Method and apparatus for detecting excessive current draw in an electrical load

Claim 1

An apparatus for sensing excessive current in an electrical load comprising: means for providing an actuating signal; means for connecting or disconnecting the electrical load to a source of electrical energy in response to said actuating signal; means providing a load sense signal at a terminal, said load sense signal having a value indicative of the value of electrical current through the load; means for modifying said load sense signal in response to said actuating signal to offset an initial change in the value of said load sense signal when the electrical load is first connected to the source of electrical energy said means for modifying includes means for temporarily coupling said actuating signal to said load sense signal at said terminal; means for providing a reference signal having a predetermined value; and means for comparing the modified load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the modified load sense signal and a second signal when the reference signal is less than the modified load sense signal, one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 2

An apparatus for sensing excessive current in an electrical load comprising: means for providing an actuating signal; means for connecting or disconnecting the electrical load to a source of electrical energy in response to said actuating signal; means providing a load sense signal at a terminal, said load sense signal having a value indicative of the value of electrical current through the load; means for modifying said load sense signal in response to said actuating signal to offset an initial change in the value of said load sense signal when the electrical load is first connected to the source of electrical energy said means for modifying includes means for temporarily coupling said actuating signal to said load sense signal at said terminal; means for providing a reference signal having a predetermined value; and means for comparing the modified load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the modified load sense signal and a second signal when the reference signal is less than the modified load sense signal, one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 6

An apparatus for sensing excessive current in an electrical load comprising: means for providing an actuating signal, said actuating signal being changeable from a first condition to a second condition; switch means for connecting or disconnecting the electrical load to a source of electrical energy when said actuating signal changes to said second condition; sensing means sensing electrical current through the load and for providing a load sense signal at a terminal with said load sense signal having a value indicative of the sensed current, said load sense signal having one value when electrical energy is first connected to the load due to current in-rush and a second steady-state value when the electrical energy has been connected to the load for a predetermined time period; means for temporarily coupling said actuating signal to said load sense signal at said terminal when the electrical energy is first connected to the load to offset an initial change in the value of said load sense signal due to the current in-rush; means for providing a reference signal having a predetermined value; and means for comparing said load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal with one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 7

An apparatus for sensing excessive current in an electrical load comprising: means for providing an actuating signal, said actuating signal being changeable from a first condition to a second condition; switch means for connecting or disconnecting the electrical load to a source of electrical energy when said actuating signal changes to said second condition; sensing means sensing electrical current through the load and for providing a load sense signal at a terminal with said load sense signal having a value indicative of the sensed current, said load sense signal having one value when electrical energy is first connected to the load due to current in-rush and a second steady-state value when the electrical energy has been connected to the load for a predetermined time period; means for temporarily coupling said actuating signal to said load sense signal at said terminal when the electrical energy is first connected to the load to offset an initial change in the value of said load sense signal due to the current in-rush; means for providing a reference signal having a predetermined value; and means for comparing said load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal with one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 11

An apparatus for sensing excessive current draw in an electrical load comprising: actuatable switch means for connecting or disconnecting the electrical load to a source of electrical energy in response to an actuation signal; sense resistor connected in series with the electrical load, said sense resistor developing a voltage thereacross having a value indicative of the, current being drawn by the electrical load; means connected to said, sense resistor providing a load sense signal at a terminal which is responsive to the voltage developed across said sense resistor; means for providing a control signal having a first condition when it is desirable to have the electrical load not energized and a second condition when it is desired to energize the electrical load; means for momentarily coupling said control signal to said load sense signal at said terminal to offset an initial change in the voltage value developed across said sense resistor when electrical energy is first connected to the electrical load; means for providing a reference signal having a predetermined voltage value; means for comparing said load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal with one of the signals generated by said comparing means being indicative of excessive current draw by the electrical load; and means for ANDING said control signal with the generated signal from said comparing means and for providing the actuation signal when the control signal is in its second condition and the comparing means is generating a signal indicative to no excessive current draw by the electrical load.

Claim 12

An apparatus for sensing excessive current draw in an electrical load comprising: actuatable switch means for connecting or disconnecting the electrical load to a source of electrical energy in response to an actuation signal; sense resistor connected in series with the electrical load, said sense resistor developing a voltage thereacross having a value indicative of the, current being drawn by the electrical load; means connected to said, sense resistor providing a load sense signal at a terminal which is responsive to the voltage developed across said sense resistor; means for providing a control signal having a first condition when it is desirable to have the electrical load not energized and a second condition when it is desired to energize the electrical load; means for momentarily coupling said control signal to said load sense signal at said terminal to offset an initial change in the voltage value developed across said sense resistor when electrical energy is first connected to the electrical load; means for providing a reference signal having a predetermined voltage value; means for comparing said load sense signal against said reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal with one of the signals generated by said comparing means being indicative of excessive current draw by the electrical load; and means for ANDING said control signal with the generated signal from said comparing means and for providing the actuation signal when the control signal is in its second condition and the comparing means is generating a signal indicative to no excessive current draw by the electrical load.

