Reference Design Data Sheet (August, 1997) IRPLLNR1 TM POWIRLIGHT REFERENCE DESIGN : LINEAR BALLAST Features • • • • • • • • Drive 2X40WT12 Universal Input (90-255Vac) High Power Factor (0.99) & Low THD High-Frequency Operation (40kHz) Lamp Filament Preheating Lamp Fault Protection with Auto-Restart Over Temperature Protection IR2153 HVIC Ballast Controller Description The IRPLLNR1 is a high efficiency, high power factor, non-dimmable electronic ballast designed for linear fluorescent lamp types. The design contains an active power factor correction circuit for universal voltage input and a ballast control circuit using the IR2153 for controlling the lamp. Other features include EMI filtering, transient protection and lamp fault protection. The IRPLLNR1 is intended as a reference design to be used as development tool to speed up customers’ time to market. Block Diagram EMI Filter Rectifier PFC Half-Bridge Output Stage Lamps Line PFC Control IR2153 Fault Logic Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 1 IRPLLNR1 Electrical Characteristics Parameter Units Value Lamp Type 2/40T12 Input Power [W] 80 +/- 7% Input Current (120VAC) [A] 0.67 Pre-heat Output Frequency [kHz] 50 Pre-heat Output Voltage [Vpp] 350 Pre-heat Time [s] 2.0 Running Output Frequency [kHz] 39.0 +/- 4% Running Output Voltage [V] 100 Input A.C. Voltage Range [VAC] 90..255VAC/50/60Hz Input D.C. Voltage Range [VDC] 100..350 Ambient Temperature Range [ºC] 0..50 Power Factor 0.99 Total Harmonic Distortion [%] <15% Maximum Output Ignition Voltage [Vpp] 1200 Note: Other lamp types require a new ballast type with different component values. Note: Tolerances were achieved with trimming. Lamp Fault Protection Characteristics Lamps Lamp 1 or Lamp 2 lower cathode broken Lamp1 or Lamp 2 upper cathode broken Both Lamps upper cathodes broken Lamp1 or Lamp2 non-strike (cathodes intact) Open-Circuit (no lamps) Short-Circuit (false hook-up) Ballast Deactivates Restart Operation Lamp exchange or recycle line voltage Deactivates if nonzvs occurs Deactivates Exchange damaged lamp or recycle line voltage Lamp exchange or recycle line voltage Deactivates Lamp exchange or recycle line voltage Deactivates Deactivates Lamp exchange or recycle line voltage Lamp exchange or recycle line voltage Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 2 IRPLLNR1 Functional Description Overview The IRPLLNR1 consists of a power factor front end, a ballast control section, a resonant lamp output stage and shutdown circuitry. The power factor controller is a boost converter operating in critically continuous, free-running frequency mode. The ballast control section provides frequency modulation control of a traditional RCL series-parallel lamp resonant output circuit and is easily adaptable to a wide variety of lamp types. The shutdown section consists of lamp circuit current detection and comparator logic for safe turn-off and smooth auto re-starting. All functional descriptions are referred to the IRPLLNR1 schematic. Power Factor Control The power factor controller section consists of the LinFinity LX1562 Power Factor Controller IC (IC1), MOSFET M1, inductor L3, diode D5, capacitor C8 and additional biasing, sensing and compensation components (see schematic). This IC was chosen for its minimal component count, low start-up supply current and robust error amplifier. This is a boost topology designed to step-up and regulate the output DC bus voltage while drawing sinusoidal input current from the line (low THD) which is “in phase” with the AC input line voltage (HPF). The charging current of L3 is sensed in the source of M1 (R7) and the zero-crossing of the inductor current, as it charges the DC bus capacitor C8, is sensed by a secondary winding on L3. The result is critically continuous, free-running frequency operation where: L3 = I Lp = where, η Vin Vout Pout fs = = = = = Vin2 (Vout − 2Vin )η 2 PoutVout f sπ Pout 2 2 Vin min η (1) (2) efficiency nominal AC input voltage DC bus voltage lamp power switching frequency The value of the boost inductor (L3) can be calculated and the core should be dimensioned to not saturate at the worst case peak inductor currents ( I Lp ) for the desired input voltage range. For universal input, the boost inductor has been dimensioned for the highest peak currents which occur at low line (90VAC). Because of the wide input voltage range, performance can vary. It is recommended that the boost inductor be redimensioned for the exact desired input voltage plus tolerances (+/- 15%). Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 3 IRPLLNR1 Ballast Control The ballast control section includes a voltage-controlled oscillator (VCO) (Q1, C20, D9 and C13) connected to the IR2153 ballast controller IC (IC3) and programmed to different operating frequencies with a voltage divider (R17, R41, R42, R51, C12). It drives the lamp resonant output stage (L4, C21 and L5, C23) to the preheat, ignition and running operating conditions by changing the voltage at the base of Q1 and therefore the frequency of the halfbridge switches. During preheat, the half-bridge operating frequency is set by R42 and is fixed for a duration of time determined by the charging time of capacitor C28 to a threshold voltage (see Ballast Control Logic and Timing Diagram). This heats the lamp filaments to their emission temperature before the lamp ignites. This increases the life of the lamp and decreases ignition voltages and currents, yielding reduced maximum voltage and current ratings of the lamp resonant output stage and the half-bridge power MOSFETs (M4, M5). When the voltage on capacitor C28 exceeds the threshold voltage (voltage on C10), R51 is switched to ground through a comparator of IC4 (pin2) sweeping the voltage on the base of Q1 to ground momentarily, therefore sweeping the frequency lower towards the resonance frequency for ignition. The ignition frequency is the minimum frequency of the VCO defined as, f ignition = 1 113 . (C13)( R20 + 75) (3) During the ignition ramp, C12 charges at a much slower rate than C20, resulting in the voltage at the base of Q1 increasing after ignition to a value determined by the parallel connected resistor R51. R51 sets the final running frequency where the lamp is driven to the manufacturer’s recommended lamp power rating. The running frequency of the lamp resonant output stage for selected component values is defined as, 1 f run = 2π 2 PLamp P 1 + 1 − 2 Lamp − 2 LC CV 2 CV 2 LC Lamp Lamp 2 2 −4 2V 1 − DCbus V Lampπ 2 (4) L2 C 2 where, L C PLamp = = = Lamp resonant circuit inductor Lamp resonant circuit capacitor Lamp running power [H] [F] [W] VLamp = Lamp running voltage amplitude [V] Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 4 IRPLLNR1 Fault Protection The shutdown circuitry consists of 2 quad comparator ICs (IC2 and IC4), a current detection filter (R21, R22, C16 and D12), a pull-up lamp removal circuit (R23, R24, R25, R26, D16 and C22), and over-current sensing resistors (R47, R48, R49, R43, R44, R46, D10 and D19). A more detailed diagram of the logic circuitry is given in the Ballast Control Logic and Timing sections of this paper. The current detection filter rectifies and integrates a measurement of the lamp resonant current from the source of the lower MOSFET of the half-bridge and compares it against a fixed threshold voltage. Should the current exceed the threshold in the event of over-current due to a non-strike condition of the lamp or non-zero voltage switching of the half-bridge due to an open circuit or broken lamp cathodes, the CT pin of the IR2153 is latched below the internal shutdown threshold (1/6 Vcc) and the ballast is shutdown. In the event of a lamp exchange, the latch is reset with the pull-up network at the lamp, and the CT pin of the IR2153 is held below the internal shutdown threshold in an unlatched state (see Timing Diagram). When a new lamp is re-inserted, the ballast performs an auto restart without a recycling of the input line voltage. During a lamp removal, the frequency is also reset to the preheat frequency to avoid damage to the half-bridge switches due to belowresonance operation which can occur