11297 results about "Overvoltage" patented technology

An overvoltage output protector is electrically connected to a constant-voltage switching power supply which includes a switching transistor converting a DC voltage obtained by smoothing an AC voltage supplied from an AC power source into a cyclic pulse signal. In the overvoltage output protector, an overvoltage monitor whether a potential of the cyclic pulse signal is a predetermined value or more. A deactivator turns off the switching transistor in a case where the overvoltage monitor judges that the potential of the cyclic pulse signal is the predetermined value or more.

A patient-worn energy delivery apparatus for imparting electrical therapy to the body of a patient responsive to an occurrence of a treatable condition includes a voltage converter for converting electrical energy from an initial voltage to a final voltage, and a defibrillator electrically coupled between the converter and the patient and having an energy reservoir for receiving the electrical energy. The defibrillator produces preshaped electrical pulses such as defibrillation pulses and cardioversion pulses. The apparatus additionally includes an energy delivery controller electrically coupled to the patient and the converter and the defibrillator. The controller causes the converter to provide the electrical energy to the defibrillator at a specific charging rate in response to an energy level in the reservoir. The apparatus may include a plurality of electrodes interposed between the defibrillator and the patient and each electrode preferably has an impedance reducing means contained therein. One embodiment of the apparatus may include a H-bridge to produce a positive-going pulse segment and the negative-going pulse segment within the biphasic exponential signals. The apparatus periodically measures the energy as it is being delivered to the patient and can pre-emptively stop or truncate the pulse in the event an error condition is detected, such as an overvoltage condition or if the energy level approaches a predetermined level. The electrical components which store and release the energy minimize the size and expense of the apparatus, while isolating the microcomputer from the high energy levels as the therapeutic pulse is delivered.

An LDO voltage regulator includes an error amplifier having a first input coupled to a first reference voltage, a second input receiving a feedback signal, and an output producing a first control signal. An output transistor has a gate, a drain coupled to an unregulated input voltage, and a source coupled to produce a regulated output voltage on an output conductor. A feedback circuit is coupled between the output conductor and a second reference voltage. An overvoltage comparator has a first input coupled to receive the first reference voltage and a second input coupled to respond to the feedback signal to produce a discharge control signal indicating occurrence of an output overvoltage of at least a predetermined magnitude to control a discharge transistor coupled between the output conductor and the second reference voltage. An output current sensing circuit produces a control current representative of the drain current of the output transistor. An offset capacitor is coupled between the output of the error amplifier and the gate of the output transistor, and a servo amplifier has a first input coupled to receive a third reference voltage, a second input coupled to the output of the error amplifier, and an output coupled to the gate of the output transistor to produce a second control signal thereon. A current sensor circuit, a current capacitor, and an AND circuit operate to allow the discharge transistor to be turned on only if the output current is below a certain level.

The invention relates to a photovoltaic cell -DC/DC boost conversion charge method which belongs to battery technique field. The method includes: 1) a portable equipment accumulator voltage is detected by a voltage sensor, when lows to full charge capacity, the voltage sensor makes DC/DC boost converter starting DC/DC conversion, and electricity quantity flows from photovoltaic current to lithium battery for charging; 2) when the portable equipment accumulator is in full charge capacity state, accumulator need not charge again, the voltage sensor makes DC/DC boost converter forbidding DC/DC conversion, thereby, the portable equipment accumulator is protected and over charge phenomena is prevented. The method can be realized simply, and has short reaction time, high efficiency, overvoltage protection and anti-counterblast protection.

A power management system and method for multiple redundant power supplies. The present invention provides management and control of N+M power supplies, where N represents the minimum number of power supplies required and where M is the number of redundant power supplies (M>1), where any one of the power supplies may be capable of supplying power to all the loads of the power subsystems. In the preferred embodiment each power subsystem includes a power supply and a controller coupled to a power bus. A communication bus is provided common to each power subsystem. During reset or power-on periods, the controllers are programmed to uniquely delay the start time of each power supply, thereby protecting against an overcurrent/overvoltage condition on the power bus during reset periods. A master controller is provided to monitor normal operating conditions of the power subsystems and communication bus. The master controller is programmed to ensure that a predetermined number of power supplies are coupled to the power bus, even in the event of total or partial communication failure.

