HM169-06 Hendon Semiconductors, HM169-06 Datasheet - Page 14

• Manufacturer Part Number: HM169-06
• Description: Temperature Sensor Development Tools OM1682A demoboard
• Manufacturer: Hendon Semiconductors

Specifications of HM169-06

• Maximum Operating Temperature: + 45 C
• Minimum Operating Temperature: 0 C
• Operating Current: 7 mA
• Operating Voltage: 230 V
• For Use With/related Products: OM1682A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

opposite end of the package, the
points where the metal frame is
visible. The “X” package is specially
designed to meet creepage
requirements at the pins by providing
a 0.5 by 2.5 mm groove in the
package to give a 5 mm total surface
creepage to the heatsink, also it does
not have the assembly frame visible
at the other surface of the package.
In using a TO-220 packaged triac the
metal tab, and the rear surface of the
packaged device is connected to the
T2 of the triac, and is therefore live to
the mains. This gives a problem in
that it must be electrically insulated
for safety reasons, and yet a good
thermal connection must also be
made to the heatsink. There are a
number of ways this problem can be
overcome: for example by using a
mica washer or other thin electrically
insulating spacer.
A smear of thermal conductive grease
should always be used between the
packaged triac and the heatsink.
12.4
The OM1682A has been designed to
be especially insensitive to
interference. Even when the
thermistor is mounted remotely from
the HM169 control module, the signal
is an attenuated mains voltage, and
not a signal which might provide radio
frequency interference (rfi). This is
important in view of recent changes to
the law with respect to
Electromagnetic Compatibility (EMC
compliance) in Australia.
In addition to appliances needing to
be insensitive to external sources of
interference, these standards also
require appropriate measures to be
taken to ensure no appliances
generate radio frequency interference
(rfi) beyond prescribed limits.
2008 Jul 02, Revision 3.0
Radio frequency
interference (rfi), and EMC
compatibility
When controlling a resistive load, the
HM169 using it with loads up to 10 A
the OM1682A has been shown to be
fully compliant with the standard
without requiring any additional
components for rfi suppression and
filtering. (Unlike many other triac
control circuits). This is inherent
because of the system of
zero-crossing gate control used in this
module.
For an inductive load, there is
probably a need for a small amount of
filtering using mains rated capacitors.
However the size, and the best place
to connect such a capacitor depends
on the load (the construction of the
motor, and its characteristics) and the
manner in which the internal wiring is
routed within the appliance. The
characteristics of the motor load may
also require that a snubbing circuit is
used across the triac. The snubbing
circuit also assists towards meeting
the rfi limits.
The HM169 has used as initial values
for radio frequency interference
suppression an X1 rated 100 nF
250 Vac capacitor from Active to
Neutral across the supply terminals,
together with a typical snubbing
network using an X2 rated capacitor
applied across the triac.
The snubbing network is a series
connected X2 rated mains capacitor
(for example: 47 nF, 250 Vac) in
series with a 47 ohm carbon
composition or wirewound 0.6 watt
resistor connected between T1 and
T2 of the triac. The first purpose of a
snubbing network is to prevent the
dv/dt re-triggering when the triac turns
OFF. An oscilloscope is needed to
determine the rise-time, and check
whether it exceeds the rated value for
the triac used. As it also helps reduce
rfi a snubber network may be
worthwhile anyway. The dv/dt
measurement on the oscilloscope will
depend on inherent design features of
14
Precision electronic thermostat
the compressor winding (for example,
amongst other characteristics, the
stray capacitance to ground).
It is possible to have rfi generated by
a zero crossing fired triac driving a
large resistive load (>10 A). A small
suppression circuit may be required
to meet the EMC standards.
12.5
There are a number of application
notes which detail specific part of the
design process for using the
OM1682A Precision Triac Control IC.
Particularly relevant to the HM169
are:
AN001 Power Supply Circuits for
OM1682A Triac Controller IC
Applications.
AN003 Input sensing Bridge Design
for OM1682A Triac Controller IC.
Excel spreadsheets for each
application. These allow standard
resistor values to be typed in, with the
spreadsheet immediately calculating
the resulting switching temperatures
for graphical display. This is most
helpful in finding acceptable
temperature settings which can be
achieved with readily available
resistors. A spreadsheet is also
available which shows simmerstat
frequency and duty cycle against
resistor and capacitor values.
If significantly different functions are
required, spreadsheets can be written
to suit these more complex
applications. Contact IES for details.
OM1682.exe A program which
calculates suitable power supply
component values, and greatly
simplifies the task of designing the
power supply taking into account the
gate pulse constraints for various
triacs.
Engineering Sample Information
OM1682A application
information
HM169