Dual DC/DC IC Question.

Discussion in 'General Electronics Chat' started by toffee_pie, Jul 13, 2012.

  1. toffee_pie

    Thread Starter Senior Member

    Oct 31, 2009
    Hi All,

    I have sourced a buck boost converter which seems to satisfy my requirements, they are independent outputs so i can use them both as required.

    now, I also need to use a battery (backup). I am wondering if it would be possible to get a BMS (ie bq24702) and integrate it with the above?

    ie, if the power into the dc/dc IC is live it also feeds the BMS and charges the battery.

    If the power is lost the battery will supply power to the DC/DC (and loads).

    Is this feasible with mosfet switches?

    (might be too much....)
  2. crutschow


    Mar 14, 2008
    From the BMS data sheet, it would appear that it manages the supply current, the load current (the DC/DC) and the battery charge current to provide power as needed. It automatically switches to battery power when the power supply is not available. The BQ24702 is a complex control chip and I suggest you thoroughly read its data sheet and all the application notes to understand its operation.
  3. toffee_pie

    Thread Starter Senior Member

    Oct 31, 2009
    hi folk,

    i have looked at the dual dc/dc IC and it looks quite suitable.

    however i am not sure i can use a power path, BMS system like the Bq24702 with it.?

    I know the bq will detect if a source is present or not but my goal is to drive my 2 outputs from a battery IF no dc source is available.

    I dont think i can wire the output from the bq directly to the vcc of the dc/dc??

    my cells with be 2 x LFPs so charging voltage 7.2V.