AP3710

Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER General Description 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. The AP3710 is available in SOIC-8 and DIP-8 packages. AP3710 Features · · · · · · · · · · · · · 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 · · · · · Adapters Battery Chargers Set Top Boxes Auxiliary Supplies DVD SOIC-8 DIP-8 Figure 1. Package Types of AP3710 Nov. 2007 Rev. 1. 2 1 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Pin Configuration M/P Package (SOIC-8/DIP-8) GND VCC NC OUT 1 2 3 4 8 7 6 5 NC VA NC VSEN AP3710 Figure 2. Pin Configuration of AP3710 (Top View) Pin Description Pin Number 1 2 3, 6, 8 4 5 7 Pin Name GND VCC NC OUT VSEN VA Power supply ground The power supply of the IC and this terminal is also used for the feedback control Not connected The PWM output is directly connected to the emitter of NPN transistor or the source of MOSFET It is used for line voltage compensation, and PWM uses this to terminate the output switch conduction 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 Function Nov. 2007 Rev. 1. 2 2 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Functional Block Diagram AP3710 VCC 2 UVLO COMPARATOR VREF (1.2V) BIAS START-UP CURRENT SOURCE 4 OUT OSCILLATOR + PWM COMPARATOR FB 5 VSEN VREF (1.2V) DISCHARGE COMPARATOR + - DRIVER PWM CONTROL SLOP COMPENSATION DISCHARGE LOGIC 7 VA GND 1 VREF (1.2V) + _ Figure 3. Functional Block Diagram of AP3710 Nov. 2007 Rev. 1. 2 3 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Ordering Information AP3710 Circuit Type Package M: SOIC-8 P: DIP-8 E1: Lead Free TR: Tape and Reel Blank: Tube AP3710 Package SOIC-8 DIP-8 Switching Frequency 60kHz 60kHz Temperature Range -40 to 85oC -40 to 85oC Part Number AP3710M-E1 AP3710MTR-E1 AP3710P-E1 Marking ID 3710M-E1 3710M-E1 AP3710P-E1 Packing Type Tube Tape & Reel 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 Supply Voltage Voltage at OUT Analog Input at VSEN Output Current at OUT Power Dissipation Operating Junction Temperature Storage Temperature Lead Temperature (Soldering, 10s) ESD (Machine Model) Value -0.3 to 6.3 -0.3 to 40 -0.3 to 6.3 Internally limited 0.6 150 -65 to 150 300 300 Unit V V V A W o C oC o C V 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 4 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Electrical Characteristics (VCC=4V, TJ=25oC, unless otherwise specified.) Parameter UVLO SECTION Turn on Threshold Voltage Turn off Threshold Voltage Discharge Voltage VCC (on) VCC (off) VDIS 5.30 3.4 2.7 5.60 3.65 2.9 5.90 3.90 3.1 V V V Symbol Conditions Min Typ Max Unit AP3710 STANDBY CURRENT SECTION Start-up Current Operating Current VCC Zener Voltage Dynamic Impedance INTERNAL OSCILLATOR Switching Frequency Frequency Dithering Temperature Stability DRIVE OUTPUT SECTION OUT Turn-on Voltage OUT Turn-off Voltage Rise Time Fall Time Maximum Duty Cycle Minimum Duty Cycle Driver OUT On-Resistance Switch Off Current (OUT) Effective Current Limit OUT Current Coefficient CURRENT SECTION Maximum Input Signal VSEN 0.9 1.0 1.1 V ILIM GA ROUT VOUT(on) VOUT(off) TR TF DMAX CL=1nF, 15Ω pull-up CL=1nF, 15Ω pull-up VCC(off) + 0.2V VCC=VCC (on)-0.2V IOUT=0.7A Driver off, VOUT=10V VCC=VCC(off)+0.5V 800 68 7.6 5.7 9.3 6.8 60 30 75 3 3 20 900 -0.6 82 5 5 40 Ω µA mA A/V % 11 7.9 V V ns -40 to 85oC FSW (Note 3) 50 60 70 kHz kHz % IST ICC(opr) VZ RVCC ICC=10mA VCC=3.8 to 4.8V (Note 2) 6.5 10 VCC=4V 0.25 0.45 7 18 0.4 0.7 7.5 30 V kΩ mA ±2 ±3.5 5 ±5 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 5 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Electrical Characteristics (Continued) 1N5819 AP3710 R 100Ω/3W + L 70µH C1 100µF/50V 27V Zener + C2 100µF/50V + _ VIN =10V OUT AP3710 GND VCC C3 2200pF VCC=VCC(off)+0.5V Figure 4. The Test Circuit for Current Limit Nov. 2007 Rev. 1. 2 6 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Typical Performance Characteristics AP3710 680 640 400 360 320 Operating Current (µA) 600 Start-up Current (µA) -20 0 20 40 60 o 560 520 480 440 400 360 320 -40 80 100 120 280 240 200 160 120 -40 -20 0 20 40 60 o 80 100 120 Ambient Temperature ( C) Ambient Temperature ( C) Figure 5. Operating Current vs. Ambient Temperature Figure 6. Start-up Current vs. Ambient Temperature 500 70 68 400 Start-up Current (µA) Switching Frequency (KHz) 66 64 62 60 58 56 300 200 100 0 1 2 3 VCC Voltage (V) 4 5 -40 -20 0 20 40 60 o 80 100 120 Ambient Temperature ( C) Figure 7. Start-up Current vs. VCC Voltage Figure 8. Switching Frequency vs. Ambient Temperature Nov. 2007 Rev. 1. 