CN203327287U

CN203327287U - LED driving circuit

Info

Publication number: CN203327287U
Application number: CN2012207460040U
Authority: CN
Inventors: 陈榕锦
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-12-31
Filing date: 2012-12-31
Publication date: 2013-12-04
Anticipated expiration: 2022-12-31

Abstract

The utility model discloses an LED driving circuit. The LED driving circuit comprises an input protection circuit, a voltage reduction circuit, a rectifier filter circuit and an LED light source circuit which are electrically connected, and a second discharge resistor connected in parallel with a filter capacitor in the rectifier filter circuit, and further comprises at least one voltage-dividing current limit resistor connected in series with the LED light source circuit, wherein the LED driving circuit is externally connected with an alternating current, voltage reduction for the high voltage alternating current is carried out through the voltage reduction circuit, a smooth direct current voltage is outputted through the rectifier filter circuit, current limit for the LED light source circuit is carried out by the voltage-dividing current limit resistors, current limit protection for LEDs on the LED light source circuit is realized, so the LEDs can be driven to work under the stable voltage and current, the LEDs are prevented from being burned by over-large current, service life of the LEDs is guaranteed, and uniform and stable display brightness of the LEDs is realized.

Description

LED drive circuit

Technical field

The utility model relates to LED and drives field, particularly a kind of LED drive circuit.

Background technology

The LED illumination is a kind of new type light source of rapid rising development in recent years, and its many good characteristics make its application surface more and more wider.The unilateal conduction characteristic of LED makes LED must be equipped with LED drive circuit could to work, and LED drive circuit is a kind of special power supply of the LED of aiming at power supply, need have simple circuit structure, less volume and the higher conversion efficiency of taking.Existing LED drive circuit can be divided into two large classes by type of drive: a kind of is the constant current mode drive circuit, and another kind is the type voltage regulation drive circuit.The voltage stabilizing drive circuit after determining parameters, output be fixed voltage, but the electric current of output can change along with the increase and decrease of load, and the change in voltage after rectification can affect the brightness of LED; In addition, during LED work, temperature can raise, and along with the rising of LED temperature, the internal resistance meeting of LED reduces, thereby can cause the LED operating current to raise, and after surpassing its rated operational current, can affect the useful life of LED product, and serious meeting burns out LED.

Therefore, how designing the LED drive circuit that a kind of energy will carry out current limliting to LED is technical problem urgently to be resolved hurrily in the industry.

Summary of the invention

Main purpose of the present utility model is to provide a kind of LED drive circuit, is intended to realize LED is carried out to current-limiting protection, and increased the useful life of LED, prevents that LED is burned, and realizes that the brightness of LED demonstration is even, stablizes.

The utility model proposes a kind of LED drive circuit, the input protection circuit, reduction voltage circuit, current rectifying and wave filtering circuit and the LED light source circuit that comprise electric connection, described current rectifying and wave filtering circuit comprises bridge rectifier and filter capacitor, and described filter capacitor is in parallel with the output of described bridge rectifier; Described LED drive circuit also comprises at least one current-limiting resistor voltage divider, and described current-limiting resistor voltage divider is connected with described LED light source circuit.

Preferably, described current-limiting resistor voltage divider be provided with 1 ~ 6Individual, series connection mutually between described current-limiting resistor voltage divider, the resistance of described current-limiting resistor voltage divider is 22~ 68Ω.

Preferably, described current-limiting resistor voltage divider can be connected on the negative or positive electrode of described LED light source circuit.

Preferably, described input protection circuit is comprised of a fuse.

Preferably, described reduction voltage circuit is comprised of decompression capacitor and the first bleeder resistance, and described the first bleeder resistance is connected in parallel on the two ends of described decompression capacitor.

Preferably, described decompression capacitor is polypropylene film electric capacity.

Preferably, described bridge rectifier is single phase bridge type rectifier circu, four diodes, consists of.

