ATAVRFBKIT Atmel, ATAVRFBKIT Datasheet - Page 14

• Manufacturer Part Number: ATAVRFBKIT
• Description: KIT DEMO BALLAST FOR AT90PWM2
• Manufacturer: Atmel
• Series: AVR®r

Specifications of ATAVRFBKIT

• Main Purpose: Lighting, Ballast Control
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: AT90PWM2, AT90PWM3
• Primary Attributes: 18 W, Up to 2 Type T8 Lamps, Dimmable, Auto Detect of Swiss or DALI
• Secondary Attributes: Power Factor Corrected (PFC), 90 to 265 VAC, 90 to 370 VDC
• Data Bus Width: 8 bit
• Core Chip: AT90PWM2B
• Topology: Boost
• No. Of Outputs: 1
• Dimming Control Type: Digital
• Kit Contents: Board CD Docs
• Development Tool Type: Hardware / Software - Eval/Demo Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.5.4
ATAVRFBKIT / EVLB001 User Guide
Power Control
Description
Calculate input power for both lamps = PB4 (lamp current) * (lamp voltage). Use this
data for DALI feedback verification if required. Set programmable gain of AMP0 to 10.
78 watts will be 0.195 VDC at the input of AMP0+ or 1.95V internal A/D input.
Adjust frequency up (lower power) or down (higher power) at 30KHz/sec rate. Limit fre-
quency to 100% (PB4 = 0.195V and 32KHz) to 80KHz dimming range. The dimming
must be logarithmic for the best resolution. The largest lumen change will be at the low-
est power setting. A small high frequency change 70 to 80kHz will give a large perceived
dimmed range.
If PB4 > 0.220V for two lamps or > 0.110V for one lamp, set half bridge drive off to avoid
an over current. Start re-ignition sequence. Repeat 6 times and if still out of the limit, set
TX DALI fail signal & shutdown PFC and half bridge drive.
Ballast Demonstrator Operation
7597B–AVR–10/07
4-12