Sharp R-8320E

CHAPTER V
TOUCH CONTROL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section mainly consists of the following
units as shown in the block diagram.
(1) Key unit
(2) Control unit
Exchange of signals between each unit is indicated by the
arrows in the block diagram. The principal functions of
these units and the signals communicated among them are
explained below.
Key Unit
The key unit is composed of kind of matrix circuits;
in which, when one of signals Sq - S7 generated by the
LSI (IX21 07YA) operates the key, it is given to the
LSI (IX2107YA) as one of signals Ke-K6. It consists
of keys made of conductive rubber and printed circuit
board.
Control Unit
Control unit consists of two LSls (IX2107YA,
IX2075YA), converter circuit, fl circuit, ACL circuit,
buzzer circuit, thermistor sensor circuit and indicator
circuit.
I) LSI (IX2107YA)
This LSI controls the thermistor sensor signal, key
touch and relay unit control signal for oven func-
tion.
2) LSI (IX2075YA)
This LSI effects the control of the indicator circuit
and control of the buzzer signal.
3) Converter Circuit
This circuit generates voltages [VDD (for IX2107
YA) :
-15V, VDD’ (for IX2075YA) = VBB: -lOV,
vp:
-25V, VG: -3OVI necessary in the control
unit.
4) fl Circuit
The p 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 the commercial frequency.
5) ACL Circuit
The circuit to generate signals resetting the LSls
(IX2107YA, IX2075YA) to the initial state when
power is supplied.
6) Buzzer Circuit
The part responsive to signals from the LSI
(IX2075YA) t
o emit audible sounds (key touch
sound and completion sounds).
7) Thermistor Sensor Circuit
The temperature in the oven cavity is sensed by the
thermistor.
The variation of resistance according to sensed
temperature is detected by the thermistor sensor
circuit and the result applied to LSI.
The result of detecting is given to LSI (lX2107YA)
controlling the relay and display.
8) Stop Switch
The switch to “tell” open or closed condition of
the oven door to the LSI (IX2107YA).
9) Indicator Circuit
This circuit consists of 6-digits, 6-segments (Convec-
tion Fan symbol), 7-segments display, four cooking
mode indicators, CONV indicator, and the following
indicators using fluorescent display.
COOK, MIX, MEM and AUTO
The method of display is by dynamic drive using
Dl 1 through D15 as digit selecting signals. The
LSI (IX2075YA) output terminals of each indicator
are as follows.
R
21
- R23r R30 - R33
: 7 segment signals
R
10
: 4 mode power
level indicators (M.
LOW, MED, M.
HIGH and HIGH)
R
11
: MIX, MEM and AUTO
R -
12
: COOK
D9
: CONV
D3
k Da
: Convection Fan
Symbol
60