IRS2983SPBF LED FLYBACK CONTROL IC Product Summary Features Flyback VOFFSET n/a VOUT n/a Io+ & I o- (typical) 200 mA / 400 mA tON & tOFF (typical) 60 ns / 30 ns Deadtime (typical) n/a Package Typical Applications Topology Flyback LED Driver Critical-conduction / Transition mode operation Primary constant power control Burst mode operation at light load Over-current protection Micropower startup (150 A) Low quiescent current (2.5 mA) Latch immunity and ESD protection Open load over voltage protection Noise immunity LED Drivers 8-Lead SOIC IRS2983SPBF Ordering Information Standard Pack Base Part Number Package Type Complete Part Number Form IRS2983SPBF 1 www.irf.com Quantity Tube/Bulk 95 IRS2983SPBF Tape and Reel 2500 IRS2983STRPBF SO8N © 2013 International Rectifier December 10, 2013 IRS2983SPBF Table of Contents Page Description 3 Qualification Information 4 Absolute Maximum Ratings 5 Recommended Operating Conditions 5 Electrical Characteristics 6 Functional Block Diagram 8 State Diagram 9 Input/Output Pin Equivalent Circuit Diagram 10 Lead Definitions 11 Lead Assignments 11 Application Information and Additional Details 12 Package Details 15 Tape and Reel Details 16 Part Marking Information 17 2 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Description The IRS2983 is a fully integrated, fully protected SMPS control IC designed to drive Flyback converter LED drivers. The IRS2983 features include primary side power regulation, which allows a basic converter to be implemented without the need for an opto isolator in a Flyback LED driver with a fixed load enabling a low cost, high reliability isolated LED driver design to be realized. The IRS2983 may also be used in converters that do include secondary feedback through an opto isolator. Other features of the IRS2983 include a high voltage startup enabling VCC supply to be derived initially from the high voltage DC bus until the auxiliary inductor winding is able to take over. The IRS2983 operates in critical conduction (CrCM) or discontinuous (DCM) modes and is fully protected against open and short circuit as well as inductor saturation. The IRS2983 may be used in single stage Flyback LED drivers with an unsmoothed DC bus to obtain high power factor and low THD. Typical Connection Diagram DFB RADJ CSN RSN DVCC QVCC T1 DSN RIN RZ CIN BR1 HV IC1 VCC 8 1 RZX1 DZ VDC 2 AC Line Input COMP 3 ZX 4 IRS2983 CVCC CS OUT CVOUT ROUT 7 COM 6 CS 5 RG CCOMP RDC M1 CDC RF RCS CF RZX2 CI 3 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Qualification Information † †† Industrial Comments: This family of ICs has passed JEDEC’s Industrial qualification. IR’s Consumer qualification level is granted by extension of the higher Industrial level. Qualification Level ††† Moisture Sensitivity Level Machine Model ESD Human Body Model IC Latch-Up Test RoHS Compliant SOIC8 MSL2 260°C (per IPC/JEDEC J-STD-020) Class B (per JEDEC standard JESD22-A115) Class 1C (per EIA/JEDEC standard EIA/JESD22-A114) Class I, Level A (per JESD78) Yes † †† Qualification standards can be found at International Rectifier’s web site http://www.irf.com/ Higher qualification ratings may be available should the user have such requirements. Please contact your International Rectifier sales representative for further information. ††† Higher MSL ratings may be available for the specific package types listed here. Please contact your International Rectifier sales representative for further information. 4 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Absolute Maximum Ratings Absolute maximum ratings indicate sustained limits beyond which damage to the device may occur. All voltage parameters are absolute voltages referenced to COM, all currents are defined positive into any lead. The thermal resistance and power dissipation ratings are measured under board mounted and still air conditions. Symbol VCC VOUT IOMAX ICC VHV VCOMP VDC VZX ICOMP IZX ICS PD RJA IC Low Voltage Supply Min. --- Gate Driver Output Voltage -0.3 † Definition Maximum allowable output current (OUT) due to external power transistor Miller effect VCC current HV Pin Voltage COMP Pin Voltage VDC Pin Voltage ZX Pin Voltage COMP Pin Current ZX Pin Current CS Pin Current Package Power Dissipation @ TA +25ºC PD = (TJMAX-TA)/RJA (8-Pin SOIC) Thermal Resistance, Junction to Ambient (8-Pin SOIC) Max. 20.8 VCC + 0.3 Units -800 600 mA 0 -0.3 25 600 mA -0.3 VCC + 0.3 V -5 5 mA --- 1 W --- 200 ºC/W V TJ TS TL † Junction Temperature -55 150 Storage Temperature -55 150 ºC Lead Temperature (soldering, 10 seconds) --300 This IC contains a zener clamp structure between the chip VCC and COM which has a nominal breakdown voltage of 20V. This supply pin should not be driven by a DC, low impedance power source greater than the VCLAMP specified in the Electrical Characteristics section. Recommended Operating Conditions For proper operation the device should be used within recommended conditions. Symbol VCC ICC ICS IZX VDC VCS TJ 5 Definition Supply Voltage VCC Supply Current CS Pin Current ZX Pin Current VDC Pin Voltage VCS Pin Voltage Junction Temperature www.irf.com © 2013 International Rectifier Min. VCCUV+ Note 2 Max. 18 10 -1 1 0 0.1 -25 6.0 1.3 125 Units V mA V ºC December 10, 2013 IRS2983SPBF Electrical Characteristics VCC =14V +/- 0.25V, COUT = 1000pF, VCOMP = VOC = VBUS = VZX = 0V, TA=25˚C unless otherwise specified Symbol Definition Supply Characteristics VCC Supply Undervoltage Positive VCCUV+ Going Threshold VCC Supply Undervoltage Negative VCCUVGoing Threshold VCC Supply Undervoltage Lockout VUVHYS Hysteresis UVLO Mode VCC Quiescent IQCCUV Current ICC VCC Supply Current VCLAMP VCC Zener Clamp Voltage High Voltage Startup Characteristics VHVSMIN Minimum startup voltage IHV_CHARGE VCC charge current High voltage start-up circuit OFF state leakage current Error Amplifier Characteristics ICOMP COMP Pin Error Amplifier Output Current Sourcing SOURCE IHVS_OFF ICOMP COMP Pin Error Amplifier Output Current Sinking SINK Error Amplifier Output Voltage VCOMPOH Swing (high state) Error Amplifier Output Voltage VCOMPOL Swing (low state) Error Amplifier Output Voltage in VCOMPFLT Fault Mode IVBUS Input bias current Control Characteristics VZX+ ZX Pin Threshold Voltage (Arm) VZXZX Pin Threshold Voltage (Trigger) VPREF Power Regulation Reference KMULT Multiplier Gain Min Typ Max Units 11.5 12.5 13.5 9.5 10.5 11.5 1.5 2.0 3.0 --- 150 --- A VCC = 6V --19.8 2.5 20.8 5.0 21.8 mA V ICC = 10mA 30.0 --- --- 1 2 --- mA Vcc< VCCUVHV=100V~400V --- --- 50 A HV=400V --- 30 --- --- 30 --- --- 13.5 --- --- 2.5 --- --- 0 --- --- -1 --- 1.40 0.52 --1.90 1.54 0.60 1.00 2.00 1.68 0.68 --2.10 V A V GBD A VBUS=0 to 3V V tBLANK OC pin current-sensing blank time 160 200 264 ns tWD Gate Drive Restart Pulse Interval 60 100 135 s tONMIN PWM Minimum ON time 136 167 198 ns tONMAX PWM Maximum ON Time 22 32 42 s 6 www.irf.com © 2013 International Rectifier Test Conditions VCS=0.5V VBUS=2.5V COMP=4.0V CS=1.5V ZX = 0 COMP = 4.0V ZX = 0 COMP = 13V December 10, 2013 IRS2983SPBF Electrical Characteristics (cont’d) VCC =14V +/- 0.25V, COUT = 1000pF, VCOMP = VOC = VBUS = VZX = 0V, TA=25˚C unless otherwise specified. tOFFMIN VCOMPOFF_HYS VDCMAX VCSPKMAX PWM Minimum OFF Time Cut off voltage hysteresis Maximum voltage for multiplier input † Maximum peak voltage for multiplier input† Protection Circuitry Characteristics VCSTH CS Pin Over-current Sense Threshold Cut off voltage below which gate VCOMPOFF drive output is disabled ZX Pin Over-voltage Comparator VOVTH Threshold ZX Pin Over-voltage Comparator Hysteresis Gate Driver Output Characteristics (OUT pin) VOL Low-Level Output Voltage VOVHYS VOH tr tf I0+ I0† GBD 2.7 ----- 3.0 40 --- 3.3 --7.0 s mV V --- --- 1.0 V 1.19 1.25 1.31 1.12 1.40 1.68 4.90 5.15 5.40 --- 200 --- --- 0 100 High-Level Output Voltage --- 0 100 Turn-On Rise Time Turn-Off Fall Time Source Current Sink Current --------- 60 30 200 400 110 70 ----- V GBD Signal is averaged before entering multiplier input. GBD VBUS=2.6V mV mV IO = 0 VCC – VO IO = 0 ns mA Multiplier operates accurately from zero to the maximum input specified. Guaranteed by design 7 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Functional Block Diagram HV STARTUP HV 1 8 VCC 7 OUT 6 COM VCLAMP UVLO VCC VDC 2 S Q R Q Set dominant VPREF X KMULT COMP 3 Restart Timer AVERAGER CS 5 Blank Timer VCSTH VOVTH ZX 4 VZX+ /VZX- 8 www.irf.com Minimum Off Time © 2013 International Rectifier S Q R Q December 10, 2013 IRS2983SPBF State Diagram Power Turned On UVLO Mode ICC = IQCCUV