Abstract: A signal transmission circuit includes an isolation circuit, first and second grounded gate circuits, first and second MOS transistors, and a comparator. The isolation circuit such as a thin-film transformer outputs complementary first and second output signals, based on an input signal. The first and second grounded gate circuits receive and amplify the first and second output signals, respectively. The first and second MOS transistors are connected between a power supply node and the first and second grounded gate circuits, respectively, for adjusting the first and second output signals. The comparator compares output from the first grounded gate circuit with output from the second grounded gate circuit.