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PMP20183: Lowering PMP20183 voltage

Part Number: PMP20183


I am unfamiliar with PMP20183 topology, but need a high voltage source running at low current, and this design seems to fit my needs. However, I would like to run it 10% lower than 200V (because of the max voltage of my photodiode that this will be driving), so 180V. Do I only need to drop the feedback resistor R2, R100 and R3 down to a total resistance of 887k? Or are their other considerations to take into account?


  • Charles,

    Running the output voltage at 180V should not be a problem, since lowering Vout creates less voltage stress in the power stage.

    The output voltage set equation is: Vout = 1.275V * (1 + (R2+R100+R3)/R8))

    Lower the values of R2+R100+R3 to 887K will correctly set Vout to 180V.

    R2 is only for test purposes (to measure loop stability) and can be deleted or set to zero.

    R100 and R3 were split up into two components to limit each resistor to 100V between the pads. A larger package single resistor (200V rated) could be used to replace of these two components if desired.


    John Betten