Dielectric elastomer actuators (DEAs) are flexible and thin. They consume little electrical power but high voltage is required to drive DEAs. One research issue is to scale down high-voltage circuits (HVC) to construct untethered soft robots. In particular, circuits that can supply high voltage to multiple DEAs are critical for complex control of applications. In this study, we propose a design methodology for a HVC with four output ports. We develop the HVC in two steps and compare the sizes and weights of the different modifications (HVC ver.l, 2, and 3). The size and weight of the HVC ver.3 are 5024 mm² (80-mm diameter) and 56.5 g, respectively, which are 112.33 g lighter and 1600 mm² smaller than ver.l. Furthermore, the circuit weight required to build each output port was 14.13 g, the lightest among the previous studies. Because applying a voltage induces large current flows in the DEA, transients in the voltage waveform output from the HVC should be eliminated. Here, improving the transmitting command method from the microcontroller eliminates the transients in the high-voltage output waveform. We also compare the area strains of DEAs driven by HVC ver.3 and a desktop high-voltage equipment. The area strain of DEAs driven by HVC ver.3 does not return to 0% when the voltage is 0 V since the accumulated charge in the DEAs is not released immediately. However, the peak-to-peak area strain during the cycle is 4.6% for HVC ver.3 and 5.1% for the desktop high-voltage equipment, a difference of only 0.5%. This research should contribute to the realization of a system that simultaneously controls multiple DEAs or high-voltage actuators.