SLVUBB4B November   2017  – February 2023

 

  1.   Abstract
  2.   Trademarks
  3. 1 Topologies Window
  4. 2 FET Losses Calculator
  5. 3 Load Step Calculator
  6. 4 Capacitor Current Sharing Calculator
  7. 5 AC/DC Bulk Capacitor Calculator
  8. 6 RCD-Snubber Calculator for Flyback Converters
  9. 7 RC-Snubber Calculator
  10. 8 Output Voltage Resistor Divider
  11. 9 Dynamic Analog Output Voltage Scaling
  12. 10Dynamic Digital Output Voltage Scaling
  13. 11Unit Converter
  14. 12Loop Calculator
    1. 12.1 Inputs
    2. 12.2 Transfer Functions
      1. 12.2.1  Output Impedance Transfer Function
      2. 12.2.2  Transfer Function VMC Buck Power Stage
      3. 12.2.3  Transfer Function CMC Buck Power Stage
      4. 12.2.4  Transfer Function CMC Boost Power Stage
      5. 12.2.5  Transfer Function CMC Inverting Buck-Boost Power Stage
      6. 12.2.6  Transfer Function CMC Forward Power Stage
      7. 12.2.7  Transfer Function CMC Flyback Power Stage
      8. 12.2.8  Transfer Function Closed Loop
        1. 12.2.8.1 Transfer Function Type II Compensation Network
        2. 12.2.8.2 Transfer Function Type II Transconductance Compensation Network
        3. 12.2.8.3 Transfer Function Type III Compensation Network
      9. 12.2.9  Transfer Function Isolated Type II Compensation Network With a Zener Clamp
      10. 12.2.10 Transfer Function Isolated Type II Compensation Network Without a Zener Clamp
  15. 13Filter Designer
    1. 13.1 Impedances
    2. 13.2 Transfer Functions
    3. 13.3 Filter Output Impedance
    4. 13.4 Damping Factor
  16. 14Additional Information
  17. 15Revision History

10 Dynamic Digital Output Voltage Scaling

Dynamic output voltage adjustment can also be achieved by applying GPIO signals to an array of resistors and signal FET combinations in parallel with the low-side resistor of the feedback divider. For most cases, a microcontroller output in open-drain configuration can be used instead of an external signal FET because it is already part of the system. Power Stage Designer calculates the low-side feedback resistor, the voltage per step, the bias current, and the series resistance for each bit based on the output voltage range, the reference voltage, the number of bits, and the value of the high-side feedback resistor.

#T5147377-33 shows the Dynamic Output Voltage Scaling Calculator window.

GUID-C7D85D80-752F-45EA-AA31-560C46F91096-low.png Figure 10-1 Dynamic Output Voltage Scaling Calculator Window
I R 1 , m i n = V o u t , m i n - V r e f R 1
R 2 = R 1 × V r e f V o u t , m i n - V r e f
V s t e p = V o u t , m a x - V o u t , m i n 2 B i t s - 1
Equation 27. R B i t   n = 1 V o u t , m i n + 2 B i t × V s t e p - V r e f R 1 × V r e f - 1 R 2

The LM10011 is a device that has this feature integrated for 4/6-Bit VID.