Tool/software:
Hi all,
I have a question regarding the Enable (EN) pin behavior on the TPS62140. In our design, we’ve observed that if the EN pin is high before VIN is applied, the converter consumes significantly more power approximately 200 mW. This behavior occurs because EN is driven by another power domain, and we want to avoid the TPS resetting if the MCU on that domain resets(the MCU controls if VIN is present or not).
To work around this, we currently toggle the EN pin after a brown-out, ensuring that VIN is present before EN is asserted.
The TPS62140 datasheet doesn’t provide specific guidance on the power-up sequence for EN relative to VIN. However, some other TI devices include a note such as:
“It is not recommended to apply EN voltage when VIN is 0 V.”
(Source: TPS560430 datasheet)
My questions are:
-
Could applying 3.3 V to the EN pin while VIN is at 0 V damage the TPS62140 (even if we leave it in this state for only a short period, functionally the chip seems to work fine)?
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Are there any timing requirements for how long EN must remain low after VIN is applied?
Since the datasheet shows diagrams with VIN and EN connected to each other, I would assume no delay is needed, but clarification would be helpful.
