Panasonic KX-FT981LA-B Service Manual page 46

KX-FT981LA-B / KX-FT987LA-B
The following is an overview of how the power supply unit is controlled.
The control method of this power supply unit is pulse width modulation.
When Q is ON, the energy is charged in the transfer primary coil according to E
1
secondary transfer as follows.
L → D → Load → L
1
Then the power is supplied to the Load. When Q
back in the control IC according to the error amp rectifier. Then depending on how T
when the current load becomes too large, in order to decrease the voltage output, the increase in
voltage is stabilized.
Therefore, basically the timing: Ton/Toff of Q1 controls the output voltage.
is ON, power is not output from the secondary side. The output voltage is fed
1
46
. When Q is OFF, the energy is output from the
1 1
is controlled, stabilization occurs. Also,
ON
is controlled and the output