12-4
VL-E610S/VL-E610H
VL-E660S/VL-E96E
VL-E98E
12-1-3. Circuits
The circuits used for the adapter are explained according to the circuit diagram.
1.Input section
The input section consists of noise filter and condenser input rectifying smoothing circuit. The noise filter, which
consists of L1, C1, C50 and C51 reduces common mode noise.
R1 and R2 are discharging resistors which are intended to eliminate voltage from the input plug when the power is
turned off.
The rush current which is caused when the power is turned on is greatly limited by R3, DCR of L1 and the operating
resistor of D1.
2.Switching section
The switching circuit drives the transistor Q1 to act as a switch by using the DC voltage rectified through C2
corresponding to the signals sent from the primary side control section. It and the transformer T1 comprise a high-
frequency inverter.
3.Primary side control section
This section drives the switching section by converting the pulse width of the signal sent from the secondary side control
circuit through the photocoupler.
The control IC (IC1) is used to drive Q1 (Mos FET).
This IC, as an overvoltage protector, contains a function which stops oscillation when it detects the overvoltage at D7.
4.Output circuit section
For the secondary side output, a popular on-off system is applied. Ripples and common mode noise are reduced
through the chokes of L2 and L3.
Q102 is a transistor for the charging switch. It is turned on through Q103 by the output of pin 6 of IC101 during quick
charging and pre-/sub-charging.
5.Battery detection circuit
When the battery is installed, Q101 is turned on by the battery voltage.
If the DC plug is not attached to CN2 at this time, the GND level will be input to the pin 11 of IC101 by the transistor
Q104 in order to detect the installation of the battery.
6.Secondary side control circuit
The function of the secondary side control section is to control the switching section by error-amplifying the detected
output voltage and current and transmitting the signals to the primary side control circuit through the photocoupler.
The constant voltage is set and detected in IC3-II, whereas the adapter mode (4.5V)/charge mode (6.5V) selection
is made by changing the reference voltage through the voltage switching operation of pin 5 of IC3.
The overcurrent protection in the adapter mode is performed by the primary side control section.
IC2 has the constant voltage power function to provide drive power for IC101 and the reference voltage for IC3, as
well as the reset function to prevent IC101 errors.
The constant voltage output of IC2 is used as a reference voltage when error amplifying of output voltage/current.
7.Display
Only the D101 (red LED) lights up in the adapter mode.
In the charge mode, D102 (orange LED) lights up together with D101 during quick charging. When quick charging is
completed (in the trickle mode), only D102 goes out.
D102 on-off is controlled through the pin 5 of IC101.
