| 摘要 |
<p>PURPOSE:To reduce the number of resistances and to eliminate the influence of temperature characteristics and improve waveform accuracy by providing a 1st generating means which increases or decreases in its current value with an input, a 2nd current generating means which generates a constant current when the input exceeds a specific value, and a converting means which converts the composite current of currents of both current generating means to a dummy waveform. CONSTITUTION:A voltage and current converting circuit 30 which generates a 1st current I1 with a linear functional increase or decrease tendency corresponding to the input voltage VIN. A voltage and current converting circuit 40, on the other hand, generates a 2nd current I2 which increases or decreases with the input voltage VIN similarly to the 1st current I1 up to a threshold voltage Vt as a constant reference voltage and becomes constant after the input voltage VIN reaches the threshold voltage Vt. Those currents I1 and I2 are summed up on the input-side line of a current mirror circuit 52 as the current converting means. Then the respective values R1-R3 of resistances 36, 50, and 54 are set optionally to obtain a desired dummy sin wave, thus obtaining the high-accuracy dummy waveform with a small number of resistances.</p> |
