IRPLDIM1U International Rectifier • 233 Kansas Street, El Segundo, CA 90245 USA IR21592 Dimming Ballast Control IC Design Kit Features ! ! ! ! ! ! ! ! Drives: 1 x 32W T8 Lamp Input: 90-140VAC/60Hz High Power Factor/Low THD High Frequency Operation Lamp Filament Preheating Lamp Fault Protection with Auto-Restart Brownout Protection IR21592 HVIC Ballast Controller Description The IRPLDIM1U is a high efficiency, high power factor, dimming electronic ballast designed for driving rapid start fluorescent lamp types. The design contains an EMI filter, active power factor correction and a ballast control circuit using the IR21592. This demo board is intended to ease the evaluation of the IR21592 Dimming Ballast Control IC, demonstrate PCB layout techniques and serve as an aid in the development of production ballast’s using the IR21592. IR21592 Dimming Ballast Block Diagram EMI Filter Rectifier PFC Output Stage Lamp Line IR21592 Interface Dim Input www.irf.com Half-Bridge Driver Dimming Feedback Preheat Feedback Lamp Fault 1 Electrical Characteristics Parameter Lamp Type Input Power (100%) Input Current (100%) Filament Preheat Current Preheat Mode Lamp Voltage Preheat Time Input AC Voltage Range Input DC Voltage Range Power Factor Total Harmonic Distortion Maximum Output Voltage Units [W] [Arms] [Arms] [Vrms] [s] [VACrms] [VDC] [%] [Vpk] Value (IRPLDIM1U) 32W T8 32 0.27 0.6 220 1.0 90..140/50..60Hz 100..180 0.99 <10 750 Note: Measurements performed with input AC line voltage = 120Vrms Fault Protection Characteristics Fault Line voltage low Upper filament broken Lower filament broken Failure to ignite Open circuit (no lamp) Ballast Deactivates Deactivates Deactivates Deactivates Deactivates Restart Operation Increase line voltage Lamp exchange Lamp exchange Lamp exchange Lamp exchange Fault Protection Overview The IRPLDIM1U Demo Board consists of an EMI filter, an active power factor correction front end, a ballast control section and a resonant lamp output stage. The active power factor correction section is a boost converter operating in critical conduction mode , free-running frequency mode. The ballast control section provides frequency modulation control of a traditional RCL lamp resonant output circuit and is easily adaptable to a wide variety of lamp types. The ballast control section also provides the necessary circuitry to perform closed-loop dimming, lamp fault detection, shutdown and auto-restart. All functional descriptions refer to the IRPLDIM1U schematic diagram. 2 www.irf.com (L) X1A F1 X1B L1 RV1 - C1 BR1 + R1 R2 R5 R4 C3 LPFC D1 R6 IC1 8 3 C4 7 1 2 4 R7 R9 D2 RS C5 MPFC LINE INPUT (N) CY C2 R3 R10 R11 R12 + CBUS RVDC CVDC CVCO CPH RDIM CDIM RFMIN X1C X1D X1E CMIN RMIN (E) (+) (-) RMAX 5 L6561 6 1 2 3 4 5 6 7 8 VB VS HO IR21592 VDC VCO CPH VCC COM DIM MAX CS LO SD MIN IPH FMIN 16 15 14 9 10 11 12 13 CVCC1 C10 ICBALLAST RIPH RLM2 C7 RLM1 D3 R13 + CVCC2 R14 R15 R16 C11 D4 R17 RCS MHS MLS C12 D5 RDC CDC LRES CRES X2A X2B X2C X2D 3 www.irf.com 0.5 to 5VDC DIM INPUT IRPLDIM1U Schematic Diagram IRPLDIM1U Bill Of Materials Lamp Type: T8/32W Line Input Voltage: 90 to 140 VAC/50/60Hz 4 Item 1 2 3 4 5 6 7 8 Qty 1 1 1 1 1 1 2 5 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Total 1 1 1 1 1 1 2 2 1 1 1 1 1 1 2 1 1 1 