LED Dimmer using a SEPIC Converter and MCP163 PIC Attach PWM Controller
Created: May 15, 2016
No description available.
The technology today continues to change and evolve. The LED became very efficient to the point that it was able to replace the tungsten filament, gas vapor lightings and Compact Fluorescent Lamps (CFL) in lighting system. The LEDs must be carefully integrated into lighting systems because of their sensitivity to thermal and electrical stress. The excessive driving current will deteriorate LED performance, shorten the lifetime, and cause permanent reduction in the luminous intensity. The LEDs may be driven using constant current sources in order to maintain a constant color output. A method of driving an LED is by using a Pulse Width Modulation (PWM) current control like the MCP1631HV-330E/SS.
The MCP1631HV-330E/SS is a high speed PWM controller that operates at 2MHz. It can operate at a supply of +3.5V to +16V. The PWM controller and the PIC16F616 microcontroller will control the powertrain duty cycle to provide output voltage or current regulation. Varying the duty cycle dims the LEDs; the PWM controller changes the luminous intensity without changing the color of the LED by varying the duty cycle to control the brightness. Unlike controlling the current to the LED, which can cause a color shift for some LED, the PWM controller does not. The microcontroller is used to adjust the output current switching frequency and maximum duty cycle. It also provides additional features that can make the system more intelligent and adaptable.
The LEDs had become popular due to its efficiency and lifespan compared to other lighting systems. The circuit is applicable in situation that requires the brightness of the LED to be dim or controlled. The MCP1631HV-330E/SS responsible for the dimming of the LED is applicable in application that requires high-speed pulse width modulation SEPIC powertrain, LED lighting applications and programmable switching battery chargers.