Patent ID: 6535067
Filing Date: 2003-03-18
Classification: H03F,H03G

Abstract:
A method of limiting the output power of an RF Class C bipolar transistor amplifier, comprising the steps of:(a) configuring the amplifier so as to have a common base transistor configuration where an input signal is applied to an emitter electrode and an output signal is provided at a collector electrode; and (b) connecting circuit means including a semiconductor device having a non-linear high current, low voltage current-voltage transfer characteristic, connected in series with an RF choke connected to the emitter electrode and causing power saturation at a predetermined level in response to a specified power input level, wherein the circuit means also includes a feedback control circuit responsive to emitter current resulting from an RF input signal being sensed by a low ohmic valued resistor, equal to or less than about 15 milli-ohms, connected in series with the RF choke and the semiconductor device for controlling the semiconductor device.