Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER General Description Features The AP3710 is a green-mode PWM controller, its main applications are low power supplies such as offline battery chargers, adapters, STB and other auxiliary supplies, where the needs for low no load power, low total cost and high reliability are all required. · · · · · · · · · · The functional blocks of AP3710 include: under voltage lockout with low start-up current; precise voltage reference for internal comparators; PWM comparator with current limit control, feedback signal and bandgap input; short circuit comparator and open circuit protection for opto-coupler. · · · The AP3710 operates at a fixed 60kHz switching frequency, its output connects to the emitter of high voltage NPN transistor or the source of MOSFET. In normal mode, it works as a switch to turn on or turn off the external transistor. In failure modes like open loop, over voltage or overload due to short circuit, the chip enters into an auto restart mode controlled by the internal protection unit. AP3710 Current Mode Control with Skip Cycle Capability Low Start-up Current: 0.25 mA Low Operating Current: 0.45mA Output Current Capacity: 900 mA Fixed Switching Frequency: 60 kHz Frequency Dithering for Low EMI Under-Voltage Lockout with Hysteresis Built-in Slope Compensation Short Circuit Protection Open and Short Circuit Protection for OptoCoupler Maximum Input Power is 0.2W under No Load Maximum Input Power is 1W under 0.5W Load Low Total Cost Solution Applications · · · · · The AP3710 is available in SOIC-8 and DIP-8 packages. Adapters Battery Chargers Set Top Boxes Auxiliary Supplies DVD DIP-8 SOIC-8 Figure 1. Package Types of AP3710 Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 1 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Pin Configuration M/P Package (SOIC-8/DIP-8) GND 1 8 NC VCC 2 7 VA NC 3 6 NC OUT 4 5 VSEN Figure 2. Pin Configuration of AP3710 (Top View) Pin Description Pin Number Pin Name Function 1 GND Power supply ground 2 VCC The power supply of the IC and this terminal is also used for the feedback control 3, 6, 8 NC 4 OUT The PWM output is directly connected to the emitter of NPN transistor or the source of MOSFET 5 VSEN It is used for line voltage compensation, and PWM uses this to terminate the output switch conduction 7 VA It is used for short circuit protection, and this terminal will be pulled down to low level when short circuit happens at the load side Not connected Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 2 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Functional Block Diagram VCC 2 UVLO COMPARATOR 4 START-UP CURRENT SOURCE OUT BIAS - VREF (1.2V) OSCILLATOR + PWM COMPARATOR FB 5 VSEN VREF (1.2V) DISCHARGE COMPARATOR GND 1 VREF (1.2V) + _ DRIVER + - PWM CONTROL SLOP COMPENSATION 7 VA DISCHARGE LOGIC Figure 3. Functional Block Diagram of AP3710 Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 3 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Ordering Information AP3710 - Circuit Type E1: Lead Free Package TR: Tape and Reel Blank: Tube M: SOIC-8 P: DIP-8 Package Switching Frequency Temperature Range SOIC-8 60kHz -40 to 85oC DIP-8 60kHz -40 to 85oC Part Number Marking ID Packing Type AP3710M-E1 3710M-E1 Tube AP3710MTR-E1 3710M-E1 Tape & Reel AP3710P-E1 AP3710P-E1 Tube BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Absolute Maximum Ratings (Note 1) Parameter Value Unit Supply Voltage -0.3 to 6.3 V Voltage at OUT -0.3 to 40 V Analog Input at VSEN -0.3 to 6.3 V Internally limited A Power Dissipation 0.6 W Operating Junction Temperature 150 o Output Current at OUT Storage Temperature -65 to 150 C oC Lead Temperature (Soldering, 10s) 300 o ESD (Machine Model) 300 V C Note 1: 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. Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 4 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Electrical Characteristics (VCC=4V, TJ=25oC, unless otherwise specified.) Parameter Symbol Conditions Min Typ Max Unit UVLO SECTION Turn on Threshold Voltage VCC (on) 5.30 5.60 5.90 V Turn off Threshold Voltage VCC (off) 3.4 3.65 3.90 V VDIS 2.7 2.9 3.1 V 0.25 0.4 0.45 0.7 Discharge Voltage STANDBY CURRENT SECTION Start-up Current IST Operating Current ICC(opr) VCC Zener Voltage VZ Dynamic Impedance VCC=4V mA ICC=10mA 6.5 7 7.5 V RVCC VCC=3.8 to 4.8V (Note 2) 10 18 30 kΩ FSW (Note 3) 50 60 70 kHz ±2 ±3.5 ±5 kHz INTERNAL OSCILLATOR Switching Frequency Frequency Dithering Temperature Stability 5 -40 to 85oC % DRIVE OUTPUT SECTION OUT Turn-on Voltage VOUT(on) 7.6 9.3 11 V OUT Turn-off Voltage VOUT(off) 5.7 6.8 7.9 V Rise Time TR CL=1nF, 15Ω pull-up 60 Fall Time TF CL=1nF, 15Ω pull-up 30 Maximum Duty Cycle DMAX Minimum Duty Cycle Driver OUT On-Resistance ROUT Switch Off Current (OUT) Effective Current Limit OUT Current Coefficient ILIM VCC(off) + 0.2V 68 ns 75 82 VCC=VCC (on)-0.2V 3 5 IOUT=0.7A 3 5 Ω Driver off, VOUT=10V 20 40 µA VCC=VCC(off)+0.5V 800 GA % 900 mA -0.6 A/V CURRENT SECTION Maximum Input Signal VSEN 0.9 1.0 1.1 V Note 2: Guaranteed by design, not tested in production. Note 3: The fixed oscillation frequency, the frequency jittering is not included. Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 5 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Electrical Characteristics (Continued) 1N5819 L 70µH R 100Ω/3W + C1 100µF/50V + C2 100µF/50V + _ 27V Zener VIN =10V GND OUT AP3710 VCC C3 2200pF VCC=VCC(off)+0.5V Figure 4. The Test Circuit for Current Limit Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 6 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Typical Performance Characteristics 400 680 360 600 320 560 Start-up Current (µA) Operating Current (µA) 640 520 480 440 400 240 200 160 360 320 -40 280 120 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 o Ambient Temperature ( C) o Ambient Temperature ( C) Figure 5. Operating Current vs. Ambient Temperature Figure 6. Start-up Current vs. Ambient Temperature 500 70 68 Switching Frequency (KHz) Start-up Current (µA) 400 300 200 100 66 64 62 60 58 56 0 1 2 3 4 -40 5 -20 0 20 40 60 80 100 120 o Ambient Temperature ( C) VCC Voltage (V) Figure 7. Start-up Current vs. VCC Voltage Figure 8. Switching Frequency vs. Ambient Temperature Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 7 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Typical Performance Characteristics (Continued) 1.10 3.10 3.05 3.00 Discharge Voltage (V) Normalized Current Limit 1.05 1.00 0.95 0.90 2.95 2.90 2.85 2.80 0.85 2.75 0.80 -40 -20 0 20 40 60 80 100 2.70 -40 120 -20 0 20 40 60 80 100 120 o o Ambient Temperature ( C) Ambient Temperature ( C) Figure 10. Discharge Voltage vs. Ambient Temperature Figure 9. Normalized Current Limit vs. Ambient Temperature 5.5 4.0 Turn on Threshold Voltage (V) 3.8 3.6 On Resistance (Ω) 3.4 3.2 3.0 2.8 2.6 2.4 5.4 5.3 5.2 5.1 2.2 2.0 -40 -20 0 20 40 60 80 100 5.0 -40 120 -20 0 20 40 60 80 100 120 o o Ambient Temperature ( C) Ambient Temperature ( C) Figure 11. On Resistance vs. Ambient Temperature Figure 12. Turn on Voltage vs. Ambient Temperature Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 8 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 VIN Rectified AC Function Description VO 1. UVLO and Start up Circuit The AP3710's turn on threshold voltage is 5.6V and its turn off threshold voltage is 3.65V, so the UVLO hysteresis voltage is 1.95V, which helps AP3710 to draw adequate energy to supply VCC terminal during start-up. Please see Figure 13 for UVLO chart. D6 R2+R3 R5 Q1 APT13003 R13 U3 PC817 D6 R16 C7 R14 R8 ICC: Supply Current (µA) R6 R7 OUT VSEN VA + Turn off Turn on GND C4 + VCC U2 AZ431 R16 C5 C6 U1 AP3710 Figure 14. The Start-up Circuit of Typical Application 3.65 5.6 VCC: Supply Voltage (V) In start-up section of typical application shown by Figure 14, the rectified line voltage VIN charges the capacitor C4 through start-up resistor R2+R3 until Q1 is turned on so OUT terminal can directly drive external Q1, a MOSFET inside AP3710 is connected in series with the Q1. Figure 13. 