LP5560

CTRL

VDD

LED

GND

A1

CTRL

B2

B1

A2

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19

LP5560

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SNVS873D – AUGUST 2012 – REVISED JUNE 2016

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Copyright © 2012–2016, Texas Instruments Incorporated

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LP5560 is a programmable LED driver designed to generate variety of blinking sequences for indicator

LEDs. It can drive single LED with up to 19.5 mA output current. Very low headroom voltage allows driving most

indicator LEDs straight from a single Li-ion battery. Default blinking sequence with one pulse is programmed into

the LP5560 to enable the use of device in simple systems without programming capabilities. Pulling CTRL signal

high starts the default blinking sequence. Different blinking sequences with up to three pulses can be

programmed into the LP5560 through a single-wire interface. Programmable parameters include on and off times

as well as rise and fall times.

8.2 Typical Application

Figure 18. LP5560 Typical Application

8.2.1 Design Requirements

In this example LP5560 is used to drive a blue 0406-size indicator LED with a 5.3-mA output current. For this

example, use the parameters listed in Table 7.

Table 7. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

LED Output Current

5.3 mA

Maximum LED forward voltage at 5 mA

3.1 V

from 3.2 V to 5.5 V

8.2.2 Detailed Design Procedure

8.2.2.1 Step-by-Step Design Procedure

To design in the LP5560 use the following simple design steps:

•

Define the input voltage range of the system. For the LP5560 device the maximum input voltage must not

exceed 5.5 V. The minimum input voltage is critical parameter for LED selection.

•

Define the LED current. LED current affects the LED forward voltage and must be taken into account when

selecting the LED for the application.

•

Choose a LED which maximum forward voltage with desired LED current is less than minimum input voltage -

100 mV. This ensures that there is always enough headroom voltage available for the LED driver.