I am uncertain of the overvoltage hysteresis parameter and its interaction with the "tdelay" parameter as used in the BQ7716x parts.
For simplicity, assume the BQ771600 (4.3V overvoltage threshold) is monitoring a single Li-ion cell.
Assume the OV delay time is 1.5 seconds (typical with a 0.1uf delay capacitor) and the BQ771600
Assume the BQ771600 sees a transient single excursion above 4.35volts and then the monitored cell voltage drops below the 4.3volts threshold in less than 1.5 seconds (waveform 1 below).
Assume the B771600 monitors the cell voltage and it is remains above the 4.0V hysteresis threshold (4.3v -0.3v) for longer than the delay time of 1.5 seconds.
Will the output pin be driven high (BQ771600 version) to blow an attached chemical fuse ONLY if the monitored cell voltage is ABOVE 4.3V at the end of the 1.5 second interval? (see waveform 1 below)
Is it correct that simply being above the 4.3V - 0.3V hysteresis threshold at the end of 1.5seconds is NOT sufficient to drive the output pin high as the monitored cell voltage must be ABOVE 4.3 volts at the end of the 1.5 second sample interval.(BQ771600 typical) (waveform 2 below) for the output to be driven high (and an attached chemical fuse blown)?
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Thank you,
John Wright
