Fairchild FL7930和FAN7621S 150W LED街灯照明设计方案

Fairchild公司的150W LED街灯照明设计方案是采用FL7930B和FAN7621S.而FL7930是用于低到高功率的有源功率因素修正(PFC)控制器,工作在临界导通模式(CRM),提供过压,开路反馈,过流,输入电压瞬态检测和欠压锁定等保护. FAN7621S是用于高效谐振转换器的脉冲频率调制控制器,包括高边栅极驱动电路,精密的电流控制振荡器,限频电路,软起动和内置保护功能.本文介绍了FL7930主要特性, FL7930B和FL7930C方框图, 应用电路图以及采用FL7930B和FAN7621S的150W LED街灯照明设计方案电路图和材料清单.
The FL7930 is an active Power Factor Correction (PFC) controller for low-to high-power lumens applications that operate in Critical Conduction Mode (CRM). It uses a voltage-mode PWM that compares an internal ramp signal with the error amplifier output to generate a MOSFET turn-off signal. Because the voltage-mode CRM PFC controller does not need rectified AC line voltage information, it saves the power loss of an input voltage sensing network necessary for a current-mode CRM PFC controller.
FL7930 provides over-voltage, open-feedback, overcurrent, input-voltage-absent detection, and undervoltage lockout protections. The FL7930 can be disabled if the INV pin voltage is lower than 0.45V and the operating current decreases to a very low level.Using a new variable on-time control method, THD is lower than the conventional CRM boost PFC ICs. The FL3930B provides an additional OVP pin that can be used to shut down the boost power stage when output voltage exceeds OVP level due to damaged resistors connected at the INV pin. The FL7930C provides a PFC-ready pin can be used to trigger other power stages when PFC output voltage reaches the proper level (with hysteresis).
FL7930主要特性:
 Additional PFC-Ready Function (FL7930C Only)
 Input-Voltage-Absent-Detection Circuit
 Maximum Switching Frequency Limitation
 Internal Soft-Start with Overshoot Prevention
 Internal Total Harmonic Distortion (THD) Optimizer
 Precise Adjustable Output Over-Voltage Protection