LT8228: Additional Circuitry for Programmable Output Voltage?

Hello everybody,

I want to be able to dynamically program the output voltage ofthe LT8228 from a MCU, across a large range from say 10V to 60V. For a Buck only design.

I was thinking I could create an op amp gain stage between the voltage divider (RFB2A, RFB2A) and the feedback pin FB2. Assuming no significant delay is introduced to the feedback path, is there any reason why it wouldn’t work?

If not like this, can anybody recommend any approaches?

Related, what is a sensible current range through the voltage divider?

The data sheet states “The bottom resistors RFB2B and RFB1B are selected to be 1.21kΩ for 1mA bias current in the resistor dividers.”

  • Too low current would introduce noise into FB2.
  • Too high current would impact efficiency. If the voltage divider current is much less than load current?


just clarified what IC
[edited by: Chendy at 5:24 PM (GMT -4) on 27 Oct 2020]