SPV1050 No Voltage at the LDO-Out Pins

Joris2807 · ‎2024-07-26

Hi all,
I connected my SPV1050 chip as you can see in the picture and started to measure my circuit. It looks pretty good. I powered it up with 3.3V at IN_LV. And I can measure a voltage of about 2.416V at the STORE pin. And even the LDO2_EN pin got a 2.412V, but at the LDO2 pin there is nothing. Does anyone have any idea why this might be the case? Even when I connect the Battery, nothing changes.

Peter BENSCH · ‎2024-09-05

Welcome @Joris2807, to the community!

the datasheet of the SPV1050, section 6.1 says:

the pass transistor is closed once the (rising) voltage on the STORE pin triggers the over-voltage threshold VSTORE(EOC) (corresponding to VEOC > VBG)

The datasheet, table 1 says at LDO2_EN:

Note that, independently of the LDO2_EN setting, the LDO2 is not active when the internal pass transistor is open.

So if you measure a constant voltage of 2.415V at STORE, this is not enough to reach VEOC (with your values of R4, R5, R6: VEOC~4.21V) and thus close the pass transistor. It would then remain closed until the voltage at STORE has fallen below VUVP. However, as VEOC is obviously not reached, the pass transistor remains open and therefore LDO2 disabled and also pin BATT disconnected from STORE.

Regards
/Peter

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