Application Note AN-1039

Transcription

1 Application Note AN-09 IR259: Dimming Dual Lamp Parallel Configuration with Balance Transformer By T. Ribarich, R. Marenche. Basic Circuit Considerations Figure : Dual Lamp Parallel Configuration Schematic.... Bill of Materials... The IR259 dimming ballast control IC can be used with some modifications to the ballast output stage, to allow both lamps to be dimmed while maintaining equal brightness in both lamps. Through externally programmable components, the IR259 offers flexibility of various features such as preheat time and current and minimum and maximum brightness settings. Comprehensive protection features protect the circuit against conditions such as lamp strike failures, filament failures, low DC bus, thermal overload, or lamp failure during normal operation. This circuit switches off both lamps when one is taken out, and automatically restarts when both lamps are in place.

2 A P P L I C A T I O N N O T E International Rectifier 2 Kansas Street El Segundo CA 9025 USA IR259: Dimming Dual Lamp Parallel Configuration with Balance Transformer AN09 By T. Ribarich, R. Marenche TOPICS COVERED Basic Circuit Considerations Schematic Diagrams Bill of Materials A popular and economical configuration for dimmable fluorescent ballasts is for driving two lamps in parallel. The IR259 dimming ballast control IC can be used with some modifications to the ballast output stage, to allow both lamps to be dimmed while maintaining equal brightness in both lamps. Through externally programmable components, the IR259 offers flexibility of various features such as preheat time and current and minimum and maximum brightness settings. Comprehensive protection features protect the circuit against conditions such as lamp strike failures, filament failures, low DC bus, thermal overload, or lamp failure during normal operation. This circuit switches off both lamps when one is taken out, and automatically restarts when both lamps are in place.. BASIC CIRCUIT CONSIDERATIONS The output stage has been modified for two lamps in parallel (Figure ). The lamps have been placed outside the under-damped resonant circuit loop which consists of L and C5. The filament heating during preheat and dimming is achieved using voltage-mode filament heating with secondary windings off of the resonant inductor (LA, LB, LC, LD). A balance transformer (L) provides equal currents through both lamps such that equal brightness is obtained during dimming. The DC blocking capacitor, C6, is also placed outside the under-damped resonant circuit loop such that it does not influence the natural resonance frequency of L and C5. During lamp removal, both lower filament signals are OR-ed into the shutdown pin, SD, through resistors R6 and R8.

3 2 CVCO CVDC RVDC C2 CMIN C0 D C9 R RCS M R5 R C M2 D5 R9 D6 C R RFMIN IR259 VDC VCO DIM MAX MIN FMIN IPH LO COM VCC VB VS HO SD CS RIPH R2 CCS RMIN RMAX R7 R8 C D7 R20 C6 L LA LB LC LD C5 C7 C8 C9 C20 L R6 AC Rectified Line (+) (-) R2 R22 Figure, Dual lamp parallel configuration.

4 Schematic L N GND 0.5 to 5VDC DIM INPUT L Note: Thick traces represent high-frequency, high-current paths. Lead lengths should be minimized to avoid high-frequency noise problems XD (+) (-) XE RV C C2 BR C R R2 R R6 R R5 C R7 C5 M2 C D5 L2 D2 RVDC D D CVDC R VDC HO 6 C8 CVCO 2 VCO VS 5 R0 D6 2 R MC262 5 R7 R9 R8 C D7 L C5 R20 L C6 LA LB C7 C8 LC LD C9 D R2 R22 C0 C 2 M R C9 C20 R R2 VB VCC COM LO IR259 R9 C6 M C7 DIM CDIM RMAX 5 MAX 6 MIN CMIN R5 7 FMIN CS 0 R6 8 IPH SD 9 RDIM RIPH CCS C2 RCS RMIN RFMIN

