An apparatus includes a first diode and a second diode connected in series between a first voltage terminal and a second voltage terminal, a switch connected between the first voltage terminal and the second voltage terminal, and a clamping threshold circuit connected between a common node of the first diode and the second diode, and a gate of the switch, wherein the clamping threshold circuit is configured such that in response to a voltage surge applied to the common node of the first diode and the second diode, the switch is turned on once the voltage surge is greater than a predetermined threshold.

Various embodiments relate to a protection circuit, comprising: a pad configured to input an external voltage from a connector; a first circuit branch connected to the pad and configured to receive a fast ramp-up over voltage at the pad; a second circuit branch connected to the pad and configured to receive a ramp-up over voltage at the pad; a third circuit branch connected to the pad and configured to output an over voltage detection signal when an over voltage is received at the pad, wherein the third circuit branch includes a voltage divider with a variable resistor with a variable voltage node and an enable switch; and a logic circuit including an enabling transistor configured to control the variable resistor and the enable switch.

Circuits, methods, and apparatus that may provide power supply voltages in a safe and reliable manner that meets safety and regulatory concerns and does not exceed physical limitations of cables and other circuits and components used to provide the power supply voltages. One example may provide a cable having a sufficient number of conductors to provide power without exceeding a maximum current density for the conductors. Another example may provide a cable having more than the sufficient number of conductors in order to provide an amount of redundancy. Current sense circuits may be included for one or more conductors. When an excess current is sensed, a power source in the power supply may be shut down, the power source may be disconnected from one or more conductors, or both events may occur.

A power circuit with a first transistor, including a first terminal connected to a first node, a second terminal connected to an input node, and a control terminal connected to a first control node, and a second transistor, including a first terminal connected to the first node, a second terminal connected to an output node, and a control terminal connected to a second control node. A third transistor includes a first terminal connected to the first control node, a second terminal connected to a second node, and a control terminal, and a fourth transistor includes a first terminal connected to the output node, a second terminal connected to the second control node, and a control terminal connected to a third node. The power circuit also includes a current limiting circuit coupled between the second node and the third node.

A device comprises a processor, a memory for storing instruction code that is executable by the processor, and power supply circuitry. The power supply circuitry is in communication with the processor. The power supply circuitry comprises voltage regulator circuitry, a capacitor, a current limiter, and a switch. The voltage regulator circuitry comprises an input electrically coupled to a voltage source and an output configured to provide a regulated voltage output. The capacitor is configured to store energy derived from the voltage source. The capacitor comprises a first node electrically coupled with the output of the voltage regulator circuitry. The current limiter is in electrical communication with a second node of the capacitor and configured to limit inrush current through the capacitor during a start-up phase of the power supply circuitry. The switch circuit is in electrical communication with the second node of the capacitor. Capacitor current flows through the switch when the switch circuit is in an ON state, substantially bypassing the current limiter. The switch is transitioned to the ON state when a particular control signal is applied to the switch circuit. The switch circuit is configured to remain in the ON state when the particular control signal is no longer applied to the switch circuit.

Provided is an inrush current limiter and a system including the same, the inrush current limiter including first and second input nodes for receiving an input voltage from a power source, a first output node and a second output node for being connected with a load, an inrush-current-limiting portion including a transistor connected between the first input node and the first output node, and for turning on the transistor when a voltage level of the input voltage is higher than a first level, and for limiting an inrush current by controlling time until the transistor is turned on after application of the input voltage, a switch connected between a control terminal of the transistor and the second input node, and a mode controller for turning on the switch when the voltage level of the input voltage is lower than a second level that is lower than the first level.

A circuit for detecting faults affecting a power transistor comprises a conditioning circuit, a first fault status circuit, and a fault signaling circuit. The power transistor is turned on and off by assertion and de-assertion, respectively, of an input signal. The conditioning circuit produces a conditioned gate voltage signal from a gate voltage of the power transistor. The first fault status circuit asserts a first fault indication when the conditioned gate voltage signal is greater than a first fault reference voltage during a first interval after the assertion of the input signal. The fault signaling circuit asserts a fault signal in response to the first fault indication being asserted, and de-asserting the fault signal in response to the input signal being de-asserted.

An electronic circuit includes a switch coupled between an input terminal intended to receive a first voltage and an output terminal coupled to a decoupling capacitor and intended to also be coupled to a load. A comparison stage is configured to compare the first voltage and a second voltage that is present at the output terminal. A first adjustment stage is configured to limit a positive inrush current flowing between the input terminal and the output terminal and a second adjustment stage is configured to limit a negative inrush current flowing between the output terminal and the input terminal. A control circuit is configured to activate either the first adjustment stage or the second adjustment stage as a function of a result of the comparison.

Embodiments of negative pressure wound therapy systems and methods are disclosed. In one embodiment, an apparatus includes a housing, negative pressure source, circuit board, and one or more controllers. The circuit board can be supported by the housing and include a conductive pathway extending around at least part of a perimeter of a first side of the circuit board. The conductive pathway can be electrically coupled to an electrical ground for the circuit board. The one or more controllers can be mounted on the circuit board and activate and deactivate the negative pressure source.

A source circuit, a power supply and an electric system. The source circuit includes at least one voltage source supplied from a mains circuit and used to provide at least one voltage for at least one device and at least one switch respectively connected to the at least one voltage source and controlled to be turned on according to a voltage of the mains circuit and/or at a timing after the mains circuit being applied corresponding to the device.