Transistor differential amplifier circuit
AssigneeHitachi, Ltd.
InventorsYoshito Ohmura, Takahiro Okabe, Hiroshi Morozumi
Life of this patent
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Abstract
A transistor differential amplifier circuit includes a pair of NPN type amplifying transistors operated by a constant current source commonly connected to their emitters, and a pair of PNP type load transistors inserted in the collector circuits of said amplifying transistors, respectively. The load transistors are commonly biased with a constant voltage to operate within their saturation regions when input signals supplied on respective bases of the amplifying transistors are balanced, whereby pulse signals with a controlled duty ratio are obtained from the respective collectors of the amplifying transistors.
Claims23
A transistor differential amplifier circuit for producing pulse output signals from A.C. input signals comprising:
- a first amplifier stage comprising:
- a pair of first amplifying transistors of a first conductivity type connected to each other by their emitters;
- means for applying A.C. input signals between the bases of said first amplifying transistors;
- first constant current means commonly connected to both the emitters of said first amplifying transistors;
- a pair of load transistors of second conductivity type each connected by the collector thereof with the collector of a respective one of said first amplifying transistors and having their bases and emitters commonly connected to each other;
- diode means connected between the commonly connected bases and emitters of said load transistors for providing a voltage drop produced thereacross between the base and emitter of each of said load transistors;
- and
- second constant current means connected to said diode means for providing said diode means with a constant current;
- a second amplifier stage comprising:
- a pair of second amplifying transistors of the second conductivity type, and output means for deriving pairs of output signals from the emitter-collector paths of said second amplifying transistors;
- and means for connecting the collectors of said first amplifying transistors to the bases of said second amplifying transistors, respectively.
A transistor differential amplifier circuit for producing pulse output signals from A.C. input signals comprising:
- a first amplifier stage comprising:
- a pair of first amplifying transistors of first conductivity type connected to each other by their emitters;
- means for applying A.C. input signals between the bases of said first amplifying transistors;
- first constant current means commonly connected to the emitters of said first amplifying transistors;
- a pair of load transistors of second conductivity type, each of which is connected by the collector thereof with the collector of a respective one of said first amplifying transistors and having their bases and emitters commonly connected to each other;
- diode means commonly connected between the commonly connected bases and emitters of said load transistors for providing a voltage drop produced thereacross between the base and emitter of each of said load transistors;
- second constant current means connected to said diode means for providing said diode means with a constant current;
- a second amplifier stage comprising:
- a pair of second amplifying transistors of second conductivity type connected to each other by their emitters;
- third constant current means commonly connected to the emitters of said second amplifying transistors for providing operation currents to said respective second amplifying transistors therefrom;
- a pair of load elements each connected to the collector of a respective one of said second amplifying transistors;
- and
- a pair of output means connected to respective junctions between said load elements and the collectors of said second amplifying transistors, respectively, for delivering pairs of output signals therefrom;
- and means for connecting each of the collectors of said first amplifying transistors to each of the bases of said second amplifying transistors, respectively.
A transistor differential amplifier circuit for producing pulse output signals from A.C. input signals comprising at least a first amplifier stage comprising:
- a pair of amplifying transistors of a first conductivity type connected to each other by their emitters;
- means for applying A.C. input signals between the bases of said amplifying transistors;
- first constant current means commonly connected to both the emitters of said first amplifying transistors;
- means for deriving output pulse signals from the collectors of said amplifying transistors;
- a pair of load transistors of second conductivity type each connected by the collector thereof with the collector of a respective one of said amplifying transistors and having their bases and emitters commonly connected to each other;
- diode means connected between the commonly connected bases and emitters of said load transistors for providing a voltage drop produced thereacross between the base and emitter of each of said load transistors;
- and
- second constant current means connected to said diode means for providing said diode means with a constant current;
- wherein said first and second current sources are adjustable such that the duty cycle of said output pulse signals is related to the ratio of the magnitude of said first and second current sources.
Dependencies are inferred from the claim text.