MICROCONTROLLERS FOR LAMP BALLAST AT90PWM & AT8xC5114

1. MICROCONTROLLERSFOR LAMP BALLAST AT90PWM & AT8xC5114 Jean Desuché November 2006

2. Applications Fluorescent Lamp • FLuorescent ballasts (Diffused light) • Office buildings, • Stores, • Displays, • Residential houses… HID • High Intensity Discharge (HID) ballasts (Focused light) • Street and exhibition lighting, • Car headlights, • Video Projection… LED • Light Emitting Diodes (LED) ballasts • Signaling; • Automotive, • Displays.

3. AT90PWM & 5114 features summary All AT90PWM have : ISP, One pin DebugWire, RC oscillators, 64 MHz PLL for PSC & core (16 MHz), Vcc=2.7-5.5V

4. Fluorescent lamp basics • Filament is heated (starter or magnetic coupling by adjusting PWM frequency • Mercury vaporize • A high voltage is applied between 2 electrodes • Current flows in the tube, controlled by the ballast • Exited Hg ions emmit UV light • Phosphor coating convert UV to visible light

5. AT90PWM2 DALI I/F DALI SPI A/D ISP PSC0 PSC2 PSCOUT00 PSCOUT20 PSCOUT21 +5V +15V Driver + Supply Driver Lamp+ resonator PFC : BOOST CONVERTER LAMP DRIVER Fluorescent lamp application diagram

6. HID lamp basics HID lamps have internal arc tube and an outer envelope • Tube is filled by high pressure gas • Mercury vapor • Metal Halide • Sodium • Distance between electrodes is some mm • High voltage required for start-up (2 to 30 kV) • Current and voltage (100-400V) is controlled by the ballast • Arc between electrodes emmit light • Most HID lamps require warm-up period for full intensity and a cool-down period before re-strike

7. AT90PWM3 DALI I/F DALI SPI A/D ISP PSC0 PSC1 PSC2 PSCOUT20 PSCOUT00 PSCOUT23 PSCOUT10 D/A PSCOUT21 PSCOUT22 +5V +15V +15V Driver + Supply Driver Driver Driver Lamp+ resonator PFC : BOOST CONVERTER BUCK CONVERTER LAMP DRIVER HID application diagram

8. AT90PWMx Competitive advantages (1) • All advantages of Mega48/88 plus • PSC • Advanced 12 bits, dual channels, PWM generators • Two control inputs (one digital, one analog comparator) for retriggering and overcurrent handling • PLL Clock up to 64 MHz • Variable frequency and pulse width • Enhanced resolution mode (16 bits flank modulation) • Input capture register • Large number of modes for Lighting, Motor Control, DC/DC conversion • Can synchronize the ADC • DALI (Digitally Adressable Lighting Interface) communication • 16 & 17 bits frames • Manchester coding • Autobaud

9. AT90PWMx PSC Module PSC 4 ramp mode exemple PSC Block Diagram digital Sync Input Analog Sync Input PSC Edge retrigger mode exemple

10. AT90PWMx Competitive advantages (2) • A/D • 10 bits, 11 channels, speed 8 µs min • Improved 2.56V Reference voltage • Amplifier (One or Two) for A/D • 250 kHz Synchronous BW, switched capacitor amplifier, • Low offset (5mV at the output) • Programmable gain 5, 10, 20, 40 • D/A • 10 bits, with output driver (impedance < 1KOhm) • Driver speed, 1 µs on 1 nF load • A/D, Amplifier & D/A can be synchronized with Timers & PSC • Comparator • Fast clocked comparator (16 MHz) • Offset 5 mV (at the input) • Programmable comparison voltage (4 fixed levels, external, D/A) • Generates interrupt or updates PSC

11. PWM2/3B Changes • Comparator • Clock frequency can be up to 16 Mhz (8 Mhz at 3.3V) • Analog hysteresis added (+50 – 100mV) • Amplifier : new logic for ADC start leading to shorter amplified conversion time • ADC speed : sampling and accuracy at 1 Mhz fixed (Still degradation at 2Mhz) • DAC glitches corrected, DAC amplifier linearity corrected • PSC • All erratas corrected • Inverted output in centered mode • Software input capture (write in register trigger an input capture) • Activity output flags added • Prescaler modified (larger division factor possible) • DALI • Reception of manufacturer frames (17 bits) with stop bit coded on different ways (0, 1, level, Manchester) • Errata corrected • PLL can also take its source from XTAL oscillator NOTICE : Changes with  may not be upward compatible (to be checked case by case)

12. AT8xEB5114 Advantages • Optimized for fluorescent tube Ballast controller • Present system • ASIC : one board per tube • Tube caracteristics adjustment done by passive components • AT8xEB5114 system • Microcontroller control : one board for all tubes • Tube caracteristics adjustment done by software • Low power consumption for start up procedure • Analog • 10-bit, 6 channels A/D converter • Amplifier/rectifier • Two Flexible 16 bits PWM: PFC and lamp control • RC oscillators to control power consumption during start up • Flash and ROM versions • Stacked EEPROM

13. Tools/Support • STK520 Starter Kit extension • DebugWire emulator • STK520 • AT89EB5114 Emulator • AT90PWM : Dimming Fluorescent Ballast Demo Kit • AT89EB5114 : Fluorescent Ballast Demo Kit • AT90PWM : HID & LED Ballast Demo Kits in development

14. STK520 Starter Kit Extension

15. ATAVRFBKIT : AT90PWM Fluo Demo Kit • Specifications • 400 volt DC bus by a power factor correcting boost regulator (PFC) • 100% to 2% dimming. • Two lamps T8 18W • 90 to 265 VAC 50 or 60 Hz • Controls: • DALI power control • 0-10 volt power control • One touch “Swiss” dimming • Partlist • Atmel • AT90PWM2 • IXYS • IXI858/859 - Driver/Reference/Interface IC • IXTP3N50P - TO-220, 500V/3A MOSFET • IXTP02N50D – Depletion mode FET for startup voltage • IXH611S1 - 650V/600mA Half-Bridge Gate Driver • LDA111S - Clare Optocoupler

16. ATAVRFBKIT ballast design : schematic

17. ATAVRFBKIT ballast design