Telefonaktiebolaget Lm Ericsson (publ)

Telefonaktiebolaget Lm Ericsson

Mustafa Özen

Christian Fager

Ufuk Özdemir

Peter Caputa

William Hallberg

Ahmed Mahmoud

A tank circuit () includes a tunable resonator subcircuit () having a first control input and having an effective parallel resistance that varies with tuning of the tunable resonator subcircuit (). The tank circuit () further comprises a variable negative-resistance subcircuit () having a second control input and coupled in parallel to the tunable resonator subcircuit (), where the variable negative-resistance subcircuit () is configured to provide a variable negative resistance, responsive to the control input, so as to increase the effective parallel resistance of the tank circuit ().

Tuning range enhancement by negative resistance

It is provided an amplifier arrangement for optimizing efficiency at a peak power level and a back-off power level &#x3b3;. The amplifier arrangement comprises an input power splitter dividing an input signal into a first signal having a power Pand a second signal having a power P, a main transistor operating in a class-B like mode receiving the first signal, an auxiliary transistor operating in a class-C mode receiving the second signal. The received first and second signals have a phase offset value &#x3b8;, wherein &#x2212;&#x3c0;&#x3c;&#x3b8;&#x3c;&#x3c0;. The amplifier arrangement further comprises a combining network. Circuit element values of the combining network, the power Pand the power P, the phase offset value &#x3b8;, a bias condition of the auxiliary transistor; and a relative size Sof the auxiliary transistor, are based on a predetermined back-off power level &#x3b3;, a current scaling factor rof the auxiliary transistor, a main transistor oversizing factor r, and an auxiliary transistor oversizing factor r, where r&#x3c;1, r&#x2267;1 and r&#x2267;1. It is also provided a method for determining properties for an amplifier arrangement.

Class-B/C Doherty power amplifier

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Göteborg, Sweden

Mustafa Özen