Switching Regulator Design Calculator

Switching Regulator design calculator is a calculation tool for switching voltage regulator. With this online calculator, you are able to calculate the Duty Cycle, inductor, current, diode power, etc. Therefore, you can design your own DIY switching circuits according to the output values.

Maximum Input Voltage (Vin(max))Volts

Nominal Input Voltage (Vin(nominal))Volts

Minimum Input Voltage (Vin(min))Volts

Output Voltage (Vout)Volts

Diode Forward Voltage (Vd)Volts

Maximum Output Current (Imax).Amps

Minimum Output Current (Imin)Amps

Maximum Output Voltage RipplemVpp

Current Sense Resistor. Choose .01 ohms if unsure.ohms

Top Feedback Resistor Rf1 Choose 10 Kohms if unsure.Kohms

Desired Switching Frequency (Fs)KHz

MOSFET On Timenano secs

MOSFET Off Timenano secs

MOSFET Gate ChargenC

Duty Cycle%

Ton(min) (Minimum Switch On Time)nano secs

Ton(max) (Maximum Switch On Time)nano secs

Maximum Diode PowerW

Maximum LM25085 PowerW

Maximum Current Sense Resistor PowerW

Inductor (L)uH

Current Limit (Icl).(Peak Inductor Current)Amps

Output Capacitor, (Cout)uF

Input Capacitor, (Cin)uF

Rf2KOhms

RTKOhms

Radjohms

Cadjpf

R3*C1 Product

C1pf

R3KOhms

C2uf

Overview of Switching Regulator Design Calculator

This tool assists in calculating the output voltage of switching regulators, helping to create optimal switching circuits. Additionally, you can explore other calculators in the Tools category, such as those for Resistor Color Codes, SMD Resistor Codes, Series and Parallel Resistor calculations, Ohm's Law, and converting dBm to Watts.

Introduction to Switching Regulators

What is a Switching Regulator?

Switching regulators are similar to linear regulators and are a type of DC to DC converter. These regulators utilize a power switch, diode, and inductor to transfer energy from the input source to the output. They are often referred to as switching converters or switched-mode power supplies (SMPS).

Types of Switching Regulators

Type	Description	Example
Buck Regulator	Used to reduce a higher input voltage to a lower output voltage.	MC34063 in buck mode, converts 12V to 5V.
Boost Regulator	Increases output voltage above the input voltage.	Generates 5V or 12V from a 3.7V lithium-ion battery.

Core Components of Switching Voltage Regulators

The table below lists the core components of a switching voltage regulator and their respective functions:

Component	Function
Transistor	Controls the voltage in the switching regulator, hence the name "Switching Regulator".
Inductor	A passive component that stores energy in an electrical circuit.
Capacitor	Stores energy in a circuit and is one of the most fundamental passive components.
Diode	Acts as a rectifier, allowing current to flow in one direction while blocking it in the opposite direction.

Examples of Switching Regulators

Example	Description
LM3671 Buck Converter	LM3671 is an IC circuit used for a basic switching regulator, including inductors and capacitors.
LM317 Voltage Regulator	The LM317 is a 3-terminal adjustable positive voltage regulator. You can calculate resistor values using an LM317 calculator.