A Product Line of Diodes Incorporated AP31261 GREEN MODE PWM CONTROLLER Description Pin Assignments NEW PRODUCT The AP31261 is a current mode PWM controller which is optimized for high performance, low standby power and cost effective offline flyback converters. (Top View) The PWM switching frequency at normal operation is internally fixed (about 65kHz). In middle load, the IC will enter green mode to improve system efficiency with the help of frequency foldback. A minimum switching frequency (about 20kHz) is set to avoid the audible noise. In no load or light load, the IC will enter the burst mode to minimize standby power. Furthermore, the frequency dithering function is built-in to reduce EMI emission. Pin 1 Mark Internal slope compensation allows more stable Peak-Current Mode control over wide range of input voltage and load conditions. Internal line compensation ensures constant output power limit over entire universal line voltage range. Comprehensive protection features are included, such as cycle-bycycle current limit (OCP), VCC Over Voltage Protection (VOVP), internal OTP, Over Load Protection (OLP) and pins’ fault protection. GND 1 6 GATE FB 2 5 VCC CTRL 3 4 SENSE SOT26 Features Very Low Start-up Current Current Mode Control Non-audible-noise Green-mode Control Internal Slope Compensation Soft Start During Startup Process Frequency Fold Back for High Average Efficiency Secondary Winding Short Protection with FOCP Soft Switching for Reducing EMI VCC Maintain Mode Useful Pin Fault Protection: SENSE Pin Floating CTRL Pin Short to Ground FB/Opto-coupler Open/Short Comprehensive System Protection Feature: VCC Over Voltage Protection (VOVP) Over Load Protection (OLP) Mini Size Package of SOT26 Pin to Pin Compatible with AP3125A/V/R/L Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Notes: Applications Switching AC-DC Adapter/Charger ATX/BTX Auxiliary Power Set-top Box (STB) Power Supply Open Frame Switching Power Supply 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. AP31261 Document number: DS37514 Rev. 2 - 2 1 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Typical Applications Circuit L2 + T1 C6 R6 R4 C2 C5 R13 C7 C8 ~ - R5 ~ NEW PRODUCT R19 C4 R14 C3 NTC R2 U1 R8 R3 VCC GATE R10 C1 R9 CTRL AP31261 F1 VR1 R7 R15 SENSE C10 C11 R11 R16 R12 AZ431 R17 C9 FB NTC GND R18 ~ Pin Descriptions Pin Number Pin Name 1 GND 2 FB 3 CTRL 4 SENSE 5 VCC Supply voltage of driver and control circuits 6 GATE Gate driver output AP31261 Document number: DS37514 Rev. 2 - 2 Function Signal ground. Current return for driver and control circuits Feedback. Directly connected to the opto-coupler Latch trigger if this pin voltage drops below a threshold or over another threshold, leave CTRL pin open if this function is not needed. Connecting a NTC thermistor to GND can achieve OTP protection Current Sense 2 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Functional Block Diagram VCC 16V 7.6V 5 NEW PRODUCT 32V FB VDD Auto Recovery Protection VCC_OVP OLP FOCP CTRL_H OTP VCC_OVP VCC Latch-off Protection CTRL_L 28V Soft Start 2 Internal Bias UVLO 6 13V Driver GATE VDD SS D OSC with Frequency Jitter DFF Q CLK RB 0.3V 2R GND 1.3V 90ms OLP Debounce 1 VDD 250ns LEB R SS CTRL_H 3V 3 CTRL 10k PWM 1.80V 4 100mA CTRL_L FOCP 1V 0.6V 4.5V SENSE 0.95V Line Compensation AP31261 Document number: DS37514 Rev. 2 - 2 OCP OTP o o +150 C /+125 C 3 of 13 www.diodes.com AP31261 May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Absolute Maximum Ratings (Note 4) Symbol Parameter VCC IO NEW PRODUCT VFB, VSENSE, VCTRL Rating Unit Power Supply Voltage 30 V Gate Output Current 350 mA -0.3 to 7 V Input Voltage to FB, SENSE, CTRL θJA Thermal Resistance (Junction to Ambient) 250 °C/W PD Power Dissipation at TA < +25°C 500 mW TJ Operating Junction Temperature -40 to +150 °C Storage Temperature Range +150 °C – ESD (Human Body Model) 