US 4,538,117 AGranted

Transistor amplifier

OwnerBengt G. Olssoninventor

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Abstract

An amplifier comprising of two MOS-transistors Q.sub.1 and Q.sub.2 and a resistor R.sub.1 connected as a two-pole between a DC power source, PS.sub.1, and a load Z.sub.L ; in order to avoid harmful influences on the amplifier from the load current, and to obtain a simple control unit for this purpose: (a) the emitters (sources) of Q.sub.1 and Q.sub.2 form one pole of the two-pole, and one side of R.sub.1 is connected in series with the collector (drain) of Q.sub.1, and the other side of R.sub.1 together with the collector (drain) of Q.sub.2 form the other pole of the two-pole, (b) the resistance of R.sub.1 is of the same magnitude as Z.sub.L, (c) a mainly constant-DC-voltage-generating network, V.sub.B, is connected between the gates of Q.sub.1 and Q.sub.2, with a polarity causing Q.sub.2 to conduct less than Q.sub.1, and a voltage causing Q.sub.2 not to conduct before Q.sub.1 conducts or aims to conduct the full rated current, i.e. a current of the same magnitude as the output current, (d) the driver stage is connected to the gate of Q.sub.1 or to the gate of Q.sub.2 or at some other point in the constant-DC-voltage-generating network, V.sub.B.

Claims3

Dependent claims

An amplifier for connection as a two-pole device between a DC power source and a load impedance comprising:

(a) first and second MOS-transistors of the same conductivity type, each having source, drain and gate terminals, the source terminals being commonly connected and forming one pole of said two-pole device, said one pole being connectable to said load impedance;
(b) resistance means connected between the drains of the first and second MOS-transistors, said resistance means having substantially the same magnitude as said load impedance, said resistance means having a first end connected to the drain of said first MOS-transistor means and a second end connected to the drain of the second MOS-transistor to form the other pole of said two-pole device, said other pole being connectable to said DC power source;
(c) DC voltage generating means connected between the respective gates of said first and second MOS-transistors for applying a substantially constant voltage therebetween, the polarity of said constant voltage causing said second MOS-transistor to conduct less than said first MOS-transistor, the magnitude of said constant voltage precluding said second MOS-transistor from conducting until said first MOS-transistor conducts at the full rated current thereof;
and
(d) drive means connected in the gate circuits of said first and second MOS-transistors for applying a control voltage, causing said transistors to conduct.

2 more elements

Dependencies are inferred from the claim text.