SI9731_09 VISHAY [Vishay Siliconix], SI9731_09 Datasheet - Page 5

• Manufacturer Part Number: SI9731_09
• Description: uP Controlled Battery Charger for 1-Cell Li-ion or 1-Cell to 3-Cell NiCd/NiMH Batteries
• Manufacturer: VISHAY [Vishay Siliconix]

Notes:
a. "OK to Charge" is a flag signal that is enabled by satisfying all the following conditions:
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:
Document Number: 71321
S09-2249-Rev. C, 26-Oct-09
TABLE 1: BATTERY CHARGING CONTROL LOGIC Nominal Voltage Values
Not Present
Not Present
OK to Charge
Over Voltage
V
Present
OK to Charge
TABLE 2
CHARGER
V
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
4. ON/OFF pin is at logic high.
CHARGER
If MAINCHARGEEN = Logic High, V
Q1 Drive (Digital)
> 12.8 V
a
a
HIGH
HIGH
LOW
LOW
CHARGEEN
TRICKLE
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
X
X
X
X
CVMODE
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
X
X
X
X
CHARGER
CHARGER
CHARGEEN
Output of Error Amplifier
> V
> V
MAIN
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
X
X
X
X
BAT
BAT
Intermediate
+ 40 mV,
- 40 mV
HIGH
LOW
LOW
ON/OFF
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
HIGH
LOW
X
X
X
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Q1
ON
ON
ON
ON
b
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
Q2
Not Charging
Not Charging
Not Charging
Not Charging (Shutdown)
Trickle Charge
Not Charging
(Current pulse off during Constant
Current Charge)
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)
Constant Current Charge
(Output Limited to 4.1 V/4.2 V or
Constant Voltage Charge)
Intermediate (linear mode)
Should Never Happen
HIGH (fully on)
LOW (fully off)
Q1 Drive
Vishay Siliconix
Mode
www.vishay.com
Si9731
5