US-12620799-B2 - Circuit-based resettable switch controllers

Abstract

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.

Inventors

• Randy L. Brandt
• Ronald P. Dudash
• Suhat Limvorapun
• Thomas Addicks Webb
• Margaret Duenas
• Michael Fu

Assignees

• THE BOEING COMPANY

Dates

Publication Date

20260505

Application Date

20240227

Claims (20)

1. 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. 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. 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. 4 . The apparatus as defined in claim 1 , further including a trim resistor to at least partially define the function.
5. 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. 6 . The apparatus as defined in claim 5 , wherein the second comparator is to compare the first signal to a reference voltage.
7. 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. 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. 9 . The apparatus as defined in claim 8 , wherein the integrator includes the three slope integrator.
10. 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. 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. 12 . The apparatus as defined in claim 11 , including a trim resistor to define the i 2 t function.
13. 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. 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. 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. 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. 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. 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. 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. 20 . The method as defined in claim 19 , further including amplifying the first signal.

Description

FIELD OF THE DISCLOSURE This disclosure relates generally to circuit protection and, more particularly, to circuit-based resettable switch controllers. BACKGROUND To reduce design complexity many existing output switches utilize protection, such as fuses, with hard limits that are set and/or defined to be above an actual current limit. These hard limits are often set significantly above an over current limit. Some known fuses have characteristic behavior that can be approximated and/or represented by an I-squared t (i2t) function. SUMMARY An 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. An example integrated circuit for use with a switch includes 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 integrator 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. An example method includes 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, and preventing, via latch circuitry, current from flowing through at least a portion of the circuit in response to output from the comparator. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B depict components and/or systems in which examples disclosed herein can be implemented. FIGS. 2A and 2B are example graphs depicting current protection characteristics. FIG. 3 is a schematic overview of an example resettable power switch controller constructed in accordance with teachings of this disclosure. FIG. 4 is a schematic overview of an example circuit that can be implemented in examples disclosed herein. FIG. 5 is a schematic overview of another example circuit that can be implemented in examples disclosed herein. FIG. 6 is a schematic overview of yet another example circuit that can be implemented in examples disclosed herein. FIG. 7 is a flowchart representative of an example method, example machine readable instructions and/or example operations that may be executed, instantiated, and/or performed by example programmable circuitry to implement examples disclosed herein. FIG. 8 is a block diagram of an example processing platform including programmable circuitry structured to execute, instantiate, and/or perform the example machine readable instructions and/or perform the example operations of FIG. 7 to implement examples disclosed herein. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. The figures are not necessarily to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular. DETAILED DESCRIPTION Circuit-based resettable switch controllers are disclosed. Fuses are typically utilized to protect circuits and/or electrical components. In known implementations, fuses are generally single use such that they are rendered inoperable after an event and, thus, can necessitate repairs and/or replacement of components. Some fuses/fuse devices utilize I-squared t (i2t) characteristics of a single use (e.g., one-time use) fuse device. Such a single use fuse device utilized for power interruption is generally known and accepted as an industry standard. However, enabling reset capabilities with resettable solid state i2t device characteristics can be costly, and can also significantly increase size as well as weight/mass, which can be particularly disadvantageous in applications, such as aircraft, spacecraft, etc. In known implementations, single use fuses with i2t characteristics/functionality have been utilized in conjunction with switches. However, in some military and space applications, fuses with a relatively high current capability can be difficult to procure, costly, and can have a significant corresponding lead-time. In numerous applications where fuses are located in difficult-to-access areas, in an