JW7726CSOTB#TRPBF

JW7726C Synchronous Rectifier Controller Preliminary Specifications Subject to Change without Notice DESCRIPTION FEATURES JW ®7726C is a synchronous rectifier controller, used for the secondary side rectification of isolation topologies, such as Active Clamp Flyback and CCM/QR/DCM Flyback. By driving an external MOSFET, JW7726C is able to significantly improve the efficiency comparing with the conventional Diode rectifier.  When JW7726C senses Vds of MOSFET less than -140mV, it turns on the MOSFET. Once the Vds is greater than -3mV, JW7726C turns off the MOSFET. JW7726C supports multiple operation modes, such as DCM, CrCM, CCM and Quasi-Resonant. By implementing the Joulwatt proprietary technology, JW7726C is able to handle CCM operation.      Supports Active Clamp Flyback, DCM, Quasi-Resonant, and CCM Flyback Support High-side and Low-side Rectification Output Voltage Directly Supply VCC Low Quiescent Current Fast Driver Capability for CCM Operation SOT23-6 Package APPLICATIONS    Active clamp Flyback and Flyback converters Adaptor LCD and PDP TV JW7726C is available in SOT23-6 package. Company’s Logo is Protected, “JW” and “JOULWATT” are Registered Trademarks of JoulWatt technology Inc. TYPICAL APPLICATION Vo Co Vin Ro Cin GT VO SW VCC VT GND JW7726C Figure A: JW7726C Typical Application for low-side. JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 1 JW7726C JoulWatt Vo Vin Cin GT SW GND VT VCC VO Ro JW7726C Figure B: JW7726C Typical Application for high-side. JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 2 JW7726C JoulWatt ORDER INFORMATION DEVICE1) PACKAGE JW7726CSOTB#TRPBF SOT23-6 TOP MARKING2) JWFJ□ YW□□□ Notes： JW # TRPBF PB Free Tape and Reel(If”TR”is not shown, it means tube) Package Code Part No. 1) JW 2) Line1: Internal control code Product code Joulwatt LOGO YW Lot number Week code Year code Line2: PIN CONFIGURATION TOP VIEW 1 6 VO GND 2 5 SW GATE 3 4 VT VCC JW7726C ABSOLUTE MAXIMUM RATING1） SW PIN .......................................................................................................................................-1 to 140V VO PIN .......................................................................................................................................-0.3 to 28V VCC, GT PIN...............................................................................................................................-0.3 to 10V VT PIN......... ....... ........................................................................................................................-0.3 to 7V Continuous Power Dissipation(TA=+25℃)2) SOT23-6…....…..............................................................0.6W Junction Temperature 3).......................................................................................................................150ºC Lead Temperature …..........................................................................................................................260ºC Storage Temperature….........................................................................................................-65ºC to150ºC ESD Susceptibility (Human Body Model) ............................................................................................. 2kV JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 3 JW7726C JoulWatt RECOMMENDED OPERATING CONDITIONS4） SW Pin....................................................................................................................................4.7V to 120V VO Pin......................................................................................................................................4.7V to 25V VCC, GT PIN..............................................................................................................................4V to 8.5V Operation Junction Temperature ........................................................................................ -40ºC to 125ºC THERMAL PERFORMANCE5） θJA θJc SOT23-6..............................................................................................................................200 ...130ºC/W Note： 1) 2) 3) 4) 5) Exceeding these ratings may damage the device. These stress ratings do not imply function operation of the device at any other conditions beyond indicated under RECOMMENDED OPERATING CONDITIONS. