| 摘要 |
PURPOSE:To improve the resolution of a linear output sensor together with reduction of the power supply voltage of an amplifier, by providing plural differential amplifiers, an analog switch and a switch control circuit. CONSTITUTION:The output of a pressure sensor 1 is connected to a non-reverse input terminal of each of differential amplifiers 31-33 via an amplifier 2. At the same time, a power supply V is divided by resistances R1-R4 and connected to the non-reverse input terminals of amplifiers 31-33 respectively. The amplifiers 31-33 divide the output voltage of the sensor 1 into three sections and amplify them according to each amplification characteristics. A switch control circuit 5 switches an analog switch 4 by the outputs of amplifiers 31-33 according to a specific section which is under amplification. Then the output of the switch 4 is connected to an A/D converter 6. Thus it is possible to secure the 8-bit resolution for each output voltage of the amplifiers 31-33. In such a way, the resolution of a linear output sensor is improved together with reduction of the power supply voltage of an amplifier. |
