Voltage Doubler Circuit With Working Operation

Generally, a conventional power supply system provides 230V AC supply which is being used for multiple electrical and electronics loads. But, a few loads or electronics equipment like cathode ray tubes, X-ray systems, Ion pumps, electrostatic system, laser systems, traveling wave tube, and so on requires a high rating power supply for their operation. Thus, the available voltage has to be multiplied using the voltage multipliers. The voltage multiplier is an electrical circuit comprising of diodes and capacitors that can be used for multiplying or increasing the voltage and convert AC to DC by multiplying voltage and rectifying current. There are different types of voltage multipliers such as voltage doubler, voltage more triple, and voltage quadruple. Primarily, we are going to discuss the voltage doubler circuit diagram and voltage doubler working.

Voltage Doubler

An electronic voltage multiplier circuit that doubles the voltage by using the charging and the discharging principle of capacitors is called a voltage doubler. It consists of major electronics components such as capacitors and diodes.

The simple voltage doubler circuit consists of two capacitors and two diodes connected as shown in the figure. The voltage doubler circuit can be a simple rectifier which takes an input AC voltage and generates an output DC voltage that is approximate twice the input AC voltage. Even though there are DC to DC voltage doublers, but in these types of voltage doubler circuits driving circuit is required for switching control. There are different types of voltage doubler circuits such as a simple voltage doubler, as shown above, voltage doubler using 555 timer, voltage doubler rectifiers like Villard circuit, Greinacher circuit, bridge circuit, switched capacitor circuits, Dickson charge pump, cross-coupled switched capacitors.

Voltage Doubler Using 555 Timer

This voltage doubler using 555 timers is a simple DC voltage multiplier that utilizes capacitors, diodes, and IC 555 timer in astable mode. Hence, it produces a square wave approximately at 2KHz frequency with the help of R1, R2, and C1 as shown in the figure. The forward-biased diode D2 and C3 are connected such that for amplifying the signals. The diode D1 prevents the complete discharge of the capacitor C3.

Thus, these basic components such as capacitors C3, C4, diodes D1, and D2 are used for boosting the input power. As the components are selected with appropriate ratings, the circuit accepts the input supply voltage ranging from 3V to 12V. If the input supply voltage exceeds this range, then the IC 555 may get permanently damaged. The diodes used in this circuit are 1N4007, if we use other diodes such as 1N4148, then the output voltage decreases due to different breakdown voltages.

Practical Voltage Doubler Project

Step up 6V DC to 10V DC using 555 timers is a practical voltage doubler project, which consists of different blocks such as power supply block for giving input supply voltage to the circuit, 555 timers that is connected in the astable mode for developing a DC square wave, multiplier block, output voltage measurement block.

The square wave voltage developed by 555 timer IC connected in astable mode is used as input for voltage multiplier or voltage doubler block. Thus, the voltage doubler circuit multiplies the input voltage for generating an output voltage that is approximately equal to twice the input voltage. Here, in this case, the output voltage is approximately 10V DC.

The 555 timer output voltage is made to pass through the voltage doubler for producing a double output voltage. But, for maintaining good regulation and to avoid output voltage from falling below the estimated level, we must restrict the load to less than 5mA. Thus, by eliminating the high current drawing loads we can avoid the poor voltage regulation.

By adding more number of multiplier stages, we can obtain an output voltage that is equal to three to ten times the input voltage.

Voltage Doubler Circuit for High Voltage DC using Diode and Capacitors

This voltage doubler project is designed for generating high output voltage around 2kV DC by giving an input supply of 230V AC. Conventionally, step-up transformers are used for stepping up the voltage levels. But, these conventional step-up transformers increase the output voltage and decreases the current. Hence, voltage multipliers are used for stepping up the voltage where high voltages and low currents are required, and these voltage multipliers convert AC to DC.

The electrical and electronic appliances such as CRT’s, television picture tubes, and industrial applications require the generation of high DC voltages around 10kV using this concept. But, here in this project, only 2kV is generated by limiting the multiplication factor to 8 for safety reasons.

The block diagram of high voltage DC generation using diodes and capacitors is shown in the figure which consists of major blocks such as a series lamp, supply, ladder network of diodes and capacitors, voltage doubler circuit, cascade circuit, potential divider.

This project works on the principle of the voltage doubler circuit, in every stage, the voltage multiplier goes on doubling the voltage. Hence, from the 8 stages, the voltage multiplier generates an output voltage around 2kV DC. But, measuring this high DC voltage using a standard multiplier is not possible. Hence, a potential divider of 10:1 is used for measuring purposes. Thus, if the output reading is 200V, then the actual output voltage is 2kV. But, again the multimeter consists of low input impedance which reads the output voltage as approximately 7 times the supply AC voltage.

For more technical information regarding the voltage doubler and innovative electronics projects, you can feel free to approach us by posting your queries in the comments section below.