SI9731 Datasheet, PDF (5/10 Pages) Vishay Siliconix – UP Controlled Battery Charger For 1-Cell Li-ion or 1-Cell to 3-Cell NiCd/NiMH Batteries

Si9731
Vishay Siliconix
TABLE 1: BATTERY CHARGING CONTROL LOGIC (NOMINAL VOLTAGE VALUES)
V_CHARGER
TRICKLE
CHARGEEN
CVMODE
MAIN
CHARGEEN
ON/OFF
Q1^b
Q2
Mode
Not Present
X
X
X
X
OFF
OFF Not Charging
Not Present
OK to Charge^a
X
X
X
X
OFF
OFF Not Charging
Over Voltage
V_CHARGER > 12.8 V
X
X
X
X
X
OFF
OFF Not Charging
X
X
LOW
OFF
OFF Not Charging (Shutdown)
LOW
LOW
LOW
HIGH
OFF
ON Trickle Charge
HIGH
LOW
LOW
HIGH
OFF
OFF
Not Charging
(Current pulse off during Constant
Current Charge)
Present
OK to Charge^a
LOW
HIGH
LOW
HIGH
LOW
LOW
HIGH
HIGH
HIGH
HIGH
LOW
LOW
HIGH
HIGH
HIGH
HIGH
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
Constant Current Charge
(current pulse on)
Not Charging
(Current pulse off during Constant
Current Charge with output limited
to 4.1 V/4.2 V or end of charge in Li-Ion
charging)
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
ON
OFF ^{Constant Current Charge}
(Output Limited to 4.1 V/4.2 V or
HIGH
ON
OFF _{Constant Voltage Charge)}
Notes:
a. "OK to Charge" is a flag signal that is enabled by satisfying all the following conditions:
1. Battery voltage is below 5 V
2. Charger voltage is greater than 3 V but below 12.8 V
3. If MAINCHARGEEN = Logic Low, V_CHARGER > V_BAT + 40 mV,
If MAINCHARGEEN = Logic High, V_CHARGER > V_BAT - 40 mV
4. ON/OFF pin is at logic high.
b. Q1 drive is determined by the error amplifier during constant voltage mode.
Q1 drive is a combination of Q1 drive (digital) and the output of the error amplifier using the analog adder. The combinations are:
TABLE 2
Q1 Drive (Digital)
LOW
LOW
HIGH
HIGH
Output of Error Amplifier
LOW
Intermediate
LOW
HIGH
Q1 Drive
LOW (fully off)
Intermediate (linear mode)
HIGH (fully on)
Should Never Happen
Document Number: 71321
S-60869-Rev. B, 22-May-06
www.vishay.com
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