5.6/3.65V UVLO Threshold of AP3710 The VCC terminal in Figure 3 is used for both bias supply and feedback control. When AP3710 is powered on, the start-up current source turns on and it can not turn off until VCC level increases to its threshold value and PWM pulse is produced. Once the start-up is set up, the auxiliary bias winding will supply the VCC terminal enough operating current. The start-up sequence is shown in Figure 15. Figure 15. Power up Waveforms Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 9 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Function Description (Continued) 2. VCC/Feedback Control 5. Current Limit Control In Figure 14, an opto-coupler and secondary constant voltage consists of voltage feedback network. Voltage feedback loop consists of shunt regulator AZ431 and FB/VCC terminal of AP3710. When load is heavy, the voltage on VCC terminal will decrease to enlarge duty cycle; on the contrary, if load drops, the voltage on VCC will increase to reduce duty cycle. The AP3710 employs current mode control to improve transient response and voltage stability. In Figure 3, the external inductor current through the OUT pin is converted to a voltage by an internal resistor, and this voltage will participate to control duty cycle and peak inductor current. 3. Skip Cycle Mode Operation 6. Frequency Dithering The AP3710 enters skip cycle mode when load power drops below a given level, and this is performed by sensing the VCC voltage level, i.e., the heavier load power, the lower VCC voltage level. In normal operation, the VCC terminal indicates a peak inductance current under certain load power. If the load power decreases, VCC voltage level increases to ask for less peak current. When it reaches a determined value, the IC prevents the current from decreasing further down and starts to blank the output pulses, the IC then enters the skip cycle mode operation. Figure 16 is the sketch for the two operation mode. Frequency dithering is performed by periodically spreading a single switching frequency into adjacent frequency band, so the peak energy is spread. This technique can improve EMI performance by reducing both quasi peak and average EMI emissions. Normal PWM Waveform Cycle Skip Waveform 0 t Figure 16. Skip Cycle and Normal PWM Waveform Figure 17. Frequency Dither Influences the Switching Cycle 4. Slope Compensation The AP3710 is current mode PWM controller, and it regulates peak inductance current by its current control loop. It is known that a continuous condition mode SMPS may induce noise and harmonic oscillation on current sense or feedback signal, and this is especially serious when duty cycle exceeds 50%. The internal slope compensation of AP3710 can improve power supply stability by increasing the current slope. Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 10 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Function Description (Continued) 7. Short Circuit Protection From UVLO From VCC Internal short circuit control can protect a SMPS from being damaged when short circuit at its output happens. Discharge Comparator VA Discharge Logic In Figure 18, when VCC drops below its turn off threshold value, the UVLO comparator's output will control the Discharge Logic to pull VA terminal to low level, and the low level is kept before the VCC voltage drops below the threshold value of discharge comparator. Then the system will re-startup from C4 charging again and the same process will repeat indefinitely. The long start-up period makes the input power low enough to ensure the whole system in safety under output short circuit condition. VREF 1.2V Figure 18. Short Circuit Protection Block Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 11 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Typical Application R1 D1-D4 R11 C11 T1 EE16 L2 J1 AC 85-264V F1 R9 + C1 + L3 D8 C3 R4 + C8 L4 C9 + 12V/1A VO+ ZD2 C2 VO- R2 D7 D5 R3 R5 R13 U3 Q1 R15 C7 R14 D6 R8 R6 R7 OUT VSEN VCC VA + C4 + GND U2 R16 C5 C10 C6 U1 Figure 19. 12V/1A Adapter Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 12 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Bill of Materials for Figure 19 Designator R1 Part Type Designator Part Type Resistor, NTC Resistor, 5Ω C1, C2 Electrolytic Capacitor, 10 µF/400V, φ10 R2, R3 Resistor, 1MΩ, 1206 C3 Capacitor, 2200pF, d=5mm R4 Resistor, 68kΩ, 1206 C4, C5 Capacitor, 10µF, d=4.5mm R5 Resistor, 3Ω, 0805 C6 Capacitor, 22nF, 0805 R6 Resistor, 200Ω, 0805 C7 Capacitor, 0.47µF, 0805 R7 Resistor, 2kΩ, 0805 C8 Electrolytic Capacitor, 1000µF R8 Resistor, 5.1MΩ, SIP C9 Electrolytic Capacitor, 220µF R9, R15, R16 Resistor, 3kΩ, 0805 C10 Y Capacitor, 2200pF Resistor, 15 Ω, 1206 C11 Capacitor, 1nF, 0805 R13 Resistor, 1kΩ, 0805 Q1 Transistor, APT13003, TO126 R14 Resistor, 11.4kΩ, 0805 U3 Opto-coupler, PC817, DIP-4 D1 to D4 Diode, 1N4007, DO-41 L2 Inductor, 300µH/0.3A D5, D6 Diode, 1N4148, LL-34 L4 Inductor, 100µH/1A R11 D7 Diode, FR107, DO-15 ZD2 Zener, 13V/1W D8 Diode, 3100, DO-201 T1 Transformer, EE-20 Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 13 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Mechanical Dimensions SOIC-8 4.700(0.185) 5.100(0.201) 7° Unit: mm(inch) 0.320(0.013) 1.350(0.053) 1.750(0.069) 8° 8° 7° 0.675(0.027) 0.725(0.029) D 5.800(0.228) 1.270(0.050) 6.200(0.244) TYP D 20:1 φ 0.800(0.031) 0.300(0.012) R0.150(0.006) 0.100(0.004) 0.200(0.008) 0° 8° 1.000(0.039) 3.800(0.150) 4.000(0.157) 0.330(0.013) 0.190(0.007) 0.250(0.010) 1° 5° 0.510(0.020) 0.900(0.035) R0.150(0.006) 0.450(0.017) 0.800(0.031) Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 14 Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER AP3710 Mechanical Dimensions (Continued) DIP-8 Unit: mm(inch) 0.700(0.028) 7.620(0.300)TYP 1.524(0.060) TYP 6° 5° 6° 3.200(0.126) 3.600(0.142) 3.710(0.146) 4.310(0.170) 4° 4° 0.510(0.020)MIN 3.000(0.118) 3.600(0.142) 0.204(0.008) 0.360(0.014) 8.200(0.323) 9.400(0.370) 0.254(0.010)TYP 2.540(0.100) TYP 0.360(0.014) 0.560(0.022) 0.130(0.005)MIN 6.200(0.244) 6.600(0.260) R0.750(0.030) Φ3.000(0.118) Depth 0.100(0.004) 0.200(0.008) 9.000(0.354) 9.400(0.370) Nov. 2007 Rev. 1. 2 BCD Semiconductor Manufacturing Limited 15 BCD Semiconductor Manufacturing Limited http://www.bcdsemi.com IMPORTANT NOTICE BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifications herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or other rights nor the rights of others. MAIN SITE BCD Semiconductor Manufacturing Limited BCD Semiconductor Manufacturing Limited - Wafer Fab Shanghai SIM-BCD Semiconductor Manufacturing Limited 800, Yi Shan Road, Shanghai 200233, China Tel: +86-21-6485 1491, Fax: +86-21-5450 0008 - IC Design Group Advanced Analog Circuits (Shanghai) Corporation 8F, Zone B, 900, Yi Shan Road, Shanghai 200233, China Tel: +86-21-6495 9539, Fax: +86-21-6485 9673 REGIONAL SALES OFFICE Shenzhen Office Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd. 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