IRS27951S IRS27952(4)S RESONANT HALF-BRIDGE CONVERTER CONTROL IC Features • • • • • • • • • • • • Simple primary-side control solution for fixed and variable frequency DC-DC resonant converters. Max 500kHz per channel output with 50% duty cycle Floating channel bootstrap operation up to +600Vdc Programmable minimum and maximum switching frequency Programmable soft start frequency and soft start time Programmable dead time Micropower start-up & ultra low quiescent current Over-current protection using low side MOSFET Rds(on) User initiated micropower “Sleep mode” Under-voltage Lockout Simple design with minimal component count. Lead-free Product Summary Topology Half-Bridge VOFFSET 600 V VOUT VCC IO+ & IO- (typical) 300 mA & 900 mA Dead-time (programmable) 200ns~2us Package Options Typical Application • • • LCD & PDP TV Telecom SMPS, PC SMPS Home Audio Systems IRS27951S/IRS27952S 14-lead SOIC IRS279524S Ordering Information Standard Pack Base Part Number IRS27951 IRS27952 IRS279524 1 www.irf.com Package Type SOIC8N SOIC8N SOIC14N Complete Part Number Form Quantity Tube/Bulk 95 IRS27951SPBF Tape and Reel 2500 IRS27951STRPBF Tube/Bulk 95 IRS27952SPBF Tape and Reel 2500 IRS27952STRPBF Tube/Bulk 55 IRS279524SPBF Tape and Reel 2500 IRS279524STRPBF © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Typical Application Diagram DC BUS VIN R1 R2 Rcc D3 Dbs 1 CDC 2 3 4 Dss Rss RT Cbs U1 VCC VB RT HO CT/SD VS COM LO 8 M1 Rg1 D1 7 6 5 Lr IRS2795 M2 Rg2 Rmax CT Css LOAD COUT D2 Cr RTN Rled Rbias Rs1 Cf1 U2 Cf2 Rf2 U3 TL431 Rs2 2 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Table of Contents Page Ordering Information 1 Typical Application Diagram 2 Absolute Maximum Ratings 5 Recommended Operating Conditions 5 Electrical Characteristics 6 Functional Block Diagram 8 Input/Output Pin Equivalent Circuit Diagram 9 Lead Definitions 10 Lead Assignments 10 State Diagram 12 Application Information and Additional Details 13 Package Details 23 Tape and Reel Details 25 Part Marking Information 27 Qualification Information 28 3 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Description The IRS2795(1,2)(4) is a self oscillating half-bridge driver IC for DC-DC resonant converter applications, especially the LLC resonant half-bridge converter. The frequency and dead time can be programmed externally using two external components. The IC offers over current protection using the on state resistance of the low-side MOSFET. The IC can be disabled by externally pulling the voltage at the CT/SD pin below its enable voltage threshold 4 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S 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 VB VS VHO VLO VCT VRT IRT dVs/dt TJ TS PD RthJA Definition Supply Voltage High-side Floating Supply Voltage High-side Floating Supply Offset Voltage High-side Floating Output Voltage Low-side Output Voltage CT/SD Pin Voltage RT Pin Voltage RT pin source current Allowable offset voltage slew rate Operating Junction Temperature Storage Temperature Package power dissipation @ TA ≤ 25°C Thermal resistance, junction to ambient (8 lead SOIC) (14 lead SOIC) (8 lead SOIC) (14 lead SOIC) Min. Max. -0.3 -0.3 VB – 25 VS – 0.3 -0.3 -0.3 -0.3 ---50 -40 -55 — — — — 25 625 VB + 0.3 VB + 0.3 VCC + 0.3 VCC + 0.3 VCC + 0.3 2 50 150 150 0.833 1.04 150 120 Units V mA V/ns °C W °C/W Recommended Operating Conditions For proper operation the device should be used within the recommended conditions. Symbol Definition Min. Max. Units VBS High-side floating supply voltage 10 Vcc † VS Steady-state high-side floating supply offset voltage 600 V -3.0 VCC Supply voltage 12 18 fsw Switching Frequency --500 kHz † Care should be taken to avoid output switching conditions where the VS node flies inductively below ground by more than 