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I need an LED driver that can operate from a supply voltage as low as 3.3 volts and can put out a current of 350 mA or higher. The LEDs I'm using have a forward voltage of 2.7 volts at 350 mA. I only need to drive one LED.

Is there an IC that can do this? I found many that almost work, but they all either wanted a slightly higher input voltage or had a slightly lower max current than would work in this application.

Thanks for any ideas!

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  • \$\begingroup\$ What's your input power source? \$\endgroup\$ – calcium3000 Jan 13 '17 at 16:33
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    \$\begingroup\$ You using a switch to turn it on? Or is this to be programmatic control? Do you expect to PWM? Can you PWM? If the supply can be that low, how high can it be? How precise does the 350 mA need to be? Or can the current limit be fairly approximate over an input voltage range? Why don't you fully disclose what you are trying to do, to put clear context around your question? \$\endgroup\$ – jonk Jan 13 '17 at 16:57
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There's this chip: -

enter image description here

Or, I'd use a buck-boost regulator to generate 3.3 volts like this: -

enter image description here

Then consider using a dropper resistor to take the 3.3 volts to 2.7 volts at 350 mA i.e. a resistor of value of 1.7 ohms. Of course, as the LED warms you might need proper current control like this: -

enter image description here

Maximum input voltage is limited to about 3.2 volts so it would need to be pre-regulated such as by the LTC3536

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  • \$\begingroup\$ That is exactly what I've been looking for. Thanks!! \$\endgroup\$ – Matt24 Jan 14 '17 at 3:25
  • \$\begingroup\$ Oh sure-- sorry I'm new to StackExchange. \$\endgroup\$ – Matt24 Jan 18 '17 at 21:45

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