The LED1642GW and ALED1642GW basic circuit

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The LED1642GW and ALED1642GW basic circuit

The below figure shows the LED1642GW and ALED1642GW basic application schematic:

Figure 2. LED1642GW and ALED1642GW typical application circuit

a continuous square wave (0 to 3.3 V) with 50% duty cycle and a frequency of about 8 MHz

have to be applied. Starting from these conditions, a correct pattern sequence on SDI, CLK

and LE pins (0 to 3.3 V with a CLK frequency for example of about 1 MHz) have to be

provided so to obtain the LED power-on. The following examples refer to this circuit unless

otherwise specified.

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First LED power-on

There are, at least, three different registers to be managed:

•

The configuration

•

The brightness

•

The switch

As first set-up, by using the default values, the configuration register can be neglected, while

the brightness register and the switch register have to be managed in order to have the LED

power-on.Therefore:

•

The configuration register = default, no pattern needed for configuration register set-up.

•

As far as the brightness register is concerned, a 16-bit value has to be sent for each of

16 outputs, 16x16 bit patterns (256 bits totally) are necessary; the first 15 have a data

latch (LE high for 3 CLK rising edges), last pattern has a global latch (LE high for 5 CLK

rising edges). 16x16 times SDI=1 have to be sent to program the maximum

brightness.The below images shown exactly the elements of this protocol with a

AM16851v1

LED1642GW

Supply voltage

SDI

CLK

LE

PWCLK

VDD

OUT0

OUT1

OUT15

R-EXT

Current setting

resistor

Data loaded

through serial

interface

LED common rail voltage

…..

SDO

Data output

+

Cin

Cled

GND

ALED1642GW