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ADP5063: Why LDO did not turn ON when VUSB is plugged in (No Fitted Battery)

Question asked by RiscyADT00 on Mar 13, 2018
Latest reply on Mar 18, 2018 by Leo_Liu

I have off shelve ADP5063 (not factory customised), implemented the standard circuit to PCB with DIG_IO1 tied to HIGH (via 3V3 PSU) and DIG_IO2/3 tied to LOW via 600K internal pulls (which attached to MCU GPIO which depend on 3V3 PSU). This is no charger mode. 

 

With battery fitted (LIFEPO4) When the VUSB is plugged in, it provides 4.3V (LDO working) and power the 3V3S SEPIC PSU correctly fo MCU. When VUSB is disconnected, it provides 3V4. It worked fine.

 

With the battery removed, VUSB is plugged in I registering around 120mA from +5V Bench PSU. It provides 0.8V (LDO switched off). In datasheet table-7 under "Charge Mode, No Battery", it say LDO is switched on but in this case it did not activate LDO. I check DIG_IO2/3 = 0V and DIG_IO1 = also 0V. When I touched the battery to VBAT (with 3V3S PSU activated) the 120mA disappear to few mA. 

 

Have I missed something?, some kind of unexpected power up issue (latch up?) or defective part?

 

Attached schematic below.....

 

 

 

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