Other Parts Discussed in Thread: TPS54561
Hi all,
I have this design setup for a charger for dual seal lead acid batteries. The batteries charge to 14.2V x 2 (28.4V) and turn off with external control exactly as this design below which "works". I used a different design where this worked absolutely perfectly but had to swap it out for this as there were no stocks.
Design link:
The issue is that when you put "dead batteries" on this design the limit of 2Amps is ignored and it oscillates and goes switches current ultra high and low causing the power supply to go crazy and the current is definitely not limited in any way to 2Amps, it goes to 5 to 6Amps and switches on and off at 6amps by the looks of it.
The issue now is i have a design on my desk that I really need to get working.
It looks like I have to do "something" to the COMP input to control the switching method this chip uses. Can anyone give some insites on how to get the chip to "stay" at 2Amps (its ok to go over for a second or so, but it just falls apart and switchs 5Amp on and off, looks like it shuts down, gets out of control.
The input voltage is a toroidal transformer into a full bridge which is 24Vdc 10Amp, unreg output reads 36V to 40V on the 3 x 2200uF caps. This voltage goes crazy when the power supply is current limiting and the output of the regulator also goes crazy.
