Technics QUARTZ SP-15 - Page 5

m@ TECHNICAL DESCRIPTION
¢ Description of pulse power supply circuit
The
pulse
power
source
directly
rectifies
the
commercial
power
with
diode
to
make
DC
168V.
And
it
generates
pulses
(approx.
20
kHz
waves)
by
switching
the
DC
168V
with
the
special
high-voltage
withstanding,
high-speed
switching
transistor.
Thus,
the
circuit
serves
to
drive
the
power
transformer
with
the
switching
pulses
in
order
to
obtain
the
specified
voltage
on
the
secondary
side.
Fig.14
shows
a
pulse
power
supply
block
and
a
conventional
power
supply
block.
Power supply circuit blocks
Secondary | specified
rectifier voltaas
circuit 9
Primary Switchin
bee
g
rectifier |DC168V ciccutt
circuit
YVOQVQOO
(a) Pluse power source block
Power transformer
Secondary
50/60Hz rectifier
circuit
Specified
voltage
(b) Conventional power supply block
«
Pulse
power
supply
circuit
of
SP-15
1. With power supply turned ON,
C7 is charged through R4. When the charged voltage
becomes high enough to turn on trigger diode D2,
current (11) flows through R5. Then, C7_ is
discharged and, therefore, it is again charged through
R4. As the operations are repeated, trigger current
flows into N1 as shown in Fig. 15.
* Trigger diode
ALLL
AL
11
RD
Dt
1
11
11
11
111
When
a
voltage
higher
than
the
specification
is
applied
between
terminals
T1
and
T2,
it
works
to
flow
a
current
irrespective
of
the
polarity.
T1 Pd T2
D111
1"
DAN
BD
111
~~
Dh!
TP3 NALA
Trigger current (11)
flowing into N1
Fig. 15
11 i 1
111 tf 11
[S}