S-8243AACFT-TB-X Datasheet, PDF (17/35 Pages) Seiko Instruments Inc – BATTERY PROTECTION IC

Rev.3.1_00
BATTERY PROTECTION IC FOR 3-SERIAL OR 4-SERIAL CELL PACK
S-8243A/B Series
1. 5 0 V battery charging function
Regarding the charging of a self-discharged battery (0 V battery) the S-8243A/B Series 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 the voltage of one of the batteries 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-8243A/B Series is
not guaranteed.
1. 6 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, S-8243AAD, S-8243BAE, S-8243BAF, S-8243BAH
min. typ. max.
t_CU [s]
t_DL [ms]
t_IOV1 [ms]
= Delay factor (
= Delay factor (
= Delay factor (
5
10
15 ) × C_CT [μF]
500 1000 1500 ) × C_DT [μF]
50 100 150 ) × C_DT [μF]
S-8243BAD
t_CU [s]
t_DL [ms]
t_IOV1 [ms]
= Delay factor (
= Delay factor (
= Delay factor (
min.
5
555
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 When the power-down function operates, 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 When the power-down function operates, the battery monitor amp output is pulled down to the V_SS
level by an internal resistor.
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