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD(MAX) =(TJ(MAX)-TA)/ θJA. Continuous operation over the specified absolute maximum operating junction may damage the device. The device is not guaranteed to function outside of its operating conditions. Measured on JESD51-7, 4-layer PCB. JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 4 JW7726C JoulWatt ELECTRICAL CHARACTERISTICS TA = 25ºC, unless otherwise stated Item Symbol Condition Min. Typ. Max. Units 7.5 8 8.5 V VCC Section VCC Voltage VCC SW=40V, VCC=2.2uF VCC Startup voltage VCC_Startup 4.35 4.5 4.65 V VCC UVLO VCC_UVLO 3.8 3.95 4.1 V Operation Current (GT On) Quiescent Current IVCC GT=5nF,VCC=2.2uF 0.9 mA Iq VCC=6V, VCC=2.2uF 110 uA Gate Section Gate Turn on Threshold VMOS_ON -140 mV Gate Turn off Threshold VMOS_OFF -10 mV Gate Turn off Threshold in MOT VGTOFF_MOT 0.95 1 1.05 V VCC-1 VCC V Gate Turn on Voltage VGT SW=32V, VCC=2.2uF Maximum Gate Pull up current IGU 6) 0.6 A Maximum Gate Pull down current IGD 6) 4 A Gate Minimum on Time TMIN_ON 575 ns Absolutely Minimum off Time TMIN_OFF 365 nS Turn-on total delay TDON CLOAD=4.7nF 6) 50 nS Turn-off total delay TDOF CLOAD=4.7nF 6) 20 nS 75 85 mA VMOS_REG -50 -40 -20 mV VMOS_REG_MAX -185 -160 -145 mV SW and VO Section VCC Charge Current SW Regulation Voltage SW Control Voltage MAX ISW_CHG SW=40V, VCC=6V VO Enable Charge Voltage VO_EN VCC=4V, SW=0V, rising 4.5 4.6 4.7 V VO Disable Charge Voltage VO_DIS VCC=4V, SW=0V, falling 4.4 4.5 4.6 V VO Charge Current IVO_CHG 33 40 SW=0V, VCC=6V， mA VO=12V Note： 6) Guaranteed by design. JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 5 JW7726C JoulWatt PIN DESCRIPTION PIN Name 3 GT 2 GND Ground. 1 VCC Power supply. Bypass a Capacitor Between VCC and GND. 4 VT Set the voltage-second product. 6 VO Output Voltage Sensing and Charging to VCC. 5 SW External Power MOSFET Drain Voltage Sensing. Charging to VCC. Description Drive the External NMOSFET. BLOCK DIAGRAM VO LDO Voltage Detection UVLO & Regulator SW LDO GND Voltage Detection & Regulation Minimum off Time Control Logic Driver VCC GT Voltage-second Product Set VT JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 6 JW7726C JoulWatt FUNCTIONAL DESCRIPTION Operation Turn On Phase JW7726C is a synchronous rectifier controller which combined with external MOSFET can replace the Schottky Barrier Diode. It supports all operations, such as DCM, CrCM, (Quasi-Resonant) and CCM when adopted in Active Clamp Flyback and Flyback converter. There are two conditions for the JW7726C to turn on the SR, i.e. Vsw, voltage-second value on SW pin when primary side switch is on, and the turn on phase is shown in Fig. 1. Startup During the startup period, when the VCC is charged up by the two internal LDOs connected to SW and VO pin respectively. When VO is lower than 4.5V (falling), JW7726C can power itself through the internal LDO connected to SW pin during the SR turn-off period, which means primary the primary side MOSFET is turned on and SW presents a positive voltage. A capacitor between VCC and GND is required to store the energy and supply to IC during the SR turn-on period. When VO is above 4.6V (rising), the VO pin charges VCC pin. . Once the VCC voltage exceeds VCC_Startup, the JW7726C exits the UVLO. If VCC is lower than VCC_UVLO, the external MOSFET is turned off. The current flows though body diode before the VCC reaches to the startup voltage Vcc_startup. 1) Vsw: when the synchronous MOEFET is conducting, current flows through the body diode of MOSFET, which generates a negative voltage VSW across it. When VSW is lower than VMOS_ON, the part will pull the gate high to turn on the synchronous MOSFET after turn on delay time TDON if the other condition is met. 2) Volt-second of SW: in DCM and QR operation, there are parasitic oscillations. In some applications, the drain resonant voltage may fall below the SR turn on threshold, especially for the first couple rings. SR could be falsely turned on, which may cause shoot through issue and result in high power loss. The volt-second value of SW pin can be used to distinguish the parasitic ring from normal primary side switch on. The threshold can be set by the resistance at VT pin. The curve is shown in Fig. 2. ISR VDS Tonp S1=(Vds-VO)*Tonp Under-Voltage Lockout (UVLO) VO 1V When the VCC is below UVLO threshold, the external MOSFET is turned off and pulled low internally. Once the VCC exceeds the startup voltage Vcc_startup, the parts is activated again. -3mV -40mV -140mV TDOFF_PRO VGT 2V~3V 1V t0 t1 t2 TDON t4 t6 t8 TDOFF Figure-1 Turn on delay and turn off delay JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 7 JW7726C JoulWatt iS VSW -3mV -40mV Fig. 2 Volt-second value vs. VT resistance VGT VGTH Minimum On Time (MOT) Minimum on time When the synchronous MOSFET is turn on, Figure. 