1 1 1 1 2 1 2 1 1 1 3 1 2 2 1 1 1 1 1 1 1 1 1 2 66 Reference BR1 C4,CVDC C5 C3 CVCO C1 CDC,C2 C7,CVCC1,C11,CMIN, CDIM CPH CBUS CVCC2 C10 C12 CRES D1,D4 D2,D3 D5 IC1 IC2 L1 LPFC LRES MHS,MLS MPFC R15 RFMIN RDIM RMAX RMIN RVDC RIPH, R6 R12 R1,R2 R3 R4 R5 R7,R13,R14 F1 R9,R16 R10,R11 R17 RS RCS RDC X1 X2 J1 CY RV1 RLM1,RLM2 Description Bridge Rectifier, 1A, 1000V Capacitor, 0.47uF, SMT 1206 Capacitor, 0.68uF, SMT 1206 Capacitor, 0.01uF, SMT 1206 Capacitor, 0.022uF, SMT 1206 Capacitor, 0.33uF, 275VAC Capacitor, 0.1uF, 400VDC Capacitor, 0.1uF, SMT 1206 Manufacturer International Rectifier Panasonic Panasonic Panasonic Panasonic Roederstein Wima Panasonic Part Number DF10S ECJ-3YB1E474K ECJ-3YB1E684K ECU-V1H103KBM ECU-V1H223KBM F1772433-2200 MKP10 ECJ-3VB1E104K Capacitor, 0.39uF, SMT 1206 Capacitor, 10uF, 350VDC,105C Capacitor, 4.7uF, 25VDC,105C Capacitor, 100pF, SMT 1206 Capacitor, 1.5nF,1KV, SMT 1812 Capacitor, 8.2nF, 1600VDC Diode, 1N4148, SMT DL35 Diode, SMT SMB Zener Diode, 20V, SMT DL35 IC, Power Factor Controller IC, Dimming Ballast Controller EMI Inductor, 1x10mH, 0.7A PFC Inductor, 2.0mH, 2.0Apk Inductor, 2.0mH, 2.0Apk Transistor, MOSFET Transistor, MOSFET Resistor, 1K Ohm, SMT 1206 Resistor, 36K Ohm, SMT 1206 Resistor, 10K Ohm, SMT 1206 Resistor, 24K Ohm, SMT 1206 Resistor, 27K Ohm, SMT 1206 Resistor, 47K Ohm, SMT 1206 Resistor, 22K Ohm, SMT 1206 Resistor, 13K Ohm, SMT 1206 Resistor, 680K Ohm, SMT 1206 Resistor, 7.5K Ohm, SMT 1206 Resistor, 330K Ohm Resistor, 1M Ohm Resistor, 22 Ohm, SMT 1206 Resistor, 0.5 Ohm, ½ Watt Resistor, 100K Ohm, SMT 1206 Resistor, 820K Ohm, SMT 1206 Resistor, 1M Ohm, SMT 1206 Resistor, 0.5 Ohm, ¼ Watt Resistor, 0.57Ohm, ¼ Watt Resistor, 100K Ohm, ¼ Watt Connector, 5 terminal Connector, 4 terminal Jumper Y Capacitor Varistor Resistor, 10 Ohm, SMT 1206 Panasonic Panasonic Panasonic Panasonic Johanson Panasonic Diodes International Rectifier Diodes ST International Rectifier Panasonic Coilcraft Coilcraft International Rectifier International Rectifier Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Yageo Yageo Panasonic Dale Panasonic Panasonic Panasonic Yageo Yageo Yageo Wago Wago ECJ-3YB1E394K EEU-EB2V100 EEU-FC1H4R7 ECU-V1H101JCH 102S43W152KV4 ECW-H16822JV LL4148 10DF60 ZMM5250B-7 L6561D IR21592 ELF-15N007A Z9264B Z9265B IRF720 IRF730 ERJ-8GEYJ102V ERJ-8GEYJ363V ERJ-8GEYJ103V ERJ-8GEYJ243V ERJ-8GEYJ273V ERJ-8GEYJ473V ERJ-8GEYJ223V ERJ-8GEYJ133V ERJ-8GEYJ684V ERJ-8GEYJ752V CFR-25JR-330K CFR-25JR-1M0 ERJ-8GEYJ220V CW-1/2 ERJ-8GEYJ104V ERJ-8GEYJ824V ERJ-8GEYJ105V CFR-25JR-R5 CFR-25JR-R57 CFR-25JR-100K Roederstein Panasonic Panasonic WYO222MCMBFOK ERZ-VO5D471 ERJ-8GEYJ100V 236-404 www.irf.com Power Factor Correction The power factor correction section consists of the L6561D Power Factor Controller IC (IC1), MOSFET M1, inductor L2, diode D2, capacitor C8 and additional biasing, sensing and compensation components (see schematic diagram). This is a boost topology designed to step-up and regulate the output DC bus voltage while drawing sinusoidal current from the line (low THD) which is “in phase” with the AC input line voltage (HPF). The design of the power factor correction section was taken from the L6561D data sheet and information on the operation and design considerations for the L6561D