upon re-insertion of the lamp. For a dual lamp ballast, a second pull-up network is added to the second lamp (R27, R28, R29, R30) and is ‘OR-ed’ together with the first lamp. If either lamp is removed during running, the ballast is shutdown. In the event of a broken upper cathode by either lamp during normal operation, non zerovoltage switching occurs at the half-bridge and will be detected by the current detection filter at source of the lower MOSFET of the half-bridge. Both half-bridge MOSFETs are latched off. Should the DC bus decrease below a fixed threshold voltage during an undervoltage condition of the line voltage, the frequency is shifted back up to the preheat frequency to fulfill zero-voltage switching of the half-bridge, and the latch is disabled. This prevents latch-up during a fast cycling of the line voltage or a brown out. IRPLLNR1 Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 5 Trimming The final ballast running input power during production can vary due to tolerances in L, C, VBUS, frun and manufacturing of the lamp. Trimming is therefore recommended. An insulated jumper wire (JP1) is connected over resistor R50 to accommodate for this. If the final run frequency exceeds the nominal specified run frequency by 4% (39kHz), the input power will be too low, and the ballast may not ignite the lamp and/or deactivate in the event of a non-strike condition. This is because RT (R20) programs the minimum operating frequency which corresponds to the ignition frequency. If this frequency is too high, the resulting lamp voltage may be too low to ignite the lamp and the resulting current may be too low to reach the current limit threshold. Shifting this frequency up or down shifts all other operating frequencies in the same direction. In this case, JP1 should be cut in two places and removed. This will connect R50 in series with R20 and decrease all operating frequencies slightly. The running lamp power, ignition voltage and ignition current will also increase. All of these parameters should be carefully tested during production. IRPLLNR1 Ballast Control Logic For corresponding signal waveforms, see Timing Diagram. Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 6 VCC R14 R45 R18 VTH1 D7 R15 VTH2 8 D6 14 C10 LATCH 11 9 C26 R36 13 IC2C SHUTDOWN (LATCHED) 14 8 10 R16 IC4D C15 CT(IR2153) 9 IC4C D8 D20 D15 RT(IR2153) R35 TBLANK 11 R19 ENABLE 13 C24 10 3 IC2D 3 R39 5 7 2 TPHEAT 4 6 IC4A 5 SHUTDOWN (NON-LATCHED) RESET 2 4 7 1 6 IC4B IC2A IC2B LAMPOUT 12 + 12 C28 FREQSHIFT 1 COM UNDERVOLTAGE OVER-CURRENT PREHEAT IRPLLNR1 Timing Diagram (Normal operation, lamp removal/re-insertion during running) Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 7 VTH1 TPHEAT t VTH1 TBLANK t UNDERVOLTAGE VTH2 t FREQSHIFT ENABLE PREHEAT V(R41) t I(L4) t LAMPOUT PREHEAT RUN SHUTDOWN PREHEAT IGN IRPLLNR1 Measurements Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 8 The following waveforms (see Figures 1 and 2) are from a dual 40W/T12 ballast (see Bill of Materials) and include ballast input, ouput and control measurements during all modes of operation. Figure 1 : Line input voltage (upper trace, 200V/div) and current (lower trace, 0.5A/div) during 120VAC normal operation. Timescale = 5ms/div. Figure 2 : Drain-to-source voltage (upper trace, 200V/div) current (lower trace, 0.5A/div) during 230VAC normal operation. Timescale = 5ms/div. Figure 3 : Line input current (200V/div) during preheat, ignition and running operating conditions. Timescale = 0.5s/div. Figure 4 : Rectifier output voltage (upper trace, 200V/div), VCC IR2153 (middle trace, 10V/div) and VDD LX1562 (lower trace, 10V/div) during start-up. Timescale = 5ms/div. IRPLLNR1 Measurements (cont.) Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 9 Figure 5: Inductor (L4 or L5) current (0.5A/div) during preheat and ignition operating conditions. Timescale = 0.5A/div. Figure 6: Lamp voltage (200V/div) during preheat and ignition operating conditions. Timescale = 0.5A/div. Figure 7: Inductor current (L4 or L5) (0.5A/div) ramping up after preheat to ignite the lamp. Timescale = 5ms/div. Dummy filaments inserted to simulate non-strike condition. Figure 8: Lamp voltage (200V/div) ramping up after preheat to ignite the lamp. Timescale = 5ms/div. Dummy filaments inserted to simulate non-strike condition. IRPLLNR1 Measurements (cont.) Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 10 Figure 9: Filament current (upper trace, 0.5A/div) and voltage (lower trace, 10V/div) during preheat. Timescale = 0.5A/div. Figure 10: VCO voltage (5V/div) showing control sequence during preheat, ignition and running conditions. Timescale = 0.5A/div. Figure 11: Half-bridge voltage (upper trace, 200V/div), half-bridge current (middle/upper trace, 1A/div), Vth2 threshold voltage (middle/lower trace, 1V/div) and current detection voltage (lower trace, 1V/div) During normal running condtions. Timescale = 5us/div. Figure 12: Half-bridge voltage (upper trace, 200V/div) and lampout signal V:D16 (lower trace, 5V/div) during lamp removal/re-insertion condition. Timescale = 10ms/div. IRPLLNR1 Measurements (cont.) Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 11 Figure 13: Vth2 threshold voltage (upper middle trace, 1V/div), current detection signal V:C16 (upper trace, 1V/div) and inductor current (lower trace, 0.5A/div) during non-strike/ shutdown condition. Timescale = 20us/div. V:C16 exceeds Vth2 as current ramps up and ballast is shutdown. Dummy filaments inserted to simulate non-strke condtion. Figure 14: Half-bridge voltage (upper trace, 200V/div) and lower half-bridge MOSFET source current (1A/div) during hard-switching fault condition. Timescale = 1us/div. Upper filament of 1 lamp removed, other lamp remains running. Condition continues until V:C16 exceeds Vth2 (V:C26). Figure 15: Voltage (upper trace, 200V/div) and current (lower trace, 0.5A/div) waveforms of PFC MOSFET (M1) during lowest line (100VAC) condition. Figure 16: Drain-to-source voltage (upper trace, 200V/div) and source current (lower trace, 0.7A/div) of MOSFET (M5) during maximum running lamp power. IRPLLNR1 Measurements (cont.) Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 12 Figure 17: Typical Conducted EMI frequency response for phase against neutral (upper trace: Quasi Peak, lower trace: Average). EN55015 limit lines also shown. Figure 18: Typical Conducted EMI frequency response for neutral against neutral (upper trace: Quasi Peak, lower trace: Average). EN55015 limit lines also shown. Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 13 IRPLLNR1 Circuit Schematic 1 2 3 R37 4 R40 D 5 6 R13 D D5 L3 400VDC D14 R1 R19 R9 3 R45 R18 8 D17 4 R34 C8 C9 C28 D1 R5 R3 X1:1 L1 F1 C27 R28 R25 R29 D8 9 1 10 L2 D7 11 5 R39 R11 R24 D6 7 D2 R27 2 IC4 6 R23 14 TLC339 R10 R2 13 R16 12 D18 C15 D11 L C C 90..275VAC 50/60Hz 154..254VDC C2 C1 C4 8 C6 X1:2 7 D4 2 3 C3 IC1 C7 5 14 7 11 10 13 R6 D15 RT HO R50 JP1 M4 L4 C17 C19 IC3 R20 IC2 VB VCC R35 TLC339 3 E IR2153 2 M1 LX1562M N D3 D20 5 RV1 1 X2:2 VS CT 1 L5 R8 X1:3 C11 4 6 R14 12 6 8 LO R17 4 9 X3:2 M5 C21 VSS R51 C13 X3:1 X2:1 C14 C18 C23 LP1 LP2 C12 C25 D10 R15 X2:4 X3:4 B R41 X2:3 D12 D9 R26 R30 X3:3 B Q1 R36 C5 R4 R7 C10 C26 C16 R12 C24 R42 R21 D19 R22 C22 D16 C20 D13 R43 R44 R46 R47 R48 R49 Note: Thick traces represent high-frequency, high-current paths. Lead lengths should be minimized to avoid high-frequency noise problems. A A Title WARM-START UNIVERSAL INPUT FLUORESCENT BALLAST Size Number Revision B Date: File: 1 2 3 4 5 8-Jan-1998 Sheet of C:\PROTEL\SCH\IRPLLNR1\IRPLLNR1.SCH Drawn By: 6 1 of 1 Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 14 WORLD HEADQUARTERS: 233 KANSAS ST., EL SEGUNDO, CA 90245 USA • (310)322-3331 • FAX (310)322-3332 • TELEX 472-0403 EUROPEAN HEADQUARTERS: HURST GREEN, OXTED, SURREY RH8 9BB, UK • (44)0883 713215 • FAX (944)0883 714234 • TELEX 95219 Sales Offices, Agents and Distributors in Major Cities Throughout the World. Data and specifications subject to change without notice. © 1997 International Rectifier Printed in U.S.A. 4-97 Reference Design Data Sheet intended for design information only. Subjected to changes without prior notice. 15