HVREG = On OUT = Low COMP = Held Low Watchdog Timeout VCC > VCCUV+ VCS < VCSTH -VOVHYS Fault Mode OUT = Low COMP = Held Low VZX > VOVTH Startup Mode OUT = Switching VCS > VCSTH Current Limit OUT = Low VMULT > 1V VCS < VCSTH -VOVHYS VZX > VOVTH 9 www.irf.com Regulating Mode OUT = Switching HVREG = Off © 2013 International Rectifier VCS > VCSTH December 10, 2013 IRS2983SPBF Input/Output Pin Equivalent Circuit Diagrams VCC COMP, VDC, CS, ZX, OUT ESD Diode VCLAMP ESD Diode COM 10 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Lead Definitions Symbol HV VDC COMP ZX CS COM OUT VCC Description High Voltage Startup Input Full Wave Voltage Input Compensation and averaging capacitor input PFC Zero-Crossing & Over-Voltage Detection PFC Current Sensing Input IC Power & Signal Ground Gate Driver Output Logic & Low-Side Gate Driver Supply Lead Assignments HV VCC 8 VDC 2 COMP 3 ZX 4 11 www.irf.com © 2013 International Rectifier IRS2983 1 OUT 7 COM 6 CS 5 December 10, 2013 IRS2983SPBF Application Information and Additional Details The IRS2983 is a switched mode controller IC designed for use in Flyback or Buck-Boost LED drivers. An internal high voltage regulator supplies the IC low voltage VCC supply during startup allowing operation directly from a DC input voltage up to 600V. Internal high voltage regulator In order to begin operating the IRS2983 requires the low voltage VCC supply to be raised above the under voltage lockout positive threshold (VCCUV+) and to continue operating VCC must be maintained above the under voltage lockout negative threshold (VCCUV-). The HV regulator enables the IRS2983 based LED driver to start up very rapidly and deliver light within 0.5s of switch on over the range of line voltage input. When the switching converter is running VCC is normally supplied through an auxiliary winding. When operating with primary regulation (see below) as steady state operation is reached the HV regulator is deactivated. The auxiliary winding from the Flyback or BuckBoost inductor/transformer provides output voltage and zero-crossing (ZX) information as well as supplying VCC. In the event of a short circuit at the output the VCC supply from the auxiliary winding collapses below VCCUV- causing the IRS2983 to shut off. The startup sequence begins again in a continuous “hiccup” mode until the short circuit is removed thereby preventing damage to the circuit. Primary power regulation The IRS2983 can operate using primary regulation or using a secondary feedback loop. It is capable of regulating the LED output current indirectly by calculating and controlling the input power of the converter. Since the LED load voltage is essentially constant, the power consumed is approximately proportional to the DC output current. In practice there are variations in LED forward voltage drop due to tolerance and temperature, however perfect accuracy is not usually necessary in such applications. For a fixed LED load the current will be approximately proportional to the input power. The IRS2983 senses input voltage and inductor current and uses these quantities to estimate the input power. 12 www.irf.com © 2013 International Rectifier This “power” is then regulated against an accurate internal reference (VPREF) to provide regulation of the LED current typically within +/-5% over line voltage variation from 120VAC to 230VAC. Input voltage is sensed through an appropriately scaled resistor divider (RIN and RDC) to provide a voltage at VDC within the range from 0V to VDCMAX. Input current is sensed through a shunt resistor (RCS) connected from the source of the Flyback MOSFET switch to the DC bus return. This current waveform is a high frequency ramp rising from zero at the beginning of each switching cycle to reach a peak level at the point the MOSFET is switched off and remaining at zero during the off time. V(t) VOUT(t) VCS(t) t ts Figure 1: Current sense waveform In order to obtain a DC current feedback signal the IRS2983 contains an averaging circuit that takes the CS pin input and converts it to a DC level proportional to the converters input current. This signal is then multiplied with the voltage (VDC) input to produce an internal voltage proportional to the converter input power. Loop compensation