UW01+
Preliminary
CMOS IC
DESCRIPTION OF OPERATION
1.
Normal Condition
The UW01+ monitors the voltage of the battery connected between VDD and VSS. The charge and discharge
scheme will be sensed by the voltage difference between VCSI and VSS
.
When VODL<VDD<VOCU and VCH<VCSI<VOI1, UW01+ will turn on the charging (M2) and discharging (M1) control
MOSFETs. The charging and discharging processes can be operated normally.
2.
Overcharge Condition
When the battery voltage becomes higher than the overcharge detection voltage (VOCU) during normal charging
condition through a delay time longer than TOC (the overcharge detection delay time), UW01+ will turn M2 off to stop
charging.
3.
Release of Overcharge Condition
(1) When the battery is self discharging, and if VDD<VOCR and VOI1>VCSI>VCH occurs, M2 will be turned on and
back to normal condition.
(2) Remove the charger and connect UW01+ to a load. The discharging current will flow through the parasitic
diode of M2. At this moment, VCSI increases a voltage (VF) of the parasitic diode from the VSS level momentarily.
While VCSI>VOI1 and VDD<VOCU occur, M2 will be turns on and back to normal condition.
4.
Over discharge Condition
When the battery voltage falls below the overdischarge detection voltage (VODL) during discharging condition
and through a delay time longer than TOD (the overdischarge detection delay time), UW01+ will turn M1 off to stop
discharging. In the meanwhile, CSI will be pulled up to VDD through an internal resistance.
If VCSI>VOI2, UW01+ will enter into power-down mode. While in this mode, the current consumption is lower than
0.1μA.
5.
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 UW01+ will release power-down mode. While keeping
charging status, there are two ways back to normal condition:
(1) If VCSI<VCH (Charger detection), then when VDD>VODL, M1 will be turned on and system will back to normal
condition.
(2) 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.
6.
Charger Detection
While connecting to a charger after entering into power-down mode, then if VDD<VCH, M1 will be turned on when
VDD>VODL. The system will back to normal condition since the charger has been detected.
7.
Abnormal Charge Current Condition
When a charger is connected to the battery system in normal condition, then if VDD<VOCU and VCSI<VCH occur
through a delay time than TOC (delay time of overcharge detection), M2 will be turned off to stop this charging status,
which is 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.
8.
Over Current (or 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) through a delay time 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.
(1) If the over current (or short circuit) is detected and it keeps longer than the overdischarge detection delay
time with the same circumstance, the condition will be changed to the power-down mode when the battery voltage
falls below the overdischarge detection voltage.
(2) If the battery voltage falls below the overdischarge detection voltage (VODL) due to the over current (or short
circuit), the discharging control M1 will be turned off when this condition occurs. 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 be changed to power-down mode.
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