BQ25176M: May BIAS pin be floated to enable charging?

Hi John

For the BQ25176M the 10k BIAS resistor is required.

But current will only be drawn from the input not battery.  Battery leakage current with no input will be 350 nA. 

Hi Bill,

Thank you for reply. But the datasheet only specifies a low threshold for VBIAS, no high threshold. 

I am curious if the die of 25176M is in fact same as 25176M but the TS temperature is trimmed in 25176J? Say the device will stop charging once BIAS is floated?

If the same thing occured on 25176J? (the TS bias current only be drawn from the input.)

Regards,

John

Hi John 

The BQ25176M BIAS current out of TS pin typically 38uA when input voltage is applied. Range of the current is 36.5uA to 39.5uA. 

This current is only drawn from the input. 

The BQ25176M and BQ25176J are similar devices from the same family of parts.

The BQ25176J will support an NTC for temp monitoring of Hot, Warm, Cool and Cold. 

Hi Bill,

Yes, I fully understand this from datasheet. What confused me is why BQ25176M need a 10k to GND while it does not have battery temperature sensing function? Datasheet specifies a VBIAS_EN threshold, 65mV to 85mV, my understanding is the device will be enabled as long as VBIAS > 85mV, Is not it? If so I think 10k resistor on BIAS pin can be eliminated.

Thank you!

John.

Ok, thank you.