| 摘要 |
PURPOSE:To prevent an interference by a noise by a method wherein, in an IC, a ground wiring part of a micro current circuit and a ground wiring part of other circuits are connected by a MOS transistor, an output signal of a shot-pulse generation circuit is connected to a gate of the transistor and a capacity is added to a part between the ground wiring part of the micro current circuit and a substrate. CONSTITUTION:A noise prevention circuit is constituted of the following: a noise- generation circuit 1; a previous-stage circuit 2 of the noise-generation circuit 1; a micro current circuit 3; other circuits 4; a shot-pulse generation circuit 5; a MOS transistor Qf; a capacity Cf. When the circuit 5 constituted in this manner receives an output of the circuit 2, it outputs a generated waveform to a gate of the transistor Qf and controls its ON/OFF operation. That is to say, when a gate input is at H, a GND wiring part of the circuit 3 and a GND wiring part of the other circuits 4 are connected; when it is at L, they are cut off. Accordingly, when a large electric current is output to the circuit 2 from the circuit 1, it is received by the circuit 5; the transistor Qf is turned off from the time when a noise is generated by the large electric current to the time when it is attenuated; a GND potential is maintained stably by the capacity Cf. |
