Relaxation oscillators with electrical control of periodicities of oscillation

Claim 2

A relaxation oscillator with electrical control of the periodicity of its oscillations comprising: a reference voltage bus; a timing capacitor; first and second terminals between which said timing capacitor is connected; first and second electrically controlled constant current generators respectively supplying a first current to said first terminal and a second current proportional to said first current to said second terminal; R-S flip-flop means set by the voltage at said first terminal departing in a first sense from said reference voltage by a predetermined amount and reset by the voltage at said second terminal departing in said first sense from said reference voltage by a predetermined amount; first switching means responding to the set condition of said R-S flip-flop for completing connection of said first terminal to said reference voltage bus and responding to the reset condition of said R-S flip flop for interrupting connection of said first terminal to said reference voltage bus; and second switching means responding to the reset condition of said R-S flip-flop for completing connection of said second terminal to said reference voltage bus and responding to the set condition of said R-S flip-flop for interrupting connection of said second terminal to said reference voltage bus.

Claim 3

A relaxation oscillator as set forth in claim 1 wherein said first switching means comprises a first transistor with an emitter-base junction, with a collector-base junction, with an emitter electrode connected to said reference voltage bus, with a collector electrode connected to said first terminal, and with a base electrode; wherein said second switching means comprises a second transistor with an emitter-base junction, with a collector-base junction, with an emitter electrode connected to said reference voltage bus, and with a base electrode; wherein said R-S flip-flop means includes means for setting said R-S flip-flop means responsive to the voltage at said first terminal departing in a first sense from said reference voltage by an amount no larger than the offset voltage across a forward-biased semiconductor junction; wherein said R-S flip-flop means includes means for resetting said R-S flip-flop means responsive to the voltage at said second terminal departing in a first sense from said reference voltage by an amount no larger than the offset voltage across a forward-biased semiconductor junction; wherein means are provided for applying output signal from said R-S flip-flop means to the base electrode of said first transistor for biasing its emitter-base junction into conduction during the set condition of said R-S flip-flop means and for clamping the voltage at the base electrode of said first transistor to said reference voltage bus during the reset condition of said R-S flip-flop means, and wherein means are provided for applying output signal from said R-S flip-flop means to the base electrode of said second transistor for biasing its emitter-base junction into conduction during the reset condition of said R-S flip-flop means and for clamping the voltage at the base electrode of said second transistor to said reference voltage bus during the set condition of said R-S flip-flop means.

Claim 4

A relaxation oscillator as set forth in claim 1 including means responsive to said first and second electrically controlled constant current generators for setting said R-S flip-flop means when said first and second electrically controlled constant current generators are not supplying said first and second currents.

Claim 5

A relaxation oscillator as set forth in claim 3 wherein said first and second electrically controlled constant current generators comprise: a plural-output current amplifier having an input connection, having a first output connection to said first terminal for supplying said first current, and having a second output connection to said second terminal for supplying said second current; a plurality of voltage-to-current converter means with respective input connections for receiving periodicity-control voltages and with respective output connections to the input connection of said plural-output current amplifier; and selective inhibit means for inhibiting the operation of at least all but a selected one of said voltage-to-converter means at any time.