Roberto Scibilia
UCC28810 Mathcad Design Tool
This Mathcad design tool was developed to use
with the UCC38050 application note SLUU138.
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Line Frequency
Minimum Input Voltage
Maximum Input Voltage
Maximum Output Power
Output Voltage
Minimum Switching Frequency
Period of one Line Cycle
Amount of holdup voltage
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1. Inductor Size Selection and Turns Ratio (N)
Predicted Efficiency
2. Boost Switch Selection (Q1)
a. The power budget for Q1 was selected to < 2.5W.
b. Critical FET Data Sheet Specifications
Total FET loss is < 2.5W
3. Diode D1 selection
a. The power budget for D1 was selected to < 2.5W.
b. A HFA08TB60S
c. Critical Boost Diode Data Sheet Specifications
Diode loss is < 2.5W and meets the power budget.
4. Calculate the Minimum Holdup Capacitance Required and the RMS Current Going Through the
Choose a standard value capacitor to meet the design requirements.
5. Calculate Minimum Input Holdup Capacitance Required
Choose a standard value capacitance.
6. Select a Current Sense Resistor
Choose a standard value resistor.
7. Multiplier Setup
Choose a standard value
8. Voltage Loop Compensation
Choose a standard value
Choose a standard value
Choose a standard value
9. Graphicaly Check Voltage Loop Compensation
Note the loop has roughly 45 degrees of phase margin at crossover.
10. Input Filter Design
Choose a standard value