Improved temperature compensated, automatic output control (AOC) circuitry for RF signal power amplifiers is described that maintains the output power within one-half dB of a selected one of eight power levels varying from nine milliwatts to five watts, a dynamic range of twenty-eight dB. The amplification of the RF signal amplifier is proportional to a drive current signal provided by a current amplifier. A half-wave rectifier is coupled to the output of final amplifiers for generating an output power signal that has a magnitude proportional to the output power. The half-wave rectifier is temperature compensated for and biased by a diode coupled to the rectifier by one resistor and coupled to supply voltage by another resistor. The output power voltage is further coupled to an amplifier having an amplification factor selected by level control signals. The amplified output power signal is coupled to a comparator which varies the drive current provided by the current amplifier in response to the voltage difference between the amplified output power signal and a reference voltage.

Temperature compensated automatic output control circuitry for RF signal power amplifiers with wide dynamic range

The present invention is a cooking appliance or an electronic control for a cooking appliance and method of controlling the same. A remote control unit having a built-in temperature sensor, positional switch and low-battery detection circuit is in two-way intermittent wireless communication with the appliance control unit of the present invention. The appliance control unit includes a switch means for controlling the heating elements of the cooking appliance wherein the switch means for each heating element includes two power switches connected in series and coupled with a redundancy detection circuit for the detection of a failure of one of the two power switches. Two-way communication between the two control units of the present invention is constantly monitored to ensure proper operation of the cooking appliance and to provide a mechanism to report errors to the user or to shut down the cooking appliance, as appropriate, soon after an error is detected. Mechanisms are also provided whereby the wireless communication means of the control units may be diagnosed to ensure the control units are properly communicating with each other.

Over temperature condition sensing method and apparatus for a domestic appliance

Automatic power output control circuitry is disclosed in which the magnitude of a radio frequency signal is maintained at one of a plurality of magnitudes selected in response to control signals The radio frequency signal output from a variable output amplifier is sampled and the sample is further amplified and the dynamic range compressed prior to being rectified The rectified power magnitude signal, which is nonlinearly related to the radio frequency signal magnitude, is adjusted by an adjustment factor selected by the control signals and employed in varying the output of the variable output amplifier to produce a corresponding radio frequency signal output magnitude

Automatic output control circuitry for RF power amplifiers with wide dynamic range

A radio transmitter output power controller which automatically restricts the maximum transmitting time during an averaging time so that the average power remains below an acceptable level. Additionally or alternatively, the maximum transmitter output power may be automatically reduced to a lower level if and when a predetermined average power level is approached. A warning signal may be generated to inform a user that the maximum permitted power output is being approached.

Averaged RF exposure control

An adaptive thermal protection method and arrangement for a power amplifier by remote sense is disclosed in Fig. 2 which maximizes the amount of output power from electronic equipment such as a radio frequency (RF) power amplifier (118), having a finite heat sink (119) and operating intermittently over a period of time. This method and apparatus utilizes a remote temperature sensor (110A) and knowledge of the on/off, or key/dekey times in conjunction with a stored, predetermined thermal model to adjust the operating power level to a maximum permissible point within a range of operating power levels such that the projected temperature of the power amplifier does not exceed a preset limit. In so doing, the apparatus and method combines the advantages of thermal protection and power maximization and effects gradual changes in the operating power level by adapting to variable environmental and operational conditions.

Adaptive thermal protection for a power amplifier by remote sense.

Sense voltages representative of transmitter power and the temperature of the transmitter output stage are summed and fed to the input of a high gain amplifier. The output of the amplifier provides bias to the transmitter driver stage and, thus, controls the total transmitter developed power. The resulting overall feedback system provides precise transmitter power control and output stage thermal protection.

Edward F. Hume

Papers

Thermally responsive power control for a radio transmitter