| 摘要 |
<p>A pulse width modulation control monitoring apparatus 31 is provided. Input means 33 receives at least one pulse width modulated control input signal 34, 35. If a plurality of input signals are provided, these are combined into a single signal 36 by a logical OR operation. Edge detection means 37 then detects edges of the or the combined pulse width modulated control signal and generates and output signal 39 that is indicative of the detected edges. A timer 41 determines whether the period between the detected edges exceeds a predetermined threshold, which is indicative of an error in the or one of the pulse width modulated control input signals. An alarm signal 43 is then generated to shut down the pulse width modulated control to avoid potential damage caused, for example, by excessive current in a power supply.</p> |
