Charge pump voltage calculator

Enter the input voltage, choose whether that value is peak, RMS, or peak-to-peak, and set the number of doubler stages. The calculator converts the source to peak amplitude and applies the ideal multiplier of twice the stage count. It also reports the normalized peak voltage and multiplication factor so the electrical convention behind the answer remains visible.

Define the input voltage before multiplying it

A voltage multiplier is driven by an alternating waveform, but voltage sources are not always described with the same convention. A function generator may display peak-to-peak voltage, a transformer secondary is normally rated in RMS volts, and a circuit exercise may provide peak amplitude directly. Those three values are not interchangeable. This calculator first converts the entered value to positive peak amplitude. A peak input is used as entered. For a sinusoidal RMS input, peak voltage is RMS voltage multiplied by the square root of two. For a peak-to-peak input, peak voltage is one half of the entered value. The RMS conversion assumes a sine wave; it is not generally valid for a square, triangular, clipped, or irregular waveform. Selecting the correct input type is therefore as important as entering the correct number. The normalized peak value appears in the result, making it easy to check the conversion before using the calculated output in a design or report.

Apply the Cockcroft-Walton stage convention

The calculation uses a precise stage definition to avoid a common source of disagreement between multiplier diagrams. Here, one stage means one Cockcroft-Walton doubler section, and each ideal stage adds twice the input peak voltage to the no-load output. The formula is ideal output voltage equals two multiplied by the number of stages multiplied by the input peak voltage. A three-stage multiplier driven by a 12 V peak waveform therefore has a multiplier of six and an ideal output of 72 V. Some schematics count individual capacitor-diode cells, ladder columns, or total capacitors instead of complete doubler stages. A value copied from such a diagram may need to be converted before it is entered here. Check how the source labels its stages rather than relying only on component count. The returned voltage multiplier, equal to twice the entered stage count, makes this convention explicit and lets you compare the result with the notation used by a textbook, simulation, or manufacturer.

Understand why a real circuit produces less

The result is an ideal no-load ceiling, not a prediction of the voltage available from a built circuit. It assumes perfect diodes with no forward drop, capacitors with no leakage or equivalent series resistance, a source with zero impedance, enough settling time, and no output current. Real multipliers lose voltage across conducting diodes and sag as load current discharges the capacitors between charging peaks. Ripple and sag generally become more important as the stage count rises, the load current increases, the capacitance decreases, or the drive frequency falls. Diode reverse-voltage ratings, capacitor voltage ratings, inrush current, insulation, clearances, and stored energy also remain design constraints even when the arithmetic looks simple. Use this ideal result to establish the theoretical multiplication ratio, compare topologies, or perform an early feasibility check. For component selection or safety decisions, follow it with a loaded-circuit analysis or simulation that includes diode characteristics, capacitance, frequency, source resistance, tolerances, and the intended load.