A Product Line of Diodes Incorporated AP3988 PRIMARY SIDE POWER SWITCHER FOR OFF-LINE SMPS NEW PRODUCT Description Pin Assignments The AP3988 is a performance enhanced power switcher for power supplies with better conversion efficiency, better voltage & current accuracy, and improved protection functions. Typical applications include charger, adapter for ADSL, home appliance power supply, LED lighting power supply and PC auxiliary power supplies. The controller regulates the output voltage and current in the primary side by piece-wise Pulse Frequency Modulation (p-PFM) in discontinuous conduction mode (DCM). The system operating frequency reduces linearly from heavy load to light load in each interval of the p-PFM, and enters constant current mode when the load current equals to the maximum system output current. (Top View) CPC 1 FB 2 VCC CS The AP3988 provides operating frequency dithering function to improve EMC performance of power supply. It also has built-in fixed cable voltage drop compensation (5% of nominal system output voltage) and adjustable line voltage compensation. 7 GND 3 6 C 4 5 C SO-7 The AP3988 solution has fewer component number, smaller size, and lower total cost. Applications The AP3988 is packaged in SO-7. Features Primary Side Control for Eliminating Secondary CV/CC Control Circuitry Built-in NPN Transistor with 700VCBO Low Start-up Current: 0.2A (Typ.) Internal Output Cable Voltage Drop Compensation Hiccup Function to Improve Short Circuit Protection Better Over Voltage Protection Better Over Temperature Protection Low Total Cost Solution Output Power Range (Note 1): for 5.5W Adapter Totally Lead-free & Fully RoHS Compliant (Note 2 & 3) Halogen and Antimony Free. “Green” Device (Note 4) Notes: Opto-coupler Adapters Set Top Boxes Appliances and 1. Typical continuous power in a non-ventilated enclosed adapter measured at +50°C ambient. 2. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 3. 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. 4. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. AP3988 Document number: DS36722 Rev. 4 - 2 1 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Typical Applications Circuit Rf1 D1 to D4 L1 C11 R11 NEW PRODUCT Vo+ J1 AC 90-264V + C1 + C2 C5 R6 Np D12 R10 + C12 R12 R3 D5 Vo- L2 D6 R5 T1 + C3 C8 Nfb U1 VCC C R8 CPC GND CS FB R9 R7 For AP3988 (5V/1A) Item Function QTY Item Function QTY C1,C2 4.7µF/400V, electrolytic 2 Rf1 10Ω/1W, fuse resistor 1 C3 4.7µF/50V, electrolytic 1 R3 3.3M/0.25W 1 C5 1nF/250V, ceramic 1 R5 3.9, 0805 1 C8 0.01µF, 0805 1 R6 150k, 1206 1 C11 1nF, 0805 1 R7 2.7, 1206 1 C12 680µF/10V 1 R8 75k, 0805 1 D1 to D6 1N4007, rectifier diode 6 R9 43k, 0805 1 D12 APD340,Schottky diode 1 R10 200, 0805 1 L1 1mH, inductor 1 R11 27, 0805 1 L2 Bead, 0805 1 R12 1.5k, 0805 1 U1 AP3988, SO-7 1 T1 EE13 core, PC40, transformer 1 AP3988 Document number: DS36722 Rev. 4 - 2 2 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 NEW PRODUCT Pin Descriptions Pin Number Pin Name 1 CPC 2 FB 3 VCC 4 CS 5, 6 C 7 GND Function This pin connects a capacitor to GND for output cable compensation The voltage feedback from auxiliary winding This pin receives rectified voltage from the auxiliary winding of the transformer Current sense for primary side of transformer This pin is connected with an internal power BJT’s collector This pin is the signal reference ground Functional Block Diagram VCC 3 OVP OCkP Output Short OTP Max Tonp Rcs Short tOSC 0.05V FB COMP 2 Regulator & Bias OSC tONS tONS, NL and LL Detector PFM UVLO NL LL 7 Pro GND Vload UV LL UV NL PFM Dynamic Response Dyn CV_ctrl 5, 6 Vally ON (LL+NL)Bar C DetectON VFB_ref Constant Voltage Control Cable Compensation R Q Detect Pulse Driver S tosc NL LL Vload Line Comp. VCSN(N=1,2,3) Peak Current Control LEB Frequency Dither VCSN Select Vload CS UV tONS Shutdown Pre_Shutdown CV_M DetectON CC_ctrl Constant Current Control R Q S VCSN(N=1,2,3) CPC Vload 4 1 CPC AP3988 Document number: DS36722 Rev. 4 - 2 CS 3 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Absolute Maximum Ratings (Note 5) Symbol VCC VCS, VCPC NEW PRODUCT VFB Parameter Rating Unit Supply Voltage -0.3 to 30 V Voltage on CS, CPC Pin -0.3 to 7 V FB Input Voltage -0.3 to 8 V VCBO Collector-emitter Voltage 700 V ICDC Collector DC Current 1.5 A +150 °C -65 to +150 °C Operating Junction Temperature TJ TSTG Storage Temperature TLEAD Lead Temperature (Soldering, 10 sec) +300 °C – ESD (Machine Model) 200 V – ESD (Human Body Model) 2000 V 0.7 W