點晶科技股份有限公司

SILICON TOUCH TECHNOLOGY INC.

DM132

DM132

Version

：A.014

Page

：12

Detailed Description

1) Time Division Operation

Since each DM132 output could drive 1 LED or 2 LEDs, the users can choose

either MODE1 luminance data or MODE2 luminance data. After the luminance data is

given, a command should be issued so that the driver can operate in MODE1 or in

MODE2. Figure 3 shows the route of data shift-in in MODE2. Later we will explain the

data structure of MODE1 and MODE2 in more details.

Figure 3. Block Diagram for Primary Bus.

Figure 4 shows how to switch between 2 LEDs. When “LED1 Emitting” command

is sent, LED1 PWM output will start 3 GCLK later. At the same time, the switch of

LED1 should be turned on. On the other hand, LED2 switch should be turned on when

LED2 PWM output starts. Again, “Disable” command must be sent before

“LED1/LED2 Emitting”. By periodically switching the emitting commands and LED

switches, we could drive 2 LEDs per channel.

Turn on

one of the

switches

One of Iout

ST2226A

System

LED1 Emitting

or

LED2 Emitting

Figure 4. System Configuration for MODE 2 Operation

Ch0 LED1

Ch0 LED2

Ch1 LED1

Ch1 LED2

DIN

DOUT

Ch15 LED1

Ch15 LED2