are contained therein. Ballast Control The ballast control section is built around the IR21592 Ballast Control IC, IC2 of the Demo board. The IR21592 contains an oscillator, a high voltage half-bridge gate driver, an analog dimming interface and lamp fault protection circuitry. A block diagram of the IR21592 IC is shown in figure 1 and a state diagram of the IR21592 is shown in figure 2. VCC 60uA ICT RFB VCO 2 V 15uA 1uA LEVEL SHIFT VDC 1 S Q R Q PULSE FILTER & LATCH 14 VB 16 HO 15 VS 13 VCC 11 LO 12 COM 10 CS 9 SD ERR 1.3uA CT CPH 3 REF 5.1V 10V ICT DIM 4 S 5.1V R 1.0V S Q R1 T Q R Q R2 Q 15.6V I DT + Q I CT 400ns DELAY CT Q IDIM FB MAX 5 4/RFMIN MIN 6 0.1/R FMIN 0.1/R FMIN IDIM/5 IFMIN FMIN 7 5.1V IPH IGN DET 8 3V 1/RFMIN 1.6V 1 5.1V S Q R Q Q S Q R OVERTEMP DETECT UNDERVOLTAGE DETECT 2.0V 7.6V 0 Figure 1: IR21592 Block Diagram www.irf.com 5 Power Turned On UVLO Mode 1/2-Bridge Off IQCC=200mA CPH=0V Oscillator Off VCC > 12.5V and VDC > 5.1V and SD < 1.7V and TJ < 165C SD > 2.0V (Lamp Removal) or VCC < 10.9V (Power Turned Off) T > 165C J (Over-Temperature) FAULT Mode Fault Latch Set 1/2-Bridge Off IQCC=240µA CPH=0V VCC=15.6V Oscillator Off (UV+) (Bus OK) (Lamp OK) (T jmax) VCC < 10.9V (VCC Fault or Power Down) or VDC < 3.0V (dc Bus/ac Line Fault or Power Down) or SD > 2.0V (Lamp Fault or Lamp Removal) PREHEAT Mode 1/2-BridgeOscillator On VCSPK+VIPH (Peak Current Control) CPH Charging@I PH+1µA DIM+Open Circuit Over-Current Disabled CPH > 5.1V CS > V CSTH (1.6V) (End of PREHEAT Mode) (Failure to Strike Lamp or Hard Switching) or T J > 165C (Over-Temperature) IGNITION Mode fPH ramps to fMIN CPH Charging@I PH+1µA DIM=Open Circuit Over-Current Enabled CS > V (1.6V) CSTH (Over-Current or Hard Switching) or TJ > 165C VCS>VIPH(enable ignition detection) (Over-Temperature) then VCS<VIPH(ignition detected) DIM Mode Phase CS=PhaseREF DIM=CPH Over-Current Enabled Figure 2: IR21592 State Diagram 6 www.irf.com The resulting operating frequency during preheat is given as: Ballast Design Lamp Requirements Before selecting component values for the ballast output stage and the programmable inputs of the IR21592, the following lamp requirements must first be defined: Variable I ph t ph Description Filament pre-heat current Units Arms Filament pre-heat time Vpp Vign Lamp ignition voltage Vpp P100% Lamp power at 100% brightness W V100% Lamp voltage at 100% brightness Vpp P1% Lamp power at 1% brightness W V1% Lamp voltage at 1% brightness Vpp Minimum cathode heating current Arms I Cathmin 2 I ph [Hz] πCV ph f ign = 1 2π 4 π 1+ V DC V ign [Hz] LC (4) The total load current during ignition is given as: I ign = f ign CVign 2π [App] (5) The operating frequency [Hz] at maximum lamp power is given as: f100% Table I, Typical lamp requirements Ballast Output Stage The components comprising the output stage are selected using a set of equations. Different ballast operating frequencies and their respective voltages and currents are calculated. The inductor and capacitor values are obtained using equations (2) through (7). The results of these equations reveal the location of each operating frequency and the corresponding voltages and currents. For a given L, C, DC bus voltage, and pre-heat current, the resulting voltage over the lamp during pre-heat