We are observing an unexpected increase in current consumption when enabling the LED driver outputs of the nPM1304.
We configure the LED drivers to Host mode, which by itself does not cause any noticeable increase in current consumption. However, as soon as we enable any of the LEDDRV SET registers — LEDDRV0SET, LEDDRV1SET, or LEDDRV2SET — we observe an additional current consumption of approximately 300 µA.
The behavior is consistent across all three LED driver channels:
- Configuring the LEDDRV channels to Host mode: no noticeable increase in current consumption.
- Enabling LEDDRV0SET: approximately +300 µA.
- Enabling LEDDRV1SET: approximately +300 µA.
- Enabling LEDDRV2SET: approximately +300 µA.
The ~300 µA increase is observed when any one of the three SET registers is enabled. It does not increase by another 300 µA when additional LEDDRV channels are enabled.
The additional current consumption appears to be associated specifically with enabling the LEDDRV SET register, rather than with configuring the LED driver itself to Host mode.
The LEDs are physically not connected / have been removed from the board, so there is no external LED load contributing to the measured current.
All measurements are performed using a Nordic Power Profiler Kit II (PPK2).
We could not find any information in the nPM1304 datasheet specifying an expected increase in current consumption of approximately 300 µA when enabling the LEDDRV SET registers with no LED connected.
We would therefore like to clarify whether this additional ~300 µA current consumption is expected behavior, or whether it could indicate an issue with the configuration or the device.