Total Power Dissipation PD Note 5: 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 Parameter Min Max Unit – 25 V VCC Supply Voltage TOP Operating Temperature Range -40 +85 °C fS(MAX) Maximum Operating Frequency – 60 kHz Thermal Impedance (Note 6) Symbol Parameter Value θJA Junction to Ambient 140 θJC Junction to Case 70 Unit °C/W Note 6: When mounted a standard single-sided FR4 board with 300mm2 Cu (at least 35µm thick) connected to CS pin and all collectors. AP3988 Document number: DS36722 Rev. 4 - 2 4 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Electrical Characteristics Symbol (@VCC=15V, TJ=+25°C, unless otherwise specified.) Parameters Conditions Min Typ Max Unit STARTUP AND UVLO SECTION VTH_ST Turn-on Voltage – 13 15 17 V VOPR(MIN) Turn-off Voltage – 5.2 5.8 6.4 V 0 0.2 0.6 550 650 750 – – 60 kHz 4.5 5 5.5 % – 1.8 2 2.2 kHz 40% to 100% of full load 874 910 946 mV 17% to 40% of full load 581 605 630 mV 5% to 17% of full load 390 405 425 mV NEW PRODUCT STANDBY CURRENT SECTION IST ICC_OPR Turn-on Current VCC=VTH_ST-1V before startup Operating Current Static current @ no load OPERATING FREQUENCY SECTION (5% LOAD TO FULL LOAD) Operating Frequency in Full Load – fS(MAX) Condition 5% to 100% of full load Δf/f Frequency Dithering range μA OPERATING FREQUENCY SECTION (NO LOAD TO 5% OF IOUT(MAX)) fS(MIN) Output Voltage Detection Frequency CURRENT SENSE SECTION Peak Current Sense Voltage in Heavy VCS_H Load Peak Current Sense Voltage in Middle VCS_M Load Peak Current Sense Voltage in Light VCS_L Load ΔVCS/VCS VCS Modulation for Frequency Dithering – – 2.5 – % tMOD VCS Modulation Period – 225 250 275 μs RLINE Built-in Line Compensation Resistor – 260 330 400 Ω tLEB Leading Edge Blanking @ VCS_H and VCS_M 600 750 900 ns Closed loop test of VOUT 4.13 4.20 4.27 V FB Pin Input Current VFB=4V 3.36 4.20 5.04 μA Cable Compensation Drop – – 0.35 – V VFB=3V – 4/7 – – Collector-emitter Saturation Voltage IC=0.5A – – 0.3 V hFE DC Current Gain – 14 17 – – ICEO Leakage Current – – – 60 μA – 7.5 – V CONSTANT VOLTAGE SECTION Equivalent Feedback Voltage @ 90% VFB Load IFB VCABLE CONSTANT CURRENT SECTION tONS/tSW Secondary Winding Conduction Duty POWER TRANSISTOR SECTION VCE(SAT) PROTECTION FUNCTION SECTION VFB(OVP) Over Voltage Protection – VFB(SCP) Short Circuit Protection VFB @ Hiccup 2.6 3.3 3.7 V TOTP Shutdown Temperature – +125 +160 – °C THYS Temperature Hysteresis – – +40 – °C AP3988 Document number: DS36722 Rev. 4 - 2 5 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Performance Characteristics Turn-on Voltage vs. Ambient Temperature Turn-off Voltage vs. Ambient Temperature 6.5 14.8 6.0 Turn-off Voltage (V) NEW PRODUCT Turn on Voltage (V) 14.7 14.6 14.5 5.5 14.4 5.0 14.3 14.2 -40 -20 0 20 40 60 o 80 100 4.5 -40 120 -20 0 20 40 60 80 100 120 125 o Ambient Temperature ( C) Ambient Temperature ( C) Operating Current vs. Ambient Temperature 750 Operating Current (A) 700 650 600 550 500 -40 -20 0 20 40 60 80 100 120 125 o Ambient Temperature ( C) Operation Description VS Vbulk VIN + C1 LM N P NS D1 CO VO + IOUT AP3988 VAUX C NAUX Q1 RFB1 CS GND CPC FB CCPC RCS RFB2 Figure 1. Simplified Flyback Converter Controlled by AP3988 AP3988 Document number: DS36722 Rev. 4 - 2 6 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Operation Description (Cont.) Constant Primary Peak Current The primary ip(t) current is sensed by a current sense resistor RCS as shown in Figure 1. The current rises up linearly at a rate of: dip (t ) NEW PRODUCT dt Vbulk (t ) ……… (1) LM See equation 2 IPK ip(t) 0A Figure 2. Primary Current Waveform As illustrated in Figure 2, when the current ip(t) rises up to IPK, the switch Q1 turns off. The constant peak current is given by: I PK VCS ………(2) RCS The energy stored in the magnetizing inductance LM each cycle is therefore: 1 2 Eg LM I PK ………(3) 2 So the power transferring from input to output is given by: P 1 2 LM I PK f SW ………(4) 2 Where fSW is the switching frequency. When the peak current I PK is constant, the output power depends on the switching frequency fSW. Constant Voltage Operation The AP3988 captures the auxiliary winding feedback voltage at FB pin and operates in constant-voltage (CV) mode to regulate the output voltage. Assuming the secondary winding is master, the auxiliary winding is slave during the D1 on-time. The auxiliary voltage is given by: V AUX N AUX VO Vd ………(5) NS Where Vd is the diode forward drop voltage, NAUX is the turns of auxiliary winding, and NS is the turns of secondary