Voltage-controlled Current-limited switcher circuit

Posted on Feb 6, 2014

My product requires a voltage-controlled, current-limited power supply and for a number of years I have used various switcher chips with an op-amp to feed back a current sense voltage to the feedback pin. For the last couple of years I have been using an LM22680, but I seem to get variable results board to board. (Output voltage not consistent) I

Voltage-controlled Current-limited switcher circuit
Click here to download the full size of the above Circuit.

supply my circuit with an off the shelf 24 VDC switching power supply and the idea is to drive a variable load at a maximum of 1 amp. I have used WebBench for the different circuits that I have used. 3) Is there a better solution I should pursue I have used an LM25010 in the past, but the 1. 25 amps proved to be too much current. Would it work in conjunction with the op-amp feedback circuit (According to the datasheet, their is a ripple voltage requirement at the feedback pin, that may not be provided by the op-amp. ) The boards are exactly the same. The only differences are the components and the solder connections. Some boards will generate 21 volts at 1 amp and others will only generate 18 volts at 1 amp, with the same 20 ohm load. The boards do have the same voltage unloaded. So, I suppose it could be the variation in resistance values of the op-amp feedback circuit, but those components are all from the same run, so it seems unlikely they would vary significantly. Something I forgot to mention: I have also seen significant variations in ripple voltage present on the output from board to board under the same load conditions. I think it`s safe to say, in general, I have had issues with National/TI switcher chips in the past that were "unofficially" acknowledged by National/TI support staff, who suggested I migrate to other devices. Being a small company that can`t afford to make a "market mistake" by delivering an...

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    0-50V 1A power supply with CA3086
    Phone Line Simulator with PIC16F819
    Proximity Alarm I Circuit
    Complete SS Laser Power Supply Schematics
    power How can I switch a high current with a low-rated switch
    NiCd Battery Charger
    Overvoltage Protection Circuit
    555 multi-purpose repair circuit diagram
    Two electric motors on the mechanical brake circuit