A Product Line of Diodes Incorporated APR343 SECONDARY SIDE SYNCHRONOUS RECTIFICATION CONTROLLER Description Pin Assignments NEW PRODUCT APR343 is a secondary side MOSFET driver for synchronous rectification in DCM operation, which integrates the output voltage detection function for primary side control system. (Top View) The synchronous rectification can effectively reduce the secondary side rectifier power dissipation and provide high performance solution. By sensing MOSFET drain-to-source voltage, APR343 can output ideal drive signal with less external components. It can provide high performance solution for 5V output voltage application. Same as AP4341, APR343 detects the output voltage and provides a periodical signal when the output voltage is lower than a certain threshold. By fast response to secondary side voltage, APR343 can effectively improve the transient performance of primary side control system. DRISR 1 GND 2 VCC 3 5 VDET 4 AREF SOT25 The APR343 is available in SOT25 package. Applications Features Synchronous Rectification for DCM Operation Flyback Eliminate Resonant Ring Interference Fast Detector of Supply Voltage Fewest External Components Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Notes: Adapters/Chargers for Cell/Cordless Phones, ADSL Modems, MP3 and Other Portable Apparatus Standby and Auxiliary Power Supplies 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. Typical Applications Circuit T1 C20 + Q2 C22 R21 5 1 VDET DRISR 3 APR343 AREF GND 4 2 R22 VCC C21 R20 APR343 Document number: DS36884 Rev. 4 - 2 1 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 NEW PRODUCT Pin Descriptions Pin Number Pin Name Function 1 DRISR 2 GND Ground 3 VCC Power supply, connected with system output 4 AREF Program a voltage reference with a resistor from AREF to GND, to enable synchronous rectification MOSFET drive signal 5 VDET Synchronous rectification sense input and dynamic function output, connected with secondary winding Synchronous rectification MOSFET Gate drive Functional Block Diagram VCC 3 VREF VDET Integrator ( VDET -VCC )* tONP IOVP Dynamic OVP IAREF Counter tONPDET AREF DRISR 4 1 OSC SRDRIVER 2 GND 5 VDET APR343 Document number: DS36884 Rev. 4 - 2 2 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Absolute Maximum Ratings (Note 4) Symbol Rating Unit -0.3 to 7.5 V VCC Supply Voltage VDET Voltage at VDET Pin -2 to 50 V Voltage at AREF, DRISR Pin -0.3 to 6 V Internally limited A VAREF, VDRISR – NEW PRODUCT Parameter Output Current at VDET PD Power Dissipation at TA = +25ºC 0.6 W TJ Operating Junction Temperature +150 ºC -65 to +150 ºC Lead Temperature (Soldering, 10 sec) +300 ºC θJA Thermal Resistance (Junction to Ambient) 197 ºC/W θJC Thermal Resistance (Junction to Case) 76 ºC/W TSTG – Storage Temperature Note 4: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability. Recommended Operating Conditions Symbol VCC TA Parameter Supply Voltage Ambient Temperature APR343 Document number: DS36884 Rev. 4 - 2 3 of 12 www.diodes.com Min Max Unit 0 6 V -40 +85 ºC December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Electrical Characteristics Symbol (@VCC = 5V, TA = +25C, unless otherwise specified.) Parameters Conditions Min Typ Max Unit Supply Voltage ( VCC Pin ) ISTARTUP NEW PRODUCT IOP VSTARTUP – Startup Current VCC = VSTARTUP-0.1V – 100 150 µA Operating Current VDET pin floating VCC = VTRIGGER+20mV 40 100 150 µA Startup Voltage – 2.6 3.1 3.4 V UVLO – 2.3 2.8 3.1 V Internal Trigger Voltage – 5.25 5.3 5.35 V Duty Cycle – 4 8 12 % Oscillation Period VCC = 5V 18 30 37.5 µs Dynamic Output Section/Oscillator Section VTRIGGER – tOSC VCC = VTRIGGER, VCC/VDET pin Internal Trigger Current is separately connected to a 20Ω resistor 30 – 42 mA tDIS Minimum Period – 18 30 37.5 ms VDIS Discharge Voltage – 5.28 5.44 5.52 V IDIS Discharge Current VCC = VDIS+0.1V 1.5 3 4.5 mA Trigger Discharger Gap – 30 110 – mV VOVP Overshoot Voltage for Discharge – 5.8 5.9 6.0 V IOVP Overshoot Current for Discharge 40 – 100 mA ITRIGGER VDIS-VTRIGGER VCC = VOVP+0.1V, VCC pin is connected to a 20Ω resistor Synchronous Rectification Detection and Drive VTHON Gate Turn On Threshold – 0 – 1 V VTHOFF Gate Turn Off Threshold – -20 -12.5 -5 mV tDON Turn On