Preferably, also comprise second bleeder resistance in parallel with described filter capacitor.

Preferably, described LED light source circuit is composed in series by several LED.

LED drive circuit of the present utility model comprises input protection circuit, reduction voltage circuit, current rectifying and wave filtering circuit and the LED light source circuit of electric connection, and second bleeder resistance in parallel with the filter capacitor in current rectifying and wave filtering circuit, the LED drive circuit external AC, High Level AC Voltage is through the reduction voltage circuit step-down, then the direct voltage of unidirectional pulsation is exported in the bridge rectifier rectification in current rectifying and wave filtering circuit; Filter capacitor is used for the alternating component in unidirectional pulsating voltage after the filtering rectification, makes it to become level and smooth direct voltage; The second bleeder resistance provides the path of releasing to filter capacitor, so that after filter capacitor quits work, and the electric energy of its two ends storage of releasing.The utility model adopts at least one current-limiting resistor voltage divider to connect with the LED light source circuit; thereby the LED light source circuit is carried out to current limliting; realization is carried out current-limiting protection to the LED in the LED light source circuit; LED under driving, stable voltage and current is worked; prevent that LED is burned because electric current is excessive; guarantee the useful life of LED, and realize that the brightness of LED demonstration is even, stable.

The accompanying drawing explanation

The circuit diagram of LED drive circuit in the embodiment that Fig. 1 is LED drive circuit of the present utility model.

The realization of the utility model purpose, functional characteristics and advantage, in connection with embodiment, are described further with reference to accompanying drawing.

Embodiment

Should be appreciated that specific embodiment described herein is only in order to explain the utility model, and be not used in restriction the utility model.

With reference to Fig. 1, an embodiment of LED drive circuit of the present utility model is proposed, this LED drive circuit is AC driving circuit, comprises the input protection circuit, reduction voltage circuit 1, current rectifying and wave filtering circuit 2 and the LED light source circuit 3 that are electrically connected successively.The alternating current input is connected with input protection circuit; this input protection circuit is comprised of a fuse F; the effect of fuse F is to provide the circuit safety protection; in the situation that short circuit or serious overload; fuse F fusing automatically disconnects circuit, thereby realizes short-circuit protection or serious overload protection.

The input of reduction voltage circuit 1 is connected with the output of input protection circuit, for the High Level AC Voltage by input, carries out step-down.Reduction voltage circuit 1 is comprised of decompression capacitor C1 and the first bleeder resistance R1, and decompression capacitor C1 can produce capacitive reactance under certain AC signal frequency, thereby the maximum operating currenbt of restriction LED drive circuit is realized the current limliting step-down.Decompression capacitor C1 is CBB22 polypropylene film electric capacity, and volume is little, economical, reliable, efficiency is high.The first bleeder resistance R1 is connected in parallel on the two ends of decompression capacitor C1, for giving decompression capacitor C1, provides the path of releasing, so that after decompression capacitor C1 quits work, and the electric energy of the decompression capacitor C1 two ends storage of releasing.

The input of current rectifying and wave filtering circuit 2 is connected with the output of reduction voltage circuit 1, and reduction voltage circuit 1 carries out High Level AC Voltage to export to current rectifying and wave filtering circuit 2 after step-down, by current rectifying and wave filtering circuit 2, carries out rectifying and wave-filtering.Current rectifying and wave filtering circuit 2 comprises bridge rectifier, filter capacitor C2 and second a bleeder resistance R2 in parallel with described filter capacitor C2, bridge rectifier is single phase bridge type rectifier circu, by four diode D1, D2, D3, D4, formed, for the direct voltage that is unidirectional pulsation by AC voltage conversion; Filter capacitor C2 is in parallel with the output of bridge rectifier, for the alternating component of the unidirectional pulsating dc voltage after the filtering rectification, makes it to become level and smooth direct voltage.The second bleeder resistance R2 provides the path of releasing to filter capacitor C2, so that after filter capacitor C2 quits work, and the electric energy of its two ends storage of releasing.

