Atmel AT89RFD-10/EVLB002 User Manual
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Atmel AT89RFD-10/EVLB002 User Manual

Atmel AT89RFD-10/EVLB002 User Manual

Non-dimmable fluorescent ballast
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AT89RFD-10 / EVLB002
Non-Dimmable Fluorescent Ballast
..........................................................................................................................................................
User Guide
IXDN0037

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Summary of Contents for Atmel AT89RFD-10/EVLB002

  • Page 1 AT89RFD-10 / EVLB002 Non-Dimmable Fluorescent Ballast ................................User Guide IXDN0037...

  • Page 2: Table Of Contents

    Section 1 Introduction ................... 1-1 General Description .................1-2 Ballast Demonstrator Features ..............1-2 Section 2 Ballast Demonstrator Device Features ..........2-5 Atmel Supported Products ...............2-5 IXYS Supported Products ................2-5 Section 3 Ballast Description ................3-7 Circuit Topology ..................3-7 3.1.1 Line Conditioning ................3-7 3.1.2...
  • Page 3 Appendix 1: Capacitor Coupled Low Voltage Supply ......6-23 Appendix 2: PFC Basics .................6-24 Appendix 3: Bill of Materials..............6-25 Appendix 4: Schematic ................6-28 Ballast Demonstrator User Guide 7629A–AVR–04/06...

  • Page 4: Introduction

    Power Factor Correction, Half-Bridge Inverter Drives, and Charge Pump Regulators all employing a variety of IXYS / Atmel parts. Typical rapid start fluorescent lamps have two pins at each end with a filament across the pins.

  • Page 5: General Description

    As shown in the block diagram, figure 3, all of these functions can be timed, regulated, and diagnosed with the Atmel AT89EB5114 microcontroller. Ballast • Automatic microcontroller non-dimmable ballast Demonstrator •...
  • Page 6 Ballast demonstrator assembled board Figure 1-2. Non-Dimmable Ballast block diagram Figure 1-3. RESONATING BALANCE INDUCTOR TRANSFORMER FILAMENT PFC BOOST REGULATOR INVERTER LAMPS TRANSFORMER PFC Inductor POWER VOLTAGE UVLO IXD611 IX859 Driver & & 3.3V Regulator Driver PFC Driver AT89EB5114 PFC_ZCD P3.2/INT0 PFC Output P3.5/W0M1...

  • Page 7: Ballast Demonstrator Device Features

    Section 2 Ballast Demonstrator Device Features Atmel Supported AT89EB5114 Microcontroller Products • High speed configurable PWM outputs for PFC and ½ bridge inverter • 6 Analog inputs for A/D conversion, 2.4V internal reference level • 3 High speed PWM outputs used for the PFC and ½ bridge driver •...

  • Page 8: Ballast Description

    Section 3 Ballast Description Circuit Topology • Line conditioning with input filter and varistor for noise suppression and protection. • Low Voltage supply • PFC / boost regulator • PFC magnetics • Lamp drive • Microprocessor control • Charge pump regulator •...

  • Page 9: Pfc Magnetics

    3.1.6 Control The ballast is controlled by microcontroller U3. U3 is an Atmel AT8xEB5114 with an 80C51 core and specialized circuitry for controlling the ballast. Included are two PWM units that are used for controlling the PFC drive and the half-bridge drive with deadtime.

  • Page 10: Ixys Ixi859 Charge Pump Regulator

    • P3.0/W0M0 Half Bridge low side drive The Temperature monitor is a thermistor with a nominal 10K resistance at 25°C and 1.74K resistance at 80°C. It is mounted on the circuit board and so monitors ambient temperature in the lamp housing. Additional dedicated pins allow in-circuit programming of the flash memory using header J2.

  • Page 11: Ixys Ixd611 Half Bridge Mosfet Driver

    source due to the voltage drop across the source resistor. Enough energy is available from the current source circuit during the conduction angles to keep the IXI859 (U1) pin 1 greater than 14VDC as required to enable the Under Voltage Lock Out (UVLO) cir- cuitry in the IXI859.

