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PTH12040W: PTH12040W as a current source

Part Number: PTH12040W


As I saw on this post the PTH12040W module can be used as a current source.

The thread was speaking about old posts about 2011 on the subject but I was not able to find them.

How could this module could be use as a current source with an analog consign ? I would be to supply a laser diode in the range 0.8V/5.5V.

Best regards,


  • Hi Julien,

    The device should be able to, I don't see why not, but that is something we did not test in our end. So, I cannot provide you with an 100% guarantee. Make sure to carefully test before the design is finalized.

    With that in mind, the most common approach to using a CV buck converter as a CC buck is to put a current sense resistor, Rsense, between the load and ground (floating load configuration). Then, feed-back the voltage across Rsense instead of the voltage across the load.
    I've attached an example below (schematic image) recommending how to wire the module to be used as a current source.

    Make sure to calculate the correct Rsense value:

    • Iout = Isense
    • Vadj = Vsense
    • Vsense = 0.8V (therefore, depending on your desired Iout, one can determine the correct Rsense value)
    • Rsense = 0.8V / Iout