Patent ID: 6137367
Filing Date: 2000-10-24
Classification: H03F

Abstract:
An amplifier for amplifying an input signal, comprising:a plurality of semiconductor amplifying elements, each comprising a control terminal to which a signal may be applied for controlling the flow of current between additional input and output terminals, and a source of bias voltage providing power for said amplifying elements,said plurality of amplifying elements being connected in series, such that the output terminal of a first element of the series is connected to the input terminal of the next element of the series, and so on, the input signal being applied to the control terminal of the first element of the series, and the output terminal of the last element of the series being connected to an output circuit, and the output terminal of the last element of the series also being connected to the control terminals of each of the elements of the series, such that the output signal from the last element of the series is supplied to the control terminals of each of the elements of the series for feedback,wherein capacitors are connected between the control terminals of each of the amplifying elements in the series except the first and ground, the value of each said capacitor being chosen to optimize the impedance of and power output by the corresponding amplifying elements;wherein said source of bias voltage is connected to the output terminal of the last of said elements in said series through a choke, and wherein said bias voltage is provided to each of said elements by voltage-dividing resistors in series across the control terminals of said elements; andwherein said output signal is supplied to the control terminals of each of the elements of the series for feedback through the same series-connected resistors used to supply bias voltage.