  • Page 12: Circuit Operation

    Section 4 Circuit Operation General requirements • One or two lamps, type T8 of any characteristics – Ballast to compensate automatically – Hardware is capable of up to 40W per lamp • Line voltage of 90 to 265 VAC, 50 or 60 Hz –...

  • Page 13: Pfc Sequence

    width maximum of 20 uS is allowed for maximum 380 VDC error but with the high line limitation. 1% regulation of the 380 VDC bus was achieved with this control scheme. After the PFC FET ON pulse, the PFC inductor flyback boosts the voltage through D6 to the bulk filter capacitor.
  • Page 14 the drive voltage appears across the inductor. A smaller voltage appears across the res- onating capacitor and the lamps. However with 1 mH gapped inductance, there is sufficient inductor current to power the filaments. For lamp ignition, the frequency is reduced from 80 KHz to 40 KHz at 30 KHz/sec towards resonance causing the lamp voltage to rise to about 340 Vpeak.
  • Page 15 If lamp currents exceed power limits by 10% (as determined by lamp type), set half- bridge drive off due to over current. Start re-ignition sequence. Repeat 6 times and if still out of spec, shutdown PFC and half-bridge drive. PD6 rectified AC drive Checks are made for the presence of the rectified mains (haversine) and bus voltage throughout normal operation.

  • Page 16: At8Xeb5114 Non-Dimmable Software

    Section 5 AT8xEB5114 Non-dimmable Software This section of the document describes the software architecture utilizing the following source code files and related state machines. Main_at8xeb5114_fluo_demo.c – ADC State Machine Pfc_ctrl.c – PFC State Machine Lamp_ctrl.c – Lamp State Machine And their associated header files. - main_at8xeb5114_fluo_demo.h –...
  • Page 17 Main AT8xEB5114 FLUO DEMO Figure 5-1. MAIN AT8xEB5114 FLUO DEMO PFC_ZCD Analog comparator V_HAVERSINE CTRL V_BUS gv_v_haversine PFC_OUTPUT gv_v_bus gv_i_lamp LAMP_EOL gv_v_lamp gv_temperature LAMP I_LAMP CTRL INVERTER_HIGH V_LAMP INVERTER_LOW TEMPERATURE DUAL_LAMP Ballast Demonstrator User Guide 7629A–AVR–04/06...

  • Page 18: Main_At8Xeb5114_Fluo_Demo.c

    Main_AT8xEB5114_fluo_demo.c This file executes all the peripherals initializations and then schedules the different con- trol tasks. The ADC state machine is included in this file. The ADC state machine is controlled via interrupts. The ADC state machine functional diagram is shown below: 5.1.1 ADC STATE MACHINE...
  • Page 19 Start the I_LAMP_CONV conversion. I_LAMP_CONV Get back the i_lamp result. Start the next conversion cycle with a V_HAVERSINE_CONV conversion. Ballast Demonstrator User Guide 7629A–AVR–04/06...

  • Page 20: Pfc_Ctrl.c

    Pfc_ctrl.c This file executes the PFC state machine according to the scheduler in the Main_AT8xEB5114_fluo_demo.c file. 5.2.1 PFC STATE The PFC state machine functional diagram is shown below: MACHINE PFC State Machine Diagram Figure 5-3. INIT_PFC_HAVERSINE_CHECK HAVERSINE_CHECK g_pfc_time_since_previous_timer_reset <= HAVERSINE_MIN_CHECK_TIME PFC_HAVERSINE_CHECK HAVERSINE_PEAK_MIN <=gs_v_haversine_peak <= HAVERSINE_PEAK_MAX...
  • Page 21 CONFIGURE_PFC_SOFT_START Configures the peripherals PWM1 and interrupt 0 to soft start the PFC. Then jump to START_PFC_SOFT_START. START_PFC_SOFT_START Check that the soft start has been tried less than PFC_START_MAX_TRIES If OK then start PWM1 and jump to PFC_SOFT_START state. Else immediately jump to PFC_PROBLEM state. PFC_SOFT_START The PFC soft start consists on PFC_MAX_START_SHOTS pulses configured on PFC_SOFT_START_CONFIGURATION.