2 7 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Typical Performance Characteristics (Continued) AP3710 1.10 3.10 3.05 3.00 1.05 Normalized Current Limit 1.00 Discharge Voltage (V) -20 0 20 40 60 o 2.95 2.90 2.85 2.80 2.75 0.95 0.90 0.85 0.80 -40 80 100 120 2.70 -40 -20 0 20 40 60 o 80 100 120 Ambient Temperature ( C) Ambient Temperature ( C) Figure 9. Normalized Current Limit vs. Ambient Temperature Figure 10. Discharge Voltage vs. Ambient Temperature 4.0 3.8 5.5 Turn on Threshold Voltage (V) 3.6 3.4 5.4 On Resistance (Ω) 3.2 3.0 2.8 2.6 2.4 2.2 2.0 -40 5.3 5.2 5.1 -20 0 20 40 60 o 80 100 120 5.0 -40 -20 0 20 40 60 o 80 100 120 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 8 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Function Description 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 D6 R8 R6 OUT VSEN VA + VCC GND C6 + R7 C5 R13 R14 VIN Rectified AC AP3710 VO U3 PC817 R16 C7 ICC: Supply Current (µA) U2 AZ431 R16 Turn off Turn on C4 U1 AP3710 3.65 5.6 VCC: Supply Voltage (V) Figure 14. The Start-up Circuit of Typical Application 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. 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. 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 9 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Function Description (Continued) 2. VCC/Feedback 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. AP3710 5. Current Limit Control 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 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. Normal PWM Waveform Cycle Skip Waveform 0 t 6. Frequency Dithering 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. 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 10 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Function Description (Continued) 7. Short Circuit Protection Internal short circuit control can protect a SMPS from being damaged when short circuit at its output happens. 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. From VCC AP3710 From UVLO Discharge Comparator Discharge Logic VREF 1.2V VA Figure 18. Short Circuit Protection Block Nov. 2007 Rev. 1. 2 11 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Typical Application R1 AP3710 D1-D4 L2 T1 EE16 R11 C11 L3 D8 L4 12V/1A VO+ J1 AC 85-264V F1 + C1 R9 + C2 R4 C3 + C8 C9 + ZD2 R2 VOD7 D5 R3 R5 R13 Q1 D6 R8 U3 R15 C7 R14 R6 OUT VSEN VA + C4 R7 U2 R16 VCC GND C6 + C5 C10 U1 Figure 19. 12V/1A Adapter Nov. 2007 Rev. 1. 2 12 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Bill of Materials for Figure 19 Designator R1 R2, R3 R4 R5 R6 R7 R8 R11 R13 R14 D1 to D4 D5, D6 D7 D8 Part Type Resistor, NTC Resistor, 5Ω Resistor, 1MΩ, 1206 Resistor, 68kΩ, 1206 Resistor, 3Ω, 0805 Resistor, 200Ω, 0805 Resistor, 2kΩ, 0805 Resistor, 5.1MΩ, SIP Resistor, 15 Ω, 1206 Resistor, 1kΩ, 0805 Resistor, 11.4kΩ, 0805 Diode, 1N4007, DO-41 Diode, 1N4148, LL-34 Diode, FR107, DO-15 Diode, 3100, DO-201 Designator C1, C2 C3 C4, C5 C6 C7 C8 C9 C10 C11 Q1 U3 L2 L4 ZD2 T1 Part Type Electrolytic Capacitor, 10 µF/400V, φ10 Capacitor, 2200pF, d=5mm Capacitor, 10µF, d=4.5mm Capacitor, 22nF, 0805 Capacitor, 0.47µF, 0805 Electrolytic Capacitor, 1000µF Electrolytic Capacitor, 220µF Y Capacitor, 2200pF Capacitor, 1nF, 0805 Transistor, APT13003, TO126 Opto-coupler, PC817, DIP-4 Inductor, 300µH/0.3A Inductor, 100µH/1A Zener, 13V/1W Transformer, EE-20 AP3710 R9, R15, R16 Resistor, 3kΩ, 0805 Nov. 2007 Rev. 1. 2 13 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Mechanical Dimensions SOIC-8 Unit: mm(inch) AP3710 4.700(0.185) 5.100(0.201) 7° 1.350(0.053) 1.750(0.069) 0.320(0.013) 8° 7° 8° 0.675(0.027) 0.725(0.029) D 5.800(0.228) 6.200(0.244) D 20:1 1.270(0.050) TYP 0.100(0.004) 0.300(0.012) R0.150(0.006) φ 0.800(0.031) 0.200(0.008) 1.000(0.039) 3.800(0.150) 4.000(0.157) 0° 8° 0.330(0.013) 0.510(0.020) 0.190(0.007) 0.250(0.010) 0.900(0.035) 1° 5° R0.150(0.006) 0.450(0.017) 0.800(0.031) Nov. 2007 Rev. 1. 2 14 BCD Semiconductor Manufacturing Limited Preliminary Datasheet LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER Mechanical Dimensions (Continued) DIP-8 Unit: mm(inch) AP3710 0.700(0.028) 7.620(0.300)TYP 1.524(0.060) TYP 6° 6° 5° 3.710(0.146) 4.310(0.170) 4° 3.200(0.126) 3.600(0.142) 4° 3.000(0.118) 3.600(0.142) 0.510(0.020)MIN 0.254(0.010)TYP 0.360(0.014) 0.560(0.022) 2.540(0.100) TYP 0.130(0.005)MIN 0.204(0.008) 0.360(0.014) 8.200(0.323) 9.400(0.370) 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) 6.200(0.244) 6.600(0.260) Nov. 2007 Rev. 1. 2 15 BCD Semiconductor Manufacturing Limited 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 - 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 BCD Semiconductor Manufacturing Limited - 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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