and when Lamp lamps Lamp1 and Lamp2 are damaged and S3 is turned off, Lamp lamps Lamp3 and Lamp4 operate as usual. Or the lamps Lamp1, Lamp2, Lamp3 and Lamp4 are all damaged, S3 and S6 are disconnected, and the circuit 2 still works normally.

Fig. 3 is a diagram of an embodiment in which the IC employs a chip L6574D to control the operation of the switching tubes Q1 and Q2. In the figure, an input signal circuit outputs a direct-current high-voltage power supply Vin to a chip IC through a resistor R1, and the chip IC outputs a 26 KHz-90 KHz alternating-current signal for Q1 and Q2 to work.

Claims

1. An alternating current driving circuit of an LED lamp tube is characterized in that two switch tubes Q1 and Q2 are connected in series, a connection point of a drain electrode of a switch tube Q1 and a source electrode of the switch tube Q2 is connected in series with two capacitors C1 and C2, a connection point of a drain electrode of a switch tube Q1 and a capacitor C1 is connected with a positive electrode of direct current voltage, an LED lamp tube and a choke coil are connected in parallel between a node a of the switch tube Q1 and Q2 which are connected in series and a node b of the capacitors C1 and C2 which are connected in series, the LED lamp tubes connected in parallel are connected in series with the choke coil, gates of the switch tubes Q1 and Q2 are controlled by signals and are turned on and off in turn, so that the capacitors C1 and C2 discharge to the LED lamp tubes in turn, and alternating current.

2. An AC driving circuit for LED lamp tubes according to claim 1, wherein there are at least two LED lamp tubes connected in series with the choke coil.