Transmitter apparatus that is included in communication equipment typically includes a power amplifier (PA), which is used to amplify a radio frequency (RF) signal prior to its transmission by an antenna over a communication channel. A parameter associated with operating the communication equipment is its output power, which is generally measured at the output of the antenna and which is affected by (although usually not by a linear relationship) output power of the PA. However, the term output power as used herein can include the power measured at any point in an output path of the transmitter apparatus from the PA output to the antenna output.
For some applications, it may be important to limit the output power of the communication equipment to a certain maximum output power. For example, International Standard IEC 60079-0 Edition 5.0 dated 10-2007 and published by International Electrotechnical Commission specifies, for safety reasons, a maximum output power for communication equipment. However, a problem is that many operational and/or failure conditions within the communication equipment (particularly in the transmitter apparatus) may cause an increase in its output power, some of which may require a quick counteractive response to prevent the output power from exceeding the maximum output power.
Thus, there exists a need for a method and apparatus for output power control that will control the output power of communication equipment under certain operational and/or failure conditions.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments. In addition, the description and drawings do not necessarily require the order illustrated. Apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the various embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Thus, it will be appreciated that for simplicity and clarity of illustration, common and well-understood elements that are useful or necessary in a commercially feasible embodiment may not be depicted in order to facilitate a less obstructed view of these various embodiments.