Delay Time From VTHON to VDRISR = 1V – 70 130 ns tDOFF Turn Off Propagation Delay Time From VTHOFF to VDRISR = 3V – 100 150 ns tRG Turn On Rising Time From 1V to 3V, CL = 4.7nF – 50 100 ns tFG Turn Off Falling Time From 3V to 1V, CL = 4.7nF – 50 100 ns (VDET-VCC)*tONP = 25Vµs 0.9 1.8 2.7 (VDET-VCC)*tONP = 50Vµs – – 6.5 3.7 – – V tLEB_S Minimum On Time tLEB_L VDRISR_HIGH VS_MIN tOVP_LAST Kqs Notes: µs Drive Output Voltage VCC = 5V Synchronous Rectification (SR) Minimum Operating Voltage (Note 5) – – – 4.5 V Added OVP Discharge Time – – 2.0 – ms (Note 6) (VDET-VCC)*tONP = 25Vµs 0.325 – 0.625 mA*µs 5. This item specifies the minimum SR operating voltage of VIN_DC, VIN_DC≥NPS*VS_MIN. 6. This item is used to specify the value of RAREF. APR343 Document number: DS36884 Rev. 4 - 2 4 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Performance Characteristics 3.50 3.5 3.25 3.0 3.00 2.5 UVLO (V) Startup Voltage (V) UVLO vs. Temperature 2.75 2.0 2.50 1.5 2.25 2.00 -40 -20 0 20 40 60 80 100 120 1.0 -40 140 -20 0 20 60 80 100 120 140 o Temperature ( C) Internal Trigger Voltage vs. Temperature Internal Trigger Current vs. Temperature 80 5.4 70 Internal Trigger Current (mA) 5.3 Internal Trigger Voltage (V) 40 Temperature ( C) o 5.2 5.1 5.0 4.9 4.8 60 50 40 30 20 10 4.7 -40 -20 0 20 40 60 80 100 120 0 -40 140 -20 0 20 40 60 80 100 120 140 o Temperature ( C) o Temperature ( C) Overshoot Voltage for Discharge vs. Temperature Overshoot Current for Discharge vs. Temperature 160 Overshoot Current for Discharge (mA) 6.0 Overshoot Voltage for Discharge (V) NEW PRODUCT Startup Voltage vs. Temperature 5.8 5.6 5.4 5.2 140 120 100 80 60 40 20 5.0 -40 -20 0 20 40 60 80 100 120 0 -40 140 Document number: DS36884 Rev. 4 - 2 0 20 40 60 80 100 120 140 Temperature ( C) Temperature ( C) APR343 -20 o o 5 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Performance Characteristics (Cont.) Gate Turn Off Threshold vs. Temperature Kqs (See Note 6) vs. Temperature 0.7 0 0.5 Kqs (mA*s) Gate Turn Off Threshold (mV) -10 -20 0.4 0.3 0.2 -30 0.1 -40 -40 -20 0 20 40 60 80 100 120 0.0 -40 140 o -20 0 20 40 60 80 100 120 140 o Temperature ( C) Temperature ( C) Operating Current vs. Temperature 140 120 Operating Current (A) NEW PRODUCT 0.6 100 80 60 40 20 0 -40 -20 0 20 40 60 80 100 120 140 o Temperature ( C) APR343 Document number: DS36884 Rev. 4 - 2 6 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Output Voltage Detection Function Description tOSC tDIS tDIS tDIS tDIS tDIS tDIS tOSC VDET VOVP VDIS VDIS NEW PRODUCT VTRIGGER VCC VTRIGGER VON UVLO IOVP IVCC VOFF tOVP_LAST IDIS Figure 1. Typical Waveforms 1 of APR343 When VCC is beyond power-on voltage (VON), the APR343 starts up. The VDET pin asserts a periodical pulse and the oscillation period is t OSC. When VCC is beyond the trigger voltage (VTRIGGER), the periodical pulse at VDET pin is discontinued. When V CC is beyond the discharge voltage (VDIS), the discharge circuit will be enabled, and a 3mA current (IDIS) will flow into VCC pin. When VCC is higher than the overshoot voltage (VOVP), the APR343 will enable a discharge circuit, the discharge current (IOVP) will last tOVP_LAST time. After the tOVP_LAST time, APR343 will stop the discharge current and detect VCC voltage again. If VCC is still higher than VOVP, the tOVP_LAST time discharge current will be enabled again. Once the OVP discharge current is asserted, the periodical pulse at VDET pin will be disabled. When the VCC is below the power-off voltage (VOFF), the APR343 will be shut down. MOSFET Driver Operation Description I,V VDET IS VTHON 0 t VTHOFF VDRISR 0.9VDRISR 0.9VDRISR 0.1VDRISR 0 tDON tRG tDOFF 0.1VDRISR t tFG Figure 2. Typical Waveforms 2 of APR343 APR343 Document number: DS36884 Rev. 4 - 2 7 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 MOSFET Driver Operation Description (Cont.) The operation of the SR is described with timing diagram shown in Figure 2. APR343 monitors the MOSFET drain-source voltage. When the drain voltage is lower than the turn-on threshold voltage VTHON, the IC outputs a positive drive voltage after a turn-on delay time (tDON). The MOSFET will turn on and the current will transfer from the body diode into the MOSFET’s channel. NEW PRODUCT In the