Two Way Parallel Clipper Circuit

      
       In this circuit it is required to clip the portions of both positive and negative half cycles of the input. For this clipping at two different levels is required.

Note: Combining positive and negative clipper circuits with V_R, a two way parallel clipper can be obtained.

       The circuit diagram of two way parallel clipper is shown in the Fig 1.

Fig 1 two way parallel clipper

       Assume that the input is purely snusoidal in nature.

                      V_in = V_m sinωt

       The diodes D₁ and D₂ are ideal diodes.

1.1 Operation

       Positive half cycle of the input: When Vin goes positive till it becomes more than V₁, D₁ and D₂, both the diodes are reverse biased. And V_o= V_in

       When V_in >V₁, then D₁ becomes forward biased and conducts. While D₂ remains reveres biased for the entire positive half cycle of the input. This shown in the Fig 2 (a) and (b).

Fig 2 positive half cycle of input

       Thus when V_in < V₁, D₁ and D₂ are OFF and V_o=V_in

       While when V_in > V₁, D₁ is ON D₂ is OFF and V_o=V₁

       Negative half cycle of the input : In the negative half cycle, as long as V_in is greater then V₂, the diode D₂ remains reverse biased. The D₁ remains OFF for the entire negative half cycle of the input. This is shown in the Fig 3(a). The V_o= V₂ .

Fig. 3 negative half cycle of input

       When V_in becomes less than V₂, the diode D₂ becomes forward biased and conducts. The diode D₁ is still OFF. This is shown in the Fig 3 (b) where V_o= V₂. The output Vo is negative as the polarities of V₂ are opposite to that of V₁.

Fig 4 waveforms for two way parallel clipper

The input and output waveforms for the two way clipper are shown in the Fig 4.

 1.2 Transfer Characteristics

       The mathematical equations for the two way clipper are,

       The transfer characteristics are shown in the Fig 5.

Fig 5 transfer characteristics for two way parallel clipper

Note : Thus the circuit clips the input for both positive as well as negative half cycles and hence called two way parallel clipper circuit.