Circuit-based resettable switch controllers
Circuit-based resettable switch controllers are disclosed. A disclosed example apparatus for use with a circuit includes an integrator to define a function that is based on a current of the circuit and time, a comparator to receive a first signal from the circuit at a first input of the comparator, and to receive a second signal from the integrator at a second input of the comparator, and a latch to receive an output of the comparator, the latch to prevent the current from flowing to or through the circuit based on the output from the comparator.
1 . An apparatus for use with a circuit, the apparatus comprising:
an integrator to define a function that is based on a current of the circuit and time;
a comparator to receive a first signal from the circuit at a first input of the comparator, and to receive a second signal from the integrator at a second input of the comparator;
a latch to receive an output of the comparator, the latch to prevent the current from flowing to or through the circuit based on the output from the comparator; and
a reset to reset the latch subsequent to the latch preventing the current from flowing through the circuit, the reset to prevent the latch from enabling current to flow through the circuit when a number of occurrences of latch activations exceeds a threshold number of latch activations.
2 . The apparatus as defined in claim 1 , further including an amplifier to amplify the first signal for the first input of the comparator.
3 . The apparatus as defined in claim 1 , further including at least one of a light emitter or a photovoltaic driver to receive an output from the latch.
4 . The apparatus as defined in claim 1 , further including a trim resistor to at least partially define the function.
5 . The apparatus as defined in claim 1 , wherein the comparator is a first comparator and further including a second comparator to provide input to the integrator.
6 . The apparatus as defined in claim 5 , wherein the second comparator is to compare the first signal to a reference voltage.
7 . The apparatus as defined in claim 1 , including an optocoupler coupled to an output of the latch, the optocoupler to control current provided to the circuit.
8 . An apparatus for use with a circuit, the apparatus comprising:
an integrator including a three slope integrator or multiplier;
a comparator to receive a first signal from the circuit at a first input of the comparator, and to receive a second signal from the integrator at a second input of the comparator; and
a latch to receive an output of the comparator, the latch to prevent the current from flowing to or through the circuit based on the output from the comparator.
9 . The apparatus as defined in claim 8 , wherein the integrator includes the three slope integrator.
10 . The apparatus as defined in claim 9 , wherein the three slope integrator is utilized to identify a locus of an I-squared t (i 2 t) function.
11 . An apparatus for use with a circuit, the apparatus comprising:
an integrator to define a function that is based on a current of the circuit and time, wherein the function corresponds to an I-squared t (i 2 t) function;
a comparator to receive a first signal from the circuit at a first input of the comparator, and to receive a second signal from the integrator at a second input of the comparator; and
a latch to receive an output of the comparator, the latch to prevent the current from flowing to or through the circuit based on the output from the comparator.
12 . The apparatus as defined in claim 11 , including a trim resistor to define the i 2 t function.
13 . An integrated circuit for use with a switch, the integrated circuit comprising:
a sensing circuit to measure a current of the switch;
a function circuit to define a function that is based on the current and time;
a comparator circuit to receive a first signal from the circuit at a first input of the comparator circuit, and to receive a second signal from the function circuit at a second input of the comparator circuit;
a latch circuit to receive an output of the comparator circuit, the latch to prevent the current from flowing through the switch based on the output from the comparator and
a reset circuit to reset the latch circuit subsequent to the latch circuit preventing the current from flowing through the switch, wherein the reset circuit is to prevent the latch circuit from enabling current to flow through the switch when a number of occurrences of latch activations exceeds a threshold number of latch activations.
14 . The integrated circuit as defined in claim 13 , further including a current sensing amplifier circuit to amplify the first signal for the first input of the comparator.
15 . The integrated circuit as defined in claim 13 , further including at least one of a light emitter or a photovoltaic driver to receive an output signal from the latch circuit.
16 . The integrated circuit as defined in claim 13 , wherein the function circuit is electrically coupled to a trim resistor, the trim resistor to at least partially define the function.
17 . The integrated circuit as defined in claim 13 , further including an integrator reset circuit to:
provide a first output when input current does not exceed a threshold current rating, and
provide a second output when the input current exceeds the threshold current rating, the first output to enable the function circuit and the second output to disable the function circuit.
18 . An integrated circuit for use with a switch, the integrated circuit comprising:
a sensing circuit to measure a current of the switch;
a function circuit to define a function that is based on the current and time, wherein the function circuit defines a three slope integrator or multiplier;
a comparator circuit to receive a first signal from the circuit at a first input of the comparator circuit, and to receive a second signal from the function circuit at a second input of the comparator circuit; and
a latch circuit to receive an output of the comparator circuit, the latch to prevent the current from flowing through the switch based on the output from the comparator.
19 . A method comprising:
measuring a current of a first signal, the current flowing through a circuit;
comparing, via comparator circuitry, the first signal to a second signal from integrator circuitry, the integrator circuitry to define a function that is based on the current and time;
preventing, via latch circuitry, current from flowing through at least a portion of the circuit in response to output from the comparator; and
resetting, via a reset, the latch, wherein resetting of the latch is enabled based on a number of occurrences of latch activations being less than or equal to a threshold number of latch activations.
20 . The method as defined in claim 19 , further including amplifying the first signal.
21 . A method comprising:
measuring a current of a first signal, the current flowing through a circuit;
comparing, via comparator circuitry, the first signal to a second signal from integrator circuitry;
defining, via the integrator circuitry, a function that is based on the current and time, the function to be defined based on an inverse of a square root of the time; and
preventing, via latch circuitry, current from flowing through at least a portion of the circuit in response to output from the comparator.