點晶科技股份有限公司

SILICON TOUCH TECHNOLOGY INC.

-9 -

Version

：A.001

PC112/PC113

(output of a DAC or Ambient Light Sensor) increases, the output voltage will decrease.

current will be half .

Open circuit protection (PC113 only)

When the LEDs are disconnected from the circuit or the LEDs fail, PC113 will

switch to maximum duty cycle. This situation results in a high output voltage and may

cause the LX pin voltage to exceed its maximum rating of 24V and thus damages

output circuit. Normally, a Zener diode is applied to clamp the high voltage; however,

PC113 has built-in the over-voltage protection circuit, and thus no external component

is required.

Recommended PCB layout

1. C2 is placed as close to PC112/113 as possible.

2. Minimize the length and area of all traces connecting to LX pin.

3. The power path : VDD

L1

LX

D1

C3 should be kept as short as

possible to avoid EMI.

4. Fig. 6 shows the exemplary test board layout. (Reference page4. typical

application circuit )

Fig. 6