Crystal oscillator including a pair of push-pull complementary transistor amplifiers
AssigneeBell Telephone Laboratories, Incorporated
InventorVeikko Reynold Saari
Life of this patent
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Abstract
An improved integrated circuit oscillator adapted for crystal-controlled applications eliminates the need for capacitors and duty cycle control circuitry by using a cascaded pair of push-pull complementary transistor amplifier stages, a clipping-type automatic amplitude control circuit, and a resonant feed back path between the two amplifier stages. In an illustrative embodiment, floating bias voltages are established by a chain of diodes, with several bias currents set with respect to the chain current by emitter area relationships. Square-wave output is provided by a flip-flop connected to push-up and pull-down output circuits.
Claims20
An oscillator comprising
- a first push-pull non-inverting amplifier stage including a first pair of serially-connected complementary transistors,
- a second push-pull non-inverting amplifier stage connected to said first stage and including a second pair of serially-connected complementary transistors,
- resonant feedback path means connected between said first and second amplifier stages,
- and means connected to at least one of said amplifier stages for controlling the oscillation amplitude of said oscillator.
An oscillator comprising
- a first amplifier stage including a first pair of complementary transistors having their emitters interconnected,
- a second amplifier stage including a second pair of complementary transistors having their emitters interconnected,
- means individually connecting the collector of each of said first pair of transistors to the base of a corresponding one of said second pair of transistors,
- resonant feedback path means connected between said emitters of said first pair of transistors and said emitters of said second pair of transistors,
- output means connected to the collectors of said second pair of transistors,
- means for biasing said first and second amplifier stages,
- and means connected to at least one of said amplifier stages for controlling the amplitude of oscillation of said oscillator.
Dependencies are inferred from the claim text.