| 摘要 |
PURPOSE:To cancel the influence of variations in temperature and to integrate a sensor and a signal processing circuit into one chip by a method wherein a CMOS inverter is designed in such a manner that threshold voltages (absolute values) and circuit dielectric constants of a PMOS transistor and a NMOS transistor are equalized. CONSTITUTION:A PMOS 01 and a NMOS 02 both of which absolute values of threshold voltages and circuit dielectric constants are the same, are connected in series and the other sensor such as a photodiode acting as a current source is connected to the PMOS 01 or NMOS 02 in parallel. Thereby, a CMOS sensor of which output voltage is varied based on 1/2 of a source voltage as a reference value is formed. Each of outputs of the CMOS sensors 01, 02 is, for example, inputted to five inverter arrays 11-15 having logical thresholds of which values are gradually different. When the level is lower than the threshold voltage of the CMOS inverters 01, 02, (1) is outputted and when higher than the threshold voltage, (0) is outputted. These outputs are inverted and amplified by inverter arrays 21-25, then each of exclusive OR gates 31-34 takes (1) from border value of (0), (1) so that digital signal of, for example, 010000 is outputted. |