5 V. Recommended Component Values Symbol RRT CCT 5 Component RT pin resistor value CT pin capacitor value www.irf.com © 2012 International Rectifier Min. 2 200 Max. 100 2000 Units kΩ pF th November 8 , 2012 IRS27951S IRS27952(4)S Electrical Characteristics VCC=VBS=15V, VS=0V, CVCC=CBS=0.1uF, CLO=CHO=1nF, RT=50.5kΩ, CT=200pF and TA = 25°C unless otherwise specified. The output voltage and current (VO and IO) parameters are referenced to COM and are applicable to the respective HO and LO output leads. Symbol Definition Low Voltage Supply Characteristics Min Typ Max Units Test Conditions V N/A µA VCC = VCCUV+ -0.1V VCCUV+ VCC turn on threshold 10.1 11 11.9 VCCUV- VCC turn off threshold (Under Voltage Lock Out) 8.1 9 9.9 VCCUVHYS VCC undervoltage lockout hysteresis --- 2 --- ICCSTART VCC startup current --- 50 100 Sleep mode VCC supply current --- 150 200 VCT/SD<VEN2, VBS=0V Quiescent VCC supply current --- 2 2.5 VEN1 < VCT/SD < 4.5V ICC46KHz VCC operating current @ fosc = 46KHz --- 3.1 4.5 ICC285KHz VCC operating current @ fosc = 285KHz --- 8.7 11 7.6 8.5 9.4 ISLEEP IQCC Floating Supply Characteristics VBS turn on threshold VBSUV+ VBS turn on threshold (Under Voltage Lock Out) VBS undervoltage lockout hysteresis 7 7.9 8.8 --- 0.6 --- VS Offset supply leakage current --- --- 50 VBS startup current --- 50 100 Quiescent VBS supply current --- 50 100 IBS46KHz VBS operating current @ fosc = 46KHz --- 1 1.5 IBS285KHz VBS operating current @ fosc = 285KHz --- 5.7 7 44.3 46.6 48.9 271 285 299 VBSUVVBSUVHYS ILKVS IBSSTART IQBS mA RT=50.5kΩ RT=7.32kΩ V N/A VB = VS = 600 V µA VBS ≤ VBSUV+ - 0.1V VEN1 < VCT/SD < 4.5V mA RT=50.5kΩ RT=7.32kΩ Oscillator I/O Characteristics fSW Oscillator frequency kHz CT=200pF, RT=50.5kΩ CT=200pF, RT=7.32kΩ V GBD VCT/SD < VEN1 VCT+ Upper CT ramp voltage threshold --- 5.0 --- VCT- Lower CT ramp voltage threshold --- 3.0 --- CT/SD pin startup current --- 10 --- µA 1.92 2.0 2.08 V --- 1 --- A/A --170 50 210 --250 % ns ICTSTART VRT Voltage reference at RT pin CM Current mirror ratio D Output duty cycle (LO and HO) tDT High/low output dead time 6 www.irf.com © 2012 International Rectifier CT=200pF th November 8 , 2012 IRS27951S IRS27952(4)S Electrical Characteristics VCC=VBS=15V, VS=0V, CVCC=CBS=0.1uF, CLO=CHO=1nF, RT=50.5kΩ, CT=200pF and TA = 25°C unless otherwise specified. The output voltage and current (VO and IO) parameters are referenced to COM and are applicable to the respective HO and LO output leads. Symbol Definition Protection Characteristics Min Typ Max RRTD RT discharge resistance --- 115 --- RCTD CT/SD discharge resistance --- 115 --- VEN1 CT/SD rising enable voltage 0.75 1.05 1.4 VEN2 CT/SD standby voltage 0.6 0.85 1.1 CT/SD enable hysteresis voltage --- 0.2 --- 1.9 2 2.1 3 300 3.15 --- VENHYST VOCP Overcurrent VS threshold tBLANK Leading edge blanking on LO 2.85 --- tSD Shutdown propagation delay --- 300 --- Units Test Conditions Ω V V ns IRS27951 IRS27952(4) GBD GBD Gate Driver Output Characteristics VOH Gate High Voltage Vcc-1 --- --- VOL Gate Low Voltage --- 0.05 0.15 tr Output rise time --- 60 --- tr Output rise time --- 200 --- tf Output fall time --- 16 --- tf Output fall time --- 65 --- MDT Output deadtime matching |(DTLO-HO) – (DTHO-LO)| --- --- 25 IO+ Output source current --- 300 --- IO- Output sink current --- 900 --- RUP Pull up Resistance --- 20 --- Pull down Resistance --- 3 --- RDOWN † V IGATE = 20mA IGATE = -20mA CLOAD=1nF ns CLOAD=4.7nF CLOAD=1nF CLOAD=4.7nF ns mA Ω GBD IGATE = 20mA IGATE =-20mA GBD: Guaranteed by design. 