S-8243A Datasheet, PDF (17/34 Pages) Seiko Instruments Inc – BATTRY PROTECTION IC FOR 3-SERIAL OR 4-SERIAL CELL PACK

Rev.2.4_00
BATTERY PROTECTION IC FOR 3-SERIAL OR 4-SERIAL CELL PACK
S-8243A/B Series
1-6 0 V battery charging function
Regarding the charging of a self-discharged battery (0 V battery) the S-8243 has two functions from
which one should be selected.
a) 0 V battery charging is allowed (0 V battery charging is available)
When a charger voltage is higher than V_0CHA, 0 V battery can be charged.
b) 0 V battery charging is forbidden (0 V battery charging is impossible)
When one of the battery voltages is lower than V_0INH, 0 V battery can not be charged.
Caution When the VDD pin voltage is lower than minimum of V_DSOP, the operation of S-8243
series is not guaranteed.
1-7 Delay time setting
Overcharge detection delay times (t_CU1 to t_CU4) are determined by the external capacitor at the CCT
pin. Overdischarge detection delay times (t_DL1 to t_DL4) and overcurrent detection delay time 1 (t_IOV1)
are determined by the external capacitor at CDT pin. Overcurrent detection delay time 2,3 (t_IOV2,
t_IOV3) are fixed internally.
S-8243AAC, AAD, BAE, BAF
min. typ. max.
t_CU [s] = Delay factor ( 5 10 15 )×C_CT [μF]
t_DL [ms] = Delay factor ( 500 1000 1500 )×C_DT [μF]
t_IOV1 [ms] = Delay factor ( 50 100 150 )×C_DT [μF]
S-8243BAD
min.
t_CU [s] = Delay factor ( 5
t_DL [ms] = Delay factor ( 555
t_IOV1 [ms] = Delay factor ( 33.1
typ.
10
1110
66.2
max.
15
2220
132
)×C_CT [μF]
)×C_DT [μF]
)×C_DT [μF]
2. Voltage regulator circuit
Built-in voltage regulator can be used to drive a micro computer, etc. The voltage regulator supplies
voltage of 3.3 V (3 mA maximum) and an external capacitor is needed.
Caution In the power down condition the voltage regulator output is pulled down to the V_SS level
by an internal resistor.
3. Battery monitor amp circuit
Battery monitor amp sends information of the batteries to a microcomputer. The battery monitor amp
output is controlled and selected by CTL3 and CTL4 pins to give the following two voltages.
a) V_BATn = GAMPn × V_BATTERYn + V_OFFn where GAMPn is the n-th voltage gain of the amp, V _BATTERYn is
the n-th battery voltage, and V_OFFn is the n-th offset voltage of the amp.
b) N-th offset voltage V_OFFn
Each battery voltage V_BATTERYn (n = 1 to 4) is thus calculated by following equation.
V_BATTERYn = {(V_BATn − V_OFFn} / GAMPn (n=1,2,3,4)
After the state of CTL3 and CTL4 are changed, a time between 25 μs and 250 μs is needed for the battery
monitor amp to become stable.
Caution In the power down condition the battery monitor amp output is the V_SS level.
Seiko Instruments Inc.
17