Patent ID: 7405919

Claim:
An electronic circuit, comprising: a power supply circuit which generates a supply voltage to be supplied to an integrated circuit; a transmission line type noise filter, comprised of a signal input terminal, a signal output terminal and two ground terminals corresponding respectively to the signal input terminal and the signal output terminal, which removes a high-frequency component of direct-current voltage applied to the signal input terminal and outputs the direct-current voltage from the signal output terminal; and a printed-circuit board on which said power supply circuit and said transmission line type noise filter are mounted on a same surface thereof, said printed-circuit board including: a first power supply line pattern which connects an output terminal of said power supply circuit with the signal input terminal of said transmission line type noise filter; a second power supply line pattern which connects the signal output terminal of said transmission line type noise filter with a power supply terminal of the integrated circuit; and a ground land pattern, connected with an external ground potential, which makes a connection between the two ground terminals, wherein the first power supply line pattern, the second power supply line pattern and the ground land pattern are formed on a mounting surface of said power supply circuit and said transmission line type noise filter.