3000 V – ESD (Machine Model) 300 V TSTG 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 Parameter Supply Voltage AP31261 Document number: DS37514 Rev. 2 - 2 4 of 13 www.diodes.com Min Max Unit 10 25 V May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Electrical Characteristics (@TA = +25°C, VCC = 16V, unless otherwise specified.) Symbol Parameter Conditions Min Typ Max Unit – 1 10 μA VFB=0V, CL=1nF 0.5 0.7 1 VFB=3V, CL=0nF 0.6 1.2 2.0 Supply Voltage (VCC Pin) ISTARTUP NEW PRODUCT ICC – Startup Current Operating Supply Current mA – UVLO (on) – 14.5 15.8 16.5 V – VCC Maintain – 8.6 9.1 9.6 V – UVLO (off) – 7.1 7.6 8.1 V – VCC OVP – 27 28.5 30 V – VCC Clamp ICC=5mA 31 34 – V PWM Section/Oscillator Section – Maximum Duty Cycle – 70 75 80 % – Oscillation Frequency – 60 65 70 kHz – Green Mode Frequency – 20 – 30 kHz – Frequency Temperature Stability -20°C to +125°C (Note 5) – – 5 % – Frequency Voltage Stability VCC=12V to 30V – – 3 % Frequency Dithering – ±4 ±6 ±8 % Maximum SENSE Voltage VFB=4.5V 0.9 0.95 1 V – FOCP Voltage – 1.5 1.7 1.9 V – SENSE Shorted Protection Threshold(Note 5) – – 50 – mV – LEB Time of SENSE – 150 250 350 ns – Delay to Output (Note 5) – – 100 – ns – Soft-start Time – 3 5 8 ms – 2.5 3 3.5 V/V 12 15 18 kΩ -0.2 -0.27 -0.34 mA – Current Sense Section (SENSE Pin) VCS Feedback Input Section (FB Pin) The Ratio of Input Voltage to – Current Sense Voltage – Input Impedance – – Source Current VFB=0V – Green Mode Threshold – – 2.1 – V – Input Voltage for Zero Duty – 1.3 1.55 1.8 V – Output Low Level IO=20mA, VCC=12V – – 1 V – Output High Level IO=20mA, VCC=12V 8 – – V – Output Clamping Voltage – 11 13 15 V – Rising Time CL=1nF, VCC=13V – 150 250 ns – Falling Time CL=1nF, VCC=13V – 50 100 ns Output Section (GATE Pin) AP31261 Document number: DS37514 Rev. 2 - 2 5 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Electrical Characteristics Symbol (Cont.) (@TA = +25°C, VCC = 16V, unless otherwise specified.) Parameter Conditions Min Typ Max Unit NEW PRODUCT Protection Section (CTRL Pin) – Source Current – 90 100 110 μA – Internal Reference Voltage – – 1.9 – V – Low Threshold Trigger for Latch – 0.94 1 1.06 V – High Threshold Trigger for Latch – 2.85 3 3.15 V – Pull-up Current (Note 6) – – – 2 mA Delay of Short Circuit Protection Delay of Hiccup Protection (Note 5) – 70 90 110 ms VCC OVP – 6 – Cycles – OTP Enter (Note 5) – – +150 – °C – OTP Exit (Note 5) – – +125 – °C Delay Time Section – – Internal OTP Section Notes: 5. Guaranteed by design. 6. The sourcing current of CTRL pin must be limited below 5mA. Otherwise it may cause permanent damage to the device. AP31261 Document number: DS37514 Rev. 2 - 2 6 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Performance Characteristics 18 9.0 17 8.5 Shutdown Voltage (V) Startup Voltage (V) Shutdown Voltage vs. Ambient Temperature 16 15 14 8.0 7.5 7.0 13 -40 -20 0 20 40 60 80 100 120 6.5 -40 140 -20 0 o 20 40 60 80 100 120 140 o Ambient Temperature ( C) Ambient Temperature ( C) Startup Current vs. Ambient Temperature Operating Current vs. Ambient Temperature 2.0 0.9 1.8 VFB=3V, CL=0 1.6 Operating Current (mA) 0.8 Startup Current (mA) NEW PRODUCT Startup Voltage vs. Ambient Temperature 1.4 1.2 1.0 0.8 0.6 0.4 0.7 0.6 0.2 0.0 -40 -20 0 20 40 60 80 100 120 0.5 -40 140 o -20 0 20 40 60 80 100 120 140 o Ambient Temperature ( C) Ambient Tempture ( C) CTRL Utilization for Latch VCC VCC CTRL CTRL NTC OVP and OTP AP31261 Document number: DS37514 Rev. 2 - 2 VCC NTC CTRL NTC OVP 7 of 13 www.diodes.com OTP May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Operation Description The AP31261 is specifically designed for off-line AC-DC power supply used in LCD monitor, notebook adapter and battery charger applications. It offers a cost effective solution with a versatile protection function. Start-up Current and UVLO NEW PRODUCT The start-up current