ETS2228 Maintenance Manual
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Page 7, Total 43
Figure 2 Power-on Circuit With Battery
Charging Circuit
When charging or discharging to battery, the management module is controlled by MSM6000 in TCPU.
MSM6000 detects the voltage of the battery to output the signal CHG_EN, which control the charging to
battery or not. If needed, the system will charge the battery.
1. Battery discharging: If there is no external power, MSM6000 control PM6610 to power supply the
system by battery.
2. Battery charging: if there is external power, MSM6000 control PM6610 to charge the battery or not.
The battery is charged or not, which by controlling the output current form the secondary power.
When the battery in fast charging status, the grid of Q303 is low and not through. The internal
differential amplifier (TL494) will control the pulse duty ratio of PWM, which the current output of
switch power supply will be restricted to 830mA; when the battery in slow charging status, the grid of
Q303 is high and through. The internal differential amplifier (TL494) will control the pulse duty ratio of
PWM, which the current output of switch power supply will be restricted to 75mA. Finally the fast
charging operation will be stopped and replaced by the slow charging operation. The feedback loop is
accomplished by the internal differential amplifier (TL494).