A transfer gate or pass gate circuit for transferring logic signals between nodes for a range of available high-potential supply levels. The primary transfer gate is designed to protect against potentials that either exceed either a high-potential or a low-potential level or that undershoot such potential levels. For overshoot (overvoltage) tolerance, this is achieved by coupling a NMOS transistor in parallel with a pair of PMOS transistors that are coupled in series. All three transistors are located between two nodes, either of which can be the input or the output of the transfer gate. The NMOS transistor is designed to be larger than the PMOS transistors and carries most of the transfer capability. The smaller PMOS transistors are designed to eliminate potential drops that would otherwise occur with a single NMOS transistor or with a complementary pair of transistors. For undershoot (undervoltage) tolerance, a PMOS transistor is coupled in parallel with a pair of NMOS transistors that are coupled in series.

To avoid burning out a capacitor in a synchronous rectification type DC-to-DC converter due to overvoltages, the synchronous rectification type DC-to-DC converter includes a storage unit storing therein power derived from a power supply, switching elements connecting and disconnecting respective signal paths from power and ground, and a control unit controlling the connecting/disconnecting operations of the switching elements to maintain a voltage output from the storage unit at a predetermined value. The DC/DC converter also includes an overvoltage detecting unit monitoring a voltage derived from the power supply to thereby output an alarm signal when the voltage derived from the power supply exceeds a preselected voltage value, a shortcircuiting unit influencing the connecting conditions of the switching elements when the alarm signal from the overvoltage detecting unit is input therein, whereby the voltage derived from the power supply is shortcircuited, and an interrupting unit interrupting one of the signal paths by the power shortcircuited by the shortcircuiting unit.

A charging method includes a constant-current charging step wherein a constant charge current is supplied to a secondary battery to be charged to a predetermined end voltage; and a constant-voltage charging step wherein the predetermined end voltage is maintained by reducing the charge current after said secondary battery is charged to the end voltage, wherein: said constant-current charging step includes the charging step to be carried out with the end voltage set to OCV which is a voltage when no current is flowing, and with a voltage of a charge terminal of said battery pack set to an overvoltage above said OCV, and said constant-voltage charging step includes the step of reducing the voltage across the charge terminals to the after the voltage across the charge terminals is increased to the overvoltage or after the charge current of the charge terminal is reduced to or below a predetermined current level.

The semiconductor device according to the present invention has an n-channel output transistor wherein an input voltage is impressed on a drain, and a pulsed switching voltage that corresponds to a switching drive of the transistor is brought out from a source; a bootstrap circuit for generating a boost voltage enhanced by a predetermined electric potential above the switching voltage; an internal circuit for receiving a supply of the boost voltage to generate a switching drive signal, and supplying the signal to a gate of the output transistor; an overvoltage protection circuit for monitoring an electric potential difference between the switching voltage and the boost voltage, and generating an overvoltage detection signal; and a switching element for establishing/blocking electrical conduction between the internal circuit and the end impressed with the boost voltage, in accordance with the overvoltage detection signal.

An overvoltage/overcurrent electrostatic discharge protection single circuit structure for Integrated Circuits protects on all paths and polarities between In/Out, Supply, and Ground pins. The structure is built on the chip substrate with an N well with three P Diffusions therein each containing N+ and P+ diffusions therein to form 6 transistors and 8 parasitic resistors to yield 5 thyristors. The structure provides very fast, symmetrical, full protection while using minimal chip area.

