SLUAAB9A March   2021  – December 2021 UCC25800-Q1

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Open-Loop LLC Converter Operation Principle
  4. 3 Primary-side and Secondary-side Resonant Configurations
  5. 4 Rectification Methods
    1. 4.1 One Resonant Capacitor, Voltage Doubler
    2. 4.2 Two Resonant Capacitors, Voltage Doubler
    3. 4.3 One Resonant Capacitor, Full-wave Rectifier
  6. 5  LLC Transformer Design Steps
    1. 5.1 Transformer Turns Ratio Selection
    2. 5.2 Transformer Volt-second Rating Calculation
    3. 5.3 Transformer Construction
    4. 5.4 Transformer Winding Selection
    5. 5.5 Transformer Inductance
      1. 5.5.1 Leakage inductance
      2. 5.5.2 Magnetizing inductance
    6. 5.6 Transformer Selections
  7. 6 Negative Voltage Generation
    1. 6.1 Using a Zener Diode
    2. 6.2 Using a Shunt Regulator
    3. 6.3 Using a Shunt Regulator and Linear Regulator
  8. 7 Multiple-output Design
    1. 7.1 One UCC25800-Q1 Drives Each Output
    2. 7.2 Transformer With Multiple Secondary-side Windings
    3. 7.3 Multiple Transformers
  9. 8 EMI Performance
    1. 8.1 EMI Performance With Standalone Converter
    2. 8.2 EMI performance with an inverter power stage
  10. 9 Common-Mode Transient Immunity (CMTI)
  11. 10Summary
  12. 11Revision History

5.6 Transformer Selections

To simplify the design process, different transformer vendors have designed and released stardard LLC transformers for the isolated bias supply applications. In Table 5-2 , there is a summarized set of transformers that can be used together with UCC25800-Q1 for the typical input and output voltage for different applications. This list is not exhaustive and there are many other standard transformers that work for this type of application.

Table 5-2 List of Transformers for Typical Input and Output Voltages
Input voltage VIN Output voltage VOUT Transformer turns ratio needed Manufacturer: Part number (Turns ratio) Isolation rating
12 V 5 V 2:1 Wurth: 750319831 (2.2:1) 4000VAC
Coilcraft: ZC1576-AL (2:1) 1500VAC
12 V 1.08 Wurth: 750319331 (1:1) 4000VAC
Wurth: 750319688 (1:1)1 3125VAC
Wurth: 750319834 (1.08:1) 4000VAC
Wurth: 750319848 (1:1)12 3125VAC
15 V 1:1.33 Wurth: 750319835 (1:1.29) 4000VAC
Coilcraft: ZC1580-AL (1:1.33) 1500VAC
18 V 1:1.58 Wurth: 750319836 (1:1.57) 4000VAC
Sumida: 13399-T052 (1:1.5) 1800VAC
24 V 1:2.08 Wurth: 750319831 (1:2.2) 4000VAC
Coilcraft: ZC1576-AL (1:2) 1500VAC
15 V 5 V 2.5:1 Wurth: 750319831 (2.2:1) 4000VAC
Coilcraft: ZC1582-AL (2.5:1) 1500VAC
12 V 1.15:1 Wurth: 750319833 (1.2:1) 4000VAC
15 V 1:1.07 Wurth: 750319331 (1:1) 4000VAC
Wurth: 750319688 (1:1)1 3125VAC
Wurth: 750319834 (1.08:1) 4000VAC
Wurth: 750319848 (1:1)12 3125VAC
18 V 1:1.27 Wurth: 750319835 (1:1.29) 4000VAC
Coilcraft: ZC1580-AL (1:1.33) 1500VAC
24 V 1:1.67 Wurth: 750319177 (1:1.67) 2500VAC
Coilcraft: ZC1581-AL (1:1.67) 1500VAC
24 V 12 V 1.85:1 Wurth: 750319832 (1.83:1) 4000VAC
Renco: RLTI-1430 (1.85:1)3 6000VAC
15 V 1.5:1 Wurth: 750319836 (1.57:1) 4000VAC
Sumida: 13399-T052 (1:1.5) 1800VAC
18 V 1.26:1 Wurth: 750319833 (1.2:1) 4000VAC
24 V 1:1.04 Wurth: 750319331 (1:1) 4000VAC
Wurth: 750319688 (1:1)1 3125VAC
Wurth: 750319834 (1.08:1) 4000VAC
Wurth: 750319848 (1:1)12 3125VAC
30 V 12 V 2.31:1 Wurth: 750319831 (2.2:1) 4000VAC
15V 1.88:1 Wurth: 750319832 (1.83:1) 4000VAC
Renco: RLTI-1430 (1.85:1)3 6000VAC
18 V 1.58:1 Wurth: 750319836 (1.58:1) 4000VAC
24 V 1.2:1 Wurth: 750319833 (1.2:1) 4000VAC
  1. Low profile design
  2. Dual outputs
  3. 16 mm between primary-side pins to secondary-side pins