FAN6747 Datasheet | Fairchild Semiconductor

- Highly Integrated Green-Mode PWM Controller September 2010 FAN6747 Highly Integrated Green-Mode PWM Controller Features - - - - - - - - - - - - - High-Voltage Startup AC-Line Brownout Protection by HV Pin Constant Output Power Limit by HV Pin (Full AC-Line Range) Built-in 8ms Soft-Start Function Two-Level Over-Current Protection (OCP) with 220ms Debounce Short-Circuit Protection (SCP) with 15ms Debounce as Output Short Peak-Current Mode Operation with Cycle-by-Cycle Current Limiting Low Startup Current: 30µA Low Operating Current: 1.7m A Over-Temperature Protection (OTP) with an External Negative-Temperature-Coefficient (NTC) Thermistor PWM Frequency Decreasing at Green-Mode VDD Over-Voltage Protection (OVP) Internal Latch Circuit for OVP, OTP, SCP, and OCP Description The highly integrated FAN6747 PWM controller 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 decrease the switching frequency with load condition. Under zero-load condition, the power supply enters burst mode and burst frequency can be low to save more power. Green-mode function enables the power supply to meet international power conservation requirements. The FAN6747 is especially designed for SMPS with peak-current output. It incorporates a cycle-by-cycle current limiting and two-level Over-Current-Protection (OCP) that can handle peak load with a debounce time. Once the current is over the threshold level, it triggers the first counter 15ms and checks if VDD is below 10V; if it is, the PWM latches off for SCP. If VDD is higher than 10V; it keeps counting to 220ms, then the PWM latches off for OCP. FAN6747 also integrates a frequency-hopping function internally to help reduce EMI emission of a power supply with minimum line filters. Built-in proprietary internal synchronized slope pensation achieves constant output power limit over universal AC line...