| 摘要 |
PURPOSE:To prevent production of nonlinear distortion by providing an external resistor between a source of an N-channel transistor (TR) among TRs composing an inverter circuit and the ground of an integrated circuit. CONSTITUTION:A filter 6 is connected to an output of a pulse width modulator converting a digital input signal into a pulse signal via an inverter circuit 5 being an integrated circuit 8 and an analog signal is obtained from an output of the filter 6. In this case, a variable resistor 13 is connected between the earth of the circuit 8 and the source of the TR 4 in the P-channel TR 3 and the N-channel TR 4. Thus, the difference of both ON-resistances is corrected by a resistor 13 to approach the discharge current I2 flowing from the filter 6 to the earth via the TR 4 to a charging current I1 of the TR 3 from the power supply to the filter 6, thereby preventing the production of nonlinear distortion.
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