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US 4,378,531 AGranted
Negative resistance oscillator suited for partial integration
AssigneeGeneral Electric Company
InventorGlenn B. Gawler
Life of this patent
Estimating the term…
Abstract
A novel negative resistance oscillator is disclosed for partial integration. The oscillator has a tank circuit and a load, which are non-integrated, and active circuitry, which is integrated. The active circuit consists of a current "source" and two current "sinks", arranged to provide a negative resistance. The oscillator, which is designed to drive an erase head in a tape recorder, as a part of a tape recorder integrated circuit, requires only a single additional pin, has a controlled peak current range, a large dc voltage swing for a given dc supply potential, and an efficient dc to ac current conversion ratio.
Claims9
A negative resistance oscillator comprising:
- A. a first terminal for connection to a positive dc bias potential;
- a second terminal for connection to a reference dc potential;
- and a third terminal,
- B. a resonant tank circuit including an inductance which is connected between said first and said third terminal;
- C. means for coupling a load to said resonant tank circuit,
- D. a current source comprising a first transistor gain element having
- (1) the emitter thereof conductively connected to said first terminal,
- (2) the base thereof connected to the node of a three branch circuit in which:
- (a) the first branch includes a first diode connected to conduct current to said node from said first terminal;
- (b) the second branch includes a second diode connected to conduct current to said node from said third terminal;
- and
- (c) the third branch is connected to said second terminal and comprises a first current sink to withdraw a controlled current I.sub.CC from said node,
- any decrease in current in said second branch increasing the current in said first branch and vice versa;
- and
- (3) the collector thereof connected through a load including a third diode to said second terminal, the source current occurring in said collector having a first proportionality (M1) to said controlled current (I.sub.CC), when said diode in said second branch is nonconductive, and
- E. a second current sink comprising a second transistor gain element having
- (1) the emitter thereof conductively connected to said second terminal,
- (2) the collector thereof connected in a sense to withdraw from said third terminal a current which has a second proportionality (M2) to said source current [(M1) (I.sub.CC)] substantially greater than one, when the diode in said second branch is nonconductive,
- oscillation occurring between a first state in which said first branch is conductive and the oscillator output current is equal to said controlled current (I.sub.CC) times said first (M1) and second (M2) proportionality;
- (I.sub.CC) (M1) (M2)
- and a second state in which said second branch is conductive and the oscillator output current is approximately equal to said controlled current (I.sub.CC).
18 more elements
A negative resistance circuit comprising:
- A. a first terminal for connection to a positive dc bias potential;
- a second terminal for connection to a reference dc potential;
- and a third terminal at which said negative resistance appears;
- B. a current source comprising a first transistor gain element having
- (1) the emitter thereof conductively connected to said first terminal,
- (2) the base thereof connected to the node of a three branch circuit in which:
- (a) the first branch includes a first diode connected to conduct current to said node from said first terminal,
- (b) the second branch includes a second diode connected to conduct current to said node from said third terminal;
- and
- (c) the third branch is connected to said second terminal and comprises a first current sink to withdraw a controlled current (I.sub.CC) from said node,
- any decreases in current in said second branch increasing the current in said first branch and vice versa;
- and
- (3) the collector thereof connected through a load including a third diode to said second terminal, the source current occurring in said collector having a first proportionality (M1) to said controlled current (I.sub.CC) when said diode in said second branch is nonconductive, and
- C. a second current sink comprising a second transistor gain element having
- (1) the emitter thereof conductively connected to said second terminal,
- (2) the collector thereof connected in a sense to withdraw from said third terminal a current which has a second proportionality (M2) to said source current [(M1) (I.sub.CC)] substantially greater than one, when the diode in said second branch is nonconductive,
- the circuit having a first state in which said first branch is conductive and said second branch is nonconductive, and a second state in which said second branch is conductive and said first branch is nonconductive.
14 more elements
Dependencies are inferred from the claim text.