IRPLDIM4E Miniature Dimmable 26W Ballast Using IRS2530D DIM8TM Control IC Table of Contents Page 1. Overview ..........................................................................................2 2. Features ...........................................................................................2 3. Electrical Characteristics ..................................................................3 4. Fault Protection Characteristics .......................................................3 5. IRS2530D DIM8TM Ballast Control IC...............................................4 6. Circuit Description ............................................................................4 7. Circuit Schematics ...........................................................................5 8. Bill of Materials.................................................................................6 9. Functional Description......................................................................7 10. Fault Conditions ...........................................................................10 11. PCB Layout and Component Placement......................................14 12. Inductor Specifications .................................................................17 www.irf.com RD0801 -1- 1. Overview The IRPLDIM4E Reference Design is a miniature dimmable electronic ballast for driving 26W compact fluorescent lamps from a 220VAC line. The circuit provides all of the necessary functions for preheat, ignition, and dimming control of the lamp and also includes the EMI filter and AC rectification stage. The ballast size is 1.42in x 2.44in (36mm x 62mm). The circuit is designed around the IRS2530D(S)PbF DIM8TM Ballast Control IC. The IRS2530D includes adjustable preheat time, frequency sweeping for filament preheating and lamp ignition, a dimming reference and feedback input, a high soft-start frequency to avoid lamp flash, lamp and ballast fault protection for open filament condition, failure to strike, and no lamp fault conditions, automatic restart during lamp exchange, and, low AC line protection. The IRS2530D is simple to use, has only 8 pins, and drastically reduces component count for a complete dimming solution. 2. Features Closed-loop dimming control Programmable preheat time Frequency sweep for filament preheat and lamp ignition Open filaments and no-lamp protection Failure to strike and deactivated-lamp protection Low AC line protection Lamp exchange auto restart www.irf.com RD0801 -2- 3. Electrical Characteristics Parameter Lamp Type Units Input Power [W] Input Current [mArms] Lamp Running Voltage [Vpp] Lamp Running Current [mArms] Start Frequency [kHz] Run Frequency [kHz] Preheat Time Input AC Voltage Range Ballast turn-off voltage Dimming Level 100% 10% 100% 10% 100% 10% 100% 10% 100% 10% [s] [VACrms] [VACrms] Value 26W CFL 25 9 180 78 320† 480 271 26 115 42 68 1 200 - 250 85 TABLE 3.1: Ballast Parameters. † The lamp running voltage at 100% dimming level is not perfectly sinusoidal and has some distortion. 4. Fault Protection Characteristics Fault Brown-out Protection Non-ZVS Upper filament broken Lower filament broken Lamp removed Failure to ignite No lamp Crest Factor Over Current Crest Factor Over Current Crest Factor Over Current VVCOFLT+ VLOSD- End of life Crest Factor Over Current Ballast Increase frequency Deactivates Deactivates Deactivates Deactivates Does not start Deactivates Restart Operation Line voltage increase Lamp exchange Lamp exchange Lamp inserted Lamp exchange Lamp inserted Lamp exchange TABLE 4.1: Fault Protections Characteristics. www.irf.com RD0801 -3- 5. IRS2530D DIM8TM Ballast Control IC The IRS2530D is an application specific solution for dimming CFL and TL lamps in CFL or matchbox (small size ballasts) applications. It integrates all of the necessary functions for preheat, ignition and dimming control of the lamp, plus lamp fault protection, low AC-line protection, lamp exchange auto-restart, and a 600V half-bridge driver into a standard SO8 or DIP8 package. The IRS2530D includes adaptive zero-voltage switching, non-zero voltage switching (ZVS) protection, as well as an integrated 600V bootstrap MOSFET. The heart of this IC is a voltage-controlled oscillator (VCO) with a dimming