L6566B数据手册集成电路（IC）的ACDC转换器离线开关规格书PDF

描述 Description

The L6566B is an extremely versatile current-mode primary controller ICs, specifically designed for high-performance offline flyback converters. It is also suited for single-stage single-switch input-current-shaping converters (single-stage PFC) for applications supposed to comply with EN61000-3-2 or JEITA-MITI regulations.

Both fixed-frequency (FF) and quasi-resonant (QR) operation are supported. The user can pick either of the two depending on application needs. The device features an externally programmable oscillator: it defines converter’s switching frequency in FF mode and the maximum allowed switching frequency in QR mode.

When FF operation is selected, the ICs work like a standard current-mode controller with a maximum duty cycle limited at 70 % min. The oscillator frequency can be modulated to mitigate EMI emissions.

QR operation, when selected, occurs at heavy load and is achieved through a transformer demagnetization sensing input that triggers MOSFET’s turn-on. Under some conditions, ZVS (zero-voltage switching) can be achieved. Converter’s power capability rise with the mains voltage is compensated by line voltage feedforward. At medium and light load, as the QR operating frequency equals the oscillator frequency, a function (valley skipping) is activated to prevent further frequency rise and keep the operation as close to ZVS as possible.

With either FF or QR operation, at very light load the ICs enter a controlled burst-mode operation that, along with the built-in non-dissipative high-voltage start-up circuit and the low quiescent current, helps keep low the consumption from the mains and meet energy saving recommendations.

An innovative adaptive UVLO helps minimize the issues related to the fluctuations of the self-supply voltage due to transformer’s parasites.

The protection functions included in this device are: not-latched input undervoltage (brownout), output OVP (auto-restart or latch-mode selectable), a first-level OCP with delayed shutdown to protect the system during overload or short circuit conditions (autorestart or latch-mode selectable) and a second-level OCP that is invoked when the transformer saturates or the secondary diode fails short. A latched disable input allows easy implementation of OTP with an external NTC, while an internal thermal shutdown prevents IC overheating.

Programmable soft-start, leading-edge blanking on the current sense input for greater noise immunity, slope compensation (in FF mode only), and a shutdown function for externally controlled burst-mode operation or remote ON/OFF control complete the equipment of this device.

特性 Features

• Latched or autorestart OVP
• Programmable frequency modulation for EMI reduction
• -600/+800 mA totem pole gate driver with active pull-down during UVLO
• Brownout protection
• SO16N package
• Pulse-by-pulse OCP, shutdown on overload (latched or autorestart)
• Line feedforward for constant power capability vs. mains voltage
• Selectable multi-mode operation: fixed frequency or quasi-resonant
• Advanced light load management
• On-board 700 V high-voltage start-up
• Adaptive UVLO
• Transformer saturation detection
• Low quiescent current (< 3 mA)

简介

L6566B属于集成电路（IC）的ACDC转换器离线开关。由制造生产的L6566BAC DC 转换器，离线开关该系列是元器件级控制产品，用于构建将交流市电转换为直流电（通常电压大幅降低）的设备。集成和未集成系统主要开关元件的器件均包括在内。由于高输入输出电压比，以及此类系统中通常需要隔离，这些器件通常与外部变压器配合使用。尽管通常使用定制变压器来实现此用途，但也有许多专门用于此用途的库存产品，请参见“开关转换器，SMPS 变压器”标题。