Four-Diode Three-Segment Triangular To Sine Wave Shaper

The circuit reshapes a triangular waveform into a segmented approximation of a sine wave. This version uses four diodes to produce an output with three segments per quarter cycle. When the magnitude of the input signal is at very low level all diodes are reverse-biased, the output voltage is determined simply from the voltage divider formed by Rs and Rload. As the magnitude of the input voltage increases, diode D4 (positive input voltage) and D3 (negative input voltage) are forward-biased. The current diverted to D3/D4 branch reduces the slope of the output voltage, this results to the second segment of the approximation to sine wave. As the magnitude of the input voltage further increases, diode D2 (positive input voltage) and D1 (negative input voltage) become forward-biased as well. The additional current diverted from the input further reduces the slope of the output voltage resulting to the third segment of the approximation to sine wave.