Full cycle current detector

Claim 2

A circuit for detecting current flowing in an external circuit and for generating discrete outputs responsive thereto the outputs respectively identifying current in the external circuit which is either (1) constant zero or constant direct current or (2) both non-zero and varying, said circuit comprising: means for sensing current flowing in the external circuit and for generating a voltage in accordance with the magnitude of the current; means for establishing a preselected threshold voltage range; comparing means for generating first signals when said voltage is within said preselected voltage range and second signals when said voltage is outside said preselected voltage range; and means associated with said comparing means for triggering a first output means in response to successive first signals and for triggering a second output means in response to successive second signals.

Claim 3

A detecting circuit as defined in claim 1 in which said sensing means comprises a transformer having a primary winding in the external circuit and a secondary winding in the detecting circuit.

Claim 4

A detecting circuit as defined in claim 1 wherein said establishing means comprises a plurality of resistors connected in series across a voltage supply and said voltage range comprises the difference between voltages at a plurality junctions between said resistors.

Claim 5

A detecting circuit as defined in claim 1 in which said comparator means comprises a plurality of operational amplifiers.

Claim 6

A detecting circuit as defined in claim 4 in which a first voltage comparator compares said voltage to the more positive end of said voltage range and in which a second voltage comparator compares said voltage to the more negative end of said voltage range.

Claim 7

A circuit as defined in claim 1 wherein said first output means comprises a first AND gate having an output, a first input and a second input and said second output means comprises a second AND gate having an output, a first input and a second input.

Claim 8

A circuit as defined in claim 6 wherein said means associated with said comparing means comprises: a first flip-flop means and a second flip-flop means, each said flip-flop means having a voltage input, a clock input, a current-constant output and a current-varying output, said voltage input of said first flip-flop means connected to said comparing means for receiving said first and second signals, said current-constant output of said first flip-flop means connected to said voltage input of said second flip-flop means and the current-constant output of said first flip-flop means and the current-constant output of said second flip-flop means respectively connected to first and second inputs of said first AND gate, the current-varying output of said first flip-flop means and the current-varying output of said second flip-flop means respectively connected to said first and second inputs of said second AND gate; and clock means associated with said clock input of said first flip-flop means and said clock input of said second flip-flop means for triggering at a first clock pulse either said current-constant output of said first flip-flop means in response to a first signal or said current-varying output of said first flip-flop means in response to a second signal and for transferring at a second clock pulse the state of said first flip-flop means to said second flip-flop means and for triggering at said second clock pulse either said current-constant output of said first flip-flop means in response to a first signal or said current-varying output of said first flip-flop means in response to a second signal.

Claim 9

A circuit for detecting current flowing in an external circuit having a varying amplitude and for generating an output representing a correlation of the state of said current at different times represented by clock pulses, said detecting circuit comprising: means for sensing current flowing in the external circuit and for generating a voltage in accordance with the magnitude of said current; means for establishing a preselected threshold voltage range; comparing means for generating first signals when said voltage is within said preselected voltage range, and second signals when said voltage is outside of said preselected voltage range; clock means; and shift register means clocked by said clock means and cooperating with said comparing means for storing the signals generated by said comparing means during a predetermined number of successive clock pulses, and for interrogating said successively stored signals to trigger a first output means if said succession of stored signals comprise said first signals, or a second output means if said succession of stored signals comprise said second signals.

Claim 10

A circuit for detecting current flowing in an external circuit having a varying amplitude and for generating an output representing a correlation of the state of said current at different times represented by clock pulses, said detecting circuit comprising: means for sensing current flowing in the external circuit and for generating a voltage in accordance with the magnitude of said current; means for establishing a preselected threshold voltage range; comparing means for generating first signals when said voltage is within said preselected voltage range, and second signals when said voltage is outside of said preselected voltage range; clock means; and shift register means clocked by said clock means and cooperating with said comparing means for storing the signals generated by said comparing means during a predetermined number of successive clock pulses, and for interrogating said successively stored signals to trigger a first output means if said succession of stored signals comprise said first signals, or a second output means if said succession of stored signals comprise said second signals.

Claim 11

A circuit as defined in claim 8 in which said shift register means comprises a first flip-flop and a second flip-flop, said first flip-flop serving to store the signals generated by the comparing means at a first clock pulse and at a second succeeding clock pulse to transfer said signal to said second flip-flop and to store the signal generated by said comparing means at said second clock pulse.

Claim 12

A circuit as defined in claim 9 in which said first output means and said second output means comprise respective AND gates.

Claim 13

A circuit for detecting currents flowing in any of a plurality of external circuits and for generating outputs identifying the currents as either (1) constant zero or constant direct current or (2) both non-zero and varying, said detection circuit comprising: a plurality of sensing means singly associated with respective ones of said plurality of external circuits for sensing current flowing therein, and for generating voltages in response to said currents; means for establishing a preselected threshold voltage range; a plurality of comparing means singly associated with respective ones of said plurality of sensing means, each comparing means generating first signals when the associated voltage is within said preselected range, and second signals when said associated voltage is outside of said preselected voltage range; a plurality of flip-flop circuit means singly associated with respective ones of said plurality of comparing means, each flip-flop circuit means triggering a first output means in response to successive said first signals and a second output means in response to successive said second signals; and means associated with said plurality of flip-flop means for correlating the outputs of said plurality of flip-flop means.

Claim 14

A circuit for detecting currents flowing in any of a plurality of external circuits and for generating outputs identifying the currents as either (1) constant zero or constant direct current or (2) both non-zero and varying, said detection circuit comprising: a plurality of sensing means singly associated with respective ones of said plurality of external circuits for sensing current flowing therein, and for generating voltages in response to said currents; means for establishing a preselected threshold voltage range; a plurality of comparing means singly associated with respective ones of said plurality of sensing means, each comparing means generating first signals when the associated voltage is within said preselected range, and second signals when said associated voltage is outside of said preselected voltage range; a plurality of flip-flop circuit means singly associated with respective ones of said plurality of comparing means, each flip-flop circuit means triggering a first output means in response to successive said first signals and a second output means in response to successive said second signals; and means associated with said plurality of flip-flop means for correlating the outputs of said plurality of flip-flop means.