CN202374493U

CN202374493U - Constant-current driving power supply for tandem LED illumination

Info

Publication number: CN202374493U
Application number: CN2011204011007U
Authority: CN
Inventors: 谢应然; 刘志远
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-10-10
Filing date: 2011-10-10
Publication date: 2012-08-08
Anticipated expiration: 2021-10-10

Abstract

The utility model discloses an LED illumination driving power supply. The driving power supply is characterized by comprising a resistance-capacitance voltage dividing circuit, a rectification filter circuit and a constant-current circuit. According to the utility model, the output current of the driving power supply is restricted within rated current of LEDs, and the phenomenon that the service life of the LEDs is seriously shortened due to overcurrent of the LEDs nearby the peak value, which is caused by the change of peak voltage of a power grid, is avoided; and importantly, elements are less in quantity and low in cost and are safe and power-saving, so that the driving power supply is particularly suitable for driving more than a dozen of tandem LED illuminating energy-saving lamps.

Description

Serial connection LED illumination constant-current driving power supply

Technical field

The utility model LED illumination driving power relates to a kind of constant-current source.

Background technology

Though it is low-power LED illumination driving circuit kind is more now, general direct by capacitance-resistance bleeder circuit, current rectifying and wave filtering circuit, resistance current limliting rear drive LED, to reduce cost; Civil power crest voltage place causes the electric current that flows through LED far to surpass its rated current like this, and LED is easy to light decay.Also have producer to adopt the constant current chip, but cost significantly improve.

Summary of the invention

It is few that the purpose of the utility model provides a kind of use components and parts, is no more than the driving constant-current power of LED rated current; Constant-current circuit HL is serially connected between current rectifying and wave filtering circuit and the output LED; Effectively improve the life-span of LED, strengthened reliability,

Guarantee least cost realization LED constant-current driving.

For realizing above-mentioned purpose, the scheme that the technology of the utility model solves is: in existing low-power led drive circuit, be connected in series constant-current control circuit.The LED constant-current driving power supply that throws light on comprises the LED illumination constant-current driving power supply that capacitance-resistance bleeder circuit, current rectifying and wave filtering circuit, constant-current circuit are formed; It is characterized in that being to be provided with constant-current circuit HL, constant-current circuit HL is serially connected between current rectifying and wave filtering circuit and the output LED.Constant-current circuit is by transistor Q1, transistor Q2, and resistance R 3, resistance R 4, resistance R 5 are formed.Resistance R 4 provides the base current of transistor Q1 to increase when line voltage half cycle peak point voltage is big, and the collector current of transistor Q1 increases, and the electric current that flows through resistance R 5 increases; The base-emitter voltage of transistor Q2 also increases, and the ducting capacity of transistor Q2 strengthens, and the collector current of transistor Q2 increases; Provide the base current of transistor Q1 to play shunting action to resistance R 4; The ducting capacity of transistor Q1 weakens, and the collector current of transistor Q1 reduces, thereby has effectively suppressed the increase of output current; Make the output current total amount keep balance, keep the constant current output of civil power crest place.

Because the utility model LED driving power is provided with constant-current control circuit; When voltage is big near the line voltage half cycle peak value, make output current not become big with it through constant-current control circuit; Therefore it is compared with existing LED driving power; Having output current, influenced by the mains ac power supply change in voltage little, and output current is limited in the characteristics in the LED rated current scope, the life-span of effectively improving LED.

Use proof: it has reached intended purposes.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described:

Fig. 1-be the electrical schematic diagram of the utility model;

Fig. 2-be the circuit diagram of a kind of embodiment of the utility model;

Fig. 3-be the circuit diagram of the another kind of embodiment of the utility model.

Embodiment

As shown in Figure 1; LED that the utility model provides illumination constant-current driving power supply is made up of capacitance-resistance bleeder circuit, current rectifying and wave filtering circuit, constant-current circuit; Constant-current circuit comprises low-power transistor Q1, transistor Q2 and resistance R 3, resistance R 4, resistance R 5; When mains fluctuations changed, output current was limited in the definite continuous current scope of constant-current circuit, and Constant Electric Current flow valuve size is confirmed by resistance R 5 resistance values.

The constant-current circuit of LED that the utility model provides illumination constant-current driving power supply can adopt multiple mode to realize; Constant-current circuit HL shown in Figure 2 is made up of transistor Q1, transistor Q2, resistance R 3, resistance R 4, resistance R 5, and transistor Q1, transistor Q2 select the small-power NPN transistor for use.Transistor Q1, transistor Q2 select the small-power NPN transistor for use; Its resistance R 4 connects collector electrode and the base stage of transistor Q1; Resistance R 3 connects collector electrode and the emitter of transistor Q1; The collector electrode of transistor Q2 links to each other with the base stage of transistor Q1, and the emitter of transistor Q1 is connected with the base stage of transistor Q2, and resistance R 5 is connected with base stage, the emitter of transistor Q2; Constant-current circuit HL shown in Figure 3 is made up of transistor Q1, transistor Q2, resistance R 3, resistance R 4, resistance R 5, and transistor Q1, transistor Q2 select small-power PNP transistor for use.Its resistance R 4 connects collector electrode and the base stage of transistor Q1; Resistance R 3 connects collector electrode and the emitter of transistor Q1; The collector electrode of transistor Q2 links to each other with the base stage of transistor Q1; The emitter of transistor Q1 is connected with the base stage of transistor Q2, and resistance R 5 is connected with base stage, the emitter of transistor Q2.

Because the LED of the utility model illumination constant-current driving power supply can adopt multiple mode to realize, everyly control the power supply that the LED illumination drives through this constant-current circuit, make its drive current be limited in the protection range that all belongs to the utility model in the LED maximum rating.

Claims

1. serial connection LED illumination constant-current driving power supply comprises the LED illumination constant-current driving power supply that capacitance-resistance bleeder circuit, current rectifying and wave filtering circuit, constant-current circuit are formed; It is characterized in that being to be provided with constant-current circuit HL, constant-current circuit HL is serially connected between current rectifying and wave filtering circuit and the output LED.

2. LED illumination constant-current driving power supply according to claim 1; It is characterized in that constant-current circuit HL is made up of transistor Q1, transistor Q2, resistance R 3, resistance R 4, resistance R 5; Transistor Q1, transistor Q2 select the small-power NPN transistor for use; Its resistance R 4 connects collector electrode and the base stage of transistor Q1, and resistance R 3 connects collector electrode and the emitter of transistor Q1, and the collector electrode of transistor Q2 links to each other with the base stage of transistor Q1; The emitter of transistor Q1 is connected with the base stage of transistor Q2, and resistance R 5 is connected with base stage, the emitter of transistor Q2.

3. LED illumination constant-current driving power supply according to claim 1; It is characterized in that constant-current circuit HL is made up of transistor Q1, transistor Q2, resistance R 3, resistance R 4, resistance R 5; Transistor Q1, transistor Q2 select small-power PNP transistor for use; Its resistance R 4 connects collector electrode and the base stage of transistor Q1, and resistance R 3 connects collector electrode and the emitter of transistor Q1, and the collector electrode of transistor Q2 links to each other with the base stage of transistor Q1; The emitter of transistor Q1 is connected with the base stage of transistor Q2, and resistance R 5 is connected with base stage, the emitter of transistor Q2.