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Regarding the constant current source to drive the High bright LEDS

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prakashvenugopal

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Hi,

Can anyone tell me the simple constant current source IC to drive High bright LEDs.
The LED spec is Vf= 3.2V and If= 350 mA. Please let me know.

Thanks,
V. Prakash
 

If you have a problem obtaining the IC recommended by alexan, you could use an LM317. The LM317 circuit below has the advantage of easy availability. Its disadvantage is relatively low efficiency compared to switched-mode drivers. The supply voltage should be higher than 6V and the IC should be mounted on a small heatsink.

68_1324453079.png
 
Hi,

Thanks. I want to drive 10 nos of High bright LEDs in series having Vf= 3.2V and If=350 mA. Able to drive these 10 LEDs with AMC7135 ? Please let me know.

Thanks,
V. Prakash
 

The AMC7135 is a low voltage device (input 2.7v - 6v) , the output is a constant current of 350 mA intended to drive a single led.
If you connect the 10 led in series then it can't work because you need a 32v driver.
 
You can drive 10 LEDs in series with the LM317 circuit without any change as long as the supply voltage is not less than (3.2*10 + 3) volts = 35V. 3.2*10 is the voltage of 10 white LEDs in series and 3V is the minimum dropout voltage required by the regulator circuit.

99_1324458239.png
 
Last edited:
Hi,

Anyother constant current led driver with the input voltage of 24V driving atleat 7 nos of High bright LEDs with Vf= 3.2V and If=350 mA?


Thanks,
V.Prakash
 

Hi,

Will this constant current led driver part suits my application. Please advise.

Thanks,
V. Prakash
 

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Hi Prakash,

Laser driver/switches are also able to drive LEDs since they are adjustable constant current sources. Here is an application report on the IC-HK from iC-Haus (https://www.ichaus.biz/upload/pdf/hkan_2111es.pdf ) show more details. You can use the two channels also to dim or reducing power dissipation by pulsing with higher current. For higher current and up to six channels you can look at the iC-HG (up to 3A).

Enjoy your design work
 

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