CN104735853A - LED driving circuit and LED fluorescent lamp using the driving circuit - Google Patents

Abstract

An LED drive circuit and an LED fluorescent lamp using the same are provided, the LED drive circuit comprises: a first capacitor connected between the first input terminal and the second input terminal; a transformer connected between the first input terminal and the second input terminal in parallel with the first capacitor; the positive temperature coefficient thermistor is connected between the first output end and the second output end of the transformer; the rectifier module is connected between the first output end and the second output end of the transformer in parallel with the positive temperature coefficient thermistor; and the constant current source module is connected between the first output end and the second output end of the rectifying module. The LED driving circuit is a negative resistance characteristic circuit, absorbs high-frequency peak voltage through the first capacitor, absorbs starting peak voltage through the positive temperature coefficient thermistor, and locks a power supply at about 100V, so that the LED power supply works normally; moreover, the LED lamp can be used independently and can be matched with an electronic ballast or an inductive ballast, and the application range is wide.

Description

LED driving circuit and LED fluorescent lamp using the driving circuit

technical field

The invention relates to a lighting device, in particular to an LED driving circuit and an LED fluorescent lamp using the driving circuit.

Background technique

As a fourth-generation lighting source, LED has significant advantages in energy saving and longevity. With the development of society, the problem of lighting energy consumption in daily life has become increasingly prominent. Therefore, LED fluorescent lamps with significant energy-saving advantages are more and more popular.

T8 fluorescent lamp is one of the traditional lamps widely used at present. The ballasts used in T8 fluorescent lamps currently on the market are generally electronic ballasts, and a small part of T8 fluorescent lamps use magnetic ballasts. The popular wide-voltage LED power supply can generally replace ordinary fluorescent lamps, and can be connected to the lamp holder of ordinary magnetic ballast fluorescent lamps for normal use. The electronic fluorescent lamp ballast cannot be connected directly, because the frequency of the power output by the electronic ballast is about 40K, and it has a high-voltage start-up characteristic. The start-up voltage is generated at the moment of power-on, and the peak value is greater than 600V, which is basically unbearable for ordinary LED power supplies. , can be burned instantly.

Contents of the invention

In view of the above-mentioned current state of the art, the technical problem to be solved by the present invention is to provide an LED driving circuit with negative resistance characteristics that can be used alone or matched with electronic ballasts or magnetic ballasts. Another technical problem to be solved by the present invention is to provide an LED fluorescent lamp using the driving circuit.

In order to solve the above technical problems, an LED driving circuit provided by the present invention includes:

a first input terminal and a second input terminal;

a first capacitor connected between the first input terminal and the second input terminal;

a transformer connected between the first input terminal and the second input terminal in parallel with the first capacitor;

a positive temperature coefficient thermistor connected between the first output terminal and the second output terminal of the transformer;

A rectification module, connected in parallel with the positive temperature coefficient thermistor between the first output terminal and the second output terminal of the transformer;

A constant current source module connected between the first output end and the second output end of the rectification module;

The first output terminal and the second output terminal are respectively connected to the first output terminal and the second output terminal of the constant current source module.

In one of the embodiments, the positive temperature coefficient thermistor is a step type thermistor.

In one of the embodiments, the rectification module is a high-speed rectification bridge.

In one of the embodiments, the LED driving circuit further includes a second capacitor, the second capacitor is connected in parallel with the PTC thermistor between the transformer and the PTC thermistor .

In one of the embodiments, the LED driving circuit further includes a third capacitor, and the third capacitor is connected in parallel between the first output terminal and the second output terminal of the rectification module.

An LED fluorescent lamp provided by the present invention includes an LED driving circuit and an LED light source, the LED driving circuit is the above-mentioned LED driving circuit, the first output terminal and the second output terminal of the LED driving circuit are respectively connected to the Connect the positive and negative poles of the LED light source.

In one of the embodiments, the first input terminal and the second input terminal of the LED driving circuit are electrically connected to a commercial power supply.

