Abstract: A surge protection circuit protection circuit includes a first series-connected line formed by at least two TVSs connected in series. One end of the line is connected to a positive terminal, and another is connected to a negative terminal. A second series-connected line is formed by at least one TSS. One end is connected between the at least two TVSs in the first series-connected line, and another end is grounded. The first line is connected in parallel to a protected circuit. When a differential-mode surge voltage appears at the ends of the first line, a voltage of a backend connection circuit is clamped to a first value. When a common-mode surge voltage appears at the two ends of the first line to the ground end, respectively, voltages to ground of the positive terminal and the negative terminal are reduced to a second value.

Abstract: A surge protection circuit protection circuit includes a first series-connected line formed by at least two TVSs connected in series. One end of the line is connected to a positive terminal, and another is connected to a negative terminal. A second series-connected line is formed by at least one TSS. One end is connected between the at least two TVSs in the first series-connected line, and another end is grounded. The first line is connected in parallel to a protected circuit. When a differential-mode surge voltage appears at the ends of the first line, a voltage of a backend connection circuit is clamped to a first value. When a common-mode surge voltage appears at the two ends of the first line to the ground end, respectively, voltages to ground of the positive terminal and the negative terminal are reduced to a second value.