Accurate 1A current source

[aslak]

1a current source

Hello all,

I need to design accurate 1A current generator to drive 1 to 10 series connected high bright LED from 48V DC source. Any ideas?

Aslak

 

[ambreesh]

current source 1a

goto this links it may help
**broken link removed**
**broken link removed**

 

[aslak]

1a constant current source

Hello all,

I need to design accurate 1A current generator to drive 1 to 10 series connected high bright LED from 48V DC source. Any ideas?

Aslak

Forgot to mention that the efficiency must be high.

Aslak

 

[IanP]

constant current source circuits 1a

This can be accomplished in the following configuration:

Connect a current sensig resistor (0.1Ω or similar) between 48V rail and Anodes of the LEDs. Signal from this current sensig resistor through 2 voltage deviders will be fed to current error opamp.
The bottom side of the circuit will be realised by a FET transistor connected between 0V and trough an inductor ( you will need electrolitic capacitor as LPF component) the output Cathode(s) of the LED(s) chain.
FET transistor will be controlled by PWM regulator such as LM3524 or similar where internal error amplifiers will be controlled by current error opamp described above.

The above circuit will work as switchmode current generator with adjustable current level around the current error opamp with efficiency >80%.

 

[ezpcb]

lm3524 current source

How accuracy do you need? I don't think 1% is required for LED. At this point of view, a power MOSFET and a adjustable resistor will do the job. adjust the pot till the current reachs 1A.
carefully deal with the heat sink issue. the temp may be very high at 48V input.

mike

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[aslak]

adjustable current source 1a

How accuracy do you need? I don't think 1% is required for LED. At this point of view, a power MOSFET and a adjustable resistor will do the job. adjust the pot till the current reachs 1A.
carefully deal with the heat sink issue. the temp may be very high at 48V input.

mike

------------------------------
www.ezpcb.com
high quality pcb
most competitive price

In this circuit efficiency is very poor, less than 10% and over 40W is dissipated in FET. This circuit would be OK for 10 LEDs in series.

The driver is for high bright Luxeon LEDs and current should be better than 5% accurate. To keep the efficiency for any number of LEDs between 1 and 10, switcher is only possibility.

Aslak

 

[ezpcb]

current regulator 1a

My MOSFET circuit is enough for 5% accuracy. For improve the stability of the current, a high quality veriable resistor must be used.

mike

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most competitive price