om5428 ETC-unknow, om5428 Datasheet - Page 6

• Manufacturer Part Number: om5428
• Description: General Purpose Triggering Circuit
• Manufacturer: ETC-unknow

Integrated Electronic Solutions, Hendon, South Australia
Output XOUT, which produces
negative-going output pulses, is an
n-p-n open-collector output that for
some applications may require an
external pull-up resistor connected to
V
7.5
IC+ and IC (pins 5 and 6) are
differential inputs of the comparator or
differential amplifier, with QC+ and
QC (pins 4 and 7) as complementary
outputs. QC+ and QC are n-p-n
open collector outputs requiring
external collector resistors to V
QC+ will be HIGH and QC will be
LOW when IC+ is higher than IC .
IC+ and IC- are both the base drive of
separate p-n-p transistors. In order for
correct operation of the comparator,
the input voltage on these pins should
be set up such that current is able to
be drawn from them. Such
arrangements may involve a pot
controlled voltage divider.
The comparator contains a current
mirror source that is activated by a
current out of DIFFEN (pin 3). The
8
In accordance with the Absolute Maximum Rating System (IEC 134).
All voltages specified with respect to V
2002 Nov 08
V
V
I
I
I
I
P
T
T
CC
I
RMNS(AV)
RMNS(RM)
TRIG
SYMBOL
V
stg
amb
I
I
tot
General purpose triggering circuit
EE
.
LIMITING VALUES
Difference amplifier
supply voltage
supply current
input voltage, all inputs excluding pins RMNS
and PW
input voltage, pins RMNS and PW
input current, all inputs excluding pin RMNS
and TRIG
rectified average
repetitive peak
output current
total power dissipation
storage temperature
operating ambient temperature
PARAMETER
CC
.
CC
current drawn from pin 3 determines
the drive for the comparator outputs.
7.6
The sawtooth generator may be used
to produce bursts of trigger pulses,
with the net effect that the load is
periodically switched on and off. The
firing burst repetition time is usually
determined by an external resistor
and capacitor connected to the
sawtooth generator trigger input SAW
(pin 14). The repetition time is
approximately 0.4 x RC.
With a time-proportional switch, the
ramp voltage produced by the
sawtooth generator serves to provide
the repetition frequency of load
switching that can be adjusted with
the control voltage.
In phase control, the flyback of the
sawtooth is used as the drive signal
for generating the trigger pulse.
The output FLY (pin 15) is an n-p-n
open-collector output. During the
flyback period of the sawtooth pulse
the transistor is ON and is capable of
sinking current.
, Common.
Sawtooth generator
6
I < 15mA
t < 300 s
I < 15mA
CONDITIONS
V
V
0
1
40
EE
EE
7.7
The output stage is driven via an
internal pull-up and therefore may be
inhibited by drawing current from
input AMPIN (pin 9). The output has
been designed to produce negative
going pulses with respect to mains
neutral. This allows a triac to be fired
in its more sensitive regions, reducing
the amount of gate current needed to
latch the triac and hence reducing the
overall current consumption.
The output TRIG (pin 10) is an n-p-n
open-collector output capable of
sinking current i.e. conventional
current flow into the circuit.
A gate resistor Rg should be
connected between the output TRIG
and the triac gate to limit the output
current to the minimum required by
the triac. By doing this, the total
supply current and the power
dissipation of the IC are minimised.
Output TRIG is protected with a diode
to V
undershoot of the output voltage, e.g.
caused by an inductive load.
MIN.
0.5
18
EE
(pin 11) against damage by
Output stage
18
15
V
V
1
15
50
300
300
+150
+125
EE
EE
MAX.
+ 18
+ 18
OM5428
V
mA
V
V
mA
mA
mA
mA
mW
Data Sheet
C
C
UNIT