In one of the embodiments, the LED fluorescent lamp further includes a ballast, the first input end and the second input end of the ballast are electrically connected to the mains power supply, and the first output end of the ballast and the second output terminal are respectively electrically connected to the first input terminal and the second input terminal of the LED driving circuit.

In one of the embodiments, the LED fluorescent lamp further includes a starter, and the starter is electrically connected with the ballast.

In one of the embodiments, the ballast is an electronic ballast or an magnetic ballast.

Compared with the prior art, the LED drive circuit of the present invention is a circuit with negative resistance characteristics, which absorbs high-frequency peak voltage through the first capacitor, absorbs the peak voltage of ignition through the positive temperature coefficient thermistor, and locks the power supply at about 100V, Make the LED power supply work normally; moreover, the LED drive circuit can be used alone (that is, directly connected to the mains power supply), or it can be connected with an electronic ballast or an inductive ballast, and can adapt to lamp holders without ballasts and lamp holders with The lamp holder of the ballast, so it has a wide range of applications.

Description of drawings

FIG. 1 is a circuit diagram of an LED driving circuit in Embodiment 1 of the present invention;

Fig. 2 is a driving circuit diagram of Embodiment 1 of an LED fluorescent lamp having the LED driving circuit in Fig. 1;

Fig. 3 is a driving circuit diagram of Embodiment 2 of the LED fluorescent lamp having the LED driving circuit in Fig. 1 .

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and examples. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

FIG. 1 is a circuit diagram of an LED driving circuit in one embodiment of the present invention. As shown in the figure, the LED driving circuit includes: a first input terminal I1, a second input terminal I2, a transformer T, a first capacitor C1, a positive temperature coefficient thermistor R, a rectifier module U1, a constant current source module U2, a first The output terminal O1 and the second output terminal O2, wherein the first capacitor C1 is connected between the first input terminal I1 and the second input terminal I2 for absorbing high-frequency peak voltage. The transformer T is connected in parallel with the first capacitor C1 between the first input terminal I1 and the second input terminal I2. The positive temperature coefficient thermistor R is connected between the first output terminal and the second output terminal of the transformer T, and is used for absorbing the peak voltage generated by the lighting of the fluorescent lamp. Preferably, the positive temperature coefficient thermistor R is a step-type thermistor, and the step-type thermistor has a low resistance before being energized, and immediately becomes a megohm high resistance after being energized, which can better absorb the fluorescent lamp start-up. The peak voltage generated by Hui. The rectification module U1 is connected in parallel with the positive temperature coefficient thermistor R between the first output end and the second output end of the transformer T, and is used for rectifying high-frequency alternating current into direct current. Preferably, the rectification module U1 is a high-speed rectification bridge. The constant current source module U2 is connected between the first output terminal and the second output terminal of the rectification module U1 for outputting constant current and constant voltage. Preferably, the constant current source module U2 charges the capacitor Power supply (CCPS). The first output terminal O1 and the second output terminal O2 are respectively connected to the first output terminal and the second output terminal of the constant current source module U2, the first output terminal O1 and the second output terminal O2 is used to connect with the positive and negative poles of the LED light source.

Preferably, the LED drive circuit further includes a second capacitor, the second capacitor C2 is connected in parallel with the PTC thermistor R between the transformer T and the PTC thermistor R Its role is to cooperate with the transformer T to further absorb high-frequency peak clutter and better match the impedance of different types of electronic ballasts.

Preferably, the LED driving circuit further includes a third capacitor, and the third capacitor C3 is connected in parallel between the first output terminal and the second output terminal of the rectification module U1. The third capacitor C3 is a high-frequency filter capacitor, and its main purpose is to further purify the rectified voltage of the constant current source module U2 to ensure the normality of subsequent circuits.

