摘要:
An RF circuit for wireless devices comprises a single differential power amplifier and an impedance balancing circuit for each frequency band. The impedance balancing circuit serves both to provide an appropriate impedance at the output of the amplifier as the operating mode of the device changes, and also transforms the differential output of the amplifier to a single-ended output. The impedance balancing circuit optionally comprises a BALUN circuit and a variable capacitor that is varied as the operating mode changes in order to vary the impedance at the output of the amplifier.
摘要:
Disclosed is a differential microphone pre-amplifier circuit (120) for providing an amplified differential signal at a first (A) and a second (B) output terminal of the microphone pre- amplifier (120), including a first voltage controlled current generator (101), a second voltage controlled current generator (102) and a third voltage controlled current generator (103) all being configured to receive, amplify and convert a voltage signal generated by an associated microphone (110) to a current signal output.
摘要:
An amplifier circuit that includes a first power amplifier configured to drive a load and a second power amplifier configured to drive the load through an impedance step-up network. The impedance step-up network is connected to an output of the second power amplifier. The impedance step-up network is configured to switch into a first mode to present an increased impedance to the first power amplifier, and switch into a second mode in which the impedance step-up network steps-up an impedance seen by the second power amplifier looking into the impedance step-up network.
摘要:
An amplifier circuit that includes a first power amplifier configured to drive a load and a second power amplifier configured to drive the load through an impedance step-up network. The impedance step-up network is connected to an output of the second power amplifier. The impedance step-up network is configured to switch into a first mode to present an increased impedance to the first power amplifier, and switch into a second mode in which the impedance step-up network steps-up an impedance seen by the second power amplifier looking into the impedance step-up network.
摘要:
Disclosed is a differential microphone pre-amplifier circuit (120) for providing an amplified differential signal at a first (A) and a second (B) output terminal of the microphone pre-amplifier (120), including a first voltage controlled current generator (101), a second voltage controlled current generator (102) and a third voltage controlled current generator (103) all being configured to receive, amplify and convert a voltage signal generated by an associated microphone (110) to a current signal output.
摘要:
An RF circuit for wireless devices comprises a single differential power amplifier and an impedance balancing circuit for each frequency band. The impedance balancing circuit serves both to provide an appropriate impedance at the output of the amplifier as the operating mode of the device changes, and also transforms the differential output of the amplifier to a single-ended output. The impedance balancing circuit optionally comprises a BALUN circuit and a variable capacitor that is varied as the operating mode changes in order to vary the impedance at the output of the amplifier.
摘要:
Bei einer HF-Mischstufe in Basisschaltung, mit:
a) zwei bipolaren Verstärkertransistoren (T₁,T₂), b) zwei jeweils einem Verstärkertransistor zugeordneten Schaltstufen (1,2) mit jeweils zwei emittergekoppelten bipolaren Schalttransistoren (T₃,T₄,T₅,T₆) und mit zwei Signalquellen (S₁,S₂), die die Basen der Schalttransistoren mit Überlagerungssignalen beaufschlagen, c) zwei Knotenpunkten (K₁,K₂), an denen die Emitter der Schalttransistoren jeweils mit dem Kollektor des zugehörigen Verstärkertransistors verbunden sind, d) zwei weiteren Knotenpunkten (K₃,K₄), an denen jeweils die Kollektoren zweier Schalttransistoren unterschiedlicher Schaltstufen miteinander verbunden sind, e) Schaltungsmitteln (C₁,C₂,TR) zur Potentialtrennung, über die die Emitter der Verstärkertransistoren miteinander verbunden sind, f) einer Eingangssignalquelle mit zugehörigem Innenwiderstand, deren eine Klemme über den Schaltungseingang mit den Schaltungsmitteln zur Potentialtrennung und deren andere Klemme mit Bezugspotential verbunden ist und deren Signal durch die Mischstufe in einen anderen Frequenzbereich transponiert werden soll, sind
g) die Verstärkertransistoren vom unterschiedlichen Leitungstyp, h) die beiden Schalttransistoren einer Schaltstufe vom gleichen Leitungstyp wie der zugeordnete Verstärkertransistor.
摘要:
An amplifier circuit that includes a first power amplifier configured to drive a load and a second power amplifier configured to drive the load through an impedance step-up network. The impedance step-up network is connected to an output of the second power amplifier. The impedance step-up network is configured to switch into a first mode to present an increased impedance to the first power amplifier, and switch into a second mode in which the impedance step-up network steps-up an impedance seen by the second power amplifier looking into the impedance step-up network.
摘要:
Gain control in complementary common gate and common source amplifiers is disclosed. In an exemplary embodiment, an apparatus includes a first amplifier stage (302) configured to amplify an input signal at an input terminal (316) to generate a first amplified signal (RF_OUTP). The first amplifier stage (302) includes a current diverter (702) that selectively diverts current to set a gain of the first amplifier stage (302). The apparatus also includes a second amplifier stage (304) configured to amplify the input signal at the input terminal (316) to generate a second amplified signal (RF_OUTN). The second amplifier stage (304) includes a gain control circuit (704) to set a gain of the second amplifier stage (304).
摘要:
An RF circuit for wireless devices comprises a single differential power amplifier and an impedance balancing circuit for each frequency band. The impedance balancing circuit serves both to provide an appropriate impedance at the output of the amplifier as the operating mode of the device changes, and also transforms the differential output of the amplifier to a single-ended output. The impedance balancing circuit optionally comprises a BALUN circuit and a variable capacitor that is varied as the operating mode changes in order to vary the impedance at the output of the amplifier.