FIGURE 4. LS7635 TRIG, Ø vs TOUCH (SENS OR EXT)

EXTENSIONS: All switching and dimming functions can be

implemented by utilizing the EXT input. Use a pushbutton 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)

APPLICATION EXAMPLE:

A typical implementation of the light dimmer circuit is shown in Fig. 5.

Here the brightness of the lamp is set by touching the touch plate.

The function of different components are as follows:

• The 5V DC supply for the chip is provided by Z, D1, R1, C2 and C4.

• R2 and C3 generate the filtered signal for the SYNC input

AC phase synchronization.

• R3 and C5 act as a filter circuit for the electronic extension.

If extensions are not used, the EXT input (Pin 6) should be

tied to Vss (Pin 7).

• R4, R5 and R6 set up the sensitivity of the SENS input.

• R8 provides current limiting and isolation between the chip

output and the triac gate.

• C1 and L are RFI filter circuits.

C1 = 0.15µF, 200V

C1 = 0.15µF, 400V

C2 = 0.22µF, 200V

C2 = 0.15µF, 400V

C3 = 0.002µF, 10V

C4 = 100µF, 10V

C5 = 0.1µF, 10V

R1 = 270

Ω, 1/2W

R1 = 1k

Ω, 1W

R2 = 680k

Ω, 1/4W

R2 = 1.5M

Ω, 1/4W

R3 = 1.5M

Ω, 1/4W

R4 = 1M

Ω to 5MΩ, 1/4W

(Select for Sensitivity)

R5, R6 = 2.7M

Ω, 1/4W

R5, R6 = 4.7M

Ω, 1/4W

R7 = 150k

Ω, 1/4W

R8 = 62

Ω, 1/4W

D1 = 1N4148

Z = 5.6V, 1W (Zener)

T = Q4004L4 Typical Triac (1)

T = Q5003L4 Typical Triac (1)

L = 100µH (RFI Filter)

L = 200µH (RFI Filter)

(1) For loads greater than 6A,

use an alternistor

.

*

*

*

*

*

*

*

EXT

10k

Ω

IN914

TOUCH PLATE

*R

200k

Ω

MPS8599

FIGURE 6.

ELECTRONIC EXTENSION

*R

P

*R = 2M

Ω for 115VAC

*R = 3.6M

Ω for 220VAC

All Resistors 1/4W

150º

100º

50º

OFF

150º

100º

50º

OFF

150º

100º

50º

OFF

Ø

MODE Ø

Ø

MODE 1

Ø

MODE 2

342ms

SHORT

SHORT

LONG

LONG

LONG

LONG

A2

A0

A0

A1

B1

B2

A2

A2

B2

B1

A1

A2

B2

B1

A1

A0

A0

A0

A0

A2

A2

MEMORY

A2

MEMORY

SHORT

SHORT

REVERSE

REVERSE

SENS

LONG

B2

B2

B2

B2

7634/7635-090606-4

P

115VAC

OR

220VAC

N

LAMP

C1

T

L

C2

R1

R2

R8

R3

C4

D1

8

7

6

5

R4

C3

TRIG

EXT

SENS

MODE

SYNC

+

LS7634 / LS7635

R6

R5

FIGURE 5. A Typical Halogen Lamp Dimmer Wall Switch

G

MT2

MT1

Z

-

ELECTRONIC

EXTENSION

(FIG. 7)

EXTN

P

C5

SEE NOTE 3

SEE NOTE 2

R7

NOTES

1. All circuits connected by broken lines are optional.

2. C5 is used only with electronic extension

and R7 is used only with mechanical switch.

3. Connection between Pin 6 & Pin 7 should

be broken when EXT is used.

4. Magnetic transformer should have thermal protection.

5. Some electronic transformers may require larger

values of C2, sensitive gate triacs and snubber

networks. C2 values may have to be adjusted to be as

high as 0.47uF for 115VAC and 0.33uF for 220VAC.

The sensitive gate triacs are chosen for their low

holding current. Typical triacs are L4004L6 and L6004L6

for 115VAC and 220VAC applications, respectively.

**C6-R9 is the snubber network: C6 = 0.1uF, 200V,

R9 = 1k Ohm, 1/2W (115VAC); C6 = 0.05uF, 400V,

R9 = 1k Ohm, 1W (220VAC)

TOUCH

PLATE

SEE

NOTE 4

TEST

1

2

3

4

**R9

**C6