TOUCH PLATE
*R
2KΩ ,1/4W
EXTN
MPS8599
*R
= 2M
Ω
,1/4W for 115VAC
*R
= 3.6M
Ω
,1/4W for 220VAC
200K
Ω
,1/4W
IN914
*R
P
FIGURE 6.
ELECTRONIC EXTENSION
EXTENSIONS:
All switching and dimming functions can also be implemented by utilizing the EXT input. This can be
done by either a mechanical switch or the electronic switch in conjunction with a Touch Plate as shown in
Figure 6. When the plate is touched, a logic high level is generated at the EXT input of the IC for both
half- cycles of the line frequency. (See Figure 5)
VSS
3.3M
,1/4W
U1-1
3.3M
,1/4W
DZ
U1-3
+
10µF
SENS
U1-2
DOZE
SWITCH
DZ
VDD
FIGURE 7.
DOZE CIRCUIT
U1 = CD4093
-
DOZE CIRCUIT:
The DOZE circuit shown in Figure 7 generates a slow clock (0.04Hz) at the DZ terminal. If the Touch Plate
(Figure 5) is not touched, the SENS terminal of the DOZE circuit of Figure 7 sits at a logic high level. A mo-
mentary pressing of the DOZE switch sets the SR flip-flop, enabling the oscillator. Every negative transition
of the clock (DZ terminal) causes the light intensity to be reduced by equal increments, until eventually the
light is shut off. The oscillator has no further effect on the dimmer circuit. When the light is turned on again
by touching theTouch Plate, the SR flip-flop is reset and the DZ clock is turned off.
When the DOZE circuit is used, the connection between DOZE input (Pin 2) and V
SS
(Pin 1) as shown in
Figure 5, should be removed.
.
7231-4-041195-7
LSI [ LSI COMPUTER SYSTEMS ]
