The TEA1995T can also be used in multi-output ... - NXP

1 TEA1995 TGreenChip dual synchronous rectifier controllerRev. 3 5 December 2017 Product data sheet 1 General descriptionThe TEA1995T is the first product of a new generation of Synchronous Rectifier (SR)controller ICs for switched mode power supplies. It incorporates an adaptive gate drivemethod for maximum efficiency at any TEA1995T is a dedicated controller IC for synchronous rectification on thesecondary side of resonant converters. It has two driver stages for driving the SRMOSFETs, which rectify the outputs of the central tap secondary transformer two gate driver stages have their own sensing inputs and operate TEA1995T can also be used in multi-output flyback converters with the SR MOSFET placed at the low TEA1995T is fabricated in a Silicon-On-Insulator (SOI) Features and features Adaptive gate drive for maximum efficiency at any load Supply current in energy save operation below 200 features Wide supply voltage range from V to 38 V Dual synchronous rectification for LLC resonant in SO8 package Synchronous rectification for multi-output flyback converters Supports 5 V operation with logic level SR MOSFETs Differential inputs for sensing the drain and source voltages of each SR features SR control without minimum on-time Adaptive gate drive for fast turn-off at the end of conduction UnderVoltage LockOut (UVLO)

2 Protection with active gate pull-downNXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20172 / 183 ApplicationsThe TEA1995T is intended for resonant power supplies. In such applications, it can drivetwo external synchronous rectifier MOSFETs for the rectification of the voltages on thetwo secondary windings of the transformer. These MOSFETs replace diodes. It can beused in all power supplies requiring high efficiency: Adapters Power supplies for desktop PC and all-in-one PC Power supplies for television Power supplies for servers4 Ordering informationTable 1. Ordering informationType numberPackageNameDescriptionVersionTEA19 95T/1SO8plastic small outline package; 8 leads; body width mmSOT96-15 MarkingTable 2. MarkingType numberMarking codeTEA1995T/1 TEA1995 NXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers.

3 NXP 2017. All rights data sheetRev. 3 5 December 20173 / 186 Block diagramaaa-016986V AND IREFERENCE5 VREGULATORDRIVERSUPPLY11 VenableUNDERVOLTAGELOCKOUTENERGY SAVECONTROLTURN ONoff regulationon regulationturn-onDSASSADSBSSBGDAVCCSWITC H OFF+150 mV-50 mV-55 mV-400 mVLOGICICTURN ONoff regulationon regulationturn-onGDBGNDSWITCH OFF+150 mV-50 mV-55 mV-400 mVFigure 1. TEA1995T block diagramNXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20174 / 187 Pinning 2. TEA1995T pin descriptionTable 3. Pin descriptionSymbolPinDescriptionGDB1gate drive output MOSFET BGND2groundDSB3drain sense input for synchronous timing MOSFET BSSB4source sense input MOSFET BSSA5source sense input MOSFET ADSA6drain sense input for synchronous timing MOSFET AVCC7supply voltageGDA8gate drive output MOSFET ANXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers.

4 NXP 2017. All rights data sheetRev. 3 5 December 20175 / 188 Functional TEA1995T is a controller IC for synchronous rectification. It is perfectly suited tobe used in resonant applications. It can drive two synchronous rectifier MOSFETs onthe secondary side of the central tap transformer winding. Figure 3 shows a IC1 Qsec2 CoutFigure 3. TEA1995T typical and undervoltage lockout (VCC pin)When the voltage on the VCC pin exceeds Vstart, the IC leaves the UVLO state andactivates the SR circuitry. When the voltage drops to below Vstop, the IC reenters theUVLO state. The SR MOSFET gate driver outputs are actively kept low. For properoperation, the VCC pin must be decoupled with an extra capacitor (not only with Cout)between the VCC pin and the GND pin. To reduce inductance effects because of highgate driver currents, the extra capacitor must be connected as close as possible to sense (DSA and DSB pins)The drain sense pins are input pins capable of handling input voltages up to 100 positive drain sense voltages, the gate driver is in off-mode with pulled-down gatedriver pins (pins GDA or GDB).

5 At negative drain sense voltages, the IC enables the SRthrough sensing the drain source differential SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20176 / Rectification (SR; DSA, SSA, DSB, and SSB pins)The IC senses the voltage difference between the drain sense (pins DSA and DSB) andthe source sense (pins SSA and SSB) connections. The drain source differential voltageof the SR MOSFET is used to drive the gate of the SR this absolute voltage difference is higher than Vact(drv), the corresponding gatedriver output turns on the external SR MOSFET. When the external SR MOSFET isswitched on, the absolute voltage difference between the drain and the source senseconnections drops to below Vact(drv). The regulation phase follows the turn-on the regulation phase, the IC regulates the difference between the drain and the sourcesense inputs to an absolute level (Vreg(drv)).

6 When the absolute difference is higher thanVreg(drv), the gate driver output increases the gate voltage of the external SR MOSFET until the Vreg(drv) level is reached. The SR MOSFET does not switch off at low IC operates without minimum the absolute difference is lower than Vdeact(drv), the gate driver output decreasesthe gate voltage of the external SR MOSFET. The voltage waveform on the gate of theSR MOSFET follows the waveform of the current through the SR MOSFET. When thecurrent through the external SR MOSFET reaches zero, the SR MOSFET is quicklyswitched the SR MOSFET switch-off, the drain voltage increases. For a drain voltage aboveVswoff, a low ohmic gate pull-down of Rpd(G) keeps the gate of the SR MOSFET SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20177 / 18aaa-0186150V0V0 AVthresholdSRswitchlowcurrenthighcurrent secondarycurrentdrainsense-sourcesensevo ltagegatedriverVact(drv)td(act)(drv)Vreg (drv)Figure 4.

