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Document overview
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Technical content
Features
Low Standby Power: Under 0.1 W Low Startup Current: 8 µA Low Operating Current in Green Mode: 600 µA Peak-Current Mode Operation with Cycle-by-Cycle Current Limiting PWM Frequency Continuously Decreasing with Burst Mode at Light Loads VDD Over-Voltage Protection (OVP) Constant Output Power Limit (Full AC Input Range) Internal Latch Circuit (FAN6862WL) for OVP, OTP Fixed PWM Frequency (65 KHz) with Frequency Hopping Feedback Open-Loop Protection: 60 ms Delay GATE Output Maximum Voltage Clamp: 13.5V Soft-Start Time: 5 ms Soft Driving for EMI Improvement Full Range Frequency Hopping Internal OTP Sensor with Hysteresis Gate Driving Capability: 400 mA
Applications
General-purpose switched-mode power supplies and flyback power converters, including: Power Adapters Open-Frame SMPS SMPS with Surge-Current Output, such as for Printers, Scanners, Motor Drivers
Description
A highly integrated PWM controller, FAN6862W provides several features to enhance the performance of flyback converters. To minimize standby power consumption, a proprietary Green Mode provides off- time modulation to continuously decrease the switching frequency under light-load conditions. Under zero-load conditions, the power supply enters Burst Mode, which completely shuts off PWM out put. Output restarts just before the supply voltage drops below the UVLO lower limit. Green Mode enables power supplies to meet international power conservation requirements. The FAN6862W is designed for SMPS and integrates a frequency-hopping function t hat helps to reduce EMI emission of a power supply with minimum line filters. To compensate the power limit variation over universal input range, a bias current limit (V LIMIT) adaptively keeps the power limit substantially constant. The gate output is clamped at 13.5 V to protect the external MOSFET from over-voltage damage. Other protection functions include V DD Over-Voltage Protection (OVP), and Over-T emperature Protection (OTP). For OTP, an external NTC thermistor can be applied to sense the ambient temperature. When V DD OVP or OTP is activated, an internal latch circuit latches off the controller. Protection types are shown in Table 1. Table 1. Protection Type
Ordering Information
-40 to +105°C 6-Lead, SOT23, JEDEC MO-178 Variation AB, 1.6 mm Wide Tape & ReelFAN6862WLTY FAN6862WRTY
Figure 3. Top Mark Figure 4. Pin Configuration
1 GND Ground Ground
2 FB Feedback
trigger level and persists at that level, the controller stops and restarts.
3 RT Temperature
pin drops below the threshold, PWM output is disabled.
4 SENSE Current Sense
5 VDD Power Supply Power supply
6 GATE Driver Output The totem-pole output driver for driving the power MOSFET
© 2012 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN6862W • Rev. 1.0.0 4 FAN6862W — Highly Integrated Green-Mode PWM Controller Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may dam age the device. The device may not function or be operable above the recommended operating conditions and stressi ng the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. All vo ltage values, except differential voltages, are given with respect to GND pin. Symbol Parameter Min. Max. Unit VDD Supply Voltage 30 V VL Input Voltage to FB, SENSE, and RT Pins -0.3 7.0 V ΘJA Thermal Resistance (Junction-to-Ambient) 244 °C/W TJ Operating Junction Temperature -40 +125 °C TSTG Storage Temperature Range -55 +150 °C TL Lead Temperature, Wave Soldering, 10 Seconds +260 °C ESD Human Body Model, JESD22-A114 5.5 kV Charge Device Model, JESD22-C101 2.0 Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ens ure optimal performance to the datasheet specificatio ns. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol Parameter Min. Max. Unit TA Operating Ambient Tem perature -40 +105 °C