winding. See equation 5 VAUX 0V Portion of Tons Tons Figure 3. Auxiliary Voltage Waveform The output voltage is different from the secondary voltage in a diode forward drop voltage V d which depends on the current. If the secondary voltage is always detected at a constant secondary current, the difference between the output voltage and the secondary voltage will be a fixed Vd. The voltage detection point is portion of Tons after D1 is turned on. The CV loop control function of AP3988 then generates a D1 off-time to regulate the output voltage. AP3988 Document number: DS36722 Rev. 4 - 2 7 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Operation Description (Cont.) Constant Current Operation The AP3988 is designed to work in constant current (CC) mode. Figure 4 shows the secondary current waveforms. NEW PRODUCT See equation 7 Is IOUT 0A Tons Toffs Figure 4. Secondary Current Waveform In CC operation, the CC loop control function of AP3988 will keep a fixed proportion between D1 on-time Tons and D1 off-time Toffs by discharging or charging the built-in capacitance connected. This fixed proportion is Tons 4 ……… (6) Toffs 3 The relation between the output constant-current and secondary peak current IPKS is given by: Tons 1 ………(7) I OUT I PKS 2 Tons Toffs At the instant of D1 turn-on, the primary current transfers to the secondary at an amplitude of: I PKS NP I PK ………(8) NS Thus the output constant current is given by: 2 N I OUT P I PK ………(9) 7 NS Leading Edge Blanking (LEB) When the power switch is turned on, a turn-on spike on the output pulse rising edge will occur on the sense-resistor. To avoid false termination of the switching pulse, a typical 750ns leading edge blanking is built in. During this blanking period, the current sense comparator is disabled and the gate driver cannot be switched off. The built-in LEB in AP3988 has shorter delay time from current sense terminal to output pulse than those IC solutions adopting external RC filter as LEB. Built-in Cable Compensation The AP3988 has built-in fixed voltage of 0.35V typical to compensate the drop of output cable when the load is changed from zero to full load. A typical 10nF external capacitor connected to the CPC pin is used to smooth voltage signal for cable compensation. Over Temperature Protection The AP3988 has internal thermal sensing circuit to shut down the PFM driver output when the die temperature reaches +160°C typical. When the die temperature drops about +40°C, the IC will recover automatically to normal operation. AP3988 Document number: DS36722 Rev. 4 - 2 8 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Ordering Information NEW PRODUCT AP3988 X XX - G1 Product Name Package Packing RoHS/Green M : SO-7 TR : Tape & Reel G1 : Green Diodes IC’s Pb-free products with "G1" suffix in the part number, are RoHS compliant and green. Package Temperature Range SO-7 -40°C to +85°C Part Number AP3988MTR-G1 Marking ID 3988M-G1 Packing 4000/Tape & Reel Marking Information (Top View) First and Second Lines: Logo and Marking ID Third Line: Date Code Y: Year WW: Work Week of Molding A: Assembly House Code th th XX: 7 and 8 Digits of Batch No. AP3988 Document number: DS36722 Rev. 4 - 2 9 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Package Outline Dimensions (All dimensions in mm(inch).) (1) Package Type: SO-7 5.800(0.228) 1.350(0.053) 1.750(0.069) NEW PRODUCT 6.200(0.244) 0.330(0.013) 0.510(0.020) 2.54(0.100) TYP 4.700(0.185) 5.100(0.201) 1.270(0.050) TYP 0.100(0.004) 0.250(0.010) 3.800(0.150) 4.000(0.157) 0.190(0.007) 0.250(0.010) 0° 8° 1.250(0.049) 1.500(0.059) 0.450(0.017) 0.800(0.031) Note: Eject hole, oriented hole and mold mark is optional. AP3988 Document number: DS36722 Rev. 4 - 2 10 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 Suggested Pad Layout Package Type: SO-7 NEW PRODUCT (1) G Z E1 Y X E Dimensions Z (mm)/(inch) G (mm)/(inch) X (mm)/(inch) Y (mm)/(inch) E (mm)/(inch) E1 (mm)/(inch) Value 6.900/0.272 3.900/0.154 0.650/0.026 1.500/0.059 1.270/0.050 2.540/0.100 AP3988 Document number: DS36722 Rev. 4 - 2 11 of 12 www.diodes.com June 2014 © Diodes Incorporated A Product Line of Diodes Incorporated AP3988 IMPORTANT NOTICE NEW PRODUCT 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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LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2014, Diodes Incorporated www.diodes.com AP3988 Document number: DS36722 Rev. 4 - 2 12 of 12 www.diodes.com June 2014 © Diodes Incorporated