Datasheet

MAX1758
Stand-Alone, Switch-Mode
Li+ Battery Charger with Internal 28V Switch
10
Maxim Integrated
STATE ENTRY CONDITIONS STATE CONDITIONS
Reset
From initial power-on
or from done state if battery voltage < recharge volt-
age threshold
or V
DCIN
- V
BATT
< dropout threshold
or V
BATT
> battery overvoltage threshold
Timers reset, charging current = 0,
FASTCHG = high, FULLCHG = high,
FAULT = high
Prequalification
From reset state if input power, reference, and inter-
nal bias are within limits
Battery voltage ≤ undervoltage threshold,
charging current = (fast-charge current / 10),
timeout = 7.5min typ (C
TIMER1
= 1nF),
FASTCHG = low, FULLCHG = high,
FAULT = high
Fast Charge
(Constant Current)
From prequalification state if battery voltage >
undervoltage threshold
Undervoltage threshold ≤ battery voltage ≤
battery regulation voltage,
charging current = charge current limit,
timeout = 90min typ (C
TIMER2
= 1nF),
FASTCHG = low, FULLCHG = high,
FAULT = high
Full Charge
(Constant Voltage)
From fast-charge state if battery voltage = battery
regulation voltage
Battery voltage = battery regulation voltage,
charging current ≤ current limit,
timeout = 90min typ (C
TIMER1
= 1nF),
FASTCHG = high, FULLCHG = low,
FAULT = high
Top-Off
(Constant Voltage)
From full-charge state if full-charge timer expires
or if charging current ≤ 330mA
Battery voltage = battery regulation voltage,
charging current ≤ 330mA,
timeout = 45min typ
(C
TIMER1
= 1nF), FASTCHG = high,
FULLCHG = high, FAULT = high
Done From top-off state if top-off timer expires
Recharge voltage threshold ≤ battery,
voltage ≤ voltage limit, charging current = 0,
FASTCHG = high, FULLCHG = high,
FAULT = high
Over/Undertemperature
From fast-charge state or full-charge state if battery
temperature is outside limits
Charge current = 0, timers suspended,
FASTCHG = no change,
FULLCHG = no change,
FAULT = no change
Fault
From reset state if battery temperature ≥ maximum
battery temperature
or from prequalification state if prequalification timer
expires
or from fast-charge state if fast-charge timer expires
Charging current = 0, FASTCHG = high,
FULLCHG = high, FAULT = low
Table 1. Charging State Table