BQ24073 TS Input

Q: BQ24073 TS Input [Plastic Logic] by 1123732

Customer uses an NTC Temp sensor => Comparator circuit => BQ24073 TS pin to disable the charger for out of bounds temp conditions. They worry however that the input to the TS pin could toggle due to noise or other effects and wondor if this is a problem. I answered them as follows:

I don’t think that this will be a problem. The TLC3702 is a slow comparator and low to high and high to low delay times are different by about .3 us (Fig. 18 and 19) in the Data Sheet. It’s likely that the device has internal hysteresis. In addition, the BQ charger device also has hysteresis built into the internal TS comparators. Toggling the Charger TS pin input above and below the charge enable/disable threshold will just interrupt then re-enable the device internal timers as indicated in the Data Sheet on page 28.

Can you provide any additional commentary?...any potential problems?

Q: Re: BQ24073 TS Input [Plastic Logic] by 96955

The time will be suspended for the length of time the TS pin is out of range and the CHg pin will stay low which means one should never see any glitches.

As per the data sheet:

During charging, INTC is sourced to TS and the voltage at TS is continuously monitored. If, at any

time, the voltage at TS is outside of the operating range (VCOLD to VHOT), charging is suspended. The timers

maintain their values but suspend counting. When the voltage measured at TS returns to within the operation

window, charging is resumed and the timers continue counting. When charging is suspended due to a battery

pack temperature fault, the CHG pin remains low and continues to indicate charging