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US 4,692,718 AGranted
Tunable astable multivibrator with buffer transistors
AssigneeU.S. Philips Corporation
InventorsEngel Roza, Hendrik G. Van Veenendaal
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AssigneeU.S. Philips Corporation
InventorsEngel Roza, Hendrik G. Van Veenendaal
Estimating the term…
A tunable oscillator circuit provided with a pair of oscillator transistors whose bases are crosscoupled to the opposite collectors, and provided with a capacitance which is arranged between the emitters of the oscillator transistors, each emitter being AC-connected via an emitter current source to a reference voltage is disclosed. In order to considerably increase the tuning range without being limited in the choice of the output amplitude, a pair of buffer transistors in common base configuration is added whose two collectors are connected via a pair of collector resistors to a supply voltage and constitute an output of the tunable oscillator circuit, said pair of buffer transistors arranged in a cascode configuration with the pair of oscillator transistors by being coupled to the collectors of the oscillator transistors.
A tunable oscillator circuit provided with a pair of oscillator transistors whose bases are connected crosswise to the opposite collectors, and a capacitance which is arranged between the emitters of the oscillator transistors, each emitter being connected via an emitter current source to a reference voltage, characterized by a pair of buffer transistors in common base configuration, whose two collectors are connected via a pair of collector resistors to a supply voltage and constitute an output of the tunable oscillator circuit, said pair of buffer transistors being arranged in a cascode configuration with the pair of oscillator transistors, the emitter current of the buffer transistors being equal to the sum of the base and collector currents of the oscillator transistors.
Dependencies are inferred from the claim text.