SPV1050 charge current

[vinsongo]

For the SPV1050, what is the charge current to the battery? Can I set the current?

Also, I would like to verify that when there is no voltage input to the SPV1050 that the two LDOs are off or not operating.

[Peter BENSCH · Accepted solution]

As mentioned in the data sheet, the charging current must not exceed 70mA. The current depends, among other things, on the pass transistor (typ. 7 ohms) and the impedance of the input voltage, which in turn is influenced by the topology used (boost, buck-boost).

The battery is disconnected from STORE as soon as its voltage exceeds EOC and connected when the voltage falls below EOC (see SPV1050 data sheet mentioned above). However, I would also like to point out that the internal LDOs can certainly draw some small current, as also mentioned in the data sheet, section 6.5:

...the LDOs are both supplied by the STORE rail: if the input source is unable to sustain the current required by the load, then the missing energy will be supplied by the battery connected to the BATT pin.

and

If VSTORE drops and UVP pin triggers the undevoltage threshold, then the pass transistor gets open and the load is no longer supplied until next end of charge condition is reached.

Even if the LDOs are deactivated, a standby current of typically 0.8µA can still flow, which can lead to a noticeable discharge depending on the type and size of the connected battery.

Does it answer your questions?

Regards
/Peter

[vinsongo]

Hello Peter,

So, if I am to understand correctly, the SPV1050 will charge the battery by a voltage mode, and the charge current is limited by the input impedance (switches, voltage source resistance, etc.) into the battery, and that this is not a current charge mode charger, as in a fast current charger.

Vinson

[Peter BENSCH]

Correct.