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What level should I provide for CHGST?
If a logic level is used, 3.3V would be a good value for a high. Note that with the low minimum for VCHG_DET1, the logic will have to provide a very good "low" level. A standard maximum high logic "low" may not be good enough. The CHGST input has a tolerance for applied voltage up to the BAT pin value as described in the absolute maximum table and notes.
Typically if a logic signal is not used, the CHGST signal might be provided by a voltage divider from the BAT pin or PACK pin. The voltage divider ratio would provide a voltage above VCHG_DET1 at the lowest allowed pack value and provide a voltage with some margin below the BAT absolute maximum under all conditions. A more complex circuit may be needed in some cases.
What pulse width should I provide for CHGST?
Typically CHGST is expected to be a DC signal. It would go high when the pack is connected to the charger and go low when removed.
The response time of the analog input will vary with voltage. A voltage just above the VCHG_DET1threshold may cause a slower response than a 3.3V level. Additionally, the evaluation of the voltages at start-up may vary with voltage. CHGST does several things and may need to last various lengths depending on the state of the part.
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