9-3A55
TOUCH CONTROL PANEL ASSEMBLY
OUTRINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units
as shown in the touch control panel circuit.
(1) Key Unit
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals gener-
ated in the LSI are sent to the key unit through RIO-
R13, R20 and R22. When a key pad is touched, a
signal is completed through the key unit and passed
back to the LSI through ROO-R03 to perform the func-
tion that was requested.
Control Unit
Control unit consists of LSI, power source circuit,
synchronizing signal circuit, ACL circuit, buzzer circuit
and indicator circuit.
1) LSI
This LSI controls the key strobe signal, relay driving
signal for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltages necessary in the control
unit.
Symbol Voltage Application
VC
-5v
LSI(IC1)
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock cir-
cuit. It accompanies a very small error because it works
on commercial frequency.
4) ACL Circuit
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
noticing sounds (key touch sound and completion-
sound).
6) Door Sensing Switch (Stop Switch)
A switch to “tell” the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
8) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is triode having a
cathode, a grid and an anode. Usually. the cathode of a
Fluorescent Display is directly heated and the filament
serves as cathode.
The Fluorescent Display has 6-digits, 13-segments are
used for displaying figures.
VP
VFl
VF2
-30v
2.2Vac
Fluorescent display tube : Grid
and anode voltage
Filament of fluorescent display
tube
(VFl to VF2 voltage)
16
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