Sony KV-32LS65AUS, Operation Manual

Page: 8 / 32

Driver / Output Stage
The oscillator voltage output at pins 12 and 16 use drivers Q6006 and
Q6007 to develop T6002 secondary voltages. IC6001’s oscillator will
shut down if the driver transistor’s current is excessive. To prevent
premature shutdown, the timer capacitor C6007 (refer to Figure2.3)
delays the shutdown.
VC1 Powers IC6001
Although the oscillator is running at the initial frequency of 200 kHz,
there is insufficient current from T6002 to produce any unregulated
output voltage because of the load. There is a little load on D6008
(refer to Figure 2.3). This voltage is returned to IC6001 / pin 8 (VC1) to
serve as regB for the IC.
IC6001 Normal Operation
At start up, IC6001 initially uses current limit +B from pin 18 to power
internal drivers. These internal drivers amplify the oscillator signal and
get out to pins 12 and 16. When the power supply stage works, the
power comes for the bottom driver, VG(L); pin 12 from pin 10 (VC2)
and for the top driver, VG(H); pin 16 from pin 14 (VB). The VB voltage
is approxi5V (average) above the reference voltage at
IC6001/pin15.
Regulator Stage
This voltage supplies the top internal driver that amplifies the oscillator
signal that leaves IC6001/pin 16. The regulating stage uses error
detector IC6003 and optical isolator PH6001 to monitor the output from
T6002. If the output is low, the voltage fed back to IC6001/pin 2 goes
HIGH, decreasing the oscillator frequency. The decrease in frequency
increases the output of T6002.
6