is given as: 1 = 2π 2 2 1 32 P100 32 P 2 % 1 % − + − 2 100 −4 4 4 LC C 2V100 % LC C V100% I Cath 1% = V1 % f1%π C 2 (2) 2 (6) (7) Design Constraints The inductor and capacitor values should be iterated until the following design constraints have been fulfilled (Table II). Design Constraint f ph − f ign > 5kHz 2 4VDC 1 − V100%π L2C 2 The cathode heating current at minimum lamp power is given as: V ph < V phmax V 8L 2 VDC Vph = DC + I ph − [Vpp] π C π (3) The resulting operating frequency during ignition is given as: s Maximum lamp pre-heat voltage V phmax f ph = I ign < I ignmax ICath1% ≥ ICathmin Reason Ignition during pre-heat Production tolerances Inductor saturation Lamp extinguishing during dimming Table II, Ballast design constraints www.irf.com 7 IR2159 Programmable Inputs In order to program the MIN and MAX settings of the dimming interface, the phase of the output stage current at minimum and maximum lamp power must be calculated. This is obtained using the following equations: 2 4V 1− DC 2 2 2 1 1 32P% 1 32P% V%π f% = − 2 4 + − 2 4 −4 2π LC C V% LC C V% L2C2 (8) This ballast design procedure has been summarized into the following 3 steps: Define Lamp Requirements Iterate L and C to fulfill constraints Calculate IR2159 Programmable Inputs Figure 3, Simplified Ballast Design Procedure ϕ% = 2 % 2 % 180 −1 V 2P V tan [( C − 2% L)2πf% −4 LC2π3 f%3] 2P% V% P% π (9) With the lamp requirements defined, the L and C of the ballast output stage selected, and the minimum and maximum phase calculated, the component values for setting the programmable inputs of the IR21592 are obtained with the following equations: RFMIN = (25e − 6) − ( f MIN − 10000) ⋅ (1e − 10) ( f MIN − 10000) ⋅ (2e − 14) RCS = 2⋅ (1.6) I ign RIPH = RFMIN RCS I ph 2 CCPH = ( 2 E − 7)(t PH ) R MIN RMAX = R ϕ = FMIN 1 − 1% 4 45 [Ohms] (10) [Ohms] (11) Ballast Designer Software Included with the design kit is the Ballast Designer Software which allows for selection of different lamp types, different input voltage ranges or different lamp configurations. The software then performes all of the necessary design iterations and generates new schematics and a bill of materials. IRPLDIM1U Design Line Input Voltage: 90 to 140VAC/50/60Hz Lamp Power/Type: 32W/T8 1) Lamp Requirements Typical high-frequency (25kHz) lamp requirements for the 32W/T8 lamp type are given as: [Ohms] (12) [Farads] (13) [Ohms] (14) 0.86 ⋅ RFMIN ⋅ RMIN [Ohms] (15) ϕ100% 4 ⋅ RMIN − RFMIN ⋅ 1 − 45 Variable Value 0.6 Units Arms t ph 1.0 s V phmax 600 Vpp Vign 1300 Vpp Pmax 30 W VPmax 400 Vpp Pmin 1 W VPmin 330 Vpp I Cathmin 0.35 Arms I ph Table III, 32W/T8 lamp requirements 8 www.irf.com 2) Iterate L and C to Fulfill Constraints To select the ballast output stage inductor and capacitor, a range of values were input into equations (2) through (7), which have been summarized in the following table: L C [mH] [nF] V ph [Vpp] f ph [kHz] f ign [kHz] I ign [App] f pmax I Cath P min [kHz] [Arms] 2.0 6.8 748 2.0 8.2 668 2.0 10 592 heat the filaments. A capacitor value of 8.2nF was chosen which fulfills the lamp requirements without over-heating the cathodes. 