UCC28700DBVT.B中文资料德州仪器数据手册PDF规格书

1 Features

1• < 30-mW No-Load Power for 5-Star Rating

• Primary-Side Regulation (PSR) Eliminates Opto-

Coupler

• ±5% Voltage and Current Regulation

• 130-kHz Maximum Switching Frequency Enables

High-Power Density Charger Designs

• Quasi-Resonant Valley-Switching Operation for

Highest Overall Efficiency

• Patent-Pending Frequency-Jitter Scheme to Ease

EMI Compliance

• Wide VDD Range Allows Small Bias Capacitor

• Clamped Gate-Drive Output for MOSFET

• Protection Functions: Overvoltage, Low-Line, and

Overcurrent

• Programmable Cable Compensation (UCC28700

Only)

• NTC Resistor Interface (UCC28701, UCC28702

and UCC28703 Only) With Fixed Cable

Compensation Options

• SOT-23 Package

2 Applications

• USB-Compliant Adapters and Chargers for

Consumer Electronics (Cell Phones, Tablets and

Cameras)

• AC and DC Power Supplies

3 Description

The UCC28700 family of flyback power supply

controllers provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the

use of an optical coupler. The devices process

information from the primary power switch and an

auxiliary flyback winding for precise control of output

voltage and current. Low start-up current, dynamically

controlled operating states and a tailored modulation

profile support very low standby power without

sacrificing start-up time or output transient response.

Control algorithms in the UCC28700 family allow

operating efficiencies to meet or exceed applicable

standards. The output drive interfaces to a MOSFET

power switch. Discontinuous Conduction Mode

(DCM) with valley switching reduces switching losses.

Modulation of switching frequency and primary current peak amplitude (FM and AM) keeps the

conversion efficiency high across the entire load and

line ranges.

The controllers have a maximum switching frequency

of 130 kHz and always maintain control of the peak-

primary current in the transformer. Protection features

help keep primary and secondary component

stresses in check. The UCC28700 allows the level of

cable compensation to be programmed. The UCC28701, UCC28702, and UCC28703 devices

allow remote temperature sensing using a Negative

Temperature Coefficient (NTC) resistor while

providing fixed cable-compensation levels.