Resources Contact Us Home
Method and apparatus for amplifying a signal

Image Number 8 for United States Patent #6020787.

A unique method and apparatus modifies the load impedance at the output of a power amplifier by varying a voltage variable capacitor (VVC) (310) to maximize the efficiency of the power amplifier (304). A comparator (509) generates amplifier control signal (211) based upon a detected power output signal (216) and a reference signal. In addition to providing power control, the control signal is also coupled to a VVC circuit (506) to control the output impedance of the power amplifier. In an alternate embodiment, a separate VVC control signal (527) based upon a comparison of the power control signal and the battery voltage is coupled to a VVC. In another alternate embodiment, a second VVC can be coupled in parallel to the first VVC. The second VVC is preferably controlled by a signal (805) based upon the current in the power amplifier. Finally, an alternate embodiment incorporates a VVC circuit (506) at the input of the power amplifier to compensate for variations in input impedance to improve other power amplifier parameters such as IM, gain, output power and noise level.

  Recently Added Patents
Squib control circuit
Key management using quasi out of band authentication architecture
Selecting modulation and coding scheme in the presence of interference
Redundant parallel operation of motor vehicle electrical system generators
Voltage generating system and memory device using the same
Moving picture decoding device and moving picture decoding method
Method of making a low-Rdson vertical power MOSFET device
  Randomly Featured Patents
Method to enhance fat content in the milk of a diary cow
Solid-state imaging device
Method and system for providing vehicle-directed services
Precursors of heterofuranobenzoxepin acetic acids
Fluorescent ballast with unique dimming control
Method for improving the performance of oxidizable ceramic materials in oxidizing environments
Multi-directional operating switch
Controlling a plant parasitic nematode with pasteuria
Vertical blind with movable auxiliary rod support