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.

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.

An electronic circuit for providing protection for an energy supply for a receiving device, includes: a supply path for connecting the receiving device to a voltage source, wherein the supply path has at least one first switching component in series with a second switching component, and also a measuring resistor, a functional assembly for providing protection against an overcurrent in the supply path, a functional assembly for detecting a connected receiving device, a functional assembly for providing protection against a polarity reversal for the voltage of the supply path, and a functional assembly for detecting a ground short for the supply path.

An electronic circuit for providing protection for an energy supply for a receiving device, includes: a supply path for connecting the receiving device to a voltage source, wherein the supply path has at least one first switching component in series with a second switching component, and also a measuring resistor, a functional assembly for providing protection against an overcurrent in the supply path, a functional assembly for detecting a connected receiving device, a functional assembly for providing protection against a polarity reversal for the voltage of the supply path, and a functional assembly for detecting a ground short for the supply path.

A method for analyzing effects of electrical perturbations on equipment in an electrical system includes processing energy-related signals from at least one intelligent electronic device in the electrical system to identify an electrical perturbation in the electrical system. An end time of the electrical perturbation may be determined, and electrical measurement data from prior to, during and/or after the end time of the electrical perturbation may be analyzed to identify and quantify the effects of the electrical perturbation on equipment in the electrical system. The effects may include, for example, equipment restarts/re-energizations due to the electrical perturbation. One or more actions may be taken or performed to reduce the effects of the electrical perturbation and extend the life of the equipment. The actions may include, for example, at least one of communicating the equipment restarts/re-energizations and controlling at least one component in the electrical system.

The invention discloses a high-voltage driver switch system and switching method. The system includes a main control chip module and an energy storage capacitor connected with a battery pack, a drive circuit module, a pre-charge circuit and a charge circuit for charging the energy storage capacitor. The pre-charge circuit is connected with the main control chip module and has a current limit resistor, so as to pre-charge the energy storage capacitor under the control of the main control chip module. The charge circuit is connected with the main control chip module and has an electronic switch module which includes two ends connected respectively with the battery pack and the energy storage capacitor, the battery pack charges the energy storage capacitor when switched-on. The invention reduces the instantaneous start-up current and avoids a high current impact caused by charging the energy storage capacitor by the battery pack directly.

Provided is a backflow prevention circuit including a backflow prevention transistor as a p-channel MOS transistor interposed in series between an input terminal to which a power supply voltage is supplied, and an output-stage transistor as a p-channel MOS transistor, configured to supply an output voltage from an output terminal, and a backflow prevention control circuit configured to turn off the backflow prevention transistor if the output voltage exceeds the power supply voltage. The backflow prevention control circuit includes a first transistor, a first current source circuit, and a level shift circuit.

In described examples, a power interface subsystem includes power transistors, each having: a conduction path coupled between a battery terminal and an accessory terminal; and a control terminal. A differential amplifier has: a first input coupled to the battery terminal; a second input coupled to the accessory terminal; and an output node. An offset voltage source is coupled to cause an offset of a selected polarity at one of the inputs to the differential amplifier. The offset has a first polarity in a first operating mode and a second polarity in a second operating mode. Gate control circuitry is coupled to apply a control level at the control terminal(s) of selected one(s) of the power transistors responsive to a voltage at the output node, and to apply an off-state control level to the control terminal(s) of unselected one(s) of the power transistors.

In described examples, a power interface subsystem includes power transistors, each having: a conduction path coupled between a battery terminal and an accessory terminal; and a control terminal. A differential amplifier has: a first input coupled to the battery terminal; a second input coupled to the accessory terminal; and an output node. An offset voltage source is coupled to cause an offset of a selected polarity at one of the inputs to the differential amplifier. The offset has a first polarity in a first operating mode and a second polarity in a second operating mode. Gate control circuitry is coupled to apply a control level at the control terminal(s) of selected one(s) of the power transistors responsive to a voltage at the output node, and to apply an off-state control level to the control terminal(s) of unselected one(s) of the power transistors.

A fall-off protection and reverse-connection protection system and method for a connecting clamp of an automobile starting power supply. The system has an internal battery, a switching circuit, an access device, a connecting clamp, an MCU control circuit, a voltage division circuit for external battery detection, an output connecting clamp current detection circuit and an anti-reverse-connection protection circuit. In the method, voltage conditions of an external power supply can be effectively detected and different operating actions are taken based on the voltage conditions of the external power supply, thus ensuring normal startup.