Temperature stable relaxation oscillator having controllable output frequency

Claim 2

An oscillator circuit including in combination: first conductive means for applying a direct current potential of a first magnitude; second conductive means for applying a direct current potential of a second magnitude; capacitive means having a first electrode connected to said second conductive means, and a second electrode; charge circuit means coupling said second electrode of said capacitive means to said first conductive means; comparator means having a first control terminal connected to said second electrode of said capacitive means, a second control terminal adapted to receive a threshold determining voltage, and an output terminal, said comparator means providing a control signal at said output terminal thereof in response to the magnitude of the voltage across said capacitive means reaching a predetermined level; switchable threshold determining circuit having a first electron control means with a control terminal connected to said output terminal of said comparator means and an output terminal coupled to said second control terminal of said comparator means, said switchable threshold determining circuit switching the threshold determining voltage of said comparator from a high value to a low value in response to said control signal applied thereto by said comparator; and discharge circuit means having a second electron control means with a first terminal coupled to said second electrode of said capacitive means, a second terminal connected to said second conductive means, and a control terminal connected to said output terminal of said comparator means and to said control terminal of said first electron control means, said discharge circuit means being responsive to said control signal to discharge said capacitive means.

Claim 3

The oscillator circuit of claim 1 wherein said charge circuit means includes a resistive means.

Claim 4

The oscillator circuit of claim 1 wherein said second electron control means includes a transistor means which is saturated by said control signal.

Claim 5

The oscillator circuit of claim 1 wherein said switchable threshold determining circuit means includes: first resistive means connected from said first conductive means to said second control electrode of said comparator means; second resistive means connected from said second control electrode of said comparator means to said second conductive means; third resistive means having one terminal connected to said second control electrode of said comparator means and a second terminal; and said first electron control means includes a threshold voltage switching transistor means having a first electrode connected to said second conductive means, a second electrode connected to said second terminal of said third resistive means, and a control electrode connected to said output terminal of said comparator means.

Claim 6

The oscillator circuit of claim 1 wherein said comparator means includes: first differentially connected electron control means having a control electrode forming said second control electrode of said comparator means, a second electrode connected to said first conductive means and a first electrode; second differentially connected electron coNtrol means having a second electrode, a first electrode connected to said first electrode of said first differentially connected electron control means and a control electrode forming said first control electrode of said comparator means and; third electron control means having a control electrode connected to said second electrode of said second differentially connected electron control means, a first electrode connected to said first conductive means, and a second electrode forming said output terminal of said comparator means.

Claim 7

The oscillator circuit of claim 5 further including current source means connected from said first electrodes of said first and second differentially connected electron control means to said second conductive means.

Claim 8

The oscillator circuit of claim 6 wherein said differentially connected electron control means and said current source means include bipolar transistors of a first conductivity type having emitter, base and collector electrodes respectively corresponding to said first, control and second electrodes and said third electron control means includes a bipolar transistor of a second conductivity type.

Claim 9

The oscillator circuit of claim 1 further including voltage regulator means connected between said first conductive means and second conductive means.

Claim 10

The oscillator circuit of claim 8 wherein said voltage regulator means includes a zener diode means.

Claim 11

The oscillator circuit of claim 1 further including adjustable current control means connected to said second electrode of said capacitive means for varying the frequency of oscillation of said oscillator.

Claim 12

A temperature stable monolithic, relaxation oscillator circuit for use with an external power supply having only a first potential terminal and a second potential terminal, an external frequency control circuit having a capacitor, and a charging circuit coupled to the capacitor, such monolithic relaxation oscillator circuit including in combination: differential amplifier means having a first control electrode adapted to be connected to the capacitor, a second control electrode adapted to receive a threshold determining voltage, and an output electrode, said differential amplifier means being structured to provide a first control signal at said output electrode thereof in response to the voltage across the capacitor falling below a first voltage magnitude at said second control electrode and being structured to provide a second control signal in response to the voltage across the capacitor rising above a second voltage magnitude at said second control electrode; discharge circuit means having a first electron control means with a first electrode adapted to be connected to the second potential terminal, a control electrode connected to said output electrode of said differential amplifier means, and a second electrode adapted to be coupled to the capacitor, said first electron control means being structured to be rendered nonconductive in response to said first control signal and conductive in response to said second control signal; and threshold determining circuit means having a second electron control means with a control electrode connected to said output electrode of said differential amplifier means and to said control electrode of said first electron control means, a first electrode adapted to be coupled to the second potential terminal and a second electrode coupled to said second control electrode of said differential amplifier means, said second electron control means being structured to be rendered nonconductive in response to said first control signal to apply said voltage of a second magnitude that is greater than said first magnitude to said second control electrode, said first electron control means tending to isolate the capacitor from temperature induced changes in said threshold determining circuit means and said second electron control means tending to isolate said second control electrode of said differential amplifier meAns from temperature induced changes in said discharge circuit means so that the repetition rate of the output signal of the oscillator tends to remain constant with temperature change.

