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EP0772292A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

RF power amplifiers

Assignee: Roke Manor Research Ltd
•
Filing: 1996-10-04
•
Granted: —
•
Expires: 2016-10-04
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Abstract

Abstract A radio frequency ( r.f.) amplifier power control system comprising an r.f. power amplifier for supplying r.f. transmission power to an antenna, a current sensing resistor via which operating current is fed to the power amplifier, a differential amplifier to a first input terminal of which a feed-back voltage derived from the sensing resistor indicative of r.f. transmission power is fed and to a second input terminal of which a reference voltage is fed thereby to produce in the presence of a voltage difference between the feed-back voltage and the reference voltage a control voltage in dependence upon which the output of the power amplifier is controlled in a sense such that the voltage difference tends to be nullified, whereby the transmission power is controllable in dependence upon the reference voltage, and a shunt which is fed with current from the sensing resistor the impedance of which shunt is arranged to vary responsively to the control voltage.

Inventors

  • 👤 Colin Michael Davis
  • 👤 Martin Victor Whittle

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-07 14:21
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H03F; H03F2200/00; H03F2200/504

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 154 words
An r.f. amplifier power control system comprising an r.f. power amplifier for supplying r.f. transmission power to an antenna, a current sensing impedance via which operating current is fed to the power amplifier, a differential amplifier to a first input terminal of which a feed-back voltage derived from the sensing impedance indicative of r.f. transmission power is fed and to a second input terminal of which a reference voltage is fed thereby to produce in the presence of a voltage difference between the feed-back voltage and the reference voltage a control voltage in dependence upon which the output of the power amplifier is controlled in a sense such that the voltage difference tends to be nullified, whereby the transmission power is controllable in dependence upon the reference voltage, and a shunt which is fed with current from the sensing impedance the impedance of which shunt is arranged to vary responsively to the control voltage.
Claim 2
Dependent Claim 18 words
An r.f. amplifier power control system as claimed in claim 1 wherein the sensing impedance is a resistor.
Claim 3
Dependent Claim 44 words
An r.f. amplifier power control system as claimed in claim 1 or claim 2 wherein the shunt comprises a transistor which is arranged effectively to shunt the power amplifier, the control voltage being applied to a base terminal of the transistor via a resistor.
Claim 4
Dependent Claim 58 words
A system as claimed in claim 3 wherein a collector terminal of the transistor is connected via a load component to the sensing impedance and an emitter terminal of the transistor is coupled via a further resistor to ground, the base of the transistor being coupled via a series resistor to an output terminal of the differential amplifier.
Claim 5
Independent Claim 19 words
A system as claimed in any preceding claim including a transmitter antenna which is fed from the power amplifier.
Claim 6
Independent Claim 21 words
A system as claimed in any preceding claim forming a part of a mobile unit transmitter of a mobile radio system.
Claim 7
Dependent Claim 18 words
A system as claimed in claim 6 wherein the mobile radio system is a GSM mobile radio system.

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