OUT0

8 Bits Color

8 Bits Color

8 Bits Color

8 Bits Color

8 Bits Color

8 Bits Color

8 Bits Brightness

8 Bits Brightness

Color-Mixing

Brightness-Control

12 Bits / 29KHz PWM

12 Bits / 29KHz PWM

12 Bits / 29KHz PWM

12 Bits / 29KHz PWM

12 Bits / 29KHz PWM

12 Bits / 29KHz PWM

PWM Generators

OUT1

OUT2

OUT9

OUT10

OUT11

10

LP5009, LP5012

SLVSEH2 – MAY 2019

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Product Folder Links: LP5009 LP5012

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Copyright © 2019, Texas Instruments Incorporated

Feature Description (continued)

The LP50xx device is designed with independent color mixing and intensity control, which makes the RGB LED

effects fancy and the control experience straightforward. With the inputs of the color-mixing register and the

intensity-control register, the final PWM generator output for each channel is 12-bit resolution and 29-kHz

dimming frequency, which helps achieve a smooth dimming effect and eliminates audible noise. See Figure 2.

Figure 2. PWM Control Scheme for Each Channel

8.3.1.1 Independent Color Mixing Per RGB LED Module

Each output channel has its own individual 8-bit color-setting register (OUTx_COLOR). The device allows every

RGB LED module to achieve >16 million (256 × 256 × 256) color-mixing.

8.3.1.2 Independent Intensity Control Per RGB LED Module

When color is fixed, the independent intensity-control is used to achieve accurate and flexible dimming control for

every RGB LED module.

8.3.1.2.1

Intensity-Control Register Configuration

Every

three

consecutive

output

channels

are

assigned

to

their

respective

intensity-control

register

(LEDx_BRIGHTNESS). For example, OUT0, OUT1, and OUT2 are assigned to LED0_BRIGHTNESS, so it is

recommended to connect the RGB LEDs in the sequence as shown in Table 1. The LP50xx device allows 256-

step intensity control for each RGB LED module, which helps achieve a smooth dimming effect.

Keeping FFh (default value) in the LED0_BRIGHTNESS register results in 100% dimming duty cycle. With this

setting, users can just configure the color mixing register by channel to achieve the target dimming effect in a

single-color LED application.

8.3.1.2.2

Logarithmic- or Linear-Scale Intensity Control

For human-eye-friendly visual performance, a logarithmic-scale dimming curve is usually implemented in LED

drivers. However, for RGB LEDs, if using a single register to achieve both color mixing and intensity control,

color distortion can be observed easily when using a logarithmic scale. The LP50xx device, with independent

color-mixing and intensity-control registers, implements the logarithmic scale dimming control inside the intensity

control function, which solves the color distortion issue effectively. See Figure 3. Also, the LP50xx device allows

users to configure the dimming scale either logarithmically or linearly through the global Log_Scale_EN register.

If a special dimming curve is desired, using the linear scale with software correction is the most flexible

approach. See Figure 4.