TIDUET3 Design guide

TIDUET3 February 2021

1
2
3
4
5
6
1. 7
8
1. 9
2. 10
3. 11
  1. 12
  2. 13
  3. 14
  4. 15
  5. 16
  6. 17
  7. 18
  8. 19
  9. 20
4. 21
  1. 22
    1. 23
    2. 24
    3. 25
    4. 26
    5. 27
    6. 28
    7. 29
    8. 30
  2. 31
    1. 32
    2. 33
    3. 34
    4. 35
    5. 36
    6. 37
    7. 38
    8. 39
    9. 40
    10. 41
    11. 42
    12. 43
44
1. 45
  1. 46
2. 47
  1. 48
    1. 49
  2. 50
    1. 51
      1. 52
      2. 53
    2. 54
      1. 55
      2. 56
      3. 57
      4. 58
      5. 59
      6. 60
      7. 61
62
1. 63
  1. 64
  2. 65
  3. 66
  4. 67
  5. 68
2. 69
3. 70
4. 71
5. 72
73

2.4.2.10 BLK Pin Voltage Divider

The BLK pin senses the LLC input voltage and determines when to turn on and off the LLC converter. Different versions of the UCC25640 have different BLK thresholds. Choose the bulk startup voltage at 360 V, then the BLK resistor divider ratio can be calculated:

Equation 45.

The desired power consumption of the BLK pin resistor is P_BLKsns = 10 mW. The total value of the BLK

sense resistor is given by:

Equation 46.

The lower BLK divider resistor value is given by:

Equation 47.

The higher BLK divider resistor value is given by:

Equation 48.