LP5562 I2C LED Driver for Particle devices

There are several possibilities for indicator RGB LEDs:

Direct PWM is the least expensive, but when you are using RGB LEDs you'll quickly run out of available PWM channels. You're pretty much limited to one additional RGB LED on most devices.

NeoPixels are a great option as you can string together dozens of LEDs off a single GPIO. There are a few downsides:

The third option is to use an I2C LED driver. That's what this library is for. It allows the use of the TI LP5562 I2C LED driver from a Particle device. Why it this useful?

What's the downside? It does add a chip ($1.14 in single quantities). The biggest challenge is that it's only available in a DSBGA12 package. This is a really, really tiny 3x4 BGA (ball grid array) chip. 1.648 mm x 1.248 mm. It's barely larger than an 0805 resistor, but with 12 pins. It can only be reflowed; it's obviously not possible to solder with a soldering iron.

On the plus side, you can put one of these on your board and it takes up less space than 3x 0603 current limiting resistors.

While it's designed to drive an RGB LED plus one extra LED (white), it actually can drive any four independent LEDs. There are a couple benefits of using "indicator mode":

The library

Using the LP5562-RK library is just a matter of adding the library to your project and initializing it:

#include "LP5562-RK.h"
LP5562 ledDriver;
void setup() {
ledDriver.setBreathe(false, true, true, 20, 0, 255);
void loop() {

You normally allocate the object as a global object:

LP5562 ledDriver;

In setup(), initialize the object. There are some options that you configure fluent-style then call the begin() method:


There are methods to set a constant color, blink, alternating blink, and breathe. This call does cyan breathing:

ledDriver.setBreathe(false, true, true, 20, 0, 255);

The options left to right are:

Full browsable API docs are available. The calls are extensively documented in the .h file. There's also a copy of the HTML docs in the docs subdirectory.

The three example programs illustrate all of the features.

I2C addressing

The LP5562 has two address select lines to allow you to connect four to a single I2C bus, using address 0x30 to 0x33.

Because of the closeness of the BGA balls if you use the external clock you'll probably be limited to using the single I2C address 0x30. The reason is that you'll probably need to route ground through pins B1 (AD1), B2 (AD0), to B3 (GND).

External Clock

If you're not using an external clock and using the same power supply for VCC and VDD, then life is much easier, and all addresses are easily routed:

Address 0 (AD1 = 0, AD0 = 0, 0x30):

Address 0

Address 1 (AD1 = 0, AD0 = 1, 0x31):

Address 1

Address 2 (AD1 = 1, AD0 = 0, 0x32):

Address 2

Address 3 (AD1 = 1, AD0 = 1, 0x33):

Address 3

RGB Demo Board

I made a simple demo board to test and illustrate the use of the chip.

Board Image

Here's the schematic.


And the board. It's an Adafruit Feather form-factor, intended to be used in a double or tripler with a Gen 3 Particle device (Argon, Boron, or Xenon). Male header pins go on the bottom side.


Close-up of the LED circuitry:

Board Close

The eagle subdirectory contains the open source design:

Quantity Item Examp
1 LP5562 LP5562TMX/NOPB $1.14
1 RGB LED Cree CLMVC-FKA-CL1D1L71BB7C3C3 $0.19
1 White LED Lite-On Inc. LTW-C191DS5 $0.55
2 10K Resistor 0603 Panasonic ERJ-PA3J103V $0.10
Male header pins 0.1" </td> <td class="markdownTableBodyNone"> [Sullins PRPC040SAAN-RC](https://www.digikey.com/product-detail/en/PRPC040SAAN-RC/S1011EC-40-ND/2775214) </td> <td class="markdownTableBodyRight">

Indicator Demo Board

This demo board tests 4 discrete LEDs instead of using an RGB LED. I made it using T-1 (3mm) through hole LEDs because I had a kit of them so I could use 3 20mA LEDs and 1 10mA LEDs.

Indicator Board


Indicator Schematic


Indicator Board

The main difference between indicator mode and RGB mode is how the engines are set up. Because there are four LEDs and 3 engines, indicator mode sets up the three engines with common patterns:

Then you can assign any LED to be on, dim, off, or one of the three available patterns. This provides a lot of flexibility given the hardware limitations of the LP5562. Of course the full LP5562 programming API is available as well if you want to go crazy with the customization.

If you are using LEDs with different current requirements you can use the withLEDCurrent() overload with separate settings for red, green, blue, and white.

ledDriver.withLEDCurrent(20.0, 20.0, 20.0, 10.0).begin();

To use indicator mode, use setIndicatorMode().


To set an LED, use one of the setLedMapping methods:

ledDriver.setLedMappingR(LP5562::REG_LED_MAP_DIRECT, 0);