The present invention provides overvoltage circuit protection. Specifically, the present invention provides a voltage variable material (“VVM”) that includes an insulative binder that is formulated to intrinsically adhere to conductive and nonconductive surfaces. The binder and thus the VVM is self-curable and may be applied to an application in the form of an ink, which dries in a final form for use. The binder eliminates the need to place the VVM in a separate device or for separate printed circuit board pads on which to electrically connect the VVM. The binder and thus the VVM can be directly applied to many different types of substrates, such as a rigid (FR-4) laminate, a polyimide or a polymer. The VVM can also be directly applied to different types of substrates that are placed inside a device.

Methods and apparatus for controlling switching in a DC-to-AC inverter to prevent overvoltages applied to an AC motor by determining the switching order of the phase voltage signals, providing gating signals at switching intervals by modulating a carrier wave with the phase voltage signals, comparing the switching intervals to a predetermined minimum time interval sufficient for reflected wave transients to dissipate, and adjusting the switching intervals to be at least equal to the predetermined minimum time interval.

A power supply system and power overvoltage safety protection control method, the power supply system comprises an AC/DC switching power supply, a spare battery and at least one DC/DC transformer, and further comprises an overvoltage detection unit which is used for detecting the output voltage of each DC/DC transformer in real time, comparing the output voltage of the DC/DC transformer with a reference voltage and outputting a fault signal. When detecting a dangerous voltage at a later stage output, the system firstly clamps and absorbs a transient dangerous voltage, uses the overvoltage detection unit to detect an overvoltage fault signal synchronously, cuts off the power supply to each transformer from the AC/DC switching power supply and the spare battery, and directly turns off a control chip after converting the fault signal into a proper voltage, thereby realizing the tertiary protection of the system, avoiding the safety risk possibly resulted from the input and output short circuit of the transformer, and improving the reliability of the system.

Electrical fire risks and consumer safety are major concerns driving regulators worldwide to implement more stringent electrical code and enforcement. While there are many commercially available protective devices available, none affords total protection, and they are made and classified only to protect circuits from specific or limited number of faults.

This invention is about an apparatus, system and method for protection of electrical circuits and consumers from literally all known electrical faults in Direct Current (DC) and Alternating Current (AC) single and multi-phase systems such as and including Arc Faults, Ground and Leakage Faults, Surge, Overload, Short Circuit, Glowing Connections, Miswired Connections, overvoltage, undervoltage and Phase-Loss. Said apparatus, system and method come in the form of or in a housing as a Circuit Breaker, Receptacle, Convenience Outlet, Attachment Plug, Equipment Controller, a circuit, or a system integrated with another system, device or apparatus.

A remotely mountable weatherproof bi-directional, half-duplex switching amplifier system is designed to provide maximum range for low power half-duplex radios such as Spread Spectrum radio transceivers. This invention automatically senses when to go into the transmitter amplification mode and puts all the transmit power right at the antenna. In the receive mode, it provides low noise pre amplification of received signals at the antenna thereby minimizing or even eliminating the effects of the coaxial transmission line from the radio transceiver to the remote location of the antenna. The invention is preferred to be in a waterproof enclosure adjacent to the antenna mounted to a pole and powered by a DC injector and excited by a transceiver, both pole and injector located remote from the mounting pole and also includes an improved electrostatic overvoltage protection device.

The invention is suitable for the field of overvoltage protection, and provides an input overvoltage protection circuit and a direct current-direct current (DC-DC) power supply conversion device. The input overvoltage protection circuit comprises a voltage detection circuit, a drive and delay circuit, an output circuit and a switching circuit which are connected in turn, wherein the voltage detection circuit detects input voltage, compares the detected voltage with set reference voltage and outputs a corresponding voltage signal according to a comparison result; the output circuit outputs a switching control signal according to a drive and delay signal output by the drive and delay circuit and controls the switching on and off of the switching circuit; the output end of the switching circuit is connected with a load; and when overvoltage is input, the switching circuit is switched off, and the load is isolated from the input voltage. In the input overvoltage protection circuit, the voltage detection circuit detects the input voltage, and the load is isolated from and disconnected with the input voltage through the switching circuit when the input voltage is higher than the set reference voltage, so that the load is prevented from being damaged.