| 摘要 |
PURPOSE:To obtain the trans-impedance amplifier circuit having a wide dynamic range, with high mass-productivity and made by the Si-bipolar process not susceptible to the effect of dispersion in components. CONSTITUTION:When an output voltage increased by an increase in an input current, a diode D1 is turned ON and the trans-impedance is reduced, then a wide dynamic range is secured. Simultaneously since a diode D2 is turned ON, a load resistance of a transistor TR Q1 is reduced, the gain of an amplifier stage is reduced to prevent the reduction in the phase margin of a feedback circuit. Thus, a small collector current of the amplifier stage TR Q1 is adopted to secure a low noise characteristic. Since the feedback resistance/load resistance of the amplifier stage is varied based on a voltage of a P-N junction diode, the amplifier circuit is not susceptible to the effect of dispersion in components, and excellent power supply voltage/temperature fluctuation is attained and excellent mass-productivity is attained because the amplifier circuit is manufactured by the Si-bipolar process. |
