STDA011 September   2025 UCC25661

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Benefits of GaN In LLC Resonant Converter
    1. 2.1 Higher Efficiency
    2. 2.2 Faster Switching Speeds
    3. 2.3 Reduced Parasitic Capacitances
    4. 2.4 Improved Power Density
    5. 2.5 High Thermal Conductivity
    6. 2.6 Lower Junction Temperatures
  6. 3LLC Resonant Converter
    1. 3.1 The Relationship Between Output Voltage (VOUT) and Switching Frequency (fS) in an LLC Resonant Controller
      1. 3.1.1 The LLC Charging Challenge
      2. 3.1.2 A Wide VIN/VOUT Capable LLC
  7. 4Practical Application of LLC Converters for a Battery Charger Leveraging GaN Switches
    1. 4.1 Requirements and Scope
    2. 4.2 Charging Curve for Lithium-Ion Battery
    3. 4.3 How to Support Wide VOUT Range in an LLC Design for Battery Chargers
    4. 4.4 The Prototype Hardware
  8. 5Summary

4.1 Requirements and Scope

  • Charge current, 1A – 8A
  • Wide VOUT regulation, 14V – 28V
  • Max component temperature < 60°C @ 25°C ambient
  • No ventilation, no heat sink
  • Low standby power
    • Target to fulfill CoC Tier 2 standard (200W rating)
Table 4-1 COC Tier 2 Single-Voltage External AC-DC Power Supply, Basic Voltage
Nameplate Output Power (POUT) Minimum Average Efficiency in Active Mode (expressed as a decimal) 10% Load Average Efficiency in Active Mode (expressed as a decimal) Maximum Power in No-Load Mode (W)
0.3W≤POUT ≤ 1W ≥ 0.50×POUT + 0.169 ≥0.50×POUT + 0.160 ≤0.075
1W≤POUT ≤49W ≥ 0.071×in(POUT)" 0.00115xPOUT + 0.670 ≥ 0.071×in(POUT)" 0.00115xPOUT + 0.570 ≤0.075
49W≤POUT ≤250W ≥0.890 ≥0.790 ≤0.150
POUT > 250W N/A N/A N/A