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I have a circuit using two step-down converters (RT8299) which take in 24V and output 12V to power a 12V, up to 6A resistive load. Each converter is rated for 3A, testing has shown the current circuit can supply up to 2.5A before thermal issues. I want to be able to power-cycle the load, for which I have a preliminary design using FETs. However the RT8299 does have an EN pin which would be cheaper. My question is: if I use a microcontroller to drive both EN pins low and shutdown both converters, is there a chance that I risk attempting to draw too much current from one chip and destroy it?

Example: the resistive load is drawing 4.1 amps. I drive the EN pins low to turn off both RT8299s. Theoretically if this connection is shared they would turn off at the same time, but maybe one of them shuts off milliseconds before the other causing a brief period of time where the load is drawing 4.1 amps. The remaining RT8299 attempts to supply that. Kaboom?

I can give more circuitry details if needed. The only important thing I can really think of is that the RT8299 outputs each go through a 0.1 Ohm resistor before joining together, allowing voltage to dissipate to avoid mismatching.

InBedded16
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    Voltage and current spikes like that for milliseconds are not unusual and I wouldn't expect them to destroy your converters. Although it's impossible to guarantee that from the information provided. If the converter is destroyed by that then it was a fragile piece of crap to begin with. Think about it, the converters are surely able to power up capacitive loads. – user253751 Jan 11 '23 at 16:29
  • Add links to each device and draw your schematic. The devil might be hiding in the detail. – Andy aka Jan 11 '23 at 17:21
  • Keep the trace connecting both ENABLE pins of both converters as close as possible together and close to the pin of MCU. This should help lower any possible delay. – Leoman12 Jan 11 '23 at 18:40
  • The datasheet states that the RT8299 has built-in current limiting so I wouldn't be too worried about that. Instead, I would be worried about the fact that the datasheet says nothing about connecting multiple units in parallel. – vir Jan 11 '23 at 20:14

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