LS7231 データシートの表示（PDF） - LSI Corporation

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LS7231

TOUCH CONTROL LAMP DIMMER

LSI Corporation  

SYNC

ø

TRIG

TW

TW

FIGURE 3. TRIG OUTPUT CONDUCTION ANGLE, Ø

SYNC 4

BUF

CAP 3

DOZE 2

BUF

EXT 6

BUF

PHASE

LOCK

LOOP

CONTROL

LOGIC

SENS 5

BUF

VSS 1

(+V)

VDD 7

(-V)

Ø

MEMORY

Ø

POINTER

DIGITAL

COMPARATOR

FIGURE 4

LS7231-4 BLOCK DIAGRAM

OUTPUT

DRIVER

8 TRIG

APPLICATION EXAMPLE:

A typical implementation of a lamp dimmer circuit is shown in Fig. 5. Here the brightness of the lamp is set by touch-

ing the Touch Plate . The functions of different components are as follows:

• The 15V DC supply for the chip is provided by Z, D1, R1, C2 and C5.

• R2 and C4 generate the filtered signal for the SYNC input for synchronizing the internal PLL with the line

frequency.

• R3 and C7 act as a filter circuit for the electronic extension. If extensions are not used, the EXT input (Pin 6)

should be tied to VDD (Pin 7).

• R4, R5, R6 set up the sensitivity of the SENS input. C6 provides noise filtering.

• C3 is the filter capacitor for the internal PLL.

• R8 provides current limiting and isolation between the chip output and the triac gate.

• C1 and L are RF filter circuits.

In the case of momentary power failure, the circuit state remains unchanged for a period of up to 1 sec. For longer

power interruptions, the output is shut off.

7231-4 040695-5

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