The present invention discloses a USB signal output circuit having reverse current prevention mechanism. A switch circuit turns on when a switch control terminal receives a first high level voltage to output a signal from a signal input terminal to a signal output terminal. A first voltage pull-low circuit includes a passive-component high-pass filter circuit and a discharging circuit. The passive-component high-pass filter circuit couples an output terminal voltage of the signal output terminal to a pull-low control terminal. The discharging circuit turns on when a voltage of the pull-low control terminal is larger than a predetermined voltage level to discharge the switch control terminal to pull the switch control terminal to a second high level voltage. A second voltage pull-low circuit pulls the switch control terminal to a low level voltage when the output terminal voltage is larger than a reference voltage and does not have a glitch.

A system and method for clearing overcurrent in a power distribution network. The network includes a feeder, a lateral line coupled to the feeder, a lateral line current interrupting device provided where the lateral line is coupled to the feeder, a plurality of service lines coupled to the lateral line, a distribution current interrupting device provided where a service line is coupled to the lateral line and a distribution transformer provided at each location where a service line is coupled to the lateral line. The method includes setting an operating time of the lateral line interrupting device to be longer than an operating time of the distribution interrupting devices, detecting overcurrent by the lateral line interrupting device and at least one of distribution interrupting devices, and operating the at least one the distribution interrupting device and not operating the lateral line interrupting device in response to detecting the overcurrent.

A system and method for clearing overcurrent in a power distribution network. The network includes a feeder, a lateral line coupled to the feeder, a lateral line current interrupting device provided where the lateral line is coupled to the feeder, a plurality of service lines coupled to the lateral line, a distribution current interrupting device provided where a service line is coupled to the lateral line and a distribution transformer provided at each location where a service line is coupled to the lateral line. The method includes setting an operating time of the lateral line interrupting device to be longer than an operating time of the distribution interrupting devices, detecting overcurrent by the lateral line interrupting device and at least one of distribution interrupting devices, and operating the at least one the distribution interrupting device and not operating the lateral line interrupting device in response to detecting the overcurrent.

For example, an overcurrent protection circuit 71 includes a hiccup controller 71b which, when an output current To passing through a switching element 10 goes into an overcurrent state, hiccup-drives the switching element 10 such that predetermined on-period ton and off-period toff alternate. For example, the hiccup controller 71b may control at least one of the on- and off-period ton and toff according to a temperature sense signal S71c. For example, the temperature sense signal S71c may be generated by detecting at least one of temperature Tj of the switching element 10 and a difference in temperature ΔTj between the switching element 10 and another element. For example, when at least one of temperature Tj and the difference in temperature ΔTj is higher than a predetermined threshold value, the hiccup controller 71b may conduct at least one of reduction of the on-period ton and increase of the off-period toff.

For example, an overcurrent protection circuit 71 includes a hiccup controller 71b which, when an output current To passing through a switching element 10 goes into an overcurrent state, hiccup-drives the switching element 10 such that predetermined on-period ton and off-period toff alternate. For example, the hiccup controller 71b may control at least one of the on- and off-period ton and toff according to a temperature sense signal S71c. For example, the temperature sense signal S71c may be generated by detecting at least one of temperature Tj of the switching element 10 and a difference in temperature ΔTj between the switching element 10 and another element. For example, when at least one of temperature Tj and the difference in temperature ΔTj is higher than a predetermined threshold value, the hiccup controller 71b may conduct at least one of reduction of the on-period ton and increase of the off-period toff.

A switching apparatus includes first and second electric terminals, and first and second electric branches comprising one or more switching devices. The second electric branch is electrically connected in parallel with said first electric branch between said first and second electric terminals. The switching apparatus comprises a current blocking circuit adapted to block a current along said second branch. The current blocking circuit includes a first switching device of solid-state type and a first electronic circuit electrically connected in parallel to said first switching device of solid-state type. The switching apparatus further comprises a current limiting circuit adapted to limit a current flowing along said second electric branch. Said current limiting circuit is electrically connected in series with said current blocking circuit and it includes a second switching device of solid-state type and a second electronic circuit electrically connected in parallel to said second switching device of solid-state type.

A switching apparatus includes first and second electric terminals, and first and second electric branches comprising one or more switching devices. The second electric branch is electrically connected in parallel with said first electric branch between said first and second electric terminals. The switching apparatus comprises a current blocking circuit adapted to block a current along said second branch. The current blocking circuit includes a first switching device of solid-state type and a first electronic circuit electrically connected in parallel to said first switching device of solid-state type. The switching apparatus further comprises a current limiting circuit adapted to limit a current flowing along said second electric branch. Said current limiting circuit is electrically connected in series with said current blocking circuit and it includes a second switching device of solid-state type and a second electronic circuit electrically connected in parallel to said second switching device of solid-state type.

A current control device brings, after a target current has been changed to an upper side, a solenoid into a full-on state at a first timing that arrives in a predetermined control transition cycle shorter than an on-off cycle, determines whether an excitation current has become equal to or larger than a full-on threshold larger than the target current, brings the solenoid into a full-off state at a first timing that arrives in a predetermined energization switching cycle shorter than the on-off cycle after the excitation current has become equal to or larger than the full-on threshold, determines whether the excitation current has become equal to or smaller than a full-off threshold smaller than the target current, and causes a transition to a steady control at a first timing that arrives in the control transition cycle after the excitation current has become equal to or smaller than the full-off threshold.

A current control device brings, after a target current has been changed to an upper side, a solenoid into a full-on state at a first timing that arrives in a predetermined control transition cycle shorter than an on-off cycle, determines whether an excitation current has become equal to or larger than a full-on threshold larger than the target current, brings the solenoid into a full-off state at a first timing that arrives in a predetermined energization switching cycle shorter than the on-off cycle after the excitation current has become equal to or larger than the full-on threshold, determines whether the excitation current has become equal to or smaller than a full-off threshold smaller than the target current, and causes a transition to a steady control at a first timing that arrives in the control transition cycle after the excitation current has become equal to or smaller than the full-off threshold.

Exemplary protection circuitry for wireless power systems can include a battery disconnect circuit, a load dump protection circuit, and/or a coil disconnect circuit. One or more of these protection circuits may be employed by a wireless power receiver. Further, one or more of these protection circuits may enable a wireless power receiver to be able to protect itself independently from a wireless power transmitter, thereby increasing safety of the wireless power system.