How to Get Started
10
SNVU650 – May 2019
Copyright © 2019, Texas Instruments Incorporated
LP5012EVM User's Guide
3.3.2.2
RGB LED Color and Intensity Control
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. When color is fixed, the
independent
intensity control
, formerly called brightness control, is used to achieve accurate and flexible
dimming control for every RGB LED module. Every three consecutive output channels are assigned to
their respective intensity-control register (LEDx_BRIGHTNESS). The LP50xx device allows 256-step
intensity control for each RGB LED module, which helps achieve a smooth dimming effect. For human-
eye-friendly visual performance, a logarithmic-scale dimming curve is usually implemented in LED drivers.
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. Also, the LP50xx device allows users to configure the dimming scale either
logarithmically or linearly through the global Log_Scale_EN register. Click the Manage button, shown in
. to set the color and brightness.
Figure 10. LED Color and Brightness Setting
3.3.2.3
Bank Management
For most LED-animation effects, like blinking and breathing, all the RGB LEDs have the same lighting
pattern. Instead of controlling the individual LED separately, which occupies the microcontroller resources
heavily, the LP50xx device provides an easy coding approach, the LED bank control. Each channel can
be configured as either independent control or bank control through the LEDx_Bank_EN register. When
LEDx_Bank_EN = 0 (default), the LED is controlled independently by the related color-mixing and
intensity-control registers. When LEDx_Bank_EN = 1, the LP50xx device drives the LED in LED bank-
control mode. The LED bank has its own independent PWM control scheme, which is the same structure
as the PWM scheme of each channel. See the register map
for more details. When a channel is
configured in LED bank-control mode, the related color mixing and intensity control is governed by the
bank control registers (BANK_A_COLOR, BANK_B_COLOR, BANK_C_COLOR, and
BANK_BRIGHTNESS) regardless of the inputs on its own color-mixing and intensity-control registers.
