17
R924 and R922, and outputs it to IC902 Pin 7. Output waveform, with not much current, is
amplified with using OP amp and output to Pin 1. Finally it is supplied to auto bias control
circuit.
6-7
SMPS CIRCUIT
SECTION
Power supply is composed of line filter, switching amp and switching trans circuit. Line
filter circuit removes noise element of power line supplied from outside and prevents noise
generated in switching amp from flowing out to external power line. The circuit is made up
of C101, L101, C102, C103 and C104."
AC voltage supplied through line filter circuit is supplied to D101 and converted to ripple
voltage, and converted to DC through the operation of C105.
"Switching circuit is made up of IC101 peripheral circuits and IC101 performs control and
switching operations such as oscillation, over-voltage protection and overload protection.
DC rectified through D102 and lowered passing R102 is supplied to IC101 3Pin(Vcc), then
IC101 start operating and outputs pulse.
NO. 3 Pin has over-voltage shutdown function embedded in chip. if high (operates stably at
approximately 23 ~ 35V) voltage or low voltage is input, it stops operating temporarily to
protect circuit, and if high load is applied momentarily, embedded overload shutdown
function blocks circuit operation and protects circuit to maintain stable operation in
outputting pulse.
KORTEK Corporation
KT-1903NA