7 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Functional Block Diagram VB dv/DT BOOSTER HV LEVEL SHIFTER 2V RT + - CURRENT FAULT LOGIC & CONTROL UVBS S Q R Q HO VS Dead Time CT/SD OSCILLATOR PULSE STEERING VCC UV DETECTION DELAY MATCH LO SLEEP MODE LOGIC 8 www.irf.com © 2012 International Rectifier COM th November 8 , 2012 IRS27951S IRS27952(4)S Input/Output Pin Equivalent Circuit Diagrams: VCC VB ESD Diode ESD Diode RT RESD 25V HO ESD Diode ESD Diode COM VS 600V VCC VCC ESD Diode ESD Diode CT ESD Diode RESD RESD LO 25V ESD Diode COM COM 9 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Lead Definitions: Symbol VCC RT CT/SD COM LO VS HO VB Description Supply Voltage Oscillator timing resistor Oscillator timing capacitor / shutdown Ground Low-side gate drive High-side gate drive return / HV current Sense High-side gate drive High-side floating supply voltage Lead Assignments: IRS2795(1,2)S 1 VCC VB 8 2 RT HO 7 3 CT/SD VS 6 4 COM LO 5 1 NC NC 14 2 VCC VB 13 3 RT HO 12 4 CT/SD VS 11 5 COM NC 10 6 NC NC 9 7 NC LO 8 Lead Assignments: IRS279524S 10 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S VCC: Power Supply Voltage This is the supply voltage pin of the IC and sense node for the under-voltage lock out circuit. It is possible to turn off the IC by pulling this pin below the minimum turn off threshold voltage, VCCUV- without damage to the IC. This pin is not internally clamped. RT: Oscillator timing resistor This pin provides a precise 2V reference and a resistor connected from this pin to COM defines a current that is used to set the minimum oscillator frequency. To close the feedback loop that regulates the converter output voltage by modulating the oscillator frequency, the phototransistor of an optocoupler will be connected to this pin through a resistor. The value of this resistor will set the maximum operating frequency. An R-C series connected from this pin to COM sets frequency shift at start-up to prevent excessive energy inrush (soft-start). CT/SD: Oscillator timing capacitor /Shutdown An external capacitor CT from this pin to COM sets the dead time and frequency of the oscillator. The CT pin has sawtooth waveform, which is charged up by the current reference programmed at RT pin during rising slope and is discharged by an internal fixed 2mA current source during the falling slope. The falling time of the sawtooth defines the dead-time. At start-up, a 10uA current source charges this capacitor and the oscillator is enabled only when the voltage at this pin exceeds VEN1. The IC can also be used to enter sleep mode by externally pulling this pin below VEN2. COM: Logic and Gate drive Ground This is ground potential pin of the integrated control circuit. All internal circuits are referenced to this point. LO: Low-side Gate Drive Output The driver is capable of 0.3A source and 0.9A sink peak current to drive the lower MOSFET of the half-bridge leg. The pin is actively pulled to GND during UVLO. VS: High Side Gate Return/Current Sense This is the floating supply return. This pin also acts as a high voltage current sense pin and uses the low-side MOSFET RDSON to detect an over current fault condition. HO: High-side Gate Drive The driver is capable of 0.3A source and 0.9A sink peak current to drive the high-side MOSFET in the half-bridge. A resistor internally connected to pin VS ensures that the pin is not floating during UVLO. VB: High Side floating supply voltage The bootstrap capacitor connected between this pin and VS is charged by the bootstrap diode when the low-side gate-drive is high. 11 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S State Diagram DC POWER ON Gate Inactive Oscillator Inactive UVLO VCC < VCCUV- Oscillator Inactive Gates Inactive VCC < VCCUVVCC > VCCUV+ SLEEP CURRENT FAULT Oscillator and Gates Inactive ICT = ICTSTART ICC=ISLEEP Oscillator and Gates Inactive Internally discharge RT and CT pins VCT < VEN2 VCT > VEN1 NORMAL VS > VOCP @ LO=High Oscillator and Gates Active ICTCHARGE=IRT Over Current Protection Active UVLO