reference/feedback input. One of the biggest advantages of the IRS2530D is that it uses the VS pin (the mid-point of the halfbridge) for over-current protection and to detect non-ZVS conditions. The IRS2530D uses the RDSon of the low-side half-bridge MOSFET for current sensing each cycle when the low-side MOSFET is on. An internal 600V MOSFET connects the VS pin to the VSsensing circuitry and allows for the VS pin to be accurately measured during the time when pin LO is high, while withstanding the high DC bus voltage during the other portion of the switching cycle when the high-side MOSFET is turned on. This eliminates the need for an external, precision current sensing resistor that is typically used to detect overcurrent. Please refer to the IRS2530D datasheet for further information including electrical parameters, a state diagram and a complete functional description. As a result of the IRS2530D features, the IRPLDIM4E Reference Design is a complete dimming ballast solution that includes lamp fault protection, low AC line protection, lamp exchange auto-restart, and reduces component count and ballast size. 6. Circuit Description The schematic for IRPLDIM4E is shown in Figure 7.1. The bill of materials with the component values is shown in Table 8.1. The ballast incorporates a fuse, input rectifier, EMI filter, bus capacitor, half-bridge, dimming control and output stage. The output stage is a series-L, parallel-RC resonant circuit consisting of an inductor (LRES), capacitor (CRES), and lamp. The AC line input voltage is rectified to provide a bus voltage of approximately 300VDC. The start-up resistors, RVCC1 and RVCC2, are sized such that they supply the micro-power current during under-voltage lockout (UVLO) mode and determine the AC line voltage where the ballast turns-on. When VCC exceeds the startup threshold (VCCUV+), the IRS2530D begins to oscillate and the charge pump circuit (CVS, DCP1 and DCP2) supplies the current to VCC while maintaining the internal VCC zener clamp at 15.6V. The IRS2530D controls the frequency of the half-bridge for satisfying the lamp operating modes. These include lamp preheat, lamp ignition, dimming, low AC line protection and lamp/ballast fault protection. www.irf.com RD0801 -4- 7. Circuit Schematic 220V AC Line Input L N RMAX RMIN F1 BR1 CF LF CBUS RVCC1 1 2 3 4 VCO DIM COM VCC RVCC2 CVCC CDIM CVCO CPH RVCO CFB IC1 RFB 8 7 6 5 VB HO VS LO RHO CBS RLO RLMP1 MHS MLS CVS DCP2 DCP1 LRES:A RLMP2 CDC CRES LRES:B CH1 CH2 LRES:C CFL LAMP -5- RD0801 www.irf.com Potentiometer Dimming PDIM Input RCS Figure 7.1: IRPLDIM4E Circuit Schematic IRS2530D 8. Bill of Materials Item # Qty 1 1 2 1 3 1 4 2 5 1 6 2 7 2 8 1 9 1 10 1 11 1 12 1 Manufacturer Digikey Diodes, Inc. Digikey Vishay Digikey Epcos Part Number RH06DICT-ND RHO6-T PPC.47BCT-ND NFR25H0004707JR500 M8301-ND 5800-102-RC 13 1 14 1 Wima Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Yageo Digikey Panasonic Digikey Panasonic Digikey Yageo Digikey Panasonic Wima TAW IR MKS2 Series P5931-ND EEU-EB2V100 PCC104BCT-ND ECJ-3VB1H104K PCC1886CT-ND ECJ-3VB1E184K 311-1171-1-ND CC1206KRX7R9BB222 PCC1892CT-ND ECJ-3YBIE684K PCC1882CT-ND ECJ-3YB1C105K 311-1174-1-ND CC1206KRX7R9BB103 P9542-ND ECK-A3A102KBP MKP-10 RM15MM MKP 472K1K6 IRS2530D 15 1 Vogt IR IL 070 503 11 02 16 2 17 2 18 1 19 1 20 1 21 1 22 1 23 1 24 1 25 2 26 1 IRFU320 P360KECT-ND ERJ-8GEYJ364V PPC7.5W-1CT-ND 5073NW7R500J12AFX P220KECT-ND ERJ-8GEYJ224V P470KECT-ND ERY-8GEYJ474V RHM430FCT-ND MCR18EZHF4300 P200KFCT-ND ERJ-8ENF2003V P1.0KALCT-ND ERJ-P08J102V 311-1.5KERCT-ND RC1206JR-071K5L P10ECT-ND ERJ-8GEYJ100V 3386P-103LF-ND 3386P-1-103LF 27 1 28 1 Digikey/Vishay Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Panasonic Digikey Yageo Digikey Panasonic Digikey Bourns Digikey Diodes, Inc. Digikey Diodes, Inc. 29 1 30 1 WAGO 31 1 32 1 Total 38 Description Reference Bridge Rectifier, 600V, 0.5A MiniDip BR1 Resistor, 0.47R, 1/2W F1 RF Chokes 1mH 200mA LF Capacitor, 47nF, 400V CF, CDC Capacitor, 10µF, 350VDC, 105C CBUS Capacitor, 0.1µF, 50V, 1206 CBS, CFB Capacitor, 0.18µF, 25V, 1206 CH1, CH2 Capacitor, 2.2nF, 50V, 1206 CVCO Capacitor, 0.68µF, 25V, 1206 CPH Capacitor, 1µF, 16V, 1206 CVCC Capacitor, 10nF, 50V, 1206 CDIM Capacitor, 1nF, 1KV, Ceramic disk CVS Polypropylene