Panasonic is part of a large worldwide groupselling relays and associated switching products under different brand names in different territories.The conditions of use in some territories may differ from those customary in Europe. In particular there are often major differences in regard to national and international specifications, such as UL, CSA, VDE, SEV, EVE, SEMKO, etc. Thus, when considering contact loads as stated in this catalogue (e.g. 10 A, 30 VDC for the SP relay) its hould be understood that these values are not necessarily an absolute maximum but tested ratings. Mostly the stated value has been tested for a certain life expectancy as stated by the manufacturer or the respective test house. Thus, under different conditions, the stated “maximum” may, in practice, be safely exceeded.
This strongly depends the type of
PhotoMOS relay used and the application’s
requirements. However the
aforementioned source-drain diode the MOSFET
may influence the linearity the output, and the output
capacitance may limit the usability for higher
frequencies.
Figure PhotoMOS connection
. integrating internal circuit the
optoelectronic device, serves control circuit for
switching the power MOSFETs and therefore the load
circuit OFF-state. Below the LED, there array solar
cells intergrated into optoelectronic device, thus
switching the output transistors.
Obviously, the PhotoMOS relay differs from the
conventional electromechanical relay, but also
distinguishes itself from other switching solutions that
utilize optocouplers semiconductors.
A single power MOSFET only capable switching a
DC voltage since its internal source-drain diode will
become forward biased the load polarity reversed.PhotoMOS Relays
What PhotoMOS?
Panasonic Electric Works offers wide range of
PhotoMOS relays for use telecommunication,
measurement, security devices and industrial control.
This LED located the upper part the relay and as
soon current flows through it, starts emitting
infrared light.
Due Panasonic’s broad product range, are able to
offer PhotoMOS relays for numerous applications,
enabling you utilize
PhotoMOS advantages:
Low control current
Control small analog signals
Low leakage current
Fast switching speed
Stable ON-resistance over lifetime
Extremely long product life
Small size
Flexible mounting position
High vibration and shock resistance
No contact bouncing
No switching noise
Due the enormous variety PhotoMOS relays, they
are suitable for numerous applications (see figure 4).
Using PhotoMOS relay for switching voltages
therefore requires two source-coupled power
MOSFETs one PhotoMOS relay.
They can used telecommunications and for
measurement equipment, for switching and controlling
small motors other power loads, and for controlling
various signals out microcontrollers.
The light emitter and detector are moulded in
translucent resin that allows light pass through but
provides dielectric barrier between the input and
output side.
The construction the PhotoMOS relay illustrated
below:
Optoelectronic
device
Power MOSFET
IN (+)
Figure PhotoMOS internal construction
The input pins are connected light emitting diode.
By connecting the two output transistors relay
in parallel, the allowable current can also be
increased (A,B connection) illustrated below:
V (AC,DC)
V (DC)
Figure PhotoMOS connection
Load
Basically, the power MOSFET’s output acts pure
ohmic resistance thus distinguishing the PhotoMOS
from optocouplerortriacsolution, since saturation
voltage offset voltage required
