| 摘要 |
The pressure-sensitive amplifier stage comprises four unipolar pressure--sensor transistors (12, 14, 16, 18), each comprising a piezoresistive current path (12d, 14d, 16d, 18d). The pressure-sensor transistors (12, 14, 16, 18) are connected as a pressure-measuring bridge (20) having two bridge legs (22, 24), each of the bridge legs comprising a first and a second pressure-sensor transistor (12, 16 and resp. 14, 18) which are connected in series with respect to their current paths. Further provided are two unipolar control transistors (26, 28), each having a control terminal (26a, 26b) and having a current path (26d, 28d) arranged between a further first and a further second terminal (26b, 26c; 28b, 28c). The respective first and second terminals (26b, 26c; 28b, 28c) of said two control transistors (26, 28) are connected in pairs, and the control terminals (26a, 28a) of the control transistors (26, 28) each are connected to a node (22a, 24a) between the pressure-sensor transistors (12, 16 and resp. 14, 18) of the two bridge legs (22, 24). The interconnected second terminals (26c, 28c) of the two parallel-connected control transistors (26, 28) are connected to the control terminals (16a, 18a) of the second pressure-sensor transistors (16, 18) of the two bridge legs (22, 24). The amplifier stage further comprises two power sources (30, 32). The control terminals (12a, 14a) of the first pressure-sensor transistors (12, 14) of the two bridge legs (22, 24) are adapted for connection thereto of a respective operating input voltage (INN, INP), and a measurement output voltage (OUTN, OUTP) is detectable between the respective pressure-sensor transistors (12, 16 and resp. 14, 18) of the two bridge legs (22, 24). The measurement output voltage (OUTN, OUTP) of the pressure-measuring bridge (20) is connectable to the control terminals (12a, 14a) of the first pressure-sensor transistors (12, 14) of the two bridge legs (22, 24) of a further pressure-measuring bridge (20) for cascading the pressure-measuring bridges (20).
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