TPS61381-Q1: Charging Questions on timer and temperature

Hi ReedKacz,

Q1: The changing end condition is Battery voltage archived target voltage 2.68V(2*Ni-MH cell) or BUB_NIMH_TIMER[1:0] timer archived?

I have tested my development board.

If Battery voltage is >=2.68V when start charging, 61381 will report changing completed.

If Battery voltage is 2.67V when start charging, 61381 will continue change for BUB_NIMH_TIMER[1:0] time event the Battery voltage exceed 2.68V.

Yes, this is the correct logic. The IC detects 1.34V x cell number before starting charging. After started charging, there will be only OVP threshold (1.7V x cell) and timer that can stop charging. NiMH battery nominal voltage can be around 1.5V per cell. 1.34V is only the initial judgement that determines whether the battery is empty or not.

And do we need set different charge timer when we have different Battery voltage when 61381 start changing?

No, the OVP threshold (1.7V x cell)  is still there so there's no need for changing timer.

Q2: 

I find the battery tempeature only can read when start chaging can you confirm?

Yes, TPS61381 is a low Iq device and the TS pin consumes 38uA when it's active. So this function is enabled only in charger and SOH mode, not in standby mode.

Best Regards,

Travis

Thank you, Travis!

Can the TPS61381 read the TS temperature value in BOOST mode? We set the charging window from 0 to 60 ℃, which means the temperature range we can read during charging is 0--60. If we need to read temperatures from -30 to 80. Please help check if the TPS61381 can read in BOOST mode.

Hi ReedKacz,

The TS function is also disabled in boost mode.

Best Regards,

Travis