Mode The IC remains in the UVLO condition until the voltage on the VCC pin exceeds the VCC turn on threshold voltage, VCCUV+. During the time the IC remains in the UVLO state, the gate drive circuit is inactive and the IC draws a quiescent current of ICC START. The UVLO mode is accessible from any other state of operation whenever the IC supply voltage condition of VCC < VCC UV- occurs. Sleep Mode When VCC exceeds the VCCUV+ threshold the IRS2795(1,2)(4) starts to charge up CT capacitor with ICT startup current towards the enable threshold, VEN1. During this period, the IC is in Sleep mode. The oscillator and gate drive circuits are disabled and the Ic consumes ISLEEP. When the voltage at the CT/SD pin exceeds VEN1, the IC is pulled out of sleep mode and the 2V reference voltage at the RT pin is enabled. The IC can be placed in Sleep mode while operating in Normal mode by externally pulling the CT/SD pin below VEN2. When this occurs, the RT pin of the IC is internally discharged to COM to ensure a system restart with softstart. Normal Mode The IC enters in normal operating mode once the UVLO voltage and VEN1 has been exceeded. The RT pin voltage is 2V under normal mode. Gate drive signal appears at HO and LO with fixed 50% duty-cycle. During this mode, the over-current protection scheme using the VS sense circuitry is active. Current Fault Mode When operating in Normal mode, the IC senses the voltage on the VS pin each time the low-side device is turned ON (with a leading edge blanking on LO, tblank). When the voltage sensed exceeds VOCP, the IC terminates the current gate pulse, disables the oscillator and gate drivers, and enters the Current Fault mode. When the IC enters this state, RT and CT/SD pins are internally discharged and IC supply voltage must be recycled before the IC can restart with soft-start again 12 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Application Information and Additional Details Information regarding the following topics is included as subsections within this section of the datasheet. • • • • • • • • • General Description IC Supply Circuit & Low start-up current Multi-function 2 Pin Oscillator Frequency and Dead-time Calculation User initiated Micropower Sleep mode Gate Drive Capability System Protection Features PCB Layout Tips Additional Documentation General Description The IRS2795(1,2)(4) is a double-ended controller for the resonant half-bridge topology. It provides complementary outputs with 50% (max) duty cycle; the high-side and low-side bridge devices are driven 180° out-of-phase for exactly the same time. A programmable dead-time inserted between the turn-OFF of one switch and the turn-ON of the other one guarantees soft-switching operation. The IC incorporates a multi-function oscillator that allows the designer to program all the necessary features to control a half bridge resonant switch-mode power supply featuring low standby power. The IC also incorporates additional protection features for robust operation and provides a high performance solution while minimizing external components, design time, and printed circuit board real estate. The IC enables the designer to externally program all the following features using a 2 pin RC oscillator – operating frequency range (start-up, minimum and maximum frequency), dead time, soft-start time and sleep mode operation. IRS2795(1,2)(4) also uses IR’s proprietary high-voltage technology to implement a VS sensing circuitry that monitors the current through the low-side half bridge MOSFET for short circuit faults. By using the RDSON of the lowside MOSFET, the IRS2795(1,2)(4) eliminates the need for an additional current sensing resistor, filter and currentsensing pin. This protection feature is latched and the thresholds are fixed