3) IR21592 Programmable Inputs With all of the lamp requirements fulfilled, the component values for setting the programmable inputs of the IR21592 are calculated as: Equation No. (8) Variable (8) f1% 58kHz f100% Value 46kHz 53 49 46 49 45 40 (9) ϕ100% -56.12deg 1.4 1.5 1.7 (9) ϕ1% -89.27deg 49 46 43 (10) RFMIN 36kOhm (11) 0.35 0.38 RCS 1.0 Ohm 0.32 (12) RIPH CTPH 22kOhm (14) RMIN 27kOhm (15) RMAX 24kOhm Table IV, Ballast parameters for different C values When compared against the lamp requirements, a capacitor value of 6.8nF gives a lamp voltage during pre-heat that exceeds the maximum allowable specified for this lamp type. This can ignite the lamp before the cathodes have reached their emission temperature, drastically reducing lamp life. The pre-heat current can be reduced to give a lower pre-heat voltage, but the pre-heat time must then be increased for proper heating. Also, I Cath is too low, which min will cause the lamp to extinguish at low light levels where the arc current alone is too low to heat the cathodes. Increasing the capacitor value to 10nF fulfills the lamp requirements quite well, even allowing some room in the pre-heat voltage for the pre-heat current to be increased and the pre-heat time shortened. During dimming, however, the lamp voltage increases with decreasing lamp power due to lamp negative incremental impedance effects. A maximum is reached around 10% brightness, after which the lamp voltage decreases as the lamp is further dimmed. The maximum filament current occurs at the maximum lamp voltage, which for a capacitor value of 10nF, is too high and will overwww.irf.com (13) 330nF Table V, IR21592 Programmable Inputs for T8/32W lamp. Important Note: These design kits are intended as a demonstration of the functionality and performance of the IR21592 Dimming Ballast Control IC only. Adequate EMI filtering, line transient protection, galvanic dim control input isolation, and ballast and lamp life testing are not considered in this design. 9 Waveforms Figure 4 shows the voltage appearing across the lamp while Figure 5 shows the current flowing through the lamp during Startup, Preheat, Ignition and Dim modes. Figure 4, Lamp voltage during Startup, Preheat, Ignition and Dim (100%) Figure 5, Lamp current during Startup, Preheat, Ignition and Dim (100%) (100mA/div.) Normal Powerdown A Normal Powerdown occurs when the AC line voltage is disconnected from the ballast. When this occurs the voltage on the VDC pin of IC2 drops below the line fault threshold (3V) and IC2 shuts down in a controlled fashion. The oscillator is stopped, the half-bridge driver outputs (LO and HO) are turned off and capacitor CPH is discharged. IC2 also goes into its UVLO/micro-power mode and the bus voltage begins to collapse. Fault Mode Fault mode is when the ballast driver is shutdown due to the detection of a lamp fault. Note that when the ballast is in this Fault mode the power factor correction section of the ballast is also shutdown and the bus voltage will drop to the non-boosted/unregulated level. There are several lamp fault conditions which can put the ballast into the Fault mode. The lamp fault conditions detected include: near/below resonance (under-current) detection, hard-switching detection and over-current detection. Resistor RCS in the source lead of the low side MOSFET (M3) serves as the current sensing point for the half-bridge which is used to