| 摘要 |
The analogue-digital conversion unit uses a current source (1) with one earthed terminal and the other connected to a bridge circuit containing four transistors (2, 3, 6, 7,). A reference voltage (VR) is applied to the control terminal of the first transistor (2) and the input voltage (VI) to that of the third transistor (6). The second transistor, of p-conductivity type, (the others being n-conductivity type) is in series with the first, which is also in parallel with the fourth. An output is taken to a differential voltage device (14) which works in conjunction with an auxiliary reference voltage (VH1). The output comes from the fourth transistor, which is effectively in one arm of the bridge, and has a polarity dependent on whether the input voltage is greater or less than the reference voltage. |
