HM169-06 Hendon Semiconductors, HM169-06 Datasheet - Page 13

• 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

12.2
The HM169 control circuit is an
electronic controller using small
currents. However the load currents
can be quite large, and adequately
rated wiring must be used for this high
current part of the circuit.
For load currents over 6 amps
problems can arise for two reasons.
The copper tracks on the printed
circuit board are unable to carry such
high currents without their
self-heating becoming a problem if
the ambient temperature is high.
Secondly, also a problem of high
ambient, the triac junction may not be
maintained at all times below 125 °C.
This means that if the ambient is likely
to be warm, and air circulation around
the HM169 is inhibited,
measurements of triac temperatures
while it is running will need to be
carried out to ensure that there is an
adequate margin and that
overheating will not occur.
When used to control very high
current loads: The HM169 controller
may also be used with high current
triacs with the triac mounted remote
from the HM169 on a large heatsink
2008 Jul 02, Revision 3.0
maximum operating junction
temperature of 125 °C, and if this
temperature is exceeded it is
possible that the triac will switch
ON (and may stay ON) even
without a gate signal. It is
therefore necessary to ensure
that under all operating
conditions, including possible
abnormal conditions, the junction
will not exceed this maximum
temperature. This is done by
using a heatsink to conduct the
heat away from the triac, and to
dissipate this heat via the free
flow of air across a sufficiently
large heatsink surface area.
Triac junction temperature
and limitations with load
current
with wiring capable of carrying the
load current.
The full load current flows from the
mains electrical supply through the
triac switch and the load. For large
currents (and especially for all load
currents over 10 Amps with a suitable
triac and adequate heatsink) this
circuit should be established
externally to the connections to the
HM169. The gate signal connections
should be made from the HM169 triac
gate solder pad directly to the triac
gate. Also the triac T1 connection
which completes the circuit loop for
the gate drive should be made
between T1 of the triac and the
neutral connection on the HM169
module.
The wiring for the gate and the T1
return circuit are small signal circuits
only, carrying no more than 50 mA.
Also the active supply current to the
HM169 is only about 4 mA, and does
not need high current capability
wiring.
Summary (high load current
requirements): For high currents
connect directly from the Active to the
Load, then from the Load to the triac
T2, and returning from triac T1 to
Neutral. These are all high current
connections, and plugs, sockets,
wiring, and soldered connections
must have been designed to carry the
full load current. The HM169 control
module, which only presents a low
current load can then be connected
with small signal wiring (but still
requiring adequate mains rated
insulation and physical strength). The
Neutral and Gate connection on the
HM169 should be connected as close
to the terminals T1 and gate on the
triac as possible to exclude voltage
drop in the main current path from
interfering with the gate drive circuit.
13
Precision electronic thermostat
12.3
One recommended range of triacs for
use with the HM169 are from the NXP
family of BT136 to BT139, or BTA140,
(although not limited to this range of
devices) depending on the load
currents to be controlled. These are
available in the non-insulated TO-220
package, or in the moulded “F” and
“X” packages where the tab of the
package is enclosed in the plastic
moulding.
On assembled samples of the HM169
the triac used is the BT139X-600E.
The X package is fully enclosed in
plastic, and meets electrical
standards for insulation and creepage
distances when assembled on an
earthed heatsink.
See the Mounting Instructions in the
Philips Semiconductors Triac Data
Book (SC03).
Various attachment methods are
available. The spring clip used in the
HM169 provides one of the best
means of attachment, avoiding the
problem of over-tightening of a screw
or eyelet attachment. Screw
connection with pressure washers is
a common means. The use of a rivet
is also common, although if the
tooling is not set to give precisely the
right holding pressure; there is a risk
that if it is loose the thermal
resistance is too high and the junction
overheats; and if it is over
compressed it will flex the soft metal
tab and fracture the crystal.
With the insulated package the
capability to dissipate heat is
degraded, but there is not the same
problem in needing to insulate the
heatsink. Consideration must also be
given to surface creepage distances
from live to earthed metal parts of the
assembly. In particular this includes
the triac pins where they enter the
moulded package, and on the
Engineering Sample Information
Triac choice, and triac
mounting
HM169