Fig. 2 is a circuit diagram of Embodiment 1 of an LED fluorescent lamp having the LED driving circuit in Fig. 1, the LED fluorescent lamp includes an LED driving circuit and an LED light source, the LED driving circuit is the LED driving circuit in the above embodiment, and the LED The first input terminal I1 and the second input terminal I2 of the driving circuit are electrically connected to the commercial power supply, and the first output terminal O1 and the second output terminal O2 of the LED driving circuit are respectively connected to the positive pole and the negative pole of the LED light source. In the LED fluorescent lamp of this embodiment, the LED drive circuit is used alone, its input terminal is directly connected to the 220V mains power supply, and its output terminal is connected to the LED light source array.

Fig. 3 is a circuit diagram of Embodiment 2 of an LED fluorescent lamp having the LED driving circuit in Fig. 1. The LED fluorescent lamp in this embodiment is generally the same as that in Embodiment 1, except that the LED fluorescent lamp also includes a ballast EB, The first input end and the second input end of the ballast EB are electrically connected to the commercial power supply, and the first output end and the second output end of the ballast EB are respectively connected to the first input end of the LED driving circuit. The terminal I1 is electrically connected to the second input terminal I2. Preferably, the LED fluorescent lamp further includes a starter, and the starter is electrically connected to the ballast EB. Preferably, the ballast EB is an electronic ballast or an magnetic ballast. The LED drive circuit of this embodiment is matched with the electronic ballast and the magnetic ballast, the input terminal is connected with the ballast, the ballast is connected with the 220V mains, the first output terminal O1 of the LED drive circuit and The second output terminal O2 is electrically connected to the LED light source.

To sum up, the LED driving circuit in the embodiment of the present invention is a circuit with negative resistance characteristics, which absorbs the high-frequency peak voltage through the first capacitor C1, absorbs the peak starting voltage through the positive temperature coefficient thermistor R, and locks the power supply at 100V or so, so that the LED power supply can work normally; moreover, the LED drive circuit can be used alone (that is, directly connected to the mains power supply), or it can be connected with an electronic ballast or an inductive ballast, and can adapt to both without ballast and with The lamp holder of the ballast, so it has a wide range of applications.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims (10)

1. a LED drive circuit, is characterized in that, comprising:

First input end and the second input terminal;

First electric capacity, is connected between described first input end and described second input terminal;

Transformer, and described first Capacitance parallel connection be connected to described first input end and described second input terminal between;

Semistor, is connected between the first output of described transformer and the second output;

Rectification module, and described semistor is connected in parallel between the first output of described transformer and the second output;

Constant-current source module, is connected between the first output of described rectification module and the second output;

First lead-out terminal and the second lead-out terminal, be connected with the first output of described constant-current source module and the second output respectively.

2. LED drive circuit according to claim 1, is characterized in that, described semistor is step change type thermistor.

3. LED drive circuit according to claim 1, is characterized in that, described rectification module is high-speed rectifier bridge.

4. the LED drive circuit according to claim 1,2 or 3, it is characterized in that, described LED drive circuit also comprises the second electric capacity, and described second electric capacity and described semistor are connected in parallel between described transformer and described semistor.

5. the LED drive circuit according to claim 1,2 or 3, is characterized in that, described LED drive circuit also comprises the 3rd electric capacity, and described 3rd Capacitance parallel connection is connected between the first output of described rectification module and the second output.

6. a LED daylight lamp, comprise LED drive circuit and LED light source, it is characterized in that, described LED drive circuit is for as the LED drive circuit in Claims 1 to 5 as described in any one, and the first lead-out terminal of described LED drive circuit and described second lead-out terminal are connected with the positive pole of described LED light source and negative pole respectively.

7. LED daylight lamp according to claim 6, is characterized in that, first input end of described LED drive circuit and the second input terminal are electrically connected with mains supply.

8. LED daylight lamp according to claim 6, it is characterized in that, also comprise ballast, first input end and second input of described ballast are electrically connected with mains supply, and the first output of described ballast and the second output respectively and second input terminal with the first input end of described LED drive circuit are electrically connected.

9. LED daylight lamp according to claim 8, is characterized in that, also comprises starter, and this starter is electrically connected with described ballast.

10. LED daylight lamp according to claim 8 or claim 9, it is characterized in that, described ballast is electric ballast or Inductive ballast.