A protection circuit includes a first PMOS and a first PDMOS receiving input of voltage of a voltage dividing point of voltage input from an external power supply terminal, and a second PMOS and a second PDMOS receiving input of drain output voltage of the first PDMOS. The first PMOS is connected on the external power supply terminal side of the first PDMOS, and the second PMOS is connected on the external power supply terminal side of the second PDMOS. During overvoltage application, the voltage of the voltage dividing point is clamped to the breakdown voltage of a Zener diode, the second PDMOS turns OFF, and supply to an integrated circuit protected from overvoltage is cut off. When the voltage source is connected in reverse, parasitic diodes of the first and second PMOSs are reverse-biased and the flow of current in a path through the parasitic diodes is inhibited.

A protection device for protecting an electronic device includes a current sensing module, for detecting a current flowing through a power supply path of the electronic device to generate a current signal; a processing device, coupled to the current sensing module, for receiving the current signal to determine whether the current corresponding to the current signal is greater than a first threshold value and outputting a control signal accordingly; a first switch, disposed on the power supply path, for controlling the power supply path to be switched on or off according to an input voltage of the power supply path; and a first control module, coupled to the processing device and the first switch, for controlling the first switch to be turned on or off according to the control signal outputted by the processing device, in order to control the power supply path to be switched on or off.

An electronic device is configured with sub-assemblies including a main logic board, flexible printed circuit, and dual battery packs that are assembled together with electrical connectors to enable power from the battery packs to flow over a power bus that is distributed along the flexible printed circuit and main logic board. A protection circuit module (PCM) in each battery pack is configured to determine a state of each of the connections among the sub-assemblies (i.e., whether or not properly assembled to provide electrical continuity through the connector) so that power from the battery packs is switched on to the power bus only when electrical continuity is verified at each of the connectors. In the event that any connection is faulty, for example due to a misalignment of a connector during assembly that prevents electrical continuity to be established through a connector, neither PCM will switch power on to the power bus.

Disclosed are an electrostatic discharge circuit and a method for preventing malfunctions of an integrated circuit due to a reverse connection of a power source. The electrostatic discharge circuit includes at least one MOSFET for providing an electrostatic discharging current path, and a control circuit coupled to the at least one MOSFET. When an external power supply is reversely connected, the control circuit is configured to change a potential of a body of at least one MOSFET, such that the at least one MOSFET is turned off, thereby preventing the integrated circuit from malfunctioning caused by a current generated by the reverse connection of the external power source flowing through the at least one MOSFET.

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 controller for an electric motor includes a protective circuit for limiting current or for polarity reversal protection, the protective circuit including a field effect transistor having a gate. The protective circuit further includes a control unit for providing a control voltage for the gate, a smoothing capacitor for charge storage being provided at the gate.

A compact, decorative and multi-functional portable power charger and cable apparatus includes a portable charger unit with a housing where the housing encloses an internal rechargeable battery unit for connecting to and recharging one or more electronic devices, and a charging cable extending from the charger housing and in operative communication with the rechargeable battery. At least the charger housing is surrounded by an aesthetic feature, which can comprise a tasseled fitting, a puffball, a luggage tag, or a doll or teddy bear to hide the charger unit. Electrical fittings including power connection interfaces for connecting the charger and cable apparatus with at least one electronic device, or an external power source, or both, can be provided on the charging cable and also hidden by the aesthetic feature. The power charger and cable apparatus can be attached to a fashion accessory, such as a purse, a bag, luggage or clothing.

A battery protection circuit has two input nodes and two output nodes. The input nodes are connected to a positive supply line and a negative or ground line respectively, and the two output nodes are connected to a positive side of a load and a negative or ground return side of the load. The circuit includes a solid state switch which is oriented such that when the switch is open current cannot flow from the battery through the load. At least one capacitor is connected in series with a diode between the two input nodes of the circuit to smooth out any negative transient voltages present at the positive input node of the circuit. The capacitor includes a polarized capacitor and the diode is oriented to protect the capacitor during normal use when a positive voltage is present at the input node that is connected to the positive supply line.

An apparatus for providing protection to an electric circuit includes a P-channel MOSFET; a freewheeling diode coupled to a drain of the P-channel MOSFET and coupled to a load; and a charge pump coupled to a gate of the P-channel MOSEFT. In a normal operating mode, the charge pump receives a voltage from a voltage regulator, and is configured to multiply and reverses the polarity of the voltage to supply to the gate of the MOSFET. In a reverse battery operating mode, the charge pump receives no voltage from the voltage regulator to supply to the gate of the MOSFET causing the MOSFET to deactivate such that when the MOSFET deactivates, current is prevented from flowing through the freewheeling diode to protect the freewheeling diode.

A semiconductor device capable of preventing deterioration of a transistor caused by a flow of an overcurrent is provided. According to an embodiment, a semiconductor chip includes a first transistor provided between a high-potential side voltage terminal to which a constant voltage generated by reducing a power-supply voltage is supplied and an output terminal, a second transistor provided between a low-potential side voltage terminal to which a ground voltage is supplied and the output terminal, a control circuit controlling turning-on/off of the first and second transistors, a boosting circuit boosting the power-supply voltage by using a voltage of the output terminal to generate an output voltage, and an overvoltage detection circuit detecting an overvoltage of a power-supply line that couples the high-potential side voltage terminal and the first transistor to each other. The control circuit performs control to turn off the second transistor, when the overvoltage has been detected.