To protect a connected electrical load from anomalous electricity, an apparatus has a condition sensing unit configured to distinguish a power event type from among power event types from characteristics of an input electricity waveform accepted through an input port. The condition sensing unit indicates the power event type when a corresponding overvoltage criterion is met by characteristics of the input electricity waveform. A power control unit generates, responsive to a power event, a modulation signal that defines at least one amplitude notch in the input electricity waveform in accordance with the power event type. A switching mechanism electrically interposed between the input port and the output port transitions into conducting and non-conducting states in accordance with the modulation signal to superimpose the notch on the input electricity waveform.

A protection IC protects an external load connected to mains supply lines from dangerous or undesired conditions such as overvoltage, undervoltage, and overcurrent, by disconnecting the external load for at least the duration of such a condition. The IC has a range detector, a zero-crossing detector, a control unit, a switch driver, and a dummy DAC. The range detector senses the presence of an unwanted condition. The control unit then waits for a zero crossing, upon which it disconnects the load. A lockout timer may introduce a minimum wait time before reconnecting the load. To prevent instabilities around the switching points, hysteresis in the window thresholds prevents impact from noise. The dummy DAC regulates a dummy current that linearizes the IC's current consumption around the switching points to prevent instabilities caused by positive feedback in non-linear transitions.

An input overvoltage protection circuit is equipped with a first wiring and a second wiring which are connected to a protected circuit in order to supply a voltage thereto, a fuse inserted in series in the first wiring and which interrupts a current flowing through the first wiring when a current greater than or equal to a predetermined value flows therethrough, a silicon surge absorber, one end of which is connected between the protected circuit and the fuse in the first wiring, and the other end of which is connected to the second wiring, and a bidirectional two-terminal thyristor connected to the first wiring and to the second wiring at a location between the silicon surge absorber and the protected circuit.

An input overvoltage protection circuit is equipped with a first wiring and a second wiring which are connected to a protected circuit in order to supply a voltage thereto, a fuse inserted in series in the first wiring and which interrupts a current flowing through the first wiring when a current greater than or equal to a predetermined value flows therethrough, a silicon surge absorber, one end of which is connected between the protected circuit and the fuse in the first wiring, and the other end of which is connected to the second wiring, and a bidirectional two-terminal thyristor connected to the first wiring and to the second wiring at a location between the silicon surge absorber and the protected circuit.

An integrated circuit (IC) provides an improved fail-safe signal to a circuit sharing a fail-safe pin at which the voltage can be greater than the voltage of an upper rail. The IC includes a first circuit segment that receives a first fail-safe signal and a first power-down signal and provides an intermediate signal, wherein the first fail-safe signal indicates when the voltage at the fail-safe pin is greater than the upper rail and the first power-down signal indicates when the module is powered down, and a second circuit segment connected to receive the intermediate signal and to provide the improved fail-safe signal to the module.

An integrated circuit (IC) provides an improved fail-safe signal to a circuit sharing a fail-safe pin at which the voltage can be greater than the voltage of an upper rail. The IC includes a first circuit segment that receives a first fail-safe signal and a first power-down signal and provides an intermediate signal, wherein the first fail-safe signal indicates when the voltage at the fail-safe pin is greater than the upper rail and the first power-down signal indicates when the module is powered down, and a second circuit segment connected to receive the intermediate signal and to provide the improved fail-safe signal to the module.

A host electronic device may be coupled to an accessory electronic device. The host device and the accessory device may be connected via power supply lines and user data lines. If the host and accessory devices are improperly connected or if the accessory device is exposed to an incorrect voltage environment, the internal circuitry on the accessory device can be damaged. The accessory device may therefore include a reverse voltage protection circuit that can help prevent a large amount of current from inadvertently flowing into the accessory device. The protection circuit may include a low-side-enabled reverse current protection switch coupled between the external and internal ground terminals and also a single low-drop switch coupled to each of the user data lines. The low-drop switch will be activated whenever the voltage at the external ground terminal exceeds the voltage at the data line to help deactivate low-side-enabled reverse current protection switch.

A host electronic device may be coupled to an accessory electronic device. The host device and the accessory device may be connected via power supply lines and user data lines. If the host and accessory devices are improperly connected or if the accessory device is exposed to an incorrect voltage environment, the internal circuitry on the accessory device can be damaged. The accessory device may therefore include a reverse voltage protection circuit that can help prevent a large amount of current from inadvertently flowing into the accessory device. The protection circuit may include a low-side-enabled reverse current protection switch coupled between the external and internal ground terminals and also a single low-drop switch coupled to each of the user data lines. The low-drop switch will be activated whenever the voltage at the external ground terminal exceeds the voltage at the data line to help deactivate low-side-enabled reverse current protection switch.

The invention relates to an overvoltage protection device with a short-circuit function for protecting installations and persons for low-voltage installations, wherein at least one overvoltage protection element and a thermally activatable short-circuit device are arranged in a common housing. The device is designed to be inserted into an NH fuse part, and the common housing is designed with contact blades so as to be spatially analogous to a NH fuse link.

The invention relates to an overvoltage protection device with a short-circuit function for protecting installations and persons for low-voltage installations, wherein at least one overvoltage protection element and a thermally activatable short-circuit device are arranged in a common housing. The device is designed to be inserted into an NH fuse part, and the common housing is designed with contact blades so as to be spatially analogous to a NH fuse link.