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Description of Operation 
                                                                     T63H0008A
TM Technology, Inc. reserves the right 
P. 10                                    
Publication Date: Dec. 2003 
to change products or specifications without notice.                                                                          Revision:A 
Normal condition 
The T63H0008A monitors the voltage of the battery connected between VDD and VSS pin and the voltage 
difference between V- and VSS pin to control charging and discharging. When the battery voltage is in the 
range from the over-discharge detection voltage (VDET2) to the overcharge detection voltage (VDET1), and 
the V- pin voltage is in the range from the charger detection voltage (VDET5) to the over-current 1 detection 
voltage (VDET3), the IC turns both the charging and discharging controlFETs on. This condition is called the 
normal condition, and in this condition charging and discharging can be carried out freely. 
Note:
 When a battery is connected to the IC for the first time, the battery may not enter dischargeable state. In this case, set the 
V- pin voltage equal to the VSS voltage or connect a charger to enter the normal condition. 
Over-current condition (Detection of Over-current 1, Over-current 2, and Load short-circuiting) 
When the condition in which V- pin voltage is equal to or higher than the over-current detection voltage, 
condition which caused by the excess of discharging current over a specified value, continues longer than the 
overcharge detection delay time in a battery under the normal condition, the T63H0008A turns the discharging 
control FET off to stop discharging. This condition is called the over-current condition.  
Though the V- and VSS pins are shorted by the RV-S resistor in the IC under the over-current condition, 
the V- pin voltage is pulled to the VDD level by the load as long as the load is connected.  
The V- pin voltage returns to V SS level when the load is released. The over-current condition returns to the 
normal condition when the impedance between the EB+ and EB- pin becomes higher than the automatic 
recoverable load resistance (see the equation [1] below), and the IC detects that the V- pin potential is lower 
than the over-current 1 detection voltage (VDET3). 
Note:
 The automatic recoverable load resistance changes depending on the battery voltage and over-current 1detection voltage 
settings. 
Overcharge condition 
When the battery voltage becomes higher than the overcharge detection voltage (VDD) during charging 
under the normal condition and the detection continues for the overcharge detection delay time (tVDET1) or 
longer, the T63H0008A turns the charging control FET off to stop charging. This condition is called the 
overcharge condition. The overcharge condition is released by the following 
 two cases ((1) and (2)): 
(1) When the battery voltage falls below the voltage difference, the overcharge detection voltage (VDET1) - 
overcharge detection hysteresis voltage (VHCT1 ), the T63H0008A turns the charging control FET on and 
turns to the normal condition. 
(2) When a load is connected and discharging starts, the T63H0008A turns the charging control FET on and 
returns to the normal condition. The mechanism is : just after the load is connected and discharging starts, 
the discharging current flows through the parasitic diode in the charging control FET. At this moment V- 
pin potential increases momentarily voltage of the parasitic diode from the VSS level When the V- pin 
voltage goes higher than the over-current 1 detection voltage, and provided that the battery voltage goes