UCC29950 High Efficiency CCM PFC/LLC Combination controller | TI.com

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High Efficiency CCM PFC/LLC Combination controller



The UCC29950 provides all the control functionality for an AC-to-DC converter with a CCM boost Power Factor Correction (PFC) stage followed by an LLC converter stage. The controller is optimized to allow ease of use.

Proprietary CCM PFC algorithms enable the system to achieve high efficiency, smaller converter size with high power factor. The integrated LLC controller enables a high-efficiency DC-to-DC conversion stage utilizing soft switching for low EMI noise. Integration of PFC control and LLC control in a combo controller allows the control algorithms to take advantage of information from both stages.

The controller includes a control circuit for start-up using a Depletion Mode MOSFET with internal device power management that minimizes external component requirements and helps lower system implementation costs.

To further reduce the standby power an X-Cap discharge circuit is integrated. The UCC29950 implements a complete suite of system protection functions, including AC line brownout, PFC bus under voltage PFC and LLC, over current and thermal shutdown.


  • High Efficiency PFC and Half-Bridge Resonant LLC Combo Controller
  • Continuous Conduction Mode (CCM) Boost Power Factor Correction
  • Supports Self-Bias or Auxiliary (external) Bias Mode of Operation
  • PFC Loops Fully Internally Compensated
  • PFC Stage Design in 3 Easy Steps
    (design voltage feedback, current feedback and power stage)
  • Fixed 100-kHz PFC Frequency with Dithering for Ease of EMI Compliance
  • True Input Power Limit, Independent of Line Voltage
  • Fixed LLC Frequency Operating Range of 70 kHz to 350 kHz
  • Dead-Time Varied Across Load Range for LLC Half-Bridge Power Stage to Extend ZVS Range
  • Three-Level LLC Over-Current Protection
  • Hiccup Mode Operation for Continuous Overload and Short-Circuit Power Protection
  • Low Standby Power Consumption Enabled by Active Control of High-Voltage Start-Up MOSFET and X-Cap Discharge Function
  • Built In Soft-Start and Converter Sequencing to Simplify Design
  • AC Line Brownout Protection, with Fail Indicator
  • PFC Bus Over-Voltage and Under-Voltage Protection
  • Over-Temperature Protection
  • External Gate Drivers for Scalability with Power Level
  • SOIC-16 Package


Compare all products in Power factor correction (PFC) controllers Email Download to Excel
Part number Order Device type Control method UVLO thresholds on/off (V) Operating supply (Max) (V) Operating supply current (mA) Operating temperature range (C) Rating Features Package Group Package size: mm2:W x L (PKG)
UCC29950 Order now PFC+LLC     CCM     16.2/7.9     18     8     -40 to 125     Catalog     Average Current Mode
SOIC | 16     16SOIC: 59 mm2: 6 x 9.9 (SOIC | 16)    
UCC28500 Samples not available PFC+PWM     CCM     16/10     18     4     -40 to 85     Catalog     Average Current Mode
PDIP | 20
SOIC | 20    
20PDIP: 229 mm2: 9.4 x 24.33 (PDIP | 20)
20SOIC: 132 mm2: 10.3 x 12.8 (SOIC | 20)    
UCC28510 Samples not available PFC+PWM     CCM     16/10     18     4     -40 to 105     Catalog     Average Current Mode
SOIC | 20     20SOIC: 132 mm2: 10.3 x 12.8 (SOIC | 20)