Control 3W led intensity with li-ion cell using potentiometer

Other Parts Discussed in Thread: LM3410, TPS54200

1. I have to control a 3W single led intensity, need to vary intensity linearly from 0 to 100% as user rotates potentioneter of 10K.

2. is there any dedicated low cost asic solution available for this, which can do this.

3. Most of i have checked need a PWM signal to ic like here
www.ti.com/.../products.html Linear;DC/DC&p2297=Analog

I am looking for some solution where a potentiometer can do the dimming directly, instead of connecting additional ckt for asic

4. Voltage of Li-Ion cell: 3 to 4.2V
if charging, then voltage go to 5V from main adapter

So input voltage for IC go from 3V to 4.2V

over 6 years ago

0 Clinton Jensen over 6 years ago

TI__Mastermind 25500 points

Hello,

The only device our group has that can work from Li-Ion voltage levels is the LM3410. But that would require a PWM signal for dimming as well and would need to be in SEPIC configuration. Or it would require a two stage solution with a low input voltage boost followed by a buck with analog dimming capability.

I will have another group take a look at this.

Regards,

Clint

0 Kenneth Du over 6 years ago

TI__Genius 14295 points

Hi,

Currently we don't have a device that meets all your requirememnts.

You can also take a look at TPS54200, but the input voltage is higher than 4.5V.

Thanks.
Regards,
Kenneth

0 VT over 6 years ago in reply to Kenneth Du

Genius 3300 points

Hi Kenneth,

Can you suggest how I can use 10K potentiometer to vary intensity of light from 0 to 100% using TPS54200

0 Kenneth Du over 6 years ago in reply to VT

TI__Genius 14295 points

Hi,

I ask my colleague to support you on this device. She will response you soon.

Thanks.
Kenneth

0 VT over 6 years ago in reply to Kenneth Du

Genius 3300 points

Hi Kenneth,
Thanks for response. Will wait for response.

Thanks
VT

0 VT over 6 years ago in reply to VT

Genius 3300 points

Hi Kenneth,
Any update on that

0 Kenneth Du over 6 years ago in reply to VT

TI__Genius 14295 points

Hi,

Sorry for the delay due to Chinese New Year holidays.

I check about the Analog Dimming Mode, and it still needs PWM input for analog dimming.

So it's not applicable by just using potentiometer.

Thanks.

Regrads,

Kenneth

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Control 3W led intensity with li-ion cell using potentiometer