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參數資料
| 型號： | ISL9212 |
| 廠商： | Intersil Corporation |
| 英文描述： | Charging System Safety Circuit |
| 中文描述： | 計費系統(tǒng)安全電路 |
| 文件頁數： | 9/11頁 |
| 文件大小： | 527K |
| 代理商： | ISL9212 |
9
FN9280.1
May 8, 2006
R
VB
Selection
The R
VB
prevents a large current from the VB pin to the
battery terminal, in case the ISL9212 fails. The
recommended value should be between 200k
Ω
to 1M
Ω
.
With 200k
Ω
resistance, the worst case current flowing from
the VB pin to the charger output is,
(30V - 4.2V)/200k
Ω
= 130
μ
A,
assuming the VB pin voltage is 30V under a failure mode
and the battery voltage is 4.2V. Such a small current can be
easily absorbed by the bias current of other components in
the handheld system. Increasing the R
VB
value reduces the
worst case current, but at the same time increases the error
for the 4.4V battery OVP threshold.
The error of the battery OVP threshold is the original
accuracy at the VB pin given in the Electrical Specification
plus the voltage built across the R
VB
by the VB pin leakage
current. The VB pin leakage current is less than 20nA, as
given in the Electrical Specification. With the 200k
Ω
resistor,
the worst-case additional error is 4mV and with a 1M
Ω
resistor, the worst-case additional error is 20mV.
Interfacing to MCU
The ISL9212 has the enable (EN) and the warning (WRN)
digital signals that can be interfaced to a microcontroller unit
(MCU). Both signals can be left floating if not used. When
interfacing to an MCU, it is highly recommended to insert a
resistor between the ISL9212 signal pin and the MCU GPIO
pin, as shown in Figure 24. The resistor creates an isolation
to limit the current, in case a high voltage shows up at the
ISL9212 pins under a failure mode. The recommended
resistance ranges from 10k
Ω
to 100k
Ω
. The selection of the
R
EN
is dependent on the IO voltage (VIO) of the MCU. R
EN
should be selected so that the ISL9212 EN pin voltage is
above the disable threshold when the GPIO output of the
MCU is high.
Capacitor Selection
The input capacitor (C1 in the Typical Application Circuit) is
for decoupling. Higher value reduces the voltage drop or the
over shoot during transients.
Two scenarios can cause the input voltage over shoot. The
first one is when the AC adapter is inserted live (hot
insertion) and the second one is when the current in the
power PFET of the ISL9212 has a step-down change. Figure
25 shows an equivalent circuit for the ISL9212 input. The
cable between the AC/DC converter output and the
handheld system input has a parasitic inductor. The parasitic
resistor is the lumped sum of various components, such as
the cable, the adapter output capacitor ESR, the connector
contact resistance, and so on.
During the load current step-down transient, the energy
stored in the parasitic inductor is used to charge the input
decoupling capacitor C2. The ISL9212 is designed to turn off
the power PFET slowly during the OCP, the battery OVP
event, and when the device is disabled via the EN pin.
Because of such design, the input over shoot during those
events is not significant. During an input OVP, however, the
PFET is turned in less than 1μs and can lead to significant
over shoot. Higher capacitance reduces this type of over
shoot.
FIGURE 23. LITHIUM-SAFE OPERATING REGIONS
5
0
1000
BATTERY VOLTAGE (V)
C
1
2
3
4
ISL9212
LIMITS
ISL6292C
LIMITS
6
FIGURE 24. DIGITAL SIGNAL INTERFACE BETWEEN ISL9212
AND MCU
WRN
R
5
Q
4
Q
5
EN
ISL9212
MCU
R
PU
R
WRN
R
EN
VIO
FIGURE 25. EQUIVALENT CIRCUIT FOR THE ISL9212 INPUT
AC/DC
ISL9212
ADAPTER
CABLE
HANDHELD SYSTEM
C1
L
R
C2
ISL9212
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| ISL9212IRZ | Charging System Safety Circuit |
| ISL9216 | 8 to 12 Cell Li-Ion Battery Overcurrent Protection and Analog Front End Chip Set |
| ISL9216IRZ | 8 to 12 Cell Li-Ion Battery Overcurrent Protection and Analog Front End Chip Set |
| ISL9217 | 8 to 12 Cell Li-Ion Battery Overcurrent Protection and Analog Front End Chip Set |
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相關代理商/技術參數 |
參數描述 |
|---|---|
| ISL9212A | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Charging System Safety Circuit |
| ISL9212AIRZ | 功能描述:IC CHARGING SYSTEM SAFETY 12-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 功能:電池監(jiān)控器 電池化學:堿性，鋰離子，鎳鎘，鎳金屬氫化物 電源電壓:1 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應商設備封裝:SOT-6 包裝:帶卷 (TR) |
| ISL9212AIRZ-T | 功能描述:IC CHARGING SYSTEM SAFETY 12-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 功能:電池監(jiān)控器 電池化學:堿性，鋰離子，鎳鎘，鎳金屬氫化物 電源電壓:1 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應商設備封裝:SOT-6 包裝:帶卷 (TR) |
| ISL9212B | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Charging System Safety Circuit |
| ISL9212BIRZ | 功能描述:IC SAFETY SYSTEM CHARGER 12-TDFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 功能:電池監(jiān)控器 電池化學:堿性，鋰離子，鎳鎘，鎳金屬氫化物 電源電壓:1 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應商設備封裝:SOT-6 包裝:帶卷 (TR) |
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