  • Page 22: Lamp State Machine

    Lamp_ctrl.c This file exec utes La mp state machine ac cording to the scheduler in the Main_AT8xEB5114_fluo_demo.c file. 5.3.1 Lamp State Machine The Lamp state machine functional diagram is shown below: LAMP state machine Figure 5-4. LAMP_OFF gv_pfc_state==PFC_CONTROL_LOOP CONFIGURE_LAMP_PREHEAT LAMP_PREHEAT gs_lamp_ignition_tries <...
  • Page 23 LAMP_NUMBER_CHECK Check the preheat current in order to know whether there is one or two lamps Then jump to the START_IGNITION state. In case there is no lamp, jump to the NO_LAMP state. START_IGNITION Decrease the frequency from the init frequency down to INVERTER_IGNITION_HALF_PERIOD.

  • Page 24: Conclusion

    Section 6 Conclusion The ballast demonstrator shows that the Atmel microcontroller and supporting IXYS devices can control and regulate one or more fluorescent lamps with precision and effi- ciency, therefore providing the lamp controller manufacturer with maximum flexibility with their design. Universal input and power factor control adds to the flexibility of the design with a minimal addition of more expensive active components.

  • Page 25: Appendix 2: Pfc Basics

    Figure 6-2. Positive Line Half Cycle Ich2 “Positive” line half -cycle: C1 charges to Vpk - V - Vo with polarity shown. 1.dV = 2Vpk-Vo-2V 2.dQ = CdV or C = dQ/dV For example, to obtain 15 ma at 20 VDC from a 220 Vrms 50 Hz line: 1.dQ/dt = (15 millijoules/sec)/(50 cycles/sec) or 0.3 millijoules / cycle.
  • Page 26 The boost switch ON time is maintained constant over each half cycle of the input volt- age sinusoid. Therefore the peak current for each switching cycle is proportional to the line voltage which is nearly constant during Ton. (Ipeak = Vin x Ton/L). Since the aver- age value of a triangular waveform is half its peak value, the average current drawn is also proportional to the line voltage.

  • Page 27: Appendix 3: Bill Of Materials

    Appendix 3: Bill Item Quantity Reference Part Manufactures Part # Distributors Part # of Materials Distributor Table 6-1. Bill of Materials Item Quantity Reference Part Manufactures Part # 600V DF10S C1,C3 1800 pF 250VAC WYO182MCMBF0K 1 nF 50V ECJ-2VB1H102K C4,C11,C14 .1 uF 600V MKP1840410634 1 nF 250 VAC...
  • Page 28 Table 6-1. Bill of Materials Item Quantity Reference Part Manufactures Part # R18,R22 402K 5% 1 /1% 1.2K 5% 464K 5% 1.8K 5% R30,R32,R41,R42 10K 5% 100K 5% R33,R34 22 OHM 5% 49.9K 1% R36,R38 4.7K 5% 12K 5% R39,R40 100 OHM 5% 5001 TP2,TP3,TP8...

  • Page 29: Appendix 4: Schematic

    Appendix 4: Figure 6-5. Schematic Ballast Demonstrator User Guide 7629A–AVR–04/06...
  • Page 30 IXYS CORPORATION IXYS Corporation Micronix, Inc. 3540 Bassett St. 145 Columbia Santa Clara, CA. 95054-2704 Aliso Viejo, CA. 92656-1490 (408) 982-0700 FAX (408) 496-0670 (949) 831-4622 FAX (949) 831-4628 www.ixys.com www.claremicronix.com Clare, Inc. 78 Cherry Hill Drive MicroWave Technology, Inc. Beverly, MA.
  • Page 31 Disclaimer: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN ATMEL’S TERMS AND CONDITIONS OF SALE LOCATED ON ATMEL’S WEB SITE, ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY...

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