Product details

Control mode Primary-side regulation Frequency (Max) (kHz) 132 UVLO thresholds on/off (V) 21/8.1 Duty cycle (Max) (%) 99 Features PSR, DCM, Soft Start, Quasi-Resonant, Current Limiting Operating temperature range (C) -20 to 125 Rating Catalog Device type Controllers Topology Buck, Flyback
Control mode Primary-side regulation Frequency (Max) (kHz) 132 UVLO thresholds on/off (V) 21/8.1 Duty cycle (Max) (%) 99 Features PSR, DCM, Soft Start, Quasi-Resonant, Current Limiting Operating temperature range (C) -20 to 125 Rating Catalog Device type Controllers Topology Buck, Flyback
SOT-23 (DBV) 6 5 mm² 2.9 x 1.6
  • < 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
  • < 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

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.

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.

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Technical documentation

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Type Title Date
* Data sheet UCC2870x Constant-Voltage, Constant-Current Controller With Primary-Side Regulation datasheet (Rev. A) 12 Dec 2014
Application note Flyback Aux Winding OVP and UVLO Fault Sensing Design and Troubleshooting Tips 31 Aug 2021
Application note L1 and L2 EV Charger Electric Vehicle Service Equipment Design Considerations (Rev. B) 09 Jun 2021
Application note Minimize Standby Consumption for UCC287XX Family 01 Aug 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Technical article Making a solar inverter more reliable than the sun 01 Aug 2017
Technical article Common challenges when choosing the auxiliary power supply for your Server PSU 20 Mar 2017
Application note Troubleshooting TI PSR controllers 03 Oct 2016
Technical article USB Wall Chargers: Conveniences and Challenges 06 Oct 2015
White paper Control Challenges for Low Power AC/DC Converters 02 Oct 2015
White paper Control Challenges for Low Power AC/DC Converters (PPT) 02 Oct 2015
User guide Using the UCC28700EVM-068 (Rev. A) 16 Sep 2015
Technical article Designing multiple output converters with primary side sensing 04 Aug 2015
Application note Analysis of Starting Up Performance for UCC28700 11 Mar 2014
Application note UCC28700 5-W USB Flyback Design Review (Rev. C) 21 Feb 2014
More literature Exposing the Inner Behavior of a Quasi-Resonant Flyback Converter 29 Oct 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

UCC28700EVM-068 — UCC28700 evaluation module

The Texas Instruments UCC28700EVM-068 evaluation module (EVM) helps designers evaluate the performance of the UCC28700 Constant-Voltage, Constant-Current PWM with Primary-Side Regulation. The 5W EVM is used for evaluating an off line adapter for USB applications. It converts a 90V to 265V RMS (...)
In stock
Limit: 3
Evaluation board

UCC28711EVM-160 — UCC28711 evaluation module

The Texas Instruments UCC28711EVM-160 evaluation module (EVM) helps designers evaluate the performance of the UCC28711 Constant-Voltage, Constant-Current PWM with Primary-Side Regulation. The 5W EVM is used for evaluating an off line adapter for USB applications. It converts a 90V to 265V RMS (...)
In stock
Limit: 3
Evaluation board

UCC28720EVM-212 — UCC28720EVM-212 5W Evaluation Module for USB off-line adapter

The UCC28720EVM-212 is a 5W evaluation module for evaluating an off line adapter for USB applications. It is intended for evaluation purposes and is not intended to be an end product. The UCC28720EVM-212 converters 100V to 240V RMS input voltage down to 5V DC, with a 1A current limit for USB (...)
In stock
Limit: 3
Simulation model

UCC2870x PSPICE Transient Model

SLUM455.ZIP (131 KB) - PSpice Model
Simulation model

UCC2870x TINA-TI Transient Spice Model

SLUM617.ZIP (101 KB) - TINA-TI Spice Model
Simulation model

UCC2870x TINA-TI Transient Reference Design

SLUM619.TSC (195 KB) - TINA-TI Reference Design
Calculation tool

MathCAD Design Tool (Rev. C)

SLUC381C.ZIP (2519 KB)
Calculation tool

UCC28700 Excel 97 Design Tool (Rev. B)

SLUC408B.ZIP (205 KB)
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