Advertisement
CIRCUIT DESCRIPTION
DESCRIPTION OF BLOCK DIAGRAM
10.
11
. Voltage selector and surge absorber.
Selects rated input voltage and limits external noise.
. Power switch (circuit protector)
This function as a power switch, and breaks the power
supply in event of an accident in the power sourcé.
. Power transformer
Provides auxiliary windings to operates the main and
accessory circuits in the transformer.
. SCR control rectification circuit
A
rectification
circuit
to control
the
DC
level
syn-
chronized with AC, with the gate pulse from the phase
control circuit.
. L, C smoothing circuit
Averages the rectified output from the choke coil and
capacitor. The choke coil limits transient current for a
high power factor and low ripple.
. Phase control circuit
Generates a trigger pulse AC synchronized
with the
SCR control rectification circuit to maintain the Vc of
the series transistors at a constant voltage.
. Series control circuit
Used to control high output with a small signal by Darl-
ington connecting the high output power transistor.
. Current detecting circuit
A
stable detection
voltage
is obtained
by effecting
adequate
derating,
using
resistor
with
a
low
temperature factor.
. Voltage detecting circuit
A stable detection voltage is obtained using a highly
precise
metal
oxide
film
resistor
with
a
low
temperature factor.
CC error (differential) amp
A highly precise amplifier which uses a high-gain, low-
drift OP Amp and compares output from the current
detecting circuit with the current reference voltage.
. CV error (differential) amp
A highly precise amplifier which uses a high-gain, low-
drift OP Amp and compares output from the voltage
detecting circuit with the voltage reference voltage.
12.
13.
14,
15.
16.
17.
18.
19.
20.
21.
OR circuit
Selects automatically one (using) the OR circuit from
the CV or CC amp depending on output and setting.
Circuit power source
Supplies regulated DC voltage to operate the control
circuit and provides a protection function.
Voltage reference circuit
This circuit is within the control power
source
feed-
back loop, and stably drives the temperature compen-
sation zener diode.
Current reference circuit
Drives the temperature compensation
zener diode us-
ing the constant current circuit to provide a stable out-
put.
OVP circuit
Detects output voltage within a range of 15%-110%
of the rated output voltage, according to the external
overvoltage setting.
,
Overcurrent detecting circuit
Detects when the current reaches a level of 125% of
the rated current, using the signal from the current
detecting circuit.
Temperature detecting switch
Detects
when
the
heat
sink
of
series
transistor
becomes 100 °C with the thermal relay.
Constant-current circuit
A discharge circuit for series transistor leakage current
and the output capacitor.
Circuit protector drive circuit
Drives the protector with the signals that come
from
the respective detecting circuits. It provides a constant
and discharge circuit to minimize influence from small
noise, etc.
Meter amp
Selects output voltage, voltage or reference voltage
with the V/I, OUTPUT and OVP and passes it through
the buffer amp to provide stablized meter output -
Advertisement