at 2V for IRS27951 and 3V for IRS27952(4). Finally, the controller IC also features a micro power startup current (ICC<100µA) and a user initiated sleep mode during which the IC power consumption is less than 200µA (@ Vcc=15V). The sleep mode function allows system designs with reduced standby power consumption and can be used to meet stringent energy standards from Blue Angel, Energy Star etc. IC Supply Circuit & Low start-up current The UVLO circuit maintains the IC in UVLO mode if the VCC pin voltage is less than the VCC turn-on threshold, VCCON. If the VCC pin voltage drops below the UVLO threshold VCCUVLO at anytime after start-up, the IC is pushed back into UVLO mode. The current consumption in this mode is less than 100uA. VCC VCCON VCCUVLO UVLO NORMAL UVLO Figure 1: VCC Under Voltage Lockout 13 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Multi-function 2 Pin Oscillator The two pin oscillator is externally programmed by a resistor RT connected between pin#2 and COM and a capacitor CT, connected from pin#3 to COM. The RT pin provides an accurate 2V reference (±2%) with a 2mA source capability (higher the current sourced by the pin, the higher is the oscillator frequency). In normal operation, CT is charged by a current defined by the network connected at the RT pin. The oscillator ramp charges and discharges between the two ramp thresholds (3 and 5V). When the ramp voltage reaches 5V, it is internally discharged by a fixed current of 2mA. The fall time for the ramp corresponds to the dead time between the bridge devices. At startup, a 10uA internal current source charges the oscillator capacitor at the CT pin to VEN1. At this point, the IC is pulled out of sleep mode and the 2V reference voltage at the RT pin is enabled. The low-side device is now also turned ON to charge the bootstrap capacitor (this sequence at startup or while exiting sleep mode ensures that the low-side device is always switched on first to charge the bootstrap capacitor which will be ready to supply the highside floating driver). The low-side device remains ON till the CT pin voltage reaches the upper ramp threshold of 5V (see Fig 2). The programmable features for the oscillator are listed below• Wide frequency range: The high-speed oscillator allows an output frequency from 50 kHz up to 500 kHz. • Programmable dead-time: The oscillator timing capacitor CT also programs the dead time between LO and HO. • Programmable soft-start time: In resonant converter applications, the output power delivered is an inverse function of frequency i.e. soft- start is achieved by sweeping the operating frequency from an initial high value until the control loop takes over. Additionally, the resonant tank has a non-linear frequency dependence that makes the converter’s power transfer capability change little when the frequency is away from resonance and change very quickly as frequency approaches the resonant tank frequency. An R-C series circuit (CSS + RSS) connected between the RT pin and COM programs the soft-start time for the converter. Initially, the capacitor CSS is totally discharged, so that the series resistor RSS is effectively in parallel to Rfmin and the resulting initial frequency is determined by RSS and RT only (the optocoupler’s phototransistor is cut off). During this frequency sweep, the operating frequency will decay following the exponential charge of CSS, that is, initially it will change relatively quickly but the rate of change will get slower. The CSS capacitor charges until its voltage reaches 2V and, consequently, the current through RSS is reduced to zero. The soft-start sequence is activated at normal startup and back to operation from Sleep mode. • Programmable start-up, minimum and maximum frequency: In resonant converter applications, it is important to operate the converter in the soft-switching region of operation. IRS2795(1,2)(4) offers a trimmed voltage reference (±2%) at the RT pin to accurately program the converter switching frequency range in the desired region of operation. - The effective resistance (RSS//RT) at pin#2 during IC power up and the CT capacitor program the start-up frequency of the converter. - RT and CT program the minimum operating frequency. 