This is a very powerful buck converter design template tool that automatically computes all the parameters for a buck converter. No need to do long calculations as this template will give everything. All you have to do is to input your design requirements and that’s it.
You can use this template for either non-synchronous and synchronous buck converter topologies. There are notes in the design template so you can understand for what this parameter to. The good thing of this design template is that you can counter check the design equations.
Requirements for this Buck Converter Design Template:
A computer with Mathcad 14 or 15.
Parameters Covered in this Buck Converter Design Template Mathcad
Below are some of the key features of this buck converter design template. They are all derived in detailed.
1. Upper and lower switch (Q1 and Q2)
1.1 RMS and peak current
1.2 Drain voltage
1.3 Power losses, conduction and switching
1.4 Thermal consideration
2. Catch diode (D1)
2.1 RMS and peak current
2.2 Peak reverse voltage
2.3 Power losses
2.4 Thermal consideration
3. Inductor (L1)
3.1 RMS and saturation current
3.2 Power losses
3.3 Ripple current
4. Output Capacitor (C1)
4.1 RMS ripple current
4.2 Output ripple voltage requirement
4.3 Voltage rating
Also covered in this design template are thermal calculations and predictions, efficiency and operation mode checking.
Derivations of Equations Buck Converter Design Template
If you want to validate the credibility of this buck converter design template, you can check the derivations in the upper portion of the template. Few snapshots below on how the derivations done.
These are complete derivations following power electronics principles.
Proven Design Template
This is a proven design template. All calculated results are matching with simulations and very close to actual values. This is being used by all the buck converter I designed and released to the market. Should you have any questions regarding the template once you have it downloaded, I am very willing to help you. The template is not locked, so you can do whatever you want. Try it now!
Sample Design: 24V to 5V 100A
This is not the intensive content of the template but only some important sections.
Given Values
The voltage drop of the MOSFET switch used is estimated in the template. However, you can put zero into it if you want to get the ideal values. Meanwhile, the voltage drop of the diode is also estimated and put in the template. You can also zero the value if you like.
The switching frequency is required to size the correct components. The output ripple voltage is also specified in the template. In addition, the templates also needing the percentage ripple to size up the inductance.
Duty Cycle
This is the duty cycle corresponds to the input values.
Inductor Selection
The computed inductance is 0.365uH but we opt to select a 1uH inductor.
Inductor RMS Current
The RMS current of the inductor is given below. Select an inductor with current rating higher than this value.
The template is asking also for the estimated DC resistance of the inductor selected for efficiency computation later.
MOSFET Q1 Selection
The RMS and DC values of the current flowing to MOSFET are given below. Select a MOSFET with a current rating far higher than these values to ensure reliability.
There are green fields asking MOSFET parameters. Fill them up to get the power losses.
The computed power losses of the MOSFET are below.
Diode D1 Selection
The RMS and DC values of the diode are computed below. Select a diode with current rating much higher than these.
Output Capacitor Selection
The minimum output capacitance needed is calculated below. Take note that the capacitor ripple current rating must be higher than the computed ripple current below.
Efficiency Calculation
The efficiency calculated by the template is given below.
