BQ2057 gets very hot

Joseph Genovese

Other Parts Discussed in Thread: BQ2057T, BQ2057

I have been evaluating the BQ2057T for a dual series wired battery pack application. I'm using the DV2057 development system unmodified. The chip works fine but gets very hot. I have tried lowering the input voltage to 9v with no change. Is this to be expected? Are there other options I could explore that would not generate as much heat?

over 13 years ago

0 Charles Mauney over 13 years ago

TI__Mastermind 31120 points

The bq2057 should not dissipate much power, however the exteranl pass transistor drops the voltage from in to out and this voltage times the current is the power dissipation. If this heat source is next to the IC then maybe it is heating the IC. The IC should be cooler than the pass transistor.

0 Joseph Genovese over 13 years ago in reply to Charles Mauney

Prodigy 130 points

It seems like there is an instability problem. The board and chip run relatively cool but can get in to a state where the current to the battery jumps (from .4 to .6A) and the bq2057 goes from warm to very hot. I can get this to happen by just handling the development board. Perhaps this is capacitance or ESD induced. I am grounded while I handle the board. Once in this mode it will stay there until I cycle the input power.