fs325a Fortune Semiconductor Corporation, fs325a Datasheet - Page 8

• Manufacturer Part Number: fs325a
• Description: Lithium-ion/polymer Battery Protection Ic
• Manufacturer: Fortune Semiconductor Corporation

Fortune Semiconductor Co.
http://www.fsc.com.tw
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Release of Power-down mode
After entering power-down mode, when the system is connected to a charger, the charging current will
flow through the parasitic diode of M1. If VCSI<VOI2 occurs, then FS325 will release power-down
mode. While keeping charging status, there are two ways back to normal condition:
1)
2)
Charger Detection
While connecting to a charger after entering into power-down mode, then if VCSI<VCH, M1 will be
turned on when VDD>VODL. The system will back to normal condition as described in
section since the charger has been detected. This action is called charger detection.
Abnormal Charge Current Condition
When a charger is connected to the battery system in normal condition, then if VDD<VOCU and
VCSI<VCH occurs through a delay time longer than TOC (delay time of overcharge detection), M2 will
be turned off to stop this charging status. It is called the abnormal charge current condition.
Abnormal charge current condition is released when the voltage of CSI pin becomes higher than
charger detection voltage (VCH), or the charger is removed.
Over Current / Short Circuit Condition
When the current is too large during discharging under normal condition as a result of the voltage
detected by CSI is greater than VOI1 (or VOI2) for a delay time longer than TOI1 (or TOI2), it satisfies
the over current (or short circuit) condition. Then M1 will be turned off and CSI will be pulled down to
VSS through an internal resistance. It is called the over current (or short circuit) condition.
Release of Over Current / Short Circuit Condition
While the protection IC remains in Over current/Short circuit condition, then if the load is removed or
the impedance between VBAT+ and VBAT- is larger than 500kΩ as well as VCSI<VOI1, M1 will be
turned on and then back to normal condition.
If VCSI<VCH (Charger detection), then when VDD>VODL, M1 will be turned on and the system
will back to normal condition.
If VCH<VCSI<VOI2, the condition VDD>VODR must be satisfied for M1 to be turned on, and then
the system will back to the normal condition.
If the over current / short circuit is detected and it keeps longer than the overdischarge detection
delay time with the same circumstance, the condition will be changed to power-down mode when
the battery voltage falls below the overdischarge detection voltage.
If the battery voltage falls below the overdischarge detection voltage (VODL) due to the over
current / short circuit, the discharging control FET (M1) will be turned off when this condition
occurred. After overdischarge detection delay time (TOD) expired, if the battery voltage is still
equal to or lower than the overdischarge detection voltage, the condition will then be changed to
power-down mode.
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Lithium-ion/Polymer Battery Protection IC
TD-0403005 Rev. 1.3
1)
FS325
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