Sharp r-3a88 Manual De Usuario

14

OUTLINE 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 com-
municated among them are explained below.

Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through R10, R11, R12, R13,
R20, R21 and R22.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through R00, R01,
R02 and R03 to perform the function that was requested.

Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit and indicator
circuit.

This LSI controls the key strobe signal, relay driving signal
for oven function and indicator signal.

This circuit generates voltages necessary in the control
unit.

Symbol

Voltage

Application

VC

-5V

LSI(IC1)

VP

-34V

Fluorescent display tube : Grid
and  anode voltage

VF1

2.2Vac

Filament of fluorescent display
tube

VF2

(VF1 to VF2 voltage)

The power source synchronizing signal is available in order
to compose a basic standard time in the clock circuit. It
accompanies a very small error because it works on com-
mercial frequency.

A circuit to generate a signals which resets the LSI to the
initial state when power is supplied.

The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).

A switch to “tell” the LSI if the door is open or closed.

To drive the magnetron, fan motor,  turntable motor and
light the oven lamp.

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 7-digits, 15-segments are
used for displaying figures.