of AP31261 is optimized to realize ultra low current (1mA typical) so that VCC capacitor can be charged more quickly. The direct benefit of low start-up current is the availability of using large start-up resistor, which minimizes the resistor power loss for high voltage AC input. An UVLO comparator is included in AP31261 to detect the voltage on VCC pin. It ensures that AP31261 can draw adequate energy from hold-up capacitor during power-on. The turn-on threshold is 16V and the turn-off threshold is 7.6V. Current Sense Comparator and PWM Latch The AP31261 operates as a current mode controller, the output switch conduction is initiated by every oscillator cycle and is terminated when the peak inductor current reaches the threshold level established by the FB pin. The inductor current signal is converted to a voltage signal by inserting a reference sense resistor RS. The inductor current under normal operating conditions is controlled by the voltage at FB pin. The relation between peak inductor current (IPK) and VFB is: I PK (VFB 0.8) / 3RS Moreover, FOCP with 1.8V threshold is only about 100ns delay, which can avoid some catastrophic damages such as secondary rectifier short test. Few drive cycles can alleviate the destruction range and get better protection. Leading-edge Blanking A narrow spike on the leading edge of the current waveform can usually be observed when the power MOSFET is turned on. A 250ns leadingedge blank is built-in to prevent the false-triggering caused by the turn-on spike. During this period, the current limit comparator is disabled and the gate driver can not be switched off. At the time of turning off the MOSFET, a negative undershoot (maybe larger than -0.3V) can occur on the SENSE pin. So it is strongly recommended to add a small RC filter or at least connect a resistor “R” on this pin to protect the IC (Shown as Figure 1). 5 VCC 3 CTRL GATE 6 AP31261 1 GND Necessary R SENSE 4 FB 2 C Large undershoot (more than -0.3V) may damage the SENSE pin Figure 1 Built-in Slope Compensation It is well known that a continuous current mode SMPS may become unstable when the duty cycle exceeds 50%. The built-in slope compensation can improve the stability, so there is no need for design engineer to spend much time on that. FB Pin and Short Circuit Protection This pin is normally connected to the opto-coupler and always paralleled with a capacitor for loop compensation. When the voltage at this pin is greater than 4.5V and lasts for about 90ms, the IC will enter the protection mode. For AP31261, the system will enter hiccup mode to wait the V CC decreasing to low UVLO level, then the IC will try to restart until the failure removed. And when this voltage is less than 1.55V, the IC will stop the drive pulse immediately. Therefore, this feature can be used for short circuit protection, which makes the system immune from damage. Normally, output short makes the VFB value to the maximum because the opto-coupler is cut off. AP31261 Document number: DS37514 Rev. 2 - 2 8 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Operation Description (Cont.) VCC Maintain Mode NEW PRODUCT During light load or step load, VFB will drop and be lower than 1.55V, thus the PWM drive signal will be stopped, and there is no more new energy transferred due to no switching. Therefore, the IC supply voltage may reduce to the shutdown threshold voltage and system may enter the unexpected restart mode. To avoid this, the AP31261 holds a so-called VCC maintain mode which can supply energy to VCC. When VCC decreases to a setting threshold, the VCC maintain comparator will output some drive signal to make the system switch and provide a proper energy to VCC pin. The VCC maintain function will cooperate with the PWM and burst mode loop which can make the output voltage variation be within the regulation. This mode is