Powerint LNK6766E 30W单输出反激电源解决方案

发布时间：2012-7-30 11:02 发布者：1770309616

Powerint公司的LinkSwitchTM-HP系列是集成了控制器和高压(650V/725V)功率MOSFET的单片器件,采用连续导通模式(CCM),初级调整(PSR),功率达90W,没有DCM的效率限制或可听见的噪音. 在230VAC时无负载时的功耗小于30mW,主要用在LCD监视器和TV,适配器,家用电器,嵌入式电源(DVD,STB)和工业电源.本文介绍了LinkSwitch-HP系列产品亮点,方框图,适配器电路图以及采用LNK6766E的30W单输出反激转换器参考设计主要特性和指标,电路图,材料清单和PCB布局图.

A LinkSwitch-HP device monolithically integrates a controller and high-voltage power MOSFET into one package. It has a newly developed analogue control scheme, which enables continuous conduction mode (CCM), primary side regulated (PSR) power supplies up to 90 W without the efficiency limitation of DCM or audible noise. It uses an enhanced peak current mode PWM control scheme with multi-mode operation. The multi-mode control engine uses the error amplifier output signal voltage at the COMPENSATION pin to set the operating peak current and switching frequency to maintain the output voltage in regulation as shown in Figure 5. For COMPENSATION pin voltages lower than VC(MCM) (typ. 1.25 V) the device enters multi-cycle modulation (MCM) with a fixed peak current of 25% of the programmed current limit. Several innovative improvements have been added to the peak current mode control to allow primary side regulated CCM operation with no instability. The device meets less than 30 mW input power with no-load at high-line (LNK67xx families).

It also offers extensive built-in features:

• External current limit selection

• Optional programmable shutdown delay time extension

• Optional remote On/Off

• Optional fast AC reset

• Primary-side sensed output overvoltage protection (OVP)

• Lost regulation protection during output overload or short-circuit (auto-restart)

• Internal current limit over line compensation for constant overload power over line

• High-voltage bus overvoltage sense (line OV) for extended line surge withstand

• High-voltage bus undervoltage sense (line UV) for brown-in/ out protection

• Accurate over-temperature protection (OTP)

• Output OVP/OCP/OTP shutdown type selection (hysteretic/ latching)

• Optional external latching shutdown input (current threshold)

• Cycle-by-cycle current limit control

LinkSwitch-HP系列产品亮点:

EcoSmart™- Energy Efficient

• Multi-mode control maximizes efficiency over full load range

• No-load consumption below 30 mW at 230 VAC (LNK67xx)

• >75% efficiency with 1 W input at 230 VAC

• >50% efficiency with 0.1 W input at 230 VAC

High Design Flexibility for Low System Cost

• Dramatically simplifies power supply designs

• Eliminates optocoupler and all secondary control circuitry

• ±5% or better output voltage tolerance

• 132 kHz operation reduces transformer and power supply size

• Accurate programmable current limit

• Compensation over line limits overload power

• Frequency jittering reduces EMI filter cost

• Fully integrated soft-start for minimum start-up stress

• 725 V MOSFET simplifies meeting derating requirements (LNK677x)

• 650 V MOSFET for lowest system cost (LNK676x/LNK666x)

• Fast transient response family option (LNK666x)

Extensive Protection Features

• Auto-restart limits power delivery to 3% during overload faults

• Output short-circuit protection (SCP)

• Output overload/over-current protection (OPP, OCP)

• Optional extended shutdown delay time

• Output overvoltage protection (OVP), hysteretic or latching

• Line brown-in/out protection (line UV)

• Line overvoltage (OV) shutdown extends line surge withstand

• Accurate thermal shutdown (OTP), hysteretic or latching

Advanced Green Package Options

• eSIP™-7C package:

• Vertical orientation for minimum PCB footprint

• Simple heat sink mounting using clip or adhesive pad

• eDIP™-12B package:

• Low profile through-hole mounted for ultra-slim designs

• Heat transfer to PCB via exposed pad or optional metal heat sink

• Extended creepage to DRAIN pin

• Heat sink is connected to SOURCE for low EMI

• Halogen free and RoHS compliant

LinkSwitch-HP系列典型应用:

• LCD Monitor and TV

• Adapter

• Appliances

• Embedded power supplies (DVD, set-top box)

• Industrial

图1. LinkSwitch-HP系列方框图

图2.通用输入30W 12V/2.5A适配器电路图

采用LNK6766E的30W单输出反激转换器参考设计

30W转换器参考设计主要特性:

 Primary side regulated isolated flyback converter with ±5% regulation.

 132 kHz switching frequency for small transformer and output filter size

 Full load continuous conduction mode operation for improved efficiency and reduced output capacitor ripple currents

 Multimode operation maximizes efficiency over full load range

 Below 30 mW power consumption with 230 VAC.

 Extensive protection features including OVP, OTP, brown-in/out, line overvoltage, and lostregulation (auto-restart)

 Meets EN-550022 and CISPR-22 Class B conducted EMI with 5 dB margin.

 Meets IEC61000-4-5, 1 kV / 2 kV surge.