Hello everyone,
I use mosfet driver TPS28225 and dc-dc controller TPS40200 in inductive charger project.
In TPS28225 datasheets there is only a simplified schematic how to connect this two IC together.
I made a test circuit that I put below.
On pin GDRV (TPS40200) i have fixed voltage 6,8V (RMS). On pin RC there is a sawtooth waveform of 620mVpp and frequency 108kHz. On pin PWM i have fixed 1.52V (RMS).
The problem is that TPS40200 does not generate a square waveform on output (GDRV pin), so transistor T1(and then TPS28225) is not controlled.
Could You tell help me why TSP40200 doesn't switch properly or where can I find a more precision information how to control TPS28225 by using TPS40200.
When I give PWM signal on pin number 3 of TPS28225 by using microcontroller Timer, then transistors T2 and T3 are driving and charging process takes place properly, so I think configuration of TPS28225 is correct.
Thanks for any help.
Peter