5 Bill Of Materials Lamp type: T8/6W X 2 Line Input Voltage: VAC/ Hz Note: Different lamp types require different frequency programming components. Item # Qt Manufacturer Part Number Description Reference y International Rectifier DF0S Bridge Rectifier, A 000V BR 2 Roederstein WY0222MCMBF0K Capacitor, 2.2nF 275 VAC Y Cap C Roederstein F Capacitor, 0.uF 275 VAC C2 Wima MKP0 Capacitor, 0.uF 00 VDC C 5 Panasonic ECU-VH0KBM Capacitor, 0.0uF SMT 206 C, CVCO, CDIM 6 2 Panasonic ECJ-YBE7K Capacitor, 0.7uF SMT 206 C5,C6 7 Panasonic EEU-FCH2R2 Capacitor, 2.2uF 50VDC 05C C7 8 Panasonic EEU-EB2V00 Capacitor, 0uF 50VDC 05C C8 9 Panasonic ECU-VH0KBM Capacitor, 0.uF SMT 206 C9,C0,C2, CMIN 0 Panasonic EEU-FCHR7 Capacitor,.7uF 50VDC 05C C 2 Vitramon 82A02KXE Capacitor, nf KV SMT 82 C,C 2 Wima MKP0 Capacitor, 6.8 nf,600v C5 Panasonic ECQ-E22KZ Capacitor, 0.22uF, 00V C6 Panasonic ECU-SH7KBB Capacitor, 0.7uF, 50V C7, C8, C9, C Panasonic ECJ-VBE Capacitor, 0.uF, SMT 206 CVDC,C 6 Panasonic ECU-VH7KBM Capacitor, 70pF SMT 206 CCS 7 Diodes LL8DICT-ND Diode, N8 SMT DL5 D, D, D5, D6 8 2 International Rectifier 0BF60 Diode, SMT SMB D2, D 9 Diodes MMSZ702T Diode, Zener 20V SMT DL5 D7 20 Motorola MC262 IC, Power Factor Controller IC 2 International Rectifier IR259 IC, Ballast Driver IC2 22 Panasonic ELF-5N007A EMI Inductor, X0mH 0.7Apk L 2 RGA RGA-EF25 PFC Inductor, 2.0mH 2.0Apk L2 2 Inductor,.0mH, 2.0Apk with secondary windings of turns 25 Panasonic ELF-5N008A EMI Inductor, X6.8mH 0.8Apk LA, LB L, LA,LB, LC, LD 26 International Rectifier IRF80 Transistor, MOSFET M, M2, M 27 2 Panasonic ERJ-8GEYJ680K Resistor, 680K ohm SMT 206 R, R2 28 Panasonic ERJ-8GEYJ7.5K Resistor, 7.5K ohm SMT 206 R 29 2 Panasonic ERJ-8GEYJ820K Resistor, 820K ohm SMT 206 R, R5 0 2 Panasonic ERJ-8GEYJ0K Resistor, 0K ohm SMT 206 R6, RDIM 2 Panasonic ERJ-8GEYJ00K Resistor, 00K ohm SMT 206 R7,R20 2 Panasonic ERJ-8GEYJ22K Resistor, 22K ohm SMT 206 R8 Panasonic ERJ-8GEYJ22 Resistor, 22 ohm SMT 206 R9, R, R Dale CW-/2 Resistor, 0.8 ohm ½ watt R0 5 Yageo.0MQBK-ND Resistor,.0megohm ¼ watt R 6 Yageo 70KQBK-ND Resistor, 70Kohm ¼ watt R2 7 Panasonic ERJ-8GEYJK Resistor, K ohm SMT 206 R5 8 2 Yageo 0KQBK-ND Resistor, 0K ohm ¼ watt R6,R8 9 2 Yageo.0MQBK-ND Resistor,.0M ohm ¼ watt R7,R9 0 Dale CW-/2 Resistor, 0.75 ohm ½ watt RCS Panasonic ERJ-8GEYJ9K Resistor, 9K ohm SMT 206 RMAX 2 Panasonic ERJ-8ENF2.9K Resistor, 2.9K ohm SMT 206 RMIN Panasonic ERJ-8GEYJ0K Resistor, 0K ohm SMT 206 RFMIN Panasonic ERJ-8GEYJ2K Resistor, 2K ohm SMT 206 RIPH 5 Panasonic ERZ-V05D7 Transient Suppressor RV 6 2 Panasonic ERJ-8GEYJ0 Resistor, 0 ohm SMT 206 R2, R22 Total 7