very useful for reducing startup resistor loss and achieving a better standby performance with a low value VCC capacitor. The VCC is not easy to touch the shutdown threshold during the startup process and step load. This will also simplify the system design. The minimum VCC voltage is suggested to be designed a little higher than V CC maintain threshold thus can achieve the best balance between the standby and step load performance. System Protection and Pin Fault Protection The AP31261 provides versatile system and pin fault protections. The OCP comparator realizes the cycle-by-cycle current limiting (OCP). In universal input line voltage, the IC realizes the constant over load protection (OLP). VCC over voltage protection can be applied as the primary OVP or opto-coupler broken protection. The AP31261 also has pin fault connection protection including floating and short connection. The floating pin protection includes the SENSE, FB, etc. The short pin protection includes the CTRL pin short protection. When these pins are floated or CTRL pin is shorted to ground, PWM switching will be disabled, thus protecting the power system. Latch Protection Function For some applications, the system requires the latch protection function. The CTRL pin has two kinds of modes to trigger the latch protection: high level trigger and low level trigger. The low threshold is 1V and high threshold voltage is 3V. Some version will have only one mode. Once the latch protection is triggered, the IC will disable the output signal, and the bulk capacitor provides the energy to IC through the startup resistor to ensure the IC disable the output (latch mode). This mode will be not released until the AC input is shut off. So, the de-latch time is mainly depending on the HV startup bulk capacitor value. Therefore, if the system wants a short de-latch time, it is better for the startup resistor take power from the point before the rectifier bridge as illustrated in Figure 2. Internal OTP Protection Function The AP31261 integrates an internal temperature sensor. It has a trigger window of +150°C enter and +125°C exit. The internal OTP protection mode is auto-recovery mode. AC Mains (90V to 265V) CBUS 5 3 VCC GATE CTRL 6 AP31261 2 FB SENSE 4 GND 1 Figure 2 AP31261 Document number: DS37514 Rev. 2 - 2 9 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Ordering Information AP31261 X XX - XX NEW PRODUCT Product Name Package Package Packing RoHS/Green K : SOT26 TR : Tape & Reel G1 : Green Part Number SOT26 AP31261KTR-G1 Marking ID Packing GPE 3000/Tape & Reel Protection Functions Product Name Frequency VOVP OLP & SOCP CTRL (Low) CTRL (High) AP31261 65kHz Latch Auto-Recoverable Latch Latch Marking Information (Top View) : Logo XXX: Marking ID (See Ordering Information) AP31261 Document number: DS37514 Rev. 2 - 2 10 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Package Outline Dimensions (All dimensions in mm(inch).) (1) Package Type: SOT26 0° 2.820(0.111) 8° 3.100(0.122) 2.650(0.104) 3.000(0.118) 6 0.200(0.008) 5 4 2 3 0.300(0.012) 0.600(0.024) 1.500(0.059) 1.700(0.067) NEW PRODUCT 0.300(0.012) 0.500(0.020) Pin 1 Mark 1 0.700(0.028)REF 0.950(0.037)TYP 0.000(0.000) 0.150(0.006) 1.800(0.071) 2.000(0.079) 0.100(0.004) 0.200(0.008) 0.900(0.035) 1.450(0.057) MAX 1.300(0.051) AP31261 Document number: DS37514 Rev. 2 - 2 11 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 Suggested Pad Layout (1) Package Type: SOT26 NEW PRODUCT E E Y G Z X Dimensions Z (mm)/(inch) G (mm)/(inch) X (mm)/(inch) Y (mm)/(inch) E (mm)/(inch) Value 3.600/0.142 1.600/0.063 0.700/0.028 1.000/0.039 0.950/0.037 AP31261 Document number: DS37514 Rev. 2 - 2 12 of 13 www.diodes.com May 2015 © Diodes Incorporated A Product Line of Diodes Incorporated AP31261 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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