Patent ID: 7589947

Claim:
A surge absorption circuit comprising: a pair of input terminals; a pair of output terminals; a first inductor device connecting one of the pair of input terminals and one of the pair of output terminals to each other; a second inductor device connecting the other of the pair of input terminals and the other of the pair of output terminals to each other; a first surge absorption part having a first surge absorbing device and connected in series between the one of the pair of input terminals and the other of the pair of output terminals; and a second surge absorption part having a second surge absorbing device and connected in series between the other of the pair of input terminals and the one of the pair of output terminals, wherein the surge absorption circuit determines a capacitance Cz, an inductance Lz, an impedance Z d0 and a coefficient Kz without a frequency, and the inductance Lz is determined to satisfy formula (A), where the Cz is a stray capacitance of each of the first and second surge absorption parts, the Lz is a coefficient of induction of each of the first and second inductor devices, the Z d0 is a characteristic impedance of a signal line in which the surge absorption circuit is inserted, the Kz is a coupling coefficient between the first inductor device and the second inductor device and the Kz satisfies 0≦Kz<1 Lz = Z d ⁢ ⁢ 0 2 ⁢ Cz 1 - Kz . ( A )