Command entering period

Blank period

Command execution

starts

CTRL

LED

Command entering period

Blank period

Command execution

starts

CTRL

LED

LP5522

SNVS488A – JUNE 2007 – REVISED MARCH 2013

www.ti.com

CONTROL INTERFACE OPERATIONAL DESCRIPTION

LP5522 has one digital control input, CTRL. Threshold levels of CTRL input are fixed to enable control from low

voltage controller. CTRL signal is used to control the mode of the circuit. A rising edge of the CTRL signal

activates the circuit and starts a command entering period. During the command entering period all rising edges

are counted. After command entering period there is a blank period when no rising edges are allowed. If CTRL is

left high after command entering period, the consequent command is performed right after the blank period.

Note that timing diagrams are not on scale!

If CTRL signal is low after command entering period, command execution starts when CTRL is pulled high. This

does not apply to Run command. With Run command CTRL must be high. Note that no rising edges are allowed

during blank period.

LED Controller Commands and Operation

There are four commands available for LP5522.

Command

Number of rising edges during command entering period

Run

One rising edge

Training start

Two rising edges

Training end

Three rising edges

Run once

Four rising edges

RUN COMMAND

One rising edge of CTRL signal within command entering period is interpreted as Run command. In programmed

mode blinking sequence is started right after Blank period and it is repeated as long as CTRL signal is kept high.

When CTRL signal is set low device goes into Standby mode.

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