UCC28703

ACTIVE

Constant-voltage, constant-current PWM with PSR, NTC option, and 300mV cable compensation

Product details

Operating temperature range (°C) -20 to 125 Control mode Primary-side regulation Topology Buck, Flyback Rating Catalog Features CC/CV output regulation, Cable compensation, DCM, Leading edge blanking, NTC resistor interface, Overcurrent protection, PSR, Primary-side regulated, Quasi-Resonant, Soft start, Valley switching Duty cycle (max) (%) 99
Operating temperature range (°C) -20 to 125 Control mode Primary-side regulation Topology Buck, Flyback Rating Catalog Features CC/CV output regulation, Cable compensation, DCM, Leading edge blanking, NTC resistor interface, Overcurrent protection, PSR, Primary-side regulated, Quasi-Resonant, Soft start, Valley switching Duty cycle (max) (%) 99
SOT-23 (DBV) 6 8.12 mm² 2.9 x 2.8
  • < 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) PDF | HTML 12 Dec 2014
Application note Flyback Aux Winding OVP and UVLO Fault Sensing Design and Troubleshooting Tips PDF | HTML 31 Aug 2021
Application note Minimize Standby Consumption for UCC287XX Family 01 Aug 2019
Application note Selecting Electrolitic Bus Capacitor for Universal Input 17 Jul 2018
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note Troubleshooting TI PSR controllers 03 Oct 2016
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
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 (...)
User guide: PDF
Not available on TI.com
Simulation model

UCC2870x PSPICE Transient Model

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

UCC2870x TINA-TI Transient Reference Design

SLUM619.TSC (195 KB) - TINA-TI Reference Design
Simulation model

UCC2870x TINA-TI Transient Spice Model

SLUM617.ZIP (101 KB) - TINA-TI Spice Model
Calculation tool

SLUC381 MathCAD Design Tool

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
UCC28700 Constant-voltage, constant-current PWM with PSR & Programmable cable compensation UCC28700-Q1 Compact primary-side regulation PWM controller with automotive grade UCC28701 Constant-voltage, constant-current PWM with PSR, NTC option, and 0 mV cable compensation UCC28702 Constant-voltage, constant-current PWM with PSR, NTC option, and 150mV cable compensation UCC28703 Constant-voltage, constant-current PWM with PSR, NTC option, and 300mV cable compensation
Calculation tool

SLUC408 UCC28700 Excel 97 Design Tool

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
UCC28700 Constant-voltage, constant-current PWM with PSR & Programmable cable compensation UCC28700-Q1 Compact primary-side regulation PWM controller with automotive grade UCC28701 Constant-voltage, constant-current PWM with PSR, NTC option, and 0 mV cable compensation UCC28702 Constant-voltage, constant-current PWM with PSR, NTC option, and 150mV cable compensation UCC28703 Constant-voltage, constant-current PWM with PSR, NTC option, and 300mV cable compensation
Package Pins CAD symbols, footprints & 3D models
SOT-23 (DBV) 6 Ultra Librarian

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  • MSL rating/Peak reflow
  • MTBF/FIT estimates
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  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

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