is performed by means of a transconductance error amplifier using an external capacitor (CCOMP) connected to 0V to realize an integrator that provides a stable error voltage used to control the converter on time. CCOMP is typically 1μF. The output current normally increases by a small amount as the input voltage is increased. RADJ is a resistor in the order of Meg-Ohms that can be added to provide a small feed forward correction to the current sense input allowing the output current to be fine-tuned to give tighter regulation over a wide input voltage range. At light loads if VCOMP drops below VCOMPOL the IRS2983 operates in burst mode. December 10, 2013 IRS2983SPBF Primary current limiting where, At very low input voltages the power regulation loop would require a very high peak current that may exceed the maximum rating of the inductor. In order to prevent this from occurring, the IRS2983 also includes cycle by cycle primary current limiting with a threshold VCSTH at the CS pin input. Under low line or fault conditions where the MOSFET current is abnormally high the gate drive is switched off after the blanking time tBLANK. Leading edge blanking is necessary to avoid false tripping due to the fast high current switch on transient that occurs at switch on of the MOSFET resulting from the circuit parasitics. This is also blanked from the averaging input that feeds the power regulation multiplier in order to prevent inaccuracies. The IRS2983 normally operates in critical conduction mode (CrCM), also known as transition or boundary mode. The transformer auxiliary winding provides a signal to the IRS2983 that indicates when all of the energy stored in the inductor has been transferred to the output. This triggers the start of the next switching cycle. The auxiliary winding voltage is divided down through RZX1 and RZX2 to provide the ZX pin input signal. NA = Number of turns on the auxiliary winding NS = Number of turns on the secondary winding VOUT = DC Output Voltage (LED voltage) V(t) VOUT(t) VCS(t) VCSTH t ts When the converter MOSFET switches off the voltage VZX transitions high. The values of RZX1 and RZX2 must be selected so that this voltage always exceeds the VZX+ threshold. If the IRS2983 is used in a converter that is required to drive loads over a range of voltage an additional feedback circuit is needed to control the output current. In this case the VZX voltage needs to exceed VZX+ at the minimum load voltage. If VZX does not exceed VZX+ the IRS2983 cannot operate in CrCM and remains pulsing and waiting for tWD timeout for the next cycle. When VZX exceeds VZX+ the IRS2983 waits until the VZX then drops below VZX- again to initiate the next switching cycle. A capacitor may be added in parallel with RZX2 to add some delay if needed to minimize switching loss by switching on in the minimum point or “valley” of the drain voltage. The IRS2983 includes a minimum off time function so that if the ZX pin input transitions high and low before tOFFMIN the gate drive output will not go high again until after this period. This prevents false tripping by ringing at the ZX input and also limits the converter maximum switching frequency by entering discontinuous mode (DCM) under conditions where the off time would otherwise be very short. This function extends the operating range of the converter allowing operation down to very low duty cycles. This thereby enables dimming designs to be implemented as well as limiting operating frequency to prevent overheating of the circuit inductor, MOSFET and snubber components. Figure 2: Cycle by cycle current limiting VZX(t) The pulse that appears at ZX has an amplitude proportional to the secondary output voltage and therefore the DC output voltage: VZX N A RZX 2 VOUT N S ( RZX 1 RZX 2) V(t) VOUT(t) t [1] ts Figure 3: Zero crossing detection 13 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Over voltage protection VCOMP(t) VZX(t) VOUT(t) V(t) t twd Figure 4: Overvoltage protection The feedback circuit is usually fed through an opto isolator. This can be connected to the IRS2983 in the following way: DVCC QVCC CIN HV VOVTH N S ( RZX 1 RZX 2) [2] N A RZX 2 IC1 VDC 2 COMP 3 VCC DZX RZX1 8 1 ZX VOUTOV T1 RVCC IRS2983 The ZX is a multi-function input