| 摘要 |
PURPOSE:To decrease remarkably the DC offset and temperature drift of a phase circuit by making the impedance viewed from a common connecting point of switch elements connected in series between a load and ground equal for the load side and the ground side. CONSTITUTION:The common connecting point between FETs Q4, Q6 being switch elements connected in series between the load and ground is grounded via a resistor 40. The FETs Q3, Q4 are turned on/off by a reference signal from terminals D1, D1' of a drive circuit 10 alternately. The rectangular waveform of the reference signal is leaked to the drain or source and the result appears as a a spike, but since the common connecting point is grounded via the resistor 40, the phase detecting circuit viewed from the drive circuit side is made symmetrical together with the load connected thereto, positive/negative spike electric charges flow equally to the load side and ground side, causing the DC offset component at the load side to be zeroed. |