7 Synchronous rectification driver (GDA and GDB pins)The gate driver circuit charges the gate of the external SR MOSFET during the rising partof the current. The driver circuit discharges the gate during the falling part of the gate driver has a source capability of typically Isource and a sink capability of typicallyIsink. The source and sink capability allow a fast turn-on and a fast turn-off of the externalSR maximum driver output voltage is limited to VG(max). This high output voltage drivesall MOSFET brands to the minimum on-state applications where the IC is supplied with 5 V, the maximum output voltage of thedriver is limited to 5 V. Logic level SR MOSFETs can be start-up conditions (VCC < Vstart) and UVLO, the driver output voltage is activelypulled SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20178 / sense connection (SSA and SSB pins)The IC is equipped with additional source sense pins (SSA and SSB).

8 These pins areused for the measurement of the SR MOSFET drain-to-source voltage. The sourcesense input must be connected as close as possible to the source pin of the external SRMOSFET. It minimizes errors caused by voltage difference on PCB tracks because ofparasitic inductance in combination with large dI/dt SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 20179 / 189 Limiting valuesTable 4. Limiting valuesIn accordance with the Absolute Maximum Rating System (IEC 60134).SymbolParameterConditionsMinMaxUn itVoltagesVCCsupply voltage +38 VVsense(D)Adrain sense voltage ADC +100 VVsense(D)Bdrain sense voltage BDC +100 VVsense(S)Asource sense voltage ADC + (S)Bsource sense voltage BDC + on pin GDADC[1] + on pin GDBDC[1] + power frequencyif not limited by Ptot-500kHzTstgstorage temperature 55+150 CTjjunction temperature 40+150 CElectroStatic Discharge (ESD)VESD electrostatic dischargevoltageHuman Body Model (HBM)[2]-2000 VCharged Device Model(CDM)[3]-500V[1][1] These pins are output pins that are forced by the IC (see Table 6)[2][2] Human body model: Equivalent to discharging a 100 pF capacitor through a k series resistor.

9 [3][3] Charged device model: Equivalent to charging the IC and discharging each pin over a 1 Thermal characteristicsTable 5. Thermal characteristicsSymbolParameterConditions TypUnitRth(j-a)thermal resistance fromjunction to ambientJEDEC test board140K/WRth(j-c)thermal resistance fromjunction to caseJEDEC test board90K/WNXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 201710 / 1811 CharacteristicsTable 6. CharacteristicsTamb = 25 C; VCC = 12 V; CGDA/CGDB = 10 nF (capacitors between GDA and GND and between GDB and GND). Allvoltages are measured with respect to ground (pin 2). Currents are positive when flowing into the IC, unless voltage management (pin VCC)Vstartstart AICC(oper)operating supply currentnormal operation (without gatecharge) (es)energy save mode activation time85110135 sSynchronous rectification sense input (pins DSA, SSA, DSB, and SSB)Vact(drv)driver activation voltageVsense(S)A/Vsense(S)B = 0 V 450 400 350mVVreg(drv)driver regulation voltageVsense(S)A/Vsense(S)B = 0 V 60 55 50mVVswoffswitch-off voltageVsense(S)A/Vsense(S)B = 0 V90150200mVtd(act)(drv)driver activation delay timeVsense(S)A/Vsense(S)B = 0 V;normal operation;time from step on VDSA/VDSB (2 V to V) to rising of VGDA/VGDB at 10 %of end value-80-nstd(deact)(drv)driver deactivation delay timeVsense(S)A/Vsense(S)B = 0 V;normal operation;time from step on VDSA/VDSB ( Vto 2 V) to falling of VGDA/VGDB at 90 %of begin value-40-nsGate driver (pins GDA and GDB)peak current atVCC = 5 V;VDS = V; VG = 0 V- currentpeak current atVCC = 12 V;VDS = V.

10 VG = 0 V- current atVCC = 5 V;VDS = 0 V; VG = 5 V-90-mAregulation current atVCC = 12 V;VDS = 0 V; VG = 10 V-100-mApeak current at VCC = 5 V;VDS = 4 V;VG = 4 currentpeak current at VCC = 12 V;VDS = 4 V;VG = 4 (G)gate pull-down resistancein off-state; VDSA/VDSB = 4 V; IGDA/IGDB = 30 mA; VCC = 12 NXP SemiconductorsTEA1995 TGreenChip dual synchronous rectifier controllerTEA1995 TAll information provided in this document is subject to legal disclaimers. NXP 2017. All rights data sheetRev. 3 5 December 201711 / 18 SymbolParameterConditionsMinTypMaxUnitVG DA/VGDB at VCC = 5 at VCC = 12 (max)maximum gate voltageVGDA/VGDB at VCC = 15 V to 38 V111213V12 Application informationA resonant switched mode power supply with the TEA1995T consists of a primary sidehalf-bridge, a transformer, a resonant capacitor, and an output stage. To obtain lowconduction loss rectification, SR MOSFETs are used in the output stage. The TEA1995 Tcontrols these SR gate drive voltage for the SR switch is derived from the voltage difference betweenthe corresponding drain sense and source sense attention must be paid to the connection of the drain sense and source sensepins.