14 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S - For closed loop systems with feedback control, a resistor Rfmax can be connected between the RT pin and the collector of the (emitter-grounded) phototransistor. The feedback loop modulates the current through the phototransistor and hence, the oscillator frequency for output voltage regulation. - The converter maximum frequency is set by (Rmax//RT) and CT. VCCON VCC 2V RT 5V CT 3V VEN1 HO LO UVLO SLEEP NORMAL Figure 2: Typical startup waveforms with soft-start Frequency and Dead-time Calculation The dead time is calculated by the following equation: t DT = (0.85CT + 40 pF ) ⋅ 15 www.irf.com © 2012 International Rectifier 2V 2mA th November 8 , 2012 IRS27951S IRS27952(4)S Dead-Time vs. CT Value 2000 1800 1600 DT (ns) 1400 1200 1000 800 600 400 200 0 0 500 1000 1500 2000 CT (pF) Figure 3: Dead-time with CT capacitor chart The running frequency of the IRS2795(1,2)(4) is given by: f SW = 1 2 ⋅ [ RTeq (0.85CT + 40 pF ) + t DT ] RTeq is the total equivalent resistance at RT pin. Or just simply select the RT value form the frequency chart shown below: Frequency Chart 500 CT=220pF Frequency (KHz) 450 400 CT=330pF 350 CT=470pF 300 CT=1nF 250 200 150 100 50 0 0 10 20 30 40 50 RT (KΩ) Figure 4: Switching frequency and RT selection The maximum duty cycle is given by: DCMAX = 0.5 − (t DT * f ) 16 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S User initiated Micro Power Sleep mode The IC can be actively pushed into a micropower sleep mode where current consumption is less than 200uA by pulling the CT pin below the sleep threshold VEN2, even while the IC VCC is above VCCON. This mode allows the user to disable the resonant power converter during application standby modes in order to meet regulation standards (Blue Angel, Energy Start, Green Power etc). This IC disabling feature can also be use to implement other system protection features. 5V CT 3V VEN2 HO LO 2V RT NORMAL SLEEP Figure 5: IC transition from normal to sleep mode by pulling down CT/SD pin Gate Drive Capability The gate drive output stage of the IC is capable of 0.3A peak source current and 0.9A peak sink current drive capability. Gate drive buffer circuits can be easily driven with the GATE pin of the IC to adapt to any system power level. System Protection Features IRS2795(1,2)(4) uses IR’s high-voltage technology to implement a VS sensing circuitry that monitors the current through the low-side half bridge MOSFET for short circuit faults. By using the RDSON of the low-side MOSFET, the need for an additional current sensing resistor is eliminated. The voltage at the VS node is sensed after a leading edge blanking time on LO. When the sensed voltage exceeds the protection thresholds, the IC enters Current Fault Mode (gate drive outputs are disabled and the oscillator pins are internally discharged to COM). This protection feature is latched and the IC supply voltage must be pulled below the UVLO threshold and then again above VCCON in order to reset the latch and restart the IC. 17 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S LO HO VS ILr VS Sensing Voltage OCP threshold VS Sensing is enabled when LO is high Figure 6: VS sensing over current protection PCB Layout Tips Distance between high and low voltage components: It is strongly recommended