Disclosed is an electrical stimulation circuit having a wide range of operating voltage while exhibiting excellent power efficiency. The disclosed electrical stimulation circuit includes a bias circuit comprising an NMOS transistor or a PMOS transistor. The bias circuit enables the transistors to operate at a stable voltage even when the operating voltage varies above or below a threshold value. The electrical stimulation circuit has a wide range of operating voltage while exhibiting excellent power efficiency, and occupies a small area, thereby being advantageous for miniaturization.
