T
treez
Guest
Hi
We have a 48vout, 12Kw output power supply powering a load.
We wish to use a load switch comprising paralleled back-to-back NFETs. The load switch must temporarily switch a battery in to supply the load if the power supply drops out due to a heavy load transient.
Also, if the power supply fails, then the battery must also be switched in permanently.
The load switch should also be switched off if the power supply starts charging the battery (the battery should only be charged via the charger).
As such , our contractor is thinking of using the LTC4368 Load switch IC...
..However, this IC only has 35uA of gate current capability. As such, the Minimum gate source resistor for the 8 pairs of paralleled back-to-back NFETs is 390kOhms. This I believe is way too high, I think we need at the most 22k gate to source to prevent the gates from suffering ESD damage….specially since we will be handling the PCBs a lot in testing for this prototype.
Also, the 16 FETs of the load switch have a combined Vgs of 240nF. As such, the LTC4368 would take about 50ms to turn these fets on after a load transient that made the PSU drop out…this is too long and means the battery wont be able to supply these transients.
Do you know of any Load switch ICs which have higher gate drive current capability? I looked everywhere but cant find one
LTC4368
https://www.analog.com/media/en/technical-documentation/data-sheets/LTC4368.pdf
We have a 48vout, 12Kw output power supply powering a load.
We wish to use a load switch comprising paralleled back-to-back NFETs. The load switch must temporarily switch a battery in to supply the load if the power supply drops out due to a heavy load transient.
Also, if the power supply fails, then the battery must also be switched in permanently.
The load switch should also be switched off if the power supply starts charging the battery (the battery should only be charged via the charger).
As such , our contractor is thinking of using the LTC4368 Load switch IC...
..However, this IC only has 35uA of gate current capability. As such, the Minimum gate source resistor for the 8 pairs of paralleled back-to-back NFETs is 390kOhms. This I believe is way too high, I think we need at the most 22k gate to source to prevent the gates from suffering ESD damage….specially since we will be handling the PCBs a lot in testing for this prototype.
Also, the 16 FETs of the load switch have a combined Vgs of 240nF. As such, the LTC4368 would take about 50ms to turn these fets on after a load transient that made the PSU drop out…this is too long and means the battery wont be able to supply these transients.
Do you know of any Load switch ICs which have higher gate drive current capability? I looked everywhere but cant find one
LTC4368
https://www.analog.com/media/en/technical-documentation/data-sheets/LTC4368.pdf