Capacitor, 4.7nF/1.6KV, 10%, RM=15mm Dimming Ballast Control IC Ballast Resonant Inductor EF20, 2.3mH Transistor, MOSFET, 400V CRES IC1 LRES MHS, MLS Resistor, 360K, 1206 RVCC1, RVCC2 Resistor, 7.5 Ohm, 5%, 1 W, Axial RCS Resistor, 220K, 1206 RLMP1 Resistor, 470K, 1206 RLMP2 Resistor, 430 Ohm, 1%, 1206 RMIN Resistor, 200K, 1%, 1206 RMAX Resistor, 1K, 1206 RFB Resistor, 1.5K, 1206 RVCO Resistor, 10 Ohm, 1206 RHO, RLO Pot, 10K, Single turn PDIM LL4148DICT-ND Diode, 1N4148 SMT DL35 DCP2 ZMM5248BDICT-ND ZMM2548B-7 Zener Diode, 18V, 500mV, SMT DCP1 Wire Jumper J1 235-202 Connector, 2 terminal X1 WAGO 235-204 Connector, 4 terminal X2 IR IRPLDIM4E PCB, Single Layer TABLE 8.1: IRPLDIM4E Bill of Materials. Lamp type: Spiral CFL 26W, Line Input Voltage: 200 - 250 VAC. Note: Different lamp types may require components with different values, voltage ratings and/or current ratings. www.irf.com RD0801 -6- 9. Functional Description When power is turned on, the IRS2530D first starts in Under Voltage Lockout (UVLO) mode. The UVLO mode is designed to maintain an ultra-low (<250µA) supply current, and to guarantee that the IC is fully functional before the high- and low-side output (HO and LO) gate drivers are activated. During UVLO, HO is ‘low’, and VCO is pulled down to COM for resetting the starting frequency to the maximum. LO is open circuit, and is used as a shutdown/reset input function for automatically restarting the IC when a lamp has been removed and re-inserted. Once VCC reaches the startup threshold (VCCUV+) and the LO pin is below VLOSD(lamp is inserted), the half-bridge FETs start to oscillate and the IC enters Preheat/Ignition Mode. At startup, VCO is 0V and the frequency starts at fMAX. The frequency ramps down towards the resonant frequency of the high-Q ballast output stage, causing the lamp voltage to increase. During this time, the filaments of the lamp are pre-heated to their emission temperature to minimize the necessary ignition voltage and to increase lamp life. The voltage on pin VCO continues to increase and the frequency keeps decreasing until the lamp ignites. If the lamp ignites successfully, the IRS2530D enters the DIM mode. The resonant output stage transitions to a series-L, parallel RC circuit with the Q-value and operating point determined by the user dim level (Figure 9.1) High-Q Vout Vin Ignition 10% Pr 100% t ea eh 50% Start Low-Q fmin f100% f50% f10% fmax Frequency Figure 9.1: Resonant tank Bode plot with lamp dimming operating points www.irf.com RD0801 -7- Figure 9.2 shows the VCO voltage, the voltage across the lamp, and the current through the lamp during Preheat, Ignition, and Dim mode for 100% dimming level. Figure 9.3 shows these waveforms for 10% dimming level. Figure 9.2: Preheat, Ignition, and Dim mode for 100% dimming level: CH1 is the VCO voltage, CH3 is the lamp current, and CH4 is the voltage across the lamp Figure 9.3: Preheat, Ignition, and Dim mode for 10% dimming level: CH1 is the VCO voltage, CH3 is the lamp current, and CH4 is the voltage across the lamp www.irf.com RD0801 -8- Figure 9.4 shows the voltage at the DIM pin, the VS (half-bridge) voltage, and the voltage at the VCO pin during Dim Mode for 100% dimming level. Figure 9.5 shows these voltages for 10% dimming level. Figure 9.4: 100% dimming level waveforms: CH1 is the DIM voltage, CH2 is the voltage at VS pin, and CH4 is the VCO voltage Figure 9.5: 10% dimming level waveforms: CH1 is the DIM voltage, CH2 is the voltage at VS pin, and CH4 is the VCO voltage www.irf.com RD0801 -9- 10. Fault Conditions In case of fault conditions such as open filaments, failure to strike, or lamp removal, the IRS2530D will go into Fault Mode. In this mode, the internal fault latch is set, HO is off, LO is open circuit, and the IRS2530D consumes an ultra-low micro-power current. The IRS2530D can be reset with a lamp exchange (as detected by the LO pin) or a recycling of VCC below and back above the UVLO thresholds. Failure to Strike At initial turn-on of the ballast, the frequency will ramp down from fMAX toward the resonance frequency. When the lamp fails to strike, the VCO voltage continues to increase and the frequency continues to decrease until the VCO voltage exceeds VVCOFLT+ (4.0V, typical), and the IRS2530D enters