SM6781BV Datasheet, PDF (5/10 Pages) Nippon Precision Circuits Inc – Ni-MH/Ni-Cd Battery Charger IC

FUNCTIONAL DESCRIPTION
Charging Flowchart
SM6781BV
_{Supply applied}
Standby mode released
Initialization (approx. 200ms)
Maximum quick charge time count start
−∆V detection prohibit time count start
Battery voltage check start
(Abnormal battery voltage detection
at VBATT ≥ 2V or 0.6V > VBATT)
Continuously battery voltage check operation
Abnormal battery voltage detection
Maximum quick charge time count stopped
−∆V detection prohibit time count stopped
Quick charge mode
(−∆V detection prohibit condition)
LEDN = LOW (ON)
CHGN = High impedance
Abnormal battery voltage detection
Quick charge hold
LEDN = High impedance (pulsing)
CHGN = LOW
NO
−∆V detection prohibit time passed
Battery voltage check
(Battery voltage: VBATT ≥ 2V or 0.6V > VBATT)
CHGN = LOW
YES
Abnormal battery voltage
(Quick charge current stop condition)
detection cleared
YES
(Return status in force
before abnormal battery
NO
Quick charge mode
voltage detected)
(−∆V detection active condition)
LEDN = LOW (ON)
CHGN = High impedance
Peak voltage data clear
− ∆V detection
NO
or
Maximum quick charge time passed
YES
Quick charge finished
Battery voltage check stop
LEDN = High impedance (OFF)
CHGN = LOW
Maximum quick charge time count restarted
−∆V detection prohibit time count restarted
Abnormal battery voltage
detection cleared
NIPPON PRECISION CIRCUITS—5