| 摘要 |
A pressure to resistance transducer or sensor (10) is connected to an amplifier (12). A three-state comparator (14) compares the amplifier output signal with a first reference voltage (15) and its comparison output is looped to another input of the amplifier (12) through a low-pass filter (16). A first controllable current source (41) in series to a first reference resistor (42) is provided in the loop path to detect a break condition of the pressure sensor (10). A second controllable current source (51) in series to a second reference resistor (52) and a voltage divider (54) are also provided in the loop path to detect a short circuit condition of the pressure sensor (10) in combination with the first current source (41). The low-pass filter (16) includes a switch (59) in parallel with a high resistor (58) having its resistance higher than that of a low resistor (17). <IMAGE> |