LED light source circuit 3 is composed in series by several LED, and LED light source circuit 3 is connected with the output of current rectifying and wave filtering circuit 2, the LED work in the direct voltage drive LED light source circuit 3 of current rectifying and wave filtering circuit 2 outputs.

For making the current stabilization of LED light source circuit 3, LED drive circuit of the present utility model also comprises at least one current-limiting resistor voltage divider R3, and current-limiting resistor voltage divider R3 connects with LED light source circuit 3, for reducing the electric current in LED light source circuit 3, plays metering function.Current-limiting resistor voltage divider R3 can arrange 1 ~ 6Individual, the current-limiting resistor voltage divider R3 in the present embodiment is provided with four, series connection mutually between current-limiting resistor voltage divider R3, and the resistance of current-limiting resistor voltage divider R3 is 22 ~ 68Ω.This LED drive circuit external AC, High Level AC Voltage is through reduction voltage circuit 1 step-down, then the direct voltage of unidirectional pulsation is exported in the bridge rectifier rectification in current rectifying and wave filtering circuit 2; Filter capacitor C2 is used for the alternating component in unidirectional pulsating voltage after the filtering rectification, makes it to become level and smooth direct voltage; Adopt again current-limiting resistor voltage divider R3 to connect with LED light source circuit 3; thereby LED light source circuit 3 is carried out to current limliting; realization is carried out current-limiting protection to the LED in LED light source circuit 3; LED under driving, stable voltage and current is worked; prevent that LED is burned because electric current is excessive; guarantee the useful life of LED, and realize that the brightness of LED demonstration is even, stable.

In addition, current-limiting resistor voltage divider R3 can partly be connected on the positive pole of LED light source circuit 3, and part is connected on the negative pole of LED light source circuit 3, facilitates current-limiting resistor voltage divider R3 the putting of position in circuit board.

The foregoing is only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure transformation that utilizes the utility model specification and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in scope of patent protection of the present utility model.

Claims

1. a LED drive circuit, the input protection circuit, reduction voltage circuit, current rectifying and wave filtering circuit and the LED light source circuit that comprise electric connection, it is characterized in that, described current rectifying and wave filtering circuit comprises bridge rectifier and filter capacitor, and described filter capacitor is in parallel with the output of described bridge rectifier; Described LED drive circuit also comprises at least one current-limiting resistor voltage divider, and described current-limiting resistor voltage divider is connected with described LED light source circuit.

2. LED drive circuit according to claim 1, is characterized in that, described current-limiting resistor voltage divider is provided with 1 ~ 6Individual, series connection mutually between described current-limiting resistor voltage divider, the resistance of described current-limiting resistor voltage divider is 22~ 68Ω.

3. LED drive circuit according to claim 2, is characterized in that, described current-limiting resistor voltage divider can be connected on the negative or positive electrode of described LED light source circuit.

4. according to claim 1 or 2 or 3 described LED drive circuits, it is characterized in that, described input protection circuit is comprised of a fuse.

5. according to claim 1 or 2 or 3 described LED drive circuits, it is characterized in that, described reduction voltage circuit is comprised of decompression capacitor and the first bleeder resistance, and described the first bleeder resistance is connected in parallel on the two ends of described decompression capacitor.

6. LED drive circuit according to claim 5, is characterized in that, described decompression capacitor is polypropylene film electric capacity.

7. according to claim 1 or 2 or 3 described LED drive circuits, it is characterized in that, described bridge rectifier is single phase bridge type rectifier circu, four diodes, consists of.

8. LED drive circuit according to claim 7, is characterized in that, also comprises second bleeder resistance in parallel with described filter capacitor.

9. according to the described LED drive circuit of any one in claims 1 to 3, it is characterized in that, described LED light source circuit is composed in series by several LED.