Hello, please help me figure out what's going wrong with my TPS62737. Thank you.
When I measure the Vout line, it goes up and down from 1.3v to 1.4v.
I checked that it's getting good Vin (4.10v). The EN2 is getting 2.5v from the processor, so it's turned on. And I double checked all the ground connections.
R1: 4.99Mohm
R2: 169Kohm
R3: 7.68Mohm
I used the calculator sheet for resistor values.
VIN is supplied from LiPo battery at 3.7v.
Schematic:
HI Keith,
The resistor values for VIN_OK aren't aligning with the the 4.1V stated above:
Also, 4.1V for VIN_OK is above the 3.7V battery for VIN? The part is behaving as if R21 is shorted. Also, take a look at d/s page 28, layout guidelines regarding solder flux residue issues when using large resistor values.
Regards,
Jeff
Hi Jeff, thanks for the quick reply.
I set VIN_OK to 3.1v, sorry for the confusion.
When I measure the resistance across all three resistors, my multimeter reads 12.835; just as it theoretically should.
I read the page 28 about flux residue, thanks for pointing that out. I don't think that's an issue on these boards, they're clean.
Now that I've cleared up the VIN_OK thing, what are your thoughts? What should I try first?
Hi Keith,
If you have an oscilloscope, can you look at VIN, VRDIV and VOUT? VRDIV should be pulsing every 64ms. Then check VOUT and SW=SW2, and if you have a current probe and can add a loop to your inductor, you can add IL:
Regards,
Jeff
