hi,
Recently, I am on a project driving EINK screen. TPS65185 is used to power up EINK screen and I meet with a problem when testing TPS65185. According to the datasheet, I design the circuit.as the attachemnet:8838.2.POWER MANAGEMENT.pdf
After I solder the PCB, I power up this PCBA(as below). Once the MCU initialiaze TPS65185, the battery power will be shut down to ground. As I dis-solder L2, the power of the system becomes good. It turns out that PIN VB_SW of TPS658185 has been grounded.
As TPS65185 datasheet shows, VB_SW is connect to DCDC1 internally .
It means that NMOS to DCDC1 keeps turning on.
Then, I test 3 more PCBA, it's wired that only one output voltage regular, but the others occur to the same issue with PIN VB_SW as described above.
I can't no figure out why once initialize TPS65185, DCDC1 turns bad.
Please help me with this trouble.
Best Regards
Jackmon
June 12,2014 in China
