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I'm working with a buck/boost LED driver that uses a 0->10V dimmer input. I would like to use the output of an open-source LED module as a switch for the LED driver. The LED module outputs 0 V in the "off" condition and 6.5 V in the "on" condition. I want to use one of the channels to control a high-power Cree LED using the buck/boost driver. So I would like to boost the 6.5 V output of the LED module to the 10 V required by the LED driver for full brightness. Is an op-amp the best way to do this?

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  • \$\begingroup\$ Do you need an analog gain (i.e. do you care what happens when the input to your "step up" circuit is 1.3 or 2.5 V)? Or do you just need a digital level translation (the only input voltages you care about are 0 V and 6.5 V)? \$\endgroup\$
    – The Photon
    Dec 28, 2020 at 4:12
  • \$\begingroup\$ I do not need an analog transition. The input will really only be 0 or 6.5V. \$\endgroup\$
    – user127813
    Dec 28, 2020 at 4:18
  • \$\begingroup\$ It looks like you could easily run that open source LED module off of 10V and make your life much easier. Just connect 10V (from a wall wart or something) to Alt Power and do not install JP2 (RX power). You still need to supply V+ from somewhere to power the rest of the board. \$\endgroup\$
    – user57037
    Dec 28, 2020 at 4:24
  • \$\begingroup\$ I'm limited to the power inputs available on an RC truck - namely, a battery (either 2S, 3S or 4S LiPo) and an open channel on the receiver (which is what I'm using), which supplies 6.5 V as long as the ESC is turned on. \$\endgroup\$
    – user127813
    Dec 28, 2020 at 4:35

1 Answer 1

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In comments you said,

I do not need an analog transition. The input will really only be 0 or 6.5V

In that case, the easiest solution is probably a comparator with an open-drain output. Based on the datasheet of your LED driver, no pull-up is required because the the input circuit on the driver sources a small current.

In this schematic, U1 is any comparator with open-drain output that can handle the input and output voltage ranges you need:

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Wow, this is awesome... I assume that OUT is the 10 V output but what is IN? \$\endgroup\$
    – user127813
    Dec 28, 2020 at 10:26
  • \$\begingroup\$ @user127813, IN is the signal coming from your "open source LED model" at either 0 or 6.5 V. \$\endgroup\$
    – The Photon
    Dec 28, 2020 at 16:22

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