Hi,
I've got a step-up supply based on the TPS40210 that was supplied by Workbench.
It's to take 11-13Vdc and step it up to 65V. I laid it out paying attention to the suggested layout provided in workbench except in some cases I used larger components so the layout is slightly tweaked to use say, 0805 instead of maybe 0603s and such.
Here's the schematic:
(Note one error on the schematic is the output flag should read 0.4A not 4A)
My problem is the regulator doesn't even start! It just sits there with Vin minus the diode drop sitting on the Cout. I can't find anything obvious as to why it's not running.
Measuring some of the regulator pins we have:
VDD = 11.85V
VBP = 8.00V
FB = 0.12V certainly low enough to demand gate drive.
Gate-Drive = 480uV !! Same exact value on the FET's gate pin so no current flow or a shorted gate.
ISNS = 28mV
RC = 0.33V
I've replaced the TPS40210 once with a second new one just on the chance it was toasted.
Where do I look next? Still scratching my head.
