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LTC4015 Recommended for New Designs
The LTC4015 is a complete synchronous buck controller/charger with pin-selectable, chemistry specific charging and termination algorithms. The LTC4015...
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LT4356 Inrush current issue with LTC4015

kengo

on Jun 12, 2018

Dear Team,

We have developed power management board with the reference of LTC4015 demo board. In our board the LTC4015 is getting burnt due to the inrush current when we power on the battery (Li-Ion battery, 26V, 3.5Ah). We implemented our own inrush current protection circuit with the reference of LT4356 demo board.

But still LTC4015 is getting burnt when we switch off and On frequently. Request your complete support to solve this issue. The MOSFET (Q1C) which we've used in the LT4356 board also went bad, this caused LTC4015 getting damaged. We've a delivery of this project to customer, sorry we are coming at the last moment. Definitely you guys have solved this kind of issues, Request you to provide the working schematic.

Thanks in Advance!!

Thank you,

Krishna

0 ADIApproved

on Jun 12, 2018 7:08 PM
Hello Krishna,

It sounds like you need to slow the turn-on of the FET suitably in order to limit inrush current. This can be done by adding an RC to the gate of the pass FET. A drain resistor in parallel with the capacitor will speed-up the turn-off of the FET which will help with rapid on/off connections. The amount of resistance and capacitance that will suitably limit your inrush current will need to be evaluated in your test setup to determine whether it will work for you.

If the pass FET is being damaged, then you need to use a FET that can dissipate more power. If that FET is being damaged, perhaps the whole problem is with the power level of the FET and not with the RC values that you have chosen.

Regards,

Zack
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