3 Conducting phase for DCM mode there is a minimum on time for the SR. The VSW voltage may have a parasitic ring when the synchronous MOSFET turns on. So, a minimum on time (MOT) is very important to avoid the iS MOSFET turn off threshold is false triggered. VSW Minimum on time is 575ns for high frequency -10mV applications. During the minimum time, the gate -40mV can still be turned off if VSW touches a positive threshold value, +1V. VGT Conducting Phase VGTH Minimum on time When the synchronous MOSFET is turned on, the drain source voltage VSW it is determined Figure. 4 Conducting phase for CCM mode by its on resistance and the current through it. The VSW rises when the current follow through the MOSFET decreases. The gate voltage will be decreased to increase its on resistance and regulate the VSW around -40mV. The part adjusts the gate voltage and regulates the VSW to the internal threshold (typical -40mV) after the synchronous MOSFET turn on. When the VSW is lower than -40mV, the gate keeps its maximum voltage. MOSFET is fully on. JW7726C Rev.0.21 And the synchronous Figure. 3 and Figure. 4 show the theoretical waveforms when a conventional Flyback converter operated in DCM mode and CCM mode respectively. JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 8 JW7726C JoulWatt For Active Clamp Flyback converter, the SR It should be noted that the typical regulation current is a kind of resonant current, like threshold (-40mV) during MOSFET on time is sinusoidal, as shown in Fig.5. The current at the not fixed, it can be internally changed to ensure beginning is small, and then it rises to its the proper operation under CCM mode. maximum value and then decreases to zero. It Turn Off Phase is similar to the LLC resonant converter. So, after the gate voltage is pulled up during the first After synchronous MOSFET conducting, once 365ns, it will decrease to a small value because the voltage VSW touches the MOSFET turn off of small current, when the current increases, the threshold (-3mV), the gate is pulled to low after gate voltage should increase too, which means a turn off delay time TDOFF. A 365nS blanking the pull up current source should always be time is necessary to avoid error trigger. The enabled during the whole SR conduction period. banking time is reset once VSW rises above The pull up current can be reduced in normal 2.5V. operation. Due to limited regulation bandwidth, Output Voltage Detection the gate voltage change may not be able to keep up with the current variation. The VSW may below -40mV regulation threshold. In this case, if the VSW reaches twice the regulation threshold (such as -80mV), the gate can be pulled up with small current source. For conventional Flyback converter, since the The JW7726C has output voltage detection function via VO pin. VCC is charged from VO pin when VO is higher than 4.6V to save power loss caused by the LDO when charging from SW pin to VCC pin. When VO drops below 4.5V, the JW7726C is powered from SW pin. current always decreases, usually the pull up current source can be disabled after the firstly 365ns. iS VDS VO 1V -3mV -40mV -40mV-40mV -140mV VGT TDOFF_PRO 2V~3V 1V t0 t3 t4 t1 t2 T_MIN_ON t5 t6 t8 TDOFF Figure.5 Conducting phase for ACF JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 9 JW7726C JoulWatt PACKAGE OUTLINE SOT23-6 UNIT: mm D MILLIMETER SYMBOL A2 A MIN NOM MAX A 1.05 1.15 1.25 A1 0 0.05 0.15 A2 0.95 1.10 1.20 b 0.20 0.40 0.60 0.21 θ c L A1 E1 E c 0.05 — D 2.72 2.92 3.12 E 2.60 2.80 3.00 E1 1.40 1.60 1.80 e b JW7726C Rev.0.21 0.95（BSC) L 0.30 0.45 0.60 θ 0° — 8° e JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 10 JW7726C JoulWatt IMPORTANT NOTICE  Joulwatt Technology Inc. reserves the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein.  Any unauthorized redistribution or copy of this document for any purpose is strictly forbidden.  Joulwatt Technology Inc. does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Copyright © 2019 JW7726C Incorporated. All rights are reserved by Joulwatt Technology Inc. JW7726C Rev.0.21 JoulWatt® Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. 11