Hi TI,
/QON has been pulled up internally. But I cannot find how much the pull up voltage is. Does this voltage change between with charger and without charger? Also looks like it is pulled up by a diode and a resistor. How much voltage drop it will be? Thanks!
cheers
Fan
Hi Fan,
This is just a simplification, but VQON is internally pulled up to either VBUS or VBAT through a diode-OR network. Hopefully the waveforms below give you an idea of the actual voltage at the QON pin (not VQON, which is internal to the IC).
Waveform 1: I set VBUS = 5 V and had no battery or system load connected, so the device float charges. QON is around 2.3 V and changes slightly depending on whether or not charging is in progress.
Waveform 2: I connected a capacitor to BAT and increased VBAT using a sourcemeter to simulate a battery charge cycle. Again, QON is around 2.3 V throughout this test while the device transitions from pre-charge to fast charge to termination.
Best regards,
Angelo
