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AS1130

Datasheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

Figure 16. AS1130 - Block Diagram

Cross-Plexing Theorem

The cross-plexing theorem is using the fact that a LED has a forward and backward direction. A LED will only glow if there is a current flowing in

forward direction. A parallel LED in backward direction will block the current flow. This effect is used in a cross-plexed matrix of LED’s.

Each CSx pin (CS0 to CS11) can be switched to VDD via the internal current source (“high”), to GND (“low”) or not connected (“highZ”).

The mode of operation which is controlled by an internal state machine looks like following. CS0 is switched to GND and all other CSx pins (CS1

to CS11) are controlled according to the settings in the On/Off Frame and Blink & PWM registers (see Table 7 on page 14).

Than CS1 is switched to GND and all other CSx pins (CS0 and CS2 to CS11) are controlled according to the settings in the On/Off Frame and

Blink & PWM registers.

In this manner all LEDs in the matrix are scanned and turned on/off depending on the register settings.