to place the components tied to the floating voltage pins (VB and VS) near the respective high voltage portions of the device. Ground Plane: In order to minimize noise coupling, the ground plane should not be placed under or near the high voltage floating side. Gate Drive Loops: Current loops behave like antennas and are able to receive and transmit EM noise. In order to reduce the EM coupling and improve the power switch turn on/off performance, the gate drive loops must be reduced as much as possible. For the low-side driver, the return of the drive loop must be directly connected to the COM pin of the IC and separate with signal ground (power ground and signal ground have star connection at COM pin). Supply Capacitor: It is recommended to place a bypass capacitor (CIN) between the VCC and COM pins. A 1μF ceramic capacitor is suitable for most applications. This component should be placed as close as possible to the pins in order to reduce parasitic elements. CBS Capacitor: The CBS capacitor should be placed as close as possible to the VB and VS pins. Routing and Placement: 1) The IC has only one COM pin for both signal return and power return, so it is strongly recommended to route the signal ground and power ground separately and with a star connection at the COM pin. 2) The RT pin provides a current reference for the internal oscillator and needs to be kept as clean as possible to avoid frequency jittering or duty-cycle mismatch between high-side and low-side. The components connected to this pin must keep away from the high frequency switching loop such as the gate driver loop and the VS node. The PCB traces connected to RT pin also need to be kept away from any switching node. 3) Connect CT capacitor directly to COM pin, don’t share the return with any other signal ground. 18 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Layout Example: VS node Signal components are kept away from switching nodes Supply bypass capacitors are close to IC pins. Star connection at COM pin Additional Documentation Please refer to application note AN-1160 for more design details of IRS2795(1,2)(4). Several technical documents related to the use of HVICs are also available at www.irf.com; use the Site Search function and the document number to quickly locate them. Below is a short list of some of these documents. AN-1160: Design of Resonant Half-Bridge converter using IRS2795(1,2) Control IC DT97-3: Managing Transients in Control IC Driven Power Stages 19 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S 12.0 V 10 VCC UVLO Thresholds ISUPPLY (mA) 11.5 V 1 0.1 11.0 V 10.5 V 10.0 V 9.5 V 9.0 V VCC UV+ 8.5 V 0.01 5.0 V VCC UV- 7.5 V 10.0 V 12.5 V 15.0 V 17.5 V Supply voltage 8.0 V -50 °C 50 °C 100 °C 150 °C Temperature Figure 7: Supply Current vs. Supply Voltage Figure 8: Undervoltage Lockout vs. Temperature ICCSTART and ISLEEP IQCC 2.6 180.0 2.4 160.0 ISLEEP ICCSTART 140.0 2.2 Current (uA) IQCC Quiescent Current (mA) 0 °C 2.0 1.8 1.6 120.0 100.0 80.0 60.0 40.0 1.4 20.0 1.2 1.0 -50 °C 0.0 -50 °C 0 °C 50 °C 100 °C Temperature 150 °C Figure 9: Icc Quiescent Currrent vs. Temperature 20 www.irf.com © 2012 International Rectifier 0 °C 50 °C 100 °C Temperature 150 °C Figure 10: Startup Current and Sleep Current vs. Temperature th November 8 , 2012 IRS27951S IRS27952(4)S Icc @46KHz, CLOAD=1nF 9.0 V 4.0 3.8 VBS UVLO Thresholds ICC Supply Current (mA) 3.6 3.4 3.2 3.0 2.8 2.6 8.5 V 8.0 V 7.5 V 2.4 VBS UV+ 2.2 VBS UV- 2.0 -50 °C 0 °C 50 °C 100 °C Temperature 7.0 V -50 °C 150 °C Figure 11: Icc Supply Currrent @1nF Load vs. Temperature 150 °C Dead Time @ CT=200pF Ibs @46KHz, CLOAD=1nF 230.0 1.03 225.0 1.02 Dead Time (ns) Ibs Supply Current (mA) 50 °C 100 °C Temperature Figure 12: VBS Undervoltage Lockout vs. Temperature 1.04 1.01 1.00 