Other Parts Discussed in Thread: TPS2553
We use TPS2335 for many years for USB power management.
Now I would like to use it as Super cap charger. At 250mA constant current charging looks fine, but at 500mA it is seems to go in thermal limit. Current is in 300mA range on multi meter until cap voltage gets to 2-3VDC.
1. How actually bad is to thermal cycle this part considering it will charge empty cap just few dozen times in lifetime. Any reliability models or rule of thumbs?
2. To mitigate the issue I am planning to place 5-10 Ohm resistor across to bypass TPS2553 at start. with EN pin tied to TPS2335 output (i.e. Cap + ). So, initially TPS2335 would be disabled until EN gets to 1V (or more with v divider) and cap would be charged thru fixed resistor. Slew rate on EN pin will be very low. Is that a concern for unstable operation, lockout etc? Vin is 5V and blocking diode are already in circuit.
