UCC28700-Q1 Compact primary-side regulation PWM controller with automotive grade | TI.com

UCC28700-Q1 (ACTIVE) Compact primary-side regulation PWM controller with automotive grade



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.


  • 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
  • < 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

WEBENCH® Designer UCC28700-Q1

AC Frequency  60 Hz  50 Hz
  Min   Max Range
VinRMS  V 85.0 to 500.0V
Vout  V 3.3 to 25V
Iout  A ≤ 10A
Ambient Temp  °C -20 to 125°C


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Part number Order Control method Duty cycle (Max) (%) Frequency (Max) (kHz) UVLO thresholds on/off (V) Features Operating temperature range (C) Package Group Rating Package size: mm2:W x L (PKG)
UCC28700-Q1 Order now Primary-side regulation     99     132     21/8     PSR
Low Power
Light Load Efficiency
Error Amplifier
Current Limiting
Green Mode
Input Line Monitor
Leading Edge Blanking    
-40 to 125     SOT-23 | 6     Automotive     6SOT-23: 5 mm2: 1.6 x 2.9 (SOT-23 | 6)    
LM5021-Q1 Order now Secondary-side regulation     80     1000     20/7.25     SSR
Frequency Synchronization    
-40 to 125     VSSOP | 8     Automotive     8VSSOP: 15 mm2: 4.9 x 3 (VSSOP | 8)    
UCC28600-Q1 Order now Secondary-side regulation     99     130     10.3/9.3     SSR
Error Amplifier
Green Mode
Light Load Efficiency    
-40 to 105     SOIC | 8     Automotive     8SOIC: 19 mm2: 3.91 x 4.9 (SOIC | 8)    
UCC28730-Q1 Order now Primary-side regulation     99     83     21/7     PSR
HV Start-up
Low Power
Light Load Efficiency
Current Limiting
Thermal Shutdown
Green Mode
Input Line Monitor
Leading Edge Blanking
Soft Start    
-40 to 125     SOIC | 7     Automotive     7SOIC: 29 mm2: 6 x 4.9 (SOIC | 7)