Charge pump (DCDC) for load cell

Discussion in 'General Electronics Chat' started by beedees, May 23, 2016.

  1. beedees

    Thread Starter Member

    Mar 29, 2015
    Hi everybody!
    I have a load cell and a power supply of 5V. I want to supply the load cell with 5V but this voltage isn't stabilized. How can I do it?
    Maybe I can use a charge pump with 5V output, but I don't know if using a charge pump is the best solution since they are characterized by noises due to switched capacitors.
    Thank you!
  2. ericgibbs


    Jan 29, 2010
    hi b,
    How unstable is the 5V supply.?
    Are you using a IA [opa] to amplify the LC signal.?
    How are you digitising the amplified output, PIC, MCU etc ...?
  3. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
    This is not a hard problem to solve. There is a power supply regulator topology called a "buck-boost regulator" that is right for this, but it has a switched inductor, is complex (4 switching FETs), and noisy. Assuming the current on the stabilized output is low, another approach is to boost the unstable 5 to something higher, then linear regulate it down to a precise 5 V with a ton of noise filtering. A one-stage charge pump would give about 9 V, and you can control the edge rate to reduce high frequency harmonics.

    "stabilized" is not enough to go on. What are the absolute value, accuracy, stability, and noise requirements (including bandwidth if you can) of the final output? Also, what is the output current requirement?