also used for output over voltage limiting. In a Flyback or Buck-Boost converter if the load becomes disconnected the output voltage can become very high causing damage to components as well as presenting an electrical hazard. In order to protect against this the IRS2983 senses the output voltage indirectly through the ZX input, which is proportional to the actual output voltage. If the ZX input voltage exceeds VOVTH when the MOSFET switches off the gate drive remains switched off for a tWD period before starting the next cycle regardless of when the ZX voltage transitions low. The IRS2983 also discharges the COMP capacitor to zero so that the next cycle will begin at minimum duty cycle and ramp up slowly. This protection scheme allows the LED load to be hot connected and disconnected from the converter output without risk of damaging the circuit or of high voltages appearing at the output. Care should be taken however to avoid LED damage due to output capacitor discharge. An NTC thermistor at the output may be needed to limit the current surge. The overvoltage threshold is set by choosing the values of RZX1 and RZX2 appropriately, according to the formula: 4 OUT CVCC 7 COM 6 CS 5 RPFC MPFC RF Secondary error feedback The recommended over voltage threshold is 25% above the normal operating voltage of the LED load. RCS CF2 RZX2 Operating with a secondary feedback circuit Figure 5: Secondary feedback circuit In applications where accurate current regulation over a wide input voltage range or range of output voltages is required, the IRS2983 can be used in conjunction with a secondary sensing and feedback circuit. A simple output voltage feedback scheme is shown in figure 5 to illustrate how the opto isolator is connected to the IRS2983 to create a feedback circuit. The VDC input is tied to COM leaving the internal multiplier output at zero so that the COMP output provides pull up. The opto isolator feedback pulls down on the COMP voltage to reduce the on time as the opto diode current is increased driven by a secondary error amplifier circuit. The HV startup is not disabled in this operating mode but draws only micro current if VCC is biased above 17V. This is easily done by using a series pass transistor with the base biased with an 18V zener diode to supply VCC. 14 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Package Details 15 www.irf.com © 2013 International Rectifier December 10, 2013 IRS2983SPBF Tape and Reel Details LOADED TAPE FEED DIRECTION A B H D F C NOTE : CONTROLLING DIM ENSION IN M M E G CARRIER TAPE DIMENSION FOR Metric Code Min Max A 7.90 8.10 B 3.90 4.10 C 11.70 12.30 D 5.45 5.55 E 6.30 6.50 F 5.10 5.30 G 1.50 n/a H 1.50 1.60 8SOICN Imperial Min Max 0.311 0.318 0.153 0.161 0.46 0.484 0.214 0.218 0.248 0.255 0.200 0.208 0.059 n/a 0.059 0.062 F D C B A E G H REEL DIMENSIONS FOR 8SOICN Metric Code Min Max A 329.60 330.25 B 20.95 21.45 C 12.80 13.20 D 1.95 2.45 E 98.00 102.00 F n/a 18.40 G 14.50 17.10 H 12.40 14.40 16 www.irf.com © 2013 International Rectifier Imperial Min Max 12.976 13.001 0.824 0.844 0.503 0.519 0.767 0.096 3.858 4.015 n/a 0.724 0.570 0.673 0.488 0.566 December 10, 2013 IRS2983SPBF Part Marking Information Part number S2983 Date code YWW ? Pin 1 Identifier IR logo ? XXXX ? MARKING CODE P Lead Free Released Non-Lead Free Released Lot Code (Prod mode – 4 digit SPN code) Assembly site code Per SCOP 200-002 The information provided in this document is believed to be accurate and reliable. However, International Rectifier assumes no responsibility for the consequences of the use of this information. International Rectifier assumes no responsibility for any infringement of patents or of other rights of third parties which may result from the use of this information. No license is granted by implication or otherwise under any patent or patent rights of International Rectifier. The specifications mentioned in this document are subject to change without notice. This document supersedes and replaces all information previously supplied. For technical support, please contact IR’s Technical Assistance Center http://www.irf.com/technical-info/ WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105 17 www.irf.com © 2013 International Rectifier December 10, 2013