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LTC3643 SuperCap Charger as Power Booster?


I had a close look at the LTC3643 for handling SuperCaps, it seems to almost match our requirements. But my application seems a bit special: My system sometimes needs more (burst) current than delivered from its power input. For these situations, I would like to use power stored in a supercap:

- in low current situation, the supercap should get charged (e.g. using the LTC3643).

- in high current situation, the supercap should deliver extra power

The major difference to the LTC3643 behaviour: The chip will deliver power only when the external power is down. I would need it's power delivery on top of the external power.

Any ideas how this can be arranged?

Thoughts and hints are welcome.

  • Hello, just curious, is this a SCAP stack? Single SCAP cells are typically low voltage.

    Sounds like the LTC3643 is to be used in a power assist application. One thought would be to pull PFI low during the high current situation. This will start the buck from the SCAP to regulate the system voltage. If desired or needed a Schottky diode can be placed in parallel with the input FET if some current is expected to flow from the input to system load as well during this time.