[AP4201]

015008157-E-00

- 13 -

2015/09

10.

Functional Descriptions

10.1. Operation Outline

The AP4201 controls external LED lights using the data that can be configured by two types of interfaces

(4-wire SCI control, serial F/F control). Fixed current output or open drain can be selected by the DRSET pin

setting. LED lighting is performed by switching the LED current using internal MOSFET controlled by the

PWM method. In this case, LED current will be set by an external resistor which is connected to each LED pin

when open drain is selected. When fixed current is selected, LED current will be set by an external resistor

which is connected to each RGB line, and the all LED pins in the same color are set with the same value.

The AP4201 has an IC address configured by OPEN/SHORT setting of the A0 to A4 pins, and the LED pin

addresses that are determined through the SCI interface. By using this IC address configuration,

diversification of the LED lighting across multiple AP4201s in a single BUS can be achieved.

By using the OENB pin, all LEDs can be simultaneously turned off regardless of the signal from the SCI

interface. However, this is not the lowest power consumption state because the LED gradation data is still

being held even while all LEDs are turned off.

Table 3. Description Table for Setting Pins

DRSET pin

DRSET setting result

SCIEN pin

SCIEN setting result

Connect to GND (“L”)

Open drain output

Connect to GND (“L”)

Serial F/F control

OPEN (“H”)

Fixed current output

OPEN (“H”)

SCI control

PWMSET pin

Dimming PWM frequency[Hz] (same as period[µs]) (typ)

Connect to GND (“L”)

1830Hz (546µs)

Connect to VDC (“H”)

2745Hz (364µs)

10.2. SCI Interface Command

Table 4. Command Description (Hereinafter initial “16-bit” data transmission is called command part)

Instruction

Content

Function

Description

Instruction

Designate instruction contents by initial “4-bit”

-

“A4~A0”

Assign the IC address

Instructions for a different configured address

(set by these pins) are ignored. (“H” display)

“RW”

“1”= Write

“0”= Read

-

“ALL”

“1”= All LED pins (all RGB sets)

“0”= Base on ch3~ch0 setting

Give the priority to the setting of “ch3~ch0”

“RST”

“1”= LED gradation PWM output stop

“0”= Normal operation setting value

Set to [1] only in case of PWM output stopped

Stopped in case of「RW」=「ALL」=「RST」

= “1”

“ch3~ch0”

Assign RGB sets in case of ALL= “0”