Voltage Multiplier Circuits, Doubler, Tripler, Four Time Voltage

Voltage Multiplier Circuits

In some applications the dc output voltage required may be much more than that can be obtained from 230V. 50Hz source by single converter. In many case ac voltage may be suitably stepped up by a transformer and then rectified to obtain the required dc output voltage. Son increase the circuit cost.

The voltage multiplier can be classified as into two types

  1. Voltage doublers Rectifier
  2. Voltage doublers Circuit
  3. Voltage Multiplier

Voltage doubler Rectifier

The voltage doubler rectifier perform the output voltage is twice time of the input voltage. This operation can be performed the Diode D1,D2 and the charging and discharging capacitor (C1 & C2).

The input source A terminal connected to positive terminal and B terminal connected to negative terminals. When positive cycle of the input through the A terminal to Diode D1 get forward bias and connected capacitor C1to peak voltage at ωt = π/2 is charged positive. And another negative cycle through the B terminal to Diode2 conduct and corresponding capacitor C2 to peak voltage Vm at ωt = 3π/2 is positive. Since the two times the peak value of ac source voltage appears across load terminals as direct voltage with upper terminal positive and lower terminal negative. The capacitor C1 and C2 must be large enough to assure smooth dc output voltage. The output dc voltage of 2Vm is available only under ideal circuit elements. Actually output dc voltage would be less than 2Vm due to volt –drops in the circuit elements.

Voltage doubler rectifier

Voltage Doubler Circuit

A voltage doubler circuit with two diode D1 & D2 and two capacitor C1 and C2 and single – phase ac source voltage. When positive half cycle ‘A’ terminal the D1 is forward biased and a current flows through the source C1 and D1 hence the charge to peak value Vm of source voltage at ωt = π/2 just after ωt = π/2 diode D1 is reverse biased and there is thus no current in the circuit formed by source. The capacitor C1 anyway reserve the voltage Vm.

See also  What is Clipper, Types, IC 741, Series, Shut Clipper, Application

During negative half cycle the charge polarity is reverse D2 is reversed at a ωt = π/2 the current flow direction is C1 and source and C2 and diode D2. As a result capacitor C2 begins to charge with positive. Charge C2 get charged to 2Vm with positive

Voltage – doubler circuit

Thus load voltage is 2Vm which is twice the input peak voltage. Load voltage polarity can be reversed if diodes D1 and D2 are reversed.

Voltage Multiplier

The voltage multiplier output dc voltage is n times the input ac peak voltage when n= 2,3,4,5,6…. Here voltage quadrupler with n = 4 is discussed. The voltage quadrupler circuit is used to transformer four diodes D1 , D2, D3, D4 and capacitor C1 , C2, C3, C4.

The diode D1 & D2 and corresponding capacitance C1 , C2 multiples the voltage level at 2Vm and the D1 , D2, D3 and corresponding capacitance C1 , C2, C3 multiples the voltage level at 3Vm and The diode diodes D1 , D2, D3, D4 and corresponding C1 , C2, C3, C4 multiplies 4Vm

Leave a Comment