Compact primary-side regulation PWM controller with automotive grade


Product details


Control mode Primary-side regulation Frequency (Max) (kHz) 132 UVLO thresholds on/off (V) 21/8 Duty cycle (Max) (%) 99 Features PSR, DCM, Low Power, Light Load Efficiency, Error Amplifier, Current Limiting, Green Mode, Input Line Monitor, Leading Edge Blanking, Soft Start, Automotive Qualified Operating temperature range (C) -40 to 125 Rating Automotive TI functional safety category Functional Safety-Capable Device type Controllers Topology Buck, Flyback open-in-new Find other Flyback controllers

Package | Pins | Size

SOT-23 (DBV) 6 5 mm² 2.9 x 1.6 open-in-new Find other Flyback controllers


  • Qualified for Automotive Applications
  • AEC-Q100 Qualified with the Following Results:
    • Device Temperature Grade 1: –40°C to 125°C
    • Device HBM Classification Level 2: ±2 kV
    • Device CDM Classification Level C4B: 750 V
  • Functional Safety-Capable
  • < 30-mW Standby Power Consumption
  • Primary-Side Regulation (PSR) Eliminates Opto-Coupler
  • ±5% Voltage and Current Regulation
  • 130-kHz Maximum Switching Frequency
  • 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
  • SOT23-6 Package
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The UCC28700-Q1 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-Q1 allows 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-Q1 allows the level of cable compensation to be programmed.

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Technical documentation

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Type Title Date
* Data sheet UCC28700-Q1 Constant-Voltage, Constant-Current Controller With Primary-Side Regulation datasheet (Rev. A) Dec. 08, 2020
Application note UCC28700-Q1 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA Aug. 18, 2020
Application note Increase Traction Inverter System Robustness With a HV to LV Backup Supply (Rev. B) Oct. 09, 2019
Application note Minimize Standby Consumption for UCC287XX Family Aug. 01, 2019
Selection guide Power Management Guide 2018 (Rev. R) Jun. 25, 2018
Technical article Hybrid electric vehicles and electric vehicles need different isolated DC/DCs to win Dec. 27, 2017
Application note Troubleshooting TI PSR controllers Oct. 03, 2016

Design & development

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

Hardware development

UCC28700 evaluation module
document-generic User guide
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 input (...)
  • <30mW no load power for 5 star rating
  • Primary Side Regulation (PSR) eliminates opto-coupler
  • +/- 5% Voltage & Current Regulation
  • 130 KHz max. switching frequency enables high power density charger designs
  • Quasi-resonant valley switching operation for highest overall efficiency
  • Wide VDD range (35V) allows (...)

Design tools & simulation

SLUM455.ZIP (131 KB) - PSpice Model
SLUM617.ZIP (101 KB) - TINA-TI Spice Model
SLUM619.TSC (195 KB) - TINA-TI Reference Design
SLUC381C.ZIP (2519 KB)
SLUC408B.ZIP (205 KB)

Reference designs

98.6% Efficiency, 6.6-kW Totem-Pole PFC Reference Design for HEV/EV Onboard Charger
TIDA-01604 — This reference design functions from a base of silicon carbide (SiC) MOSFETs that are driven by a C2000 microcontroller (MCU) with SiC-isolated gate drivers. The design implements three-phase interleaving and operates in continuous conduction mode (CCM) to achieve a 98.46% efficiency at a 240-V (...)
document-generic Schematic
Primary-Side Regulated Flyback Converter for Electric Vehicle Battery Monitoring Reference Design
PMP20583 — PMP20583 is a primary-side regulated flyback reference design which provides a ground referenced 5V output and an isolated 5V output at up to 80mA each from an input voltage of 37V to 125V. This design uses the UCC28700-Q1 flyback controller for constant voltage and constant current control of the (...)
document-generic Schematic
90 to 110Vin 12Vout @ 0.3A Non-Sync Buck Converter Reference Design
PMP10739 PMP10739 is a 3.6W buck converter using the UCC28700 controller IC. The design accepts an input voltage of 90Vin to 110Vin and provides an output of 12Vout capable of supplying 0.3A of current to the load. The UCC28700 has a frequency dithering feature for reduced EMI.
document-generic Schematic

CAD/CAE symbols

Package Pins Download
SOT-23 (DBV) 6 View options

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