POLARITY INVERSION CIRCUIT

PURPOSE:To form a small sized polarity inversion circuit with less noise without use of a filter circuit comprising a large capacitance capacitor and a choke coil by providing an LPF to an input of an inverting/noninverting signal. CONSTITUTION:When a noninverting signal is inputted to a terminal 15, a voltage (b) is outputted to constant current sources 5,6 and a voltage '0' is set to a constant current sources 7, 8 a current of the current source 6 flows to diode 10, a terminal 2, a load resistor 16, a terminal 1, a diode 9 and the current source 5. When an inverting signal whose voltage is (a) is inputted to the terminal 15, the voltage (b) is gradually decreased, and when an input voltage (c) of the current sources 7,8 is gradually increased, the noninverting output current is gradually decreased till the voltages (b), (c) are equal to each other and when the voltage (c) is larger than the voltage (b), the polarity of the output current is inverted.