原标题：Fairchild FAN6862 40W笔记本电脑电源解决方案

　　FAN6862 Highly Integrated Green-Mode PWM Controller

　　A highly integrated PWM controller, FAN6862 provides several features to enhance the performance of flyback converters. To minimize standby power consumption, a proprietary green-mode function 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 output. Output restarts just before the supply voltage drops below the UVLO lower limit. This green-mode function enables power supplies to meet international power conservation requirements.

　　The FAN6862 is designed for SMPS and integrates a frequency-hopping function that helps reduce EMI emission of a power supply with minimum line filters.

　　The built-in synchronized slope compensation is proprietary sawtooth compensation for constant output power limit over universal AC input range. The gate output is clamped at 18V to protect the external MOSFET from over-voltage damage.

　　Other protection functions include VDD over-voltage protection and over-temperature protection. For overtemperature protection, an external NTC thermistor can be applied to sense the ambient temperature. When VDD OVP or OTP is activated, an internal latch circuit latches off the controller.

　　FAN6862主要特性：

　　 Low Startup Current: 8μA

　　 Low Operating Current in Green Mode: 3mA

　　 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 for OVP, OTP

　　 Fixed PWM Frequency (65KHz) with Frequency Hopping

　　 Feedback Open-Loop Protection with 56ms Delay

　　 Soft Start Time: 4ms

　　 400mA Driving Capability

　　FAN6862应用：

　　General-purpose switch-mode power supplies and flyback power converters, including:

　　 Power Adapters

　　 Open-Frame SMPS

　　 SMPS with Surge-Current Output, such as for Printers, Scanners, and Motor Drivers

　　图1。FAN6862方框图

　　图2。FAN6862典型应用电路图

　　图3。FAN6862起动电路图

　　36W(12V/3A)应用电路材料清单(BOM)：

　　采用FAN6862的40W参考设计RD-337

　　40W参考设计主要特性：

　　 Low Startup Current: 8μA;

　　 Low Operation Current in Green Mode: 3mA

　　 Green Mode: Frequency Reduction with Burst Mode at Light Load

　　 Fixed PWM Frequency at 65kHz with Frequency Hopping to Reduce EMI

　　 Constant Output Power Limit

　　 Soft-Start Time: 4ms

　　 Driving Capability: 400mA

　　 Various Protection Functions: VDD Over-Voltage Protections (OVP), Open-Loop Protection (OLP), and Over-Temperature Protection (OTP)

　　图5。40W参考设计电路图

　　图6。40W参考设计变压器连接图

　　变压器电特性：