© 2012 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN6862W • Rev. 1.0.0 5 FAN6862W — Highly Integrated Green-Mode PWM Controller
Electrical Characteristics
VDD = 15 V and TA = 25°C, unless otherwise noted. Symbol Parameter Condition Min. Typ. Max. Unit VDD Section VDD-OP Continuously Operating Voltage 20 V VDD-ON Turn-On Threshold Voltage 15 16 17 V VDD-OFF Turn-Off Voltage 6.5 7.0 7.5 V VDD-LH Threshold Voltage for Latch-Off Release FAN6862W, FAN6862WL Only 4 V IDD-ST Startup Current V DD-ON – 0.16 V 8 15 µA IDD-OP1 Operating Supply Current in PWM Operation VDD = 20 V, VFB = 3 V Gate Open 2 mA IDD-OP2 Operating Supply Current when V FB < VFB-ZDC VDD = 15 V, VFB < VFB-ZDC 600 µA VDD-OVP V DD Over-Voltage Protection FAN6862WL-Latch, FAN6862WR-Auto Restart 21.0 22.2 23.5 V tD-VDDOVP V DD OVP Debounce Time 50 µs IDD-LH Latch-Off Holding Current VDD = 5 V; FAN6862W, FAN6862WL Only 70 80 µA Feedback Input Section AV Input-Voltage to Current-Sense A ttenuation 1/4.0 1/3.5 1/3.0 V/V ZFB Input Impedance 17 k Ω VFB-OPEN FB Pin Open Voltage 5.2 5.4 5.6 V VFB-OLP Threshold Voltage for Open-Loop Protection 4.3 4.6 4.9 V tD-OLP Open-Loop Protection Delay VFB > VFB-OLP, tON > 2.5 µs, TA = -40 to +105°C 54 60 66 ms tD-SCP Secondary Short-Circuit Protection Delay FB > VFB-OLP, tON < 2.5 µs, TA = -40 to +105°C 6 7 8 ms tON-SCP Short-Circuit Protection On-Time Detection VFB>VFB-OLP, TA = -40 to +105°C 2.5 µs Current Sense Section tPD Delay to Output 100 250 ns tLEB Leading-Edge Blanking Time 200 250 ns VLIMIT-H High Threshold Voltage for Current Limit Duty>55% 0.57 0.60 0.63 V VLIMIT-L Low Threshold Voltage for Current Li mit Duty = 0% 0.36 0.39 0.42 V tSOFT-START Period During Startup Time Star tup Time 4.75 5.00 10.00 ms Continued on the following page…
VDD = 15 V and TA = 25°C, unless otherwise noted. Figure 5. PWM Frequency
© 2012 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN6862W • Rev. 1.0.0 7 FAN6862W — Highly Integrated Green-Mode PWM Controller Electrical Characteristics (Continued) VDD = 15 V and TA = 25°C, unless otherwise noted. Symbol Parameter Condition Min. Typ. Max. Unit PWM Output Section DCYMAX Maximum Duty Cycle 60 70 75 % VOL Output Voltage LOW V DD = 15 V, IO = 50 mA 1.5 V VOH Output Voltage HIGH V DD = 8 V, IO = 50 mA 6 V tR Rising Time (with Soft Driving) GATE = 1 nF 150 ns tF Falling Time GATE = 1 nF 35 ns VCLAMP Gate Output Clamping Voltage V DD = 20 V 12.0 13.5 15.0 V IO-SOURCE Gate Source Driving Capability (1) V DD = 15 V 400 mA IO-SINK Gate Sink Driving Capability (1) V DD = 15 V 400 mA Over-Temperature Protection (OTP) Section RRT Maximum External Resistance of RT Pin to Trigger Protection 9 10 11 k Ω VOTP Threshold Voltage for Over-Temperature Protection FAN6862W, FAN6862WL-Latch, FAN6862WR-Auto Restart, at 25°C 0.94 1.00 1.06 V IRT Output Current of RT Pin 92 100 108 μA tDOTP Over-Temperature Debounce Time V FB=VFB-N 14 17 19 ms VOTP2 Second Threshold Voltage for Over- Temperature Protection FAN6862W, FAN6862WL-Latch, FAN6862WR-Auto Restart, at 25°C 0.65 0.70 0.75 V tDOTP2 Second Over-Temperature Debounce Time 80 135 200 µs TOTP Protection Junction Temperature (1,2) +135 °C TRestart Restart Junction Temperature (1,3) TOTP- 25 °C Notes: 1. Guarantee by design. 2. When activated, the output is disabled and the latch is turned off. 3. The threshold temperature for enablin g the output again and resetting the latch after OTP has been activated.
Figure 32. Transformer
Figure 33. 6-Lead, SOT23, JEDEC MO-178 Variation AB, 1.6 mm Wide warranty therein, which covers Fairchild products. http://www.fairchildsemi.com/packaging/. B. ALL DIMENSIONS ARE IN MILLIMETERS.
0.60 REF
1.45 MAX
0.15 CA - B
0.15 C D
0.20 CA - BD
© 2012 Fairchild Semiconductor Corporation www.fairchildsemi.com FAN6862W • Rev. 1.0.0 16 FAN6862W — Highly Integrated Green-Mode PWM Controller