CN202222065U

CN202222065U - Constant current module of LED lamp

Info

Publication number: CN202222065U
Application number: CN201120343329XU
Authority: CN
Inventors: 黄毅红
Original assignee: Foochow Round Dot Photoelectricity Technology Corp Ltd
Current assignee: Foochow Round Dot Photoelectricity Technology Corp Ltd
Priority date: 2011-09-14
Filing date: 2011-09-14
Publication date: 2012-05-16
Anticipated expiration: 2021-09-14

Abstract

The utility model belongs to a constant current module in a circuit, and especially belongs to a constant current module of LED lamps. The main points of the constant current module of LED lamps are that the constant current module is a voltage dividing offset transistor amplification circuit and comprises a resistor RE, a resistor RB, a transistor T, a transistor TB and a diode D; the transistor T serves as an amplifying element; the resistor RB and the transistor TB form a bias circuit; the resistor RE is disposed on the emitter electrode of the transistor T; the diode D is arranged on the collector electrode of the transistor T; and the base electrode of the transistor TB is connected on the emitter electrode of the transistor T. The advantages of the utility model are that the voltage dividing offset transistor amplification circuit is adopted for stabilization of current of the power supply circuit of LED lamps, so that the current in the circuit does not fluctuate along with fluctuation of power voltage or the change of the number of the LED lamps, thereby prolonging the service life of the LED lamps.

Description

A kind of constant flow module of LED lamp

Technical field

The utility model belongs to the constant-current device in the circuit, especially belongs to the constant flow module of LED lamp.

Background technology

The LED lamp generally adopts resistance current-limiting type circuit to adjust the electric current of LED lamp supply line at present; When the quantity of LED lamp in supply voltage instability or the circuit changes; The electric current of LED lamp also can fluctuate along with the fluctuation of voltage; It is bad to cause LED light to be imitated, and makes fluorescent tube generate heat, and the useful life that shortens the LED lamp is short.

Summary of the invention

The utility model purpose is to overcome the shortcoming that existing LED lamp exists, and the constant flow module of the LED lamp of current stabilization in a kind of ability holding circuit is provided.

The technical scheme that the utility model adopted is a kind of constant flow module of LED lamp, and its main points are that it is a bias pressure formula transistor amplifier circuit, by resistance R _E, resistance R _B, transistor T, transistor T _B, diode D forms, transistor T is as amplifier element, resistance R _B, transistor T _BConstitute biasing circuit, resistance R _EBe contained on the emitter of transistor T, diode D is contained on the collector electrode of transistor T, transistor T _BBase stage be connected on the emitter of transistor T.

The advantage of the utility model is; The utility model adopts bias pressure formula transistor amplifier circuit to stablize the electric current of LED lamp supply line, and electric current is not fluctuateed along with the fluctuation of supply voltage or LED lamp number change, has prolonged the useful life of LED lamp; The brightness of all lamps is consistent in the circuit; This circuit is the pure semiconductor circuit, and is less demanding to components and parts, is not easy to damage.

Description of drawings

Fig. 1 is the schematic diagram of the utility model

Fig. 2 is the user mode figure of the utility model

Wherein: 1 constant flow module, 2 power supplys, 3 LED lamps, 4 resistance R _E5 resistance R _B

6 transistor Ts, 7 transistor Ts _B8 diode D.

Embodiment

Below in conjunction with accompanying drawing the utility model is carried out detailed description.

Like Fig. 1, shown in Figure 2, a kind of constant flow module of LED lamp, it is a bias pressure formula transistor amplifier circuit, by resistance R _E4, resistance R _B5, transistor T 6, transistor T _B7, diode D 8 forms, and transistor T 6 is as amplifier element, resistance R _B5, transistor T _B7 constitute biasing circuit, resistance R _E4 are contained on the emitter of transistor T 6, and diode D 8 is contained on the collector electrode of transistor T 6, transistor T _B7 base stage is connected on the emitter of transistor T 6.This circuit is compared traditional resistance current-limiting type circuit, has the electric current that can make in the circuit and keeps constant outstanding feature, is connected on during use between power supply and the LED lamp.

The constant current principle of the utility model is resistance R _B5, transistor T _B7 constitute the quiescent point that biasing circuit decides circuit, the base potential V of transistor T 6 _B=I _TBR _TB=(R _BU _CC)/(R _B+ R _TB), so can think V _BOnly by resistance R _B5, transistor T _BThe resistance value decision of each element of bleeder circuit of 7, and have nothing to do with transistor T 6 parameters, and do not receive the influence of transistor T 6 temperature stabilities.

The electric current of entire circuit can be through the adjustment resistance R _B5 confirm.The adjustment resistance R _B5 can adjust the base potential V of transistor T 6 _B, if with resistance R _B5 resistances increase, then U _BEAlso will increase, thus I _BIncrease I _EIncrease, if with resistance R _B5 resistances reduce, then U _BEAlso will reduce, thus I _BReduce I _EReduce.

Resistance R _E4 as feedback resistance, and the number change that fluctuation or LED lamp 3 occur when supply voltage makes constant flow module 1 input terminal voltage U _CCIncrease or when reducing, at V _BUnder the constant prerequisite, will produce following reaction in the circuit:

U _CCDuring increase:

U _CC↑?→?I _B↑?→?I _E↑?→?U _E↑?→?V _E↑?→?U _BE↓?→?I _B↓?→?I _E↓

U _CCWhen reducing:

U _CC↓?→?I _B↓?→?I _E↓?→?U _E↓?→?V _E↓?→?U _BE↑?→?I _B↑?→?I _E↑

Promptly, make U when circuit voltage appearance fluctuation _CCDuring increase, through resistance R _EThe voltage U at 4 two ends _EAugmenting response come out, the emitter that then feeds back to transistor T 6 makes V _ERaise U _BEReduce, thus I _B, I _EReduce and be tending towards constant basically, work as U _CCWhen reducing, also pass through resistance R _EThe voltage U at 4 two ends _EReduce reflect, the emitter that then feeds back to transistor T 6 makes V _EReduce U _BEIncrease, thus I _B, I _EIncrease also is tending towards constant basically.This negative feedback can be stablized output current I effectively _E, make output current I _EDo not receive the influence of voltage fluctuation in temperature of transistor stability and the circuit.

But the negative pulse that occurs in the diode D 8 elimination circuit, protective transistor does not end because of negative pulse, causes the whole circuit of the utility model to break off.

As stated, the utility model can guarantee that LED lamp 3 works in the stable electric current environment all the time, has prolonged the useful life of LED lamp 1.

Claims

1. the constant flow module of a LED lamp, it is characterized in that: described constant flow module (1) is a bias pressure formula transistor amplifier circuit, by resistance R _E(4), resistance R _B(5), transistor T (6), transistor T _B(7), diode D (8) forms, transistor T (6) is as amplifier element, resistance R _B(5), transistor T _B(7) constitute biasing circuit, resistance R _E(4) be contained on the emitter of transistor T (6), diode D (8) is contained on the collector electrode of transistor T (6), transistor T _B(7) base stage is connected on the emitter of transistor T (6).