LMR14050: LMR14050 variable output used as battery charger

pb ben

Part Number: LMR14050
Other Parts Discussed in Thread: LM5117

Hi, I've few questions about this schematic.
I use the LMR14050 to charge 1S/2S/3S IO-LITH batteries by monitoring the charge current with a INA series current sense.
*Is stable the buck converter with this L-C value? I try in the simulator and it would seem yes.
*Is necessary D4 to avoid reverse current in case mistakenly we connect a battery with a voltate higher than the set buck output voltage?
*What is the better solution to manage the feedback? With the op amp I have a low cost solution and the complete A/D resolution of the CPU, using the digital potentiometer I' ve less resolution and more cost, but If I have a short circuit in the output the voltage at FB pin is zero.

Thanks.
Luc.

over 1 year ago

0 Richard Fu22 over 1 year ago

TI__Mastermind 19380 points

Hi Luc.

Thanks for using the LMR14050 in your design.

1) The value looks ok to me.

2) Yes, you will want to prevent the output from feeding back into the circuit. If D4 is not present, it may force the converter to enter over voltage protection.

3) I believe an op-amp would be the easiest case to control the feedback. Regarding short-circuit, the LMR14050 has cycle-by-cycle current limit, as well as frequency fold-back in severe overcurrent cases.

There is also another way to implement this charger by using the LM5117 to implement a CC/CV loop, as shown in the blog post below: How to design a simple constant-current/constant-power/constant-voltage-regulating buck converter - Power management - Technical articles - TI E2E support forums

Regards,

Richard

Power management

Power management forum

LMR14050: LMR14050 variable output used as battery charger