Fault Mode and shuts down (Figure 10.1). It should be noted that in case of failure to strike, the system will operate in capacitive side of resonance, but only for short period of time. Figure 10.1: Lamp non-strike: CH1 is the VCO voltage, CH4 is the voltage across lamp AC Mains Interrupt / Brown-Out Conditions This protection relies on the non-ZVS circuit of IRS2530D, enabled in the Dim Mode. During an AC mains interrupt or brown-out condition, the DC bus can decrease and cause the system to operate too close to, or, on the capacitive side of resonance. The result is non-ZVS switching that causes high peak currents to flow in the half-bridge MOSFETs that can damage or destroy them. To protect against this, the IRS2530D will detect non-ZVS by measuring the VS voltage at each rising edge of LO. If the voltage is greater than VZVSTH (4.5V, typical), the IC will reduce the voltage at VCO pin, and thus increase the frequency until ZVS is reached again (Figure 10.2). www.irf.com RD0801 - 10 - In case the DC bus decreases too far and the lamp extinguishes, the VCC voltage will go below VCCUV- (10.5V, typical) and the ignition/preheat ramp will be reset to reignite the lamp reliably. Figure 10.2: Brown-out conditions: CH1 is the VCO voltage, CH2 is the VS voltage Lamp Removal When the lamp is removed, the IRS2530D uses the Crest Factor Over-current Protection to enter the Fault mode and shut down. During lamp removal, the output stage will transition to a series-LC configuration, and the frequency will move towards resonance until the inductor saturates. The IRS2530D uses the VS-sensing circuitry and the RDSon of the low-side half-bridge MOSFET to measure the MOSFET current for detecting an over-current fault. Should the peak current exceed the average current by a factor of 5.5 (CF>5.5) during the on-time of LO, the IRS2530D will enter Fault Mode, where the half-bridge is off. Performing crest factor measurement provides a relative current measurement that cancels temperature and/or tolerance variations of the RDSon of the low-side half-bridge MOSFET. Figure 10.3 shows the voltage across the lamp and the VS voltage when the lower filament of the lamp is removed. Figure 10.4 shows these voltages when the upper filament of the lamp is removed. In both cases, the IRS2530D will enter the Fault Mode and shut down after detecting that the crest factor exceeds 5 during the on-time of LO. Figure 10.5 shows the VS pin, inductor current, and voltage across lamp when the inductor saturates and the ballast shuts down. www.irf.com RD0801 - 11 - Figure 10.3: Lower filament removed: CH2 is the VS voltage, CH4 is the voltage across the lamp Figure 10.4: Upper filament removed: CH2 is the VS voltage, CH4 is the voltage across the lamp www.irf.com RD0801 - 12 - Figure 10.5: Inductor saturation: CH1 is the LO voltage, CH2 is the VS voltage, CH3 is the current through the resonant inductor, and CH4 is the voltage across the lamp Figure 10.6 shows the VS voltage and the voltage across the lamp when the IC undergoes reset with a lamp exchange. When the lamp is removed, crest factor protection is triggered, and the IC enters the Fault mode and shuts down. Since the lamp is removed, LO pins is pulled above VLOSD+, and the IC goes to UVLO mode. When the lamp is re-inserted, the IC goes back to the Preheat / Ignition mode, and the halfbridge starts to oscillate again. Figure 10.6: Lamp exchange: CH1 is the LO voltage, CH2 is the VS voltage, and CH4 is the voltage across the lamp www.irf.com RD0801 - 13 - 11. PCB Layout and Component Placement www.irf.com RD0801 - 14 - www.irf.com RD0801 - 15 - www.irf.com RD0801 - 16 - 12. Inductor Specifications Vogt # IL 070 503 11 02 BI Technologies # HM00-07544 INDUCTOR SPECIFICATION E20/10/ 6 (EF20) CORE SIZE GAP LENGTH 1.0 mm CORE MATERIAL Philips3C85 , Siemens N27 or equivalent 2.3 mH 100 C NOMINAL INDUCTANCE TEST TEMPERATURE WINDING START PIN FINISH PIN TURNS WIRE DIAMETER ( mm) 1 6 240* 10/ 38 Multistranded CATHODE 2 5 5.5 26 awg insulated CATHODE 3 4 5.5 26 awg insulated MAIN PHYSICAL LAYOUT 0.4" ( Vertical6- Pin Bobbin) Pin View TEST 6 1 5 2 4 3 TEST TEMPERATURE MAIN WINDING INDUCTANCE * www.irf.com C 100 MIN 2.1 Adjust turns for specified Inductance RD0801 0.4" mH MAX 2.4 mH - 17 -