Design solution:
LED is an excellent display, it has advantage such as: long service life, save energy , high brightness, various light colors, fast response , drive low power. Can be service energy through adjust LED luminous intensity. according to the RGB tricolor light mixing principle of regulating a variety of colors, and then control to achieve a variety of display results by MCU intelligent. Now a lot of applications in the field of city lighting, architectural landscape lighting, stage lighting design. The design solution by NXP semiconductors (NXP) power management chip, micro controller, I2C devices, LED driver, to provide a full design solution for the design of LED lighting system.
Mainly application:
1，point source:
base on LED color screen display principle，the pixel amplification, reducing the overall cost, echo module is a color pixel.application environment: bar, KTV, stage, exhibition hall, as the music melody display, background wall decoration,wall advertising etc.
2,LED rainbow tube:
echo lamp is composed of a plurality of color pixels(RGB) , each monochromatic pixel can produce 256 gray level changes. Application environment: decorative lighting overpass guardrail, river, building walls and other different places. system hardware design:LED color control system mainly include: drive module, control module , LED power。
1，drive module design:
How to achieve to show difference colors, which rely on intermittent inertia principle of human vision, using the R, G, B duty ratio of RGB LED color mixing. LED color display of this design mainly relies on NXP’s I2C interface LED blinks/mixed light driver IC PCA9633 (PCA9633-4-bit PWM output, PCA9634-8-bit PWM output, PCA9635-16-bit PWM outputs) output 256 grayscale colors for color display.LED controllers just need to transfer the gray value of the RGB color of the module can be implemented a color display.
PCA9633 is I2C bus control programmable PWM outputs of the 4 bit LED drive units，main application: LEDRGB/RGBA(Red/Green/Blue/Amber)mixed light, main performance indicators are as follows:
1、 the 4-channel LED driver, each drive can be programmed to 4 kind of States, namely: on, off, blinking programmable PWM control output, programmable per channel grayscale level, while supporting the overall dimming PWM mixed light output.
2、 dimmer control, PWM output frequency 97kHz, each channel with 256 levels of gray.
3、Flash control, PWM programmable frequency range as 24Hz~10.73s, duty cycle range of programmable as 0%~99.6%.
4、 available through the 190Hz PWM output to adjust 256 grade four PWM output overall brightness.
5、 4bit output programmable settings as push-pull output (5V, sink current 25mA, pull the current as 10mA).
6、 set PIN 7 hardware address, with a maximum I2C bus can be connected with 126 tablets.
7、each PCA9633 has four programmable software address: a full response to the address and three sub address.
8、 built-in 25MHz oscillator and a power on reset circuit, can realize the software reset by I2C bus.
9、 SDA/SCL built-in noise filter, supports 1MHz I2C fast-mode.
10、supports hot insertion and low standby current, voltage range:
2.3~5.5V.
3. power supply
Power supply according to the specific quantity of LED, and connections way to determine the specific parameters。 below adopt the NXP STARplug series chip LED power solution, the design is simple, small size, wide range voltage input, low-cost, advantages of low loss, was widely used in LED field.