UCC28221屬于集成電路（IC）的ACDC轉(zhuǎn)換器離線(xiàn)開(kāi)關(guān)。由美國(guó)德州儀器公司制造生產(chǎn)的UCC28221AC DC 轉(zhuǎn)換器，離線(xiàn)開(kāi)關(guān)該系列是元器件級(jí)控制產(chǎn)品，用于構(gòu)建將交流市電轉(zhuǎn)換為直流電（通常電壓大幅降低）的設(shè)備。集成和未集成系統(tǒng)主要開(kāi)關(guān)元件的器件均包括在內(nèi)。由于高輸入輸出電壓比，以及此類(lèi)系統(tǒng)中通常需要隔離，這些器件通常與外部變壓器配合使用。盡管通常使用定制變壓器來(lái)實(shí)現(xiàn)此用途，但也有許多專(zhuān)門(mén)用于此用途的庫(kù)存產(chǎn)品，請(qǐng)參見(jiàn)“開(kāi)關(guān)轉(zhuǎn)換器，SMPS 變壓器”標(biāo)題。

1 Features

1? 2-MHz High-Frequency Oscillator With 1-MHz

Operation Per Channel

? Matched Internal Slope Compensation Circuits

? Programmable Maximum Duty Cycle Clamp 60%

to 90% Per Channel

? Peak Current Mode Control With Cycle-by-Cycle

Current Limit

? Current Sense Discharge Transistor for Improved

Noise Immunity

? Accurate Line Undervoltage and Overvoltage

Sense With Programmable Hysteresis

? Opto-Coupler Interface

? 110-V Internal Start-Up JFET (UCC28221)

? Operates From 12-V Supply (UCC28220)

? Programmable Soft Start

2 Applications

? High Output Current (50-A to 100-A) Converters

? Maximum Power Density Designs

? High-Efficiency 48-V Input With Low Output Ripple

Converters

? High-Power Offline, Telecom, and Datacom

Power Supplies

3 Description

The UCC28220 and UCC28221 are a family of

BiCMOS interleaved dual channel PWM controllers.

Peak current mode control is used to ensure current

sharing between the two channels. A precise

maximum duty cycle clamp can be set to any value

between 60% and 90% duty cycle per channel.

The UCC28220 has an UVLO turnon threshold of

10 V for use in 12-V supplies while UCC28221 has a

turnon threshold of 13 V for systems needing wider

UVLO hysteresis. Both have 8-V turnoff thresholds.

Additional features include a programmable internal

slope compensation with a special circuit which is

used to ensure exactly the same slope is added to

each channel and a high-voltage 110-V internal JFET

for easier start-up for the wider hysteresis UCC28221

version.

The UCC28220 is available in both 16-pin SOIC and

low-profile TSSOP packages. The UCC28221 also

comes in 16-pin SOIC package and a slightly larger

20-pin TSSOP package to allow for high-voltage pin

spacing to meet UL1950 creepage clearance safety

requirements.