AC-to-DC Voltage Doubler

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The actual SPICE model of this circuit is shown in Fig. 10.2. Note that there are two resistors in series with each of the capacitors, Rl and R2. These resistors model the approximate equivalent series resistance (ESR) of the tantalum capacitors in the circuit at the switching frequency. 

This circuit was built in the lab using 1N4002 1A 100V rated diodes with 1 /U.F tantalum capacitors. The input pulse was a square wave from -3 V to +3 V, with a frequency of 5 kHz at a 50% duty cycle. The PULSE statement in the SPICE model is shown below  

The input pulse and the output DC voltage were measured using an oscilloscope. The result picture is shown in Fig. 10.3a. Unfortunately, the ripple on the breadboard was small enough to be swamped by the noise in the lab, and we were not able to make an accurate measurement. The IsSpice model result is shown in Fig. 10.3b. The top waveform is the output voltage and the bottom waveform is the input pulse. 

TABLE 10.1 Output Voltage Comparison between SPICE and Breadboard 

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