0.99 220.0 215.0 210.0 205.0 0.98 0.97 -50 °C 0 °C 50 °C 100 °C Temperature 150 °C Figure 13: Ibs Currrent @1nF Load vs. Temperature 21 0 °C www.irf.com © 2012 International Rectifier 200.0 -50 °C 0 °C 50 °C 100 °C Temperature 150 °C Figure 14: Dead-Time vs Temperature th November 8 , 2012 IRS27951S IRS27952(4)S Frequency @ CT=200pF, RT=50.5KΩ Frequency @ CT=200pF, RT=7.32KΩ 49.0 297 Switching Frequency (KHz) Switching Frequency (KHz) 48.5 48.0 47.5 47.0 46.5 46.0 45.5 45.0 44.5 44.0 -50 °C 0 °C 50 °C 100 °C Temperature 285 281 277 273 0 °C 100 °C 50 °C Temperature 150 °C Figure 16: Switching Frequency vs. Temperature IRS2795(1,2) -Vs Spike SOA 95 ns 85 ns 80 75 ns 70 65 ns 60 Voltage (V) Gate Tr and Tf @ 1nF Load 289 269 -50 °C 150 °C Figure 15: Switching Frequency vs. Temperature 293 55 ns 45 ns Tr_HO Tr_LO Tf_HO Tf_LO 35 ns Failure Voltage 50 40 30 20 25 ns 10 15 ns 0 1E-7 2E-7 3E-7 4E-7 5E-7 6E-7 7E-7 8E-7 9E-7 1E-6 5 ns -50 °C 0 °C 50 °C 100 °C 150 °C Pulse Width (s) Temperature Figure 17: Gate Output Tr and Tf time @ 1nF Load vs. Temperature 22 www.irf.com © 2012 International Rectifier Figure 18: VS Negative Transient Safety Operation Area th November 8 , 2012 IRS27951S IRS27952(4)S Package Details: SOIC8N 23 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Package Details: SOIC14N 24 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Tape and Reel Details: SOIC8N LOADED TAPE FEED DIRECTION A B H D F C NOTE : CONTROLLING DIMENSION IN MM E G CARRIER TAPE DIMENSION FOR 8SOICN Metric Imperial Code Min Max Min Max A 7.90 8.10 0.311 0.318 B 3.90 4.10 0.153 0.161 C 11.70 12.30 0.46 0.484 D 5.45 5.55 0.214 0.218 E 6.30 6.50 0.248 0.255 F 5.10 5.30 0.200 0.208 G 1.50 n/a 0.059 n/a H 1.50 1.60 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 25 www.irf.com 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 © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Tape and Reel Details: SOIC14N LOADED TAPE FEED DIRECTION A B H D F C NOTE : CONTROLLING DIMENSION IN MM E G CARRIER TAPE DIMENSION FOR 14SOICN Metric Imperial Code Min Max Min Max A 7.90 8.10 0.311 0.318 B 3.90 4.10 0.153 0.161 C 15.70 16.30 0.618 0.641 D 7.40 7.60 0.291 0.299 E 6.40 6.60 0.252 0.260 F 9.40 9.60 0.370 0.378 G 1.50 n/a 0.059 n/a H 1.50 1.60 0.059 0.062 F D C B A E G H REEL DIMENSIONS FOR 14SOICN Metric Imperial Code Min Max Min Max A 329.60 330.25 12.976 13.001 B 20.95 21.45 0.824 0.844 C 12.80 13.20 0.503 0.519 D 1.95 2.45 0.767 0.096 E 98.00 102.00 3.858 4.015 F n/a 22.40 n/a 0.881 G 18.50 21.10 0.728 0.830 H 16.40 18.40 0.645 0.724 26 www.irf.com © 2012 International Rectifier th November 8 , 2012 IRS27951S IRS27952(4)S Part Marking Information SOIC8 Part number Sxxxxx Date code YWW ? Pin 1 Identifier IR logo ? XXXX ? MARKING CODE P Lead Free Released Lot Code (Prod mode – 4 digit SPN code) Assembly site code Per SCOP 200-002 Non-Lead Free Released SOIC14 Part number IRSxxxxx Date code YWW ? Pin 1 Identifier ? XXXX ? MARKING CODE P Lead Free Released Non-Lead Free Released 27 www.irf.com IR logo © 2012 International Rectifier Lot Code (Prod mode – 4 digit SPN code) Assembly site code Per SCOP 200-002 th November 8 , 2012 IRS27951S IRS27952(4)S Qualification Information† †† Qualification Level Moisture Sensitivity Level Machine Model ESD Human Body Model IC Latch-Up Test RoHS Compliant 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. ††† MSL2 260°C SOIC8N (per IPC/JEDEC J-STD-020C) ††† MSL2 260°C SOIC14N (per IPC/JEDEC J-STD-020) Class B (per JEDEC standard EIA/JESD22-A115-A) Class 2 (per EIA/JEDEC standard JESD22-A114-B) Class I, Level A (per JESD78A) 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. 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 28 www.irf.com © 2012 International Rectifier th November 8 , 2012