Installation and Operation

 2016 Microchip Technology Inc.

DS50002437A-page 17

2.3.1

How does the MCP1643 RGB LED Driver Demonstration Board

Work?

When the Start button is pressed, the MCP1643 RGB LED Driver Demonstration

Board receives an EN pulse and the device starts switching. When the output voltage

rises above 2.3V, the microcontroller starts, enables the MCP1643 and controls the

RGB LED in order to power each color independently (see Figure 2-4). The amount of

time each LED is ON is set by the user through the three potentiometers.

FIGURE 2-4:

RGB LED Enable Signals and LED Current.

An idle time is necessary between each color to ensure that the output voltage of the

MCP1643 is below the LED voltage, otherwise the LED can be damaged by a current

spike caused by the output capacitor discharge. The idle time can be optimized for

different LED voltage differences to increase performance.