ISL97632(2007) Ver la hoja de datos (PDF) - Intersil

Número de pieza

componentes Descripción

Fabricante

ISL97632
(Rev.:2007)

White LED Driver with Digital Dimming

Intersil 

Single-Wire Serial Interface

30µs

ISL97632

100µs

'1'

'0'

'1'

'0'

'0'

220µs

'LOAD'

0

200

400

600

800

1000

FIGURE 1. SINGLE-WIRE XSD INTERFACE

The ISL97632 uses a simple single-wire serial interface for

programming the output brightness of the LEDs. A 5-bit

interface is used to give a total of 32 levels of output

brightness. The interface uses a normally high connection

for use with open-drain driving schemes and Intersil’s

proprietary XSD bus. When held low for between 15µs and

45µs, the interface registers a logic 1. When held low for

between 90µs and 120µs the interface registers a logic 0.

When held low for greater that 215µs, the interface loads the

last 5 bits into the brightness control register and updates

the brightness level. The required minimum high time is 3µs.

This simple single-wire programming is summarized as

follow:

• Logic 0 = Negative pulse >90µs and <120µs

• Logic 1 = Negative pulse >15µs and <45µs

• Load = Negative pulse >215µs

Figure 1 shows an example of programming a binary code of

10100 and load it in to the device serial register.

The serial interface is automatically reset to 0 when the

device is disabled, or enters UVLO. Therefore, when the part

is enabled, the output brightness is automatically set to the

minimum level.

1200

µs

4

FN9239.2

April 10, 2007

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