Claim 13

A temperature stable monolithic, relaxation oscillator circuit for use with an external power supply having only a first potential terminal and a second potential terminal, an external frequency control circuit having a capacitor, and a charging circuit coupled to the capacitor, such monolithic relaxation oscillator circuit including in combination: differential amplifier means having a first control electrode adapted to be connected to the capacitor, a second control electrode adapted to receive a threshold determining voltage, and an output electrode, said differential amplifier means being structured to provide a first control signal at said output electrode thereof in response to the voltage across the capacitor falling below a first voltage magnitude at said second control electrode and being structured to provide a second control signal in response to the voltage across the capacitor rising above a second voltage magnitude at said second control electrode; discharge circuit means having a first electron control means with a first electrode adapted to be connected to the second potential terminal, a control electrode connected to said output electrode of said differential amplifier means, and a second electrode adapted to be coupled to the capacitor, said first electron control means being structured to be rendered nonconductive in response to said first control signal and conductive in response to said second control signal; and threshold determining circuit means having a second electron control means with a control electrode connected to said output electrode of said differential amplifier means and to said control electrode of said first electron control means, a first electrode adapted to be coupled to the second potential terminal and a second electrode coupled to said second control electrode of said differential amplifier means, said second electron control means being structured to be rendered nonconductive in response to said first control signal to apply said voltage of a second magnitude that is greater than said first magnitude to said second control electrode, said first electron control means tending to isolate the capacitor from temperature induced changes in said threshold determining circuit means and said second electron control means tending to isolate said second control electrode of said differential amplifier meAns from temperature induced changes in said discharge circuit means so that the repetition rate of the output signal of the oscillator tends to remain constant with temperature change.

Claim 14

The oscillator circuit of claim 11 wherein said first electron control means includes a transistor means which is saturated by said second control signal.

Claim 15

The oscillator circuit of claim 11 wherein said threshold determining circuit means includes: first monolithic resistive means adapted to be connected from the first potential terminal to said second control electrode of said differential amplifier means; second monolithic resistive means having one terminal connected to said second control electrode of said differential amplifier means and a second terminal adapted to be connected to the second potential terminal; third monolithic resistive means having one terminal connected to said second control electrode of said differential amplifier means and a second terminal; and monolithic threshold voltage switching transistor means having a first electrode adapted to be connected to the second potential terminal, a second electrode connected to said second terminal of said third resistive means, and a control electrode connected to said output terminal of said differential amplifier means.

Claim 16

The oscillator circuit of claim 11 wherein said differential amplifier means includes: first differentially connected electron control means having a control electrode forming said second control electrode of said differential amplifier means, a second electrode adapted to be connected to the first potential terminal and a first electrode; second differentially connected electron control means having a second electrode coupled to said output terminal of said differential amplifier means, a first electrode connected to said first electrode of said first differentially connected electron control means and a control electrode forming said first control electrode of said differential amplified means and; third electron control means having a control electrode connected to said second electrode of said second differentially connected electron control means, a first electrode connected to the first potential terminal, and a second electrode forming said output terminal of said differential amplifier means.

Claim 17

The oscillator circuit of claim 14 further including current source means having one terminal connected to said first electrodes of said first and second differentially connected electron control means means and a second terminal adapted to be connected to the second potential terminal.

Claim 18

The oscillator circuit of claim 15 wherein said differentially connected electron control means and said current source means include bipolar transistors of a first conductivity type having emitter, base and collector electrodes respectively corresponding to said first, control and second electrodes and said third electron control means includes a bipolar transistor of the second conductivity type.