The present invention relates to a circuit protection device including: a device comprising a heating element configured to comprise a body and a pair of electrodes formed on the body, and a pair of lead wires connected, respectively, to the pair of electrodes; and a case having an independent accommodating space formed therein to accommodate at least the heating element, wherein the case includes at least one heat insulating layer disposed in the vicinity of the accommodating space.

An electromagnetic interference (EMI) circuit assembly includes a first, second, and third conductive layer. A protection component disposed between the first and second conductive layers. A dielectric layer is disposed between the second and the third conductive layers. The protection component is configured to protect a load from one or both of an overcurrent condition and an over temperature condition, and the third layer define a capacitor configured to suppress EMI signals.

This electrical protection system for a DC-current medium-voltage electrical circuit, comprising a disconnection module, for generating a counter-voltage greater than the voltage of the source for a current flowing therethrough that is equal to at most a few percent of the nominal current of the device, a resistive limitation module connected between a first terminal and a second terminal and configured so as to reduce the intensity of the output current of the protection system in order to limit the current between a value and upon a low impedance fault downstream of the device, and a primary switching module coupled in parallel across the disconnection module and the resistive module. The primary switching module is configured so as to switch between a first state in which the primary switching module is conductive and a second state in which the primary switching module forms a short circuit. Control means for controlling the primary switching module are configured so as to switch the primary switching module as soon as the current flowing in the first terminal reaches an upper limit value as lower value or a lower limit as upper value.

A network apparatus includes a hybrid data/power cable further including a power conductor and a data conductor extending between a first end and a second end thereof, the first end of the hybrid data/power cable terminating with a first connector head. The first connector head includes a fuse element coupled in series with the power conductor of the hybrid data/power cable. A remote device is coupled to the second end of the hybrid data/power cable for receiving a data signal from the data conductor of the hybrid data/power cable and a DC voltage from the power conductor of the first hybrid data/power cable. The remote device includes a current-limiting circuit coupled in series with the power conductor of the first hybrid data/power cable to produce a DC voltage at an output of the current-limiting circuit. The remote device further includes a buck/boost converter coupled to the output of the current-limiting circuit for adjusting the DC voltage. An external power supply may also be provided for the remote device.

A composite circuit protection device includes first and second positive temperature coefficient (PTC) components, a voltage-dependent resistor, and first, second and third conductive leads. The first PTC component includes a first PTC layer, and first and second electrode layers respectively disposed on two opposite surfaces of the first PTC layer. The second PTC component includes a second PTC layer, and third and fourth electrode layers respectively disposed on the two opposite surfaces of the second PTC layer. The voltage-dependent resistor is connected to the second and third electrode layers. The first, second and third conductive leads are bonded to the first electrode layer, the voltage-dependent resistor, and the fourth electrode layer, respectively.

An over-current protection device includes first and second electrode layers and a PTC material layer laminated therebetween. The PTC material layer includes a polymer matrix, a conductive filler, and a titanium-containing dielectric filler. The polymer matrix has a fluoropolymer. The titanium-containing dielectric filler has a compound represented by a general formula of MTiO.sub.3, wherein the M represents transition metal or alkaline earth metal. The total volume of the PTC material layer is calculated as 100%, and the titanium-containing dielectric filler accounts to for 5-15% by volume of the PTC material layer.

A circuit protection device includes a temperature sensitive resistor element, a dielectric layer, a first electrically insulating layer, a first electrode and a second electrode. The temperature sensitive resistor element has a first electrically conductive layer, a second electrically conductive layer and a positive temperature coefficient (PTC) layer disposed therebetween. The first electrically conductive layer has two electrically conductive blocks. The two electrically conductive blocks dispose on the surface of the PTC layer, thus forming a trench in the PTC layer. The dielectric layer is disposed in the trench. The first electrically insulating layer is disposed on the first electrically conductive layer and covers the dielectric layer. The first and second electrodes are disposed on the first electrically insulating layer, and electrically connected to the two electrically conductive blocks, respectively.

A power system includes a battery charge path and capacitor charge path arranged in parallel. During an inrush event, a current limiting element restricts current flow along the battery charge path to relieve battery stress. During the inrush event, current flow between the battery and load along a bypass path is also prevented by a switch element. Under steady state charging conditions, the resistance of the current limiting element decreases, thus increasing current flow between the battery and load along the battery charge path. During steady state conditions, a switch circuit controls operation of the switch element to also allow current flow between the battery and load along the bypass path. The change in the resistance of the current limiting element and/or actuation of the switch element by the switch circuit are optionally based on changes in temperature, and are passively effectuated without requiring an external control input signal.

A fuse device may include a PPTC body; a first electrode, disposed on a first side of the PPTC body; and a second electrode, disposed on a second side of the PPTC body. The PPTC body may comprise a polymer matrix and a conductive filler, wherein the fuse device has a trip temperature of less than 120° C.

Polymeric positive temperature coefficient (PPTC) bodies and fuse devices formed therefrom are described. In various embodiments, the PPTC bodies comprise a matrix polymer and a conductive filler comprising a compound of general formula M.sub.n+1AX.sub.n, where M is a transition d metal element, A is a p-block element, X is carbon or nitrogen, and n is 1, 2 or 3.