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LED Lighting System. Team 18. Jonathan Chambers Hyungrae Cha SeungJin Nam. Objectives. Create an LED lighting system to replace incandescent and fluorescent lights typically found in a home

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led lighting system

LED Lighting System

Team 18

Jonathan Chambers

Hyungrae Cha

SeungJin Nam

objectives
Objectives
  • Create an LED lighting system to replace incandescent and fluorescent lights typically found in a home
  • Occupancy sensor to turn on lights when a person enters a room and turn off the lights when they leave
  • Light sensor to detect ambient light level and adjust intensity of LEDs accordingly
  • User has option of switching between automatic and manual intensity adjustment
outline
Outline
  • Motion Detector
  • Automatic/Manual Dimmer
  • Power Protection Circuit
  • LED Driver
  • LEDs
motion detector
Motion Detector
  • Leviton OSSNL-IDW Occupancy Sensor
automatic dimmer schematic
Automatic Dimmer Schematic

PR1: CdSPhotoresistor

Sense light from 400-700 nm

Dark Resistance: 150 kΩ

Bright Resistance: 4 kΩ

power protection circuit
Power Protection Circuit

Bridge Retifier

Low pass Filter (LC)

TVS

Common mode Filter

Thermistor

Terminal Block

power protection circuit2
Power Protection Circuit

Actual VBR output

Expected VBR output

Actual VAC output

Expected VAC output

output measurement at v buck
Output Measurement at VBUCK

Expected Result:

Actual measurement :

slide19
LEDs
  • 10x Cree cool white XLamp XP-E LEDs
  • Minimum 114 lumens each at 350mA
  • Driven at a maximum current of 500mA
led output characteristics
LED Output Characteristics
  • 10x LEDs driven at 500 mA
  • Power Consumption 500 mA * 3.3 V * 10 = 16.5 W
  • Lumen Output 114 lumens at 350 mA 114 * 1.4 * 10 = 1596 lumens
  • Efficiency at 500 mA 1596/16.5 = 96.7 lumens/watt
leds vs incandescent fluorescent lights
LEDs vs. Incandescent/Fluorescent Lights
  • Efficiency at light output of 1600 lumens

http://www.energystar.gov/index.cfm?c=cfls.pr_cfls_lumens

led driver efficiency
LED Driver Efficiency
  • Testing results obtained using Variac input set to 30 V.
  • Efficiency: (8.7/9.7)*100 = 89.7 %
performance issues solutions
Performance Issues/Solutions
  • Issues
  • Flickering
  • Reason for Flickering – The output frequency of LM3445 Driver didn’t reach the minimum standard point which is 120 Hz because our rectifier didn’t work as the full rectifier. Normally, LEDs can turn on and off at high frequency with varying the total on time to achieve perceived dimming. Driver output frequency should be at least 120 Hertz (Hz) to avoid flickering.
slide24

Performance Issues/Solutions

  • Issues
  • Delivering too much current to the LEDs
  • ( typically at the max power)
  • Reason for overflow current – Pin ISNS at LM3445 sets the
  • maximum LED current. However, our LM 3445 circuit didn’t work properly specially in ISNS pins.
  • Therefore, the ISNS didn’t control the constant maximum current to the LEDs.
slide25

Performance Issues/Solutions

  • Solution for Flickering
  • replace the bridge rectifier with diodes in parallel to make the full wave rectifier and make test easier to find whether it provide constantly high frequency to the LM 3445 driver or not.
  • Solution for overflow current to the LEDs
  • - Based on the LM3445 working properly, then we can increase the value of the limiting current resistor R3 to decrease the maximum current.
summary
Summary
  • We experienced a flickering issue when dimming the LEDs and an overflow of current provided to the LEDs at the maximum dimmer setting.
  • Based on our objectives, we were able to successfully implement the motion detector, manual/automatic dimmers, and LEDs.
  • Our efficiency values measured were high, so we successfully created an LED lighting system that produces sufficient light with a small amount of power.
special thanks
Special Thanks
  • Cree for donating our LEDs
  • The parts shop for soldering help and components
  • The power lab for help testing our circuits
  • TDK, Coilcraft for donating inductors and capacitors
  • LM3445 Designer who gave some ideas for the LED driver.