| 摘要 |
<p>24 A current limiter is provided which responds to the magnitude of the output current signal from a power amplifier. A full wave rectified signal is provided in response to the magnitude of the current output signal and is used as an input to a comparator. The other input of the comparator is a voltage reference signal that represents a maximum desired current level for the output current signal of the power amplifier. When the output current signal exceeds its reference level, a signal is provided which is used as an input to an exclusive-OR gate which has, as its other input, a modulated square wave signal. The effect of the exclusive-OR gate is to notch the square wave modulated signal in such a way so as to alter its shape. The altered square wave carrier signal causes the MOSFETs of the power amplifier to switch on and switch off at additional occurrences which has the effect of reducing the maximum current level of the output current signal being output by the power amplifier.</p> |