Claim 19

An apparatus for sensing excessive current draw in an electrical load comprising: means providing an electrical signal having a value indicative of the amount of electrical current through the electrical load; means for providing a variable threshold signal at a terminal, said threshold signal having a value indicative of the maximum current permitted to be drawn by the electrical load; means for comparing the value of said signal indicative of the amount of electrical current through the electrical load against said variable threshold signal and for providing a signal indicative of the electrical current drawn by the electrical load exceeding the maximum permitted current to be drawn as established by the variable theshold signal; and means for varying the value of said threshold signal at said terminal for a predetermined time period when electrical energy is first applied to the electrical load, the maximum allowable current permitted to be drawn by the load varying with the varying threshold value.

Claim 20

An apparatus for sensing excessive current draw in an electrical load comprising: means providing an electrical signal having a value indicative of the amount of electrical current through the electrical load; means for providing a variable threshold signal at a terminal, said threshold signal having a value indicative of the maximum current permitted to be drawn by the electrical load; means for comparing the value of said signal indicative of the amount of electrical current through the electrical load against said variable threshold signal and for providing a signal indicative of the electrical current drawn by the electrical load exceeding the maximum permitted current to be drawn as established by the variable theshold signal; and means for varying the value of said threshold signal at said terminal for a predetermined time period when electrical energy is first applied to the electrical load, the maximum allowable current permitted to be drawn by the load varying with the varying threshold value.

Claim 21

A method for sensing excessive current in an electrical load comprising: providing an actuating signal; connecting the electrical load to a source of electrical energy in response to said actuating signal; providing a load sense signal at a terminal, said load sense signal having a value indicative of the value of electrical through the load; modifying said load sense signal in response to said actuating signal to offset an initial change in the value of said sense signal by temporarily coupling the actuating signal to said load sense signal at said terminal; providing a re signal having a predetermined value; and comparing the modified load sense signal against the reference signal and for generating a first signal when the reference signal is greater than the modified load sense signal and a second signal when the reference signal is less than the modified load sense signal, one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 22

A method for sensing excessive current in an electrical load comprising: providing an actuating signal; connecting the electrical load to a source of electrical energy in response to said actuating signal; providing a load sense signal at a terminal, said load sense signal having a value indicative of the value of electrical through the load; modifying said load sense signal in response to said actuating signal to offset an initial change in the value of said sense signal by temporarily coupling the actuating signal to said load sense signal at said terminal; providing a re signal having a predetermined value; and comparing the modified load sense signal against the reference signal and for generating a first signal when the reference signal is greater than the modified load sense signal and a second signal when the reference signal is less than the modified load sense signal, one of the signals generated by the comparing means being indicative of excessive current draw by the electrical load.

Claim 23

A method for sensing excessive current in an electrical load comprising: providing an actuating signal, said actuating signal being changeable from a first condition to a second condition; connecting the electrical load to a source of electrical energy when said actuating signal changes to said second condition; sensing electrical current through the load; providing a load sense signal at a terminal having a value indicative of the sensed current, said load sense signal having one value when electrical energy is first connected to the load due to current in-rush and a second steady-state value when the electrical energy has been connected to the load for a predetermined time period; coupling said actuating signal to said load sense signal at said terminal when the electrical energy is first connected to the load to offset an initial change in the value of said load sense signal due to the current in-rush; providing a reference signal having a predetermined value; and comparing said load sense signal against the reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal, one of the signals generated in the comparing means being indicative of excessive current draw by the electrical load.

Claim 24

A method for sensing excessive current in an electrical load comprising: providing an actuating signal, said actuating signal being changeable from a first condition to a second condition; connecting the electrical load to a source of electrical energy when said actuating signal changes to said second condition; sensing electrical current through the load; providing a load sense signal at a terminal having a value indicative of the sensed current, said load sense signal having one value when electrical energy is first connected to the load due to current in-rush and a second steady-state value when the electrical energy has been connected to the load for a predetermined time period; coupling said actuating signal to said load sense signal at said terminal when the electrical energy is first connected to the load to offset an initial change in the value of said load sense signal due to the current in-rush; providing a reference signal having a predetermined value; and comparing said load sense signal against the reference signal and for generating a first signal when the reference signal is greater than the load sense signal and a second signal when the reference signal is less than the load sense signal, one of the signals generated in the comparing means being indicative of excessive current draw by the electrical load.

Claim 25

A method for sensing excessive current draw in an electrical load comprising: providing an electrical signal having a value indicative of the amount of electrical current through the electrical load; providing a variable threshold signal at a terminal, said variable threshold signal having a value indicative of the maximum current draw permitted to flow through the electrical load; comparing the value of said signal indicative of the amount of electrical current through the electrical load against said variable threshold signal; providing a signal indicative of the electrical current through the load exceeding the maximum permitted value established by the variable threshold signal; and varying the value of said threshold signal at said terminal for a predetermined time period when electrical energy is first applied to the electrical load, the maximum allowable current permitted to flow through the load varying with the varying threshold value.

Claim 26

A method for sensing excessive current draw in an electrical load comprising: providing an electrical signal having a value indicative of the amount of electrical current through the electrical load; providing a variable threshold signal at a terminal, said variable threshold signal having a value indicative of the maximum current draw permitted to flow through the electrical load; comparing the value of said signal indicative of the amount of electrical current through the electrical load against said variable threshold signal; providing a signal indicative of the electrical current through the load exceeding the maximum permitted value established by the variable threshold signal; and varying the value of said threshold signal at said terminal for a predetermined time period when electrical energy is first applied to the electrical load, the maximum allowable current permitted to flow through the load varying with the varying threshold value.