Fairchild 公司的FAN6756是采用创新mWSaver™技术的绿色模式PWM控制器,能大大地降低待机和无负载功耗,满足世界范围的待机模式效率指引.在230VAC时待机和无负载功耗为30mW(包括EMI滤波器功耗),具有多种保护如过载/开路保护(OLP),UVLO,VDD OVP,超温保护(OTP)和电流检测短路保护(SSCP),主要用于笔记本电脑,打引机,LCD监视器,游戏机控制台.本文介绍了FAN6756主要特性,方框图,典型应用电路以及FAN6765MR评估板指标,电路图,材料清单和PCB元件布局图.
The FAN6756 is a next-generation Green Mode PWM controller with innovative mWSaver™ technology, which dramatically reduces standby and no-load power consumption, enabling conformance to worldwide Standby Mode efficiency guidelines.
An innovative AX-CAP™ method minimizes losses in the EMI filter stage by eliminating the X-cap discharge resistors while meeting IEC61010-1 safety requirements. Standby Mode clamps feedback voltage and modulates feedback impedance with an impedance
modulator during Burst Mode operation, which forces the system to operate in a “deep” Burst Mode with minimum switching losses.
Protections ensure safe operation of power system in various abnormal conditions. Proprietary frequencyhopping function decreases EMI emission and built-in synchronized slope compensation allows more stable Peak-Current-Mode control over wide range of input voltage and load conditions. The proprietary internal line compensation ensures constant output power limit over entire universal line voltage range.
Requiring a minimum number of external components, FAN6756 provides a basic platform that is well suited for cost-effective flyback converter designs that require extremely low standby power consumption.

FAN6756主要特性:
 Single-Ended Topologies, such as Flyback and Forward Converters
 mWSaver™ Technology
- Achieves Low No-Load Power Consumption:
Less than 30mW at 230VAC (EMI Filter Loss Included)
- Eliminates X Capacitor Discharge Resistor Loss with AX-CAP™ Technology
- Linearly Decreases Switching Frequency to 23KHz
- Burst Mode Operation at Light-Load Condition
- Impedance Modulation in Standby Mode for “Deep” Burst Mode Operation
- Low Operating Current (450μA) in Standby Mode
- 500V High-Voltage JFET Startup Circuit to Eliminate Startup Resistor Loss
 Highly Integrated with Rich Features
- Proprietary Frequency Hopping to Reduce EMI
- High-Voltage Sampling to Detect Input Voltage
- Peak-Current-Mode Control with Slope Compensation
- Cycle-by-Cycle Current Limiting with Line Compensation
- Leading Edge Blanking (LEB)
- Built-In 8ms Soft-Start
 Advanced Protections
- Brown-In/Brownout Recovery
- Internal Overload/Open-Loop Protection (OLP)
- VDD Under-Voltage Lockout (UVLO)
- VDD Over-Voltage Protection (VDD OVP)
- Over-Temperature Protection (OTP)
- Current-Sense Short-Circuit Protection (SSCP)

FAN6756应用:
Flyback power supplies that demand extremely low standby power consumption, such as:
 Adapters for Notebooks, Printers, Game Consoles, etc.
 Open-Frame SMPS for LCD TV, LCD Monitors, Printer Power, etc.

图1.FAN6756方框图

图2.FAN6756典型应用电路图


图3.FAN6756 65W笔记本电脑电源电路图

FAN6765MR评估板
This user guide supports the evaluation kit for the FAN6765MR.This document describes a 65W power supply using FAN6756MR. The FAN6756MR mWSaver™ controller targets power adapters that demand extremely low standby power consumption. With innovative mWSaver™ technology, FAN6756MR dramatically reduces standby and no-load power consumption. The AX-CAP™ technology minimizes losses in the EMI filter stage by eliminating the X-cap discharge resistors while meeting IEC61010-1 safety requirements. Standby Mode switches feedback impedance during Burst Mode operation, which forces the system to operate in a “Deep” Burst Mode with minimum switching losses. Proprietary asynchronous jitter decreases EMI emission and built-in synchronized slope compensation allows more stable Peak-Current-Mode control over a wide range of input voltage and load conditions.

FAN6765MR评估板指标:

FAN6765MR评估板主要特性:

 Single-Ended Topologies, such as Flyback and Forward Converters  mWSaver™ Technology
- Achieves Low No-Load Power Consumption: Less than 30mW at 230VAC (EMI Filter Loss Included)
- Eliminates X Capacitor Discharge Resistor Loss with AX-CAP™ Technology
- Linearly Decreases Switching Frequency to 23KHz
- Burst Mode Operation at Light-Load Condition
- Impedance Modulation in Standby Mode for “Deep” Burst Mode Operation
- Low Operating Current (450μA) in Standby Mode
- 500V High-Voltage JFET Startup Circuit to Eliminate Startup Resistor Loss
 Highly Integrated with Rich Features
- Proprietary Asynchronous-Jitter to Reduce EMI
- High-Voltage Sampling to Detect Input Voltage
- Peak-Current-Mode Control with Slope Compensation
- Cycle-by-Cycle Current Limiting with Line Compensation
- Leading Edge Blanking (LEB)
- Built-In 8ms Soft-Start
 Advanced Protections
- Brown-In/Brownout Recovery
- Internal Overload/Open-Loop Protection (OLP)
- VDD Under-Voltage Lockout (UVLO)
- VDD Over-Voltage Protection (VDD OVP)
- Over-Temperature Protection (OTP)
- Current-Sense Short-Circuit Protection (SSCP)

图4.FAN6765MR评估板外形图

图5.FAN6765MR评估板电路图

FAN6765MR评估板材料清单(BOM):



图6.FAN6765MR评估板变压器电路和指标图

图7.FAN6765MR评估板元件布局图(顶层)

图8.FAN6765MR评估板元件布局图(底层)