Hi guys,
I'm looking for a solution of Automotive cold crank power management.
For LM5150RUMEVM www.ti.com/tool/LM5150RUMEVM, which the input voltage range is from 2.5V to 40V.(Requires minimum 6V voltage to start-up）
1) What's the reason for the requirement of the 6V start-up voltage?
2) How to modify the solution to be suitable for cold crank? (In another word, the board can be started up from 3.2V rather than 6V.)
Thank you very much.
Hi Mark,
Thanks for using the e2e forum.
1) The start-up voltage is required to turn on the device.
The device draws its VCC from the Vout pin. This voltage is required to configure the output voltage setting and supply the gate drivers.
Once startup is complete, the input voltage can drop as the system voltage is supplied via the output side of the boost controller.
For more details, please look at this datasheet section:
2) LM5150 is not able to start up with 3.2V, as this is still below the VCC UVLO threshold.
Here, I would suggest switching to another device:
LM5155 is a similar boost controller without this start-up limitation.
https://www.ti.com/product/LM5155-Q1
The minimum Vin to turn on the device is 2.97V.
Please let me know if you have additional questions on either device.
Best regards,
Niklas
