Hello everyone,
I have some questions regarding the active discharge of the load switch in LDO mode. We have an in-house hw with the nPM1300 configured as described in the data sheet under 9.3 reference circuitry configuration 1. Both load switches are used as LDOs.
When I enable the LDO I can see the expected voltage at the output. As soon as I disable the output voltage, the voltage slowely goes down to 0 V. I checked this with a multimeter and an oscilloscope. As there is currently no consumer drawing any power from the output of the LDO, the voltage slowely drops to zero after disabling it.
In the description of the load switch a discharge resistor is mentioned and can be enabled. However, this resistor is not mentioned for mode LDO. I activated the discharge resistor in mode LDO, which lead to a non-functional nPM1300. The output voltage was set to 3.3 V.
My questions:
- Can the discharge resistor be used in mode LDO?
- If no, in load switch mode the datasheet says, that the discharge resistor is only used when the load switch is Off. Can I disable the discharge resistor during usage of the LDO and only enable the discharge resistor shortly when the LDO is off? This would ideally lead to a discharge when the LDO is off and disconnect the resistor during operation of the LDO.
We did some measurements ourselfs on this matter, we tried out multiple configurations already and can not produce reliable results, I expect this is is either not possible or the nPM1300s used for testing already have a damage from misconfiguraitons.
Any help on this matter is greatly appreciated! Thanks!
Markus
