Amplifier employing complementary field-effect transistors
AssigneeRCA Corporation
InventorSheng Teng Hsu
Life of this patent
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Abstract
Separate nonlinear load elements connected between the output terminal and each operating potential terminal of a complementary field-effect transistor amplifier determine the amplifier voltage gain and render it insensitive to variations in the operating potentials. The load elements may comprise other field-effect transistors whereby the effective amplifier gain is determined in accordance with a transconductance ratio. The transconductance ratio may be specified in terms of easily manipulated device parameters such as channel width-to-length ratios of the various transistors.
Claims10
In an amplifier of the kind comprising a first terminal for receiving an input signal, a second terminal for providing an output signal, third and fourth terminals for receiving a direct current operating potential thereacross, first and second complementary field effect transistors, each transistor having source, gate and drain electrodes, the source electrodes of said first and second transistors being connected to said third and fourth terminals, respectively, said gate electrodes being connected to said first terminal, and said drain electrodes being connected to said second terminal, said first and second transistors being quiescently biased such that both are in saturation, the improvement comprising:
- first voltage dependent variable conductance means continuously connected between said second and third terminals, said first means for conducting current therebetween in the same relative sense as said first transistor and having a conductance which increases as the potential difference between said second and third terminals increases;
- and
- second voltage dependent variable conductance means continuously connected between said second and fourth terminals, said second means for conducting current therebetween in the same relative sense as said second transistor and having a conductance which increases as the potential difference between said second and fourth terminals increases.
An amplifier, comprising, in combination:
- first, second, third and fourth terminals, said first terminal for receiving an input signal to be amplified, said second terminal for providing an output signal, said third and fourth terminals for receiving a direct current operating potential thereacross;
- first and second complementary field effect transistors, each having source, gate and drain electrodes, said gate electrodes being connected to said first terminal, said drain electrodes being directly connected to said second terminal, said source electrodes being connected to separate ones of said third and fourth terminals;
- a third field effect transistor having a conduction channel and a gate electrode, said conduction channel being connected between said second and third terminals, said gate electrode being connected to a selected one of said second and third terminals for receiving turn-on bias;
- and
- a fourth field effect transistor having a conduction channel and a gate electrode, said conduction channel being connected between said second and fourth terminals, said gate electrode being connected to a selected one of said second and fourth terminals for receiving turn-on bias.
In combination:
- a complementary field effect transistor amplifier having an input terminal, an output terminal and two operating potential supply terminals;
- a first diode-connected field effect transistor connected between said output terminal and one of said supply terminals;
- a second diode-connected field effect transistor connected between said output terminal and the other of said supply terminals;
- and wherein
- each said diode-connected field effect transistor is poled in a sense to be forward biased upon application of an operating potential across said supply terminals thereby providing a voltage dependent load impedance for said amplifier which decreases as said operating potential increases.
Dependencies are inferred from the claim text.