process of drain current decreasing linearly toward zero, the drain-source voltage rises synchronically. When it rises over the turn off threshold voltage VTHOFF, APR343 pulls the drive signal down after a turn off delay (t DOFF). Minimum On Time When the controlled MOSFET gate is turned on, some ringing noise is generated. The minimum on-time timer blanks the VTHOFF comparator, keeping the controlled MOSFET on for at least the minimum on time. If VTHOFF falls below the threshold before minimum on time expires, the MOSFET will keep on until the end of the minimum on time. The minimum on time is in direct proportion to the (VDET-VCC)*tONP. When (VDET-VCC)*tONP=5V*5µs, the minimum on time is about 1.8µs. The Value and Meaning of AREF Resistor As to DCM operation Flyback converter, after secondary rectifier stops conduction the primary MOSFET Drain-to-source ringing waveform is resulted from the resonant of primary inductance and equivalent switch device output capacitance. This ringing waveform probably leads to Synchronous Rectifier error conduction. To avoid this fault happening, APR343 has a special function design by means of volt-second product detecting. From the sensed voltage of VDET pin to see, the volt-second product of voltage above VCC at primary switch on time is much higher than the volt-second product of each cycle ringing voltage above VCC. Therefore, before every time Synchronous Rectifier turning on, APR343 judges if the detected volt-second product of VDET voltage above VCC is higher than a threshold and then turn on synchronous Rectifier. The purpose of AREF resistor is to determine the volt-second product threshold. APR343 has a parameter, Kqs, which converts R AREF value to voltsecond product. Area2 R AREF * Kqs In general, Area1 and Area3 value depend on system design and always are fixed after system design frozen. As to BCD PSR design, the Area1 value changes with primary peak current value and Area3 value generally keeps constant at all of conditions. So the AREF resistor design should consider the worst case, the minimum primary peak current condition. Since of system design parameter distribution, Area1 and Area3 have moderate tolerance. So Area2 should be designed between the middle of Area1 and Area3 to keep enough design margin. Area3 R AREF * Kqs Area1 Area1=(VDET-VCC)*tONP Area3 VDET VCC Area2=Kqs*RAREF Figure 3. AREF Function SR Minimum Operating Voltage APR343 sets a minimum SR operating voltage by comparing the difference between VDET and output voltage (VCC). The value of VDET–VCC must be higher than its internal reference, then APR343 will begin to integrate the area of (VDET–VCC)*tONP. If not, the area integrating will not begin and the SR driver will be disabled. APR343 Document number: DS36884 Rev. 4 - 2 8 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Ordering Information APR343 X XX – XX NEW PRODUCT Product Name Package Temperature Range SOT25 -40C to +85C Package Packing RoHS/Green K : SOT25 TR : Tape & Reel G1 : Green Part Number APR343KTR-G1 Marking ID GHZ Packing 3000/Tape & Reel Marking Information (Top View) : Logo GHZ: Marking ID APR343 Document number: DS36884 Rev. 4 - 2 9 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Package Outline Dimensions (All dimensions in mm(inch).) (1) Package Type: SOT25 0.300(0.012) 0.600(0.024) 0.100(0.004) 0.200(0.008) 1.500(0.059) 1.700(0.067) 3.000(0.118) 2.650(0.104) NEW PRODUCT 2.820(0.111) 3.100(0.122) 0.200(0.008) 0.700(0.028) REF 0.300(0.012) 0.500(0.020) 0° 8° 1.800(0.071) 2.000(0.079) 0.000(0.000) MAX 1.450(0.057) 0.950(0.037) TYP 0.150(0.006) 0.900(0.035) 1.300(0.051) APR343 Document number: DS36884 Rev. 4 - 2 10 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 Suggested Pad Layout Package Type: SOT25 NEW PRODUCT (1) E2 G Z E1 Y X Dimensions Z (mm)/(inch) G (mm)/(inch) X (mm)/(inch) Y (mm)/(inch) E1 (mm)/(inch) E2 (mm)/(inch) Value 3.600/0.142 1.600/0.063 0.700/0.028 1.000/0.039 0.950/0.037 1.900/0.075 APR343 Document number: DS36884 Rev. 4 - 2 11 of 12 www.diodes.com December 2014 © Diodes Incorporated A Product Line of Diodes Incorporated APR343 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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