detect these lamp fault conditions. In operation when the half-bridge is oscillating, a voltage appears across RCS whenever the low side MOSFET, M3, is turned on or the high side MOSFET, M2, is turned off. The magnitude of this voltage directly relates to the current in the lamp resonant circuit. Figure 6 shows the voltage which appears across resistor RCS during normal Run mode conditions while Figure 14 shows the voltage appearing across the lamp during the end of Preheat mode, Ignition Ramp mode and the beginning of Run mode. Also shown in Figure 7 are the gate drive signals for the low side MOSFET (LO pin) and the high side MOSFET (HO-VS pin). 10 www.irf.com Figure 6, Normal Run mode, Upper trace: voltage across RCS, Middle trace: IC2 LO pin voltage, Lower trace: IC2 HO-VS pin voltage Figure 7, Normal lamp ignition: Lamp voltage during the end of Preheat mode, Ignition Ramp mode and the beginning of the Run mode During the Preheat mode the over-current protection is disabled. However, at the end of Preheat mode (the beginning of the Ignition mode) the hard-switching and over-current detection are enabled. If at any time thereafter the voltage magnitude across resistor RCS rises above the overcurrent threshold (1.6V) of the CS pin of IC2, a lamp fault condition is signaled and the half-bridge output MOSFETs’, (M2 and M3) are turned off and the ballast goes into Fault mode. This can happen if the lamp fails to ignite or if the upper filament is open. For failure to ignite the lamp, the current in the half-bridge increases and thus the voltage across resistor RCS increases above the over-current threshold signaling a fault. Figure 8 shows the voltage across resistor RCS and the voltage appearing across the lamp when the ballast detects a failure to ignite the lamp and goes into Fault mode. Figure 9 shows the voltage appearing across the lamp during the tail end of the Preheat mode and the Ignition mode for a failure of the lamp to ignite condition. If the upper filament is open, the halfbridge output hard-switches and each time the low side MOSFET (M3) is turned on a large current pulse occurs and thus a large voltage pulse occurs across resistor RCS signaling a fault, Figure 10 shows this hard-switching condition. Figure 11 shows the lamp voltage during the Preheat mode and beginning of Ignition Ramp mode for this hard-switching condition when the lamp fault condition is detected. The ballast will remain in Fault mode until either the line voltage is cycled or a lamp replacement is performed. www.irf.com 11 Figure 8, Failure of lamp to ignite condition (lamp filaments good): Upper trace: voltage across RCS, Lower trace: lamp voltage Figure 9, Failure of lamp to ignite condition (lamp filaments good): Lamp voltage during the end of Preheat and Ignition Ramp modes Figure 10, Hard-switching condition (upper trace filament open): Upper trace: voltage across RCS, Middle trace: IC2 LO pin voltage, Lower trace: IC2 HO-VS pin voltage Figure 11, Hard-switching condition (upper filament open): Lamp voltage during Preheat mode and beginning of Ignition Ramp mode when lamp fault is detected IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105 Data and specifications subject to change without notice. 11/13/2002 12 www.irf.com