122results about How to "Limit voltage" patented technology

This disclosure provides systems, methods, and apparatus for the limiting of voltage in wireless power receivers. In one aspect, an apparatus includes a power transfer component configured to receive power wirelessly from a transmitter. The apparatus further includes a circuit coupled to the power transfer component and configured to reduce a received voltage when activated. The apparatus further includes a controller configured to activate the circuit when the received voltage reaches a first threshold value and configured to deactivate the circuit when the received voltage reaches a second threshold value. The apparatus further includes an antenna configured to generate a signal to the transmitter that signals to the transmitter that the received voltage reached the first threshold value.

A magnesium battery electrode assembly is described, including a current collector comprising a carbonaceous material and an electrode layer comprising an electrode active material disposed on the current collector.

The present invention discloses a liquid crystal display driving system that uses at least one temperature sensor to detect a temperature of a LCD panel, and outputs a gamma compensation voltage value according to the detected temperature, and further uses an overdrive compensation unit to receive the gamma compensation voltage value, and obtains the overdrive compensation voltage value of two gamma overdrive compensation curves of a temperature gradient corresponding to a region of the LCD panel by a gamma mapping method, or uses an overdrive compensation unit to derive a corresponding partial compensation data table according to the temperature and the compensation data table, and at least one overdrive compensation table (OD compensation table) corresponding to the change of temperature gradient in a region of the LCD panel is derived, an outputted display image after being processed by an overdrive lookup table (OD LUT) is compensated, so as to adjust the overdrive voltage of the LCD panel and enhance the response time of the liquid crystal display.

The subject matter of the invention is an inverter (3), more specifically for use in a photovoltaic plant (1) with a direct voltage input (connection terminals 4; 5) for connection to a generator (2) and an alternating voltage output (connection terminals 7; 8) for feeding into an energy supply network (6) as well as with a DC-AC converter (12) with semiconductor switch elements (15) and an intermediate circuit (11), at least one short-circuit switch element (18) being connected in parallel to the generator (2), so that the voltage will not exceed a maximum voltage value neither at the connection terminals (4; 5) of the generator (2) nor between the connection terminals (9; 10) of the inverter. This is achieved in that the inverter (3) comprises, in the intermediate circuit (12), a buffer capacitor (14) that is connected to the generator (2) through a protection diode (17) so that said buffer capacitor (14) will not be discharged upon actuation of the short-circuit switch element (18), the generator (2) working according to a clock rate in the short-circuit mode of operation.

A circuit can be used for controlling a plurality of LEDs coupled in series. A switching converter operates as a current source coupled to the plurality of LEDs to provide a constant load current thereto. The switching converter includes an inductor coupled in series with the plurality of LEDs such that the same load current flows through the inductor and the plurality of LEDs. No substantial capacitance is coupled between the inductor and the plurality of LEDs. A floating driver circuit is coupled in parallel with each individual LED of the plurality of LEDs. The floating driver circuit is configured to fully or partially take over the load current thereby bypassing the respective LED in accordance with a respective modulated input signal to control the intensity of the light emitted by the LED.

The method of charging a battery array performs constant current, constant voltage charging of a battery array while detecting the voltage of each battery. The battery array is a plurality of series connected batteries. The charging method detects the voltage of each battery cell at a prescribed sampling rate. When the voltage of any battery cell exceeds a preset maximum specified voltage, charging power is reduced for constant current, constant voltage charging of the battery array.

RFID tags are provided for incorporation into the packaging of a microwavable food item, with the RFID tag being configured to be safely microwaved. The RFID tag includes an antenna defining a gap and configured to operate at a first frequency. An RFID chip is electrically coupled to the antenna across the gap. A shielding structure is electrically coupled to the antenna across the gap and overlays the RFID chip. The shielding structure includes a shield conductor and a shield dielectric at least partially positioned between the shield conductor and the RFID chip. The shielding structure is configured to limit the voltage across the gap when the antenna is exposed to a second frequency that is greater than first frequency. In additional embodiments, RFID tags are provided for incorporation into the packaging of a microwavable food item, with the RFID tag being configured to be safely microwaved. The RFID tag includes an RFID chip and an antenna electrically coupled to the RFID chip. The antenna may have a sheet resistance in the range of approximately 100 ohms to approximately 230 ohms, optionally with an optical density in the range of approximately 0.18 to approximately 0.29. Alternatively, or additionally, the antenna may be configured to fracture into multiple pieces upon being subjected to heating in a microwave oven. Alternatively, or additionally, the RFID tag may be incorporated in an RFID label that is secured to the package by a joinder material with a greater resistance than that of the antenna, such as a sheet resistance in the range of approximately 100 ohms to approximately 230 ohms.

An arc welding method of the present invention controls a short-circuit current increasing gradient (di/dt), an inflection point at which the short-circuit current increasing gradient (di/dt) changes, the current in a peak period and in a base period, and the time of the peak period in accordance with a difference between a set voltage and an output voltage. This allows the output voltage to be matched with the set voltage, and stabilizes the arc. Thereby, a stable arc welding method can be implemented, even as a method for outputting a welding current based on a welding voltage.

A method and circuit for setting a reference voltage in a dual floating gate circuit is disclosed. During a set mode, a first and second floating gate are programmed to different charge levels that are a function of an input set voltage capacitively coupled to the first floating gate during the set mode. During a read mode, this difference in charge level is used by the dual floating gate circuit to generate a reference voltage that is a function of the input set voltage, and is preferably equal to the input set voltage.

A method of automatically adjusting a voltage level used in an induction type power supply system includes detecting an output voltage of a signal analysis circuit; adding a first threshold value to the output voltage to generate a first determination voltage and subtracting a second threshold value from the output voltage to generate a second determination voltage; outputting the first determination voltage as a reference voltage; and comparing a trigger signal of the signal analysis circuit and the reference voltage, in order to generate a first data code; wherein when the step of comparing the trigger signal of the signal analysis circuit and the reference voltage in order to generate the first data code fails, the method further includes outputting the second determination voltage as the reference voltage and comparing the trigger signal of the signal analysis circuit and the reference voltage, in order to generate a second data code.

A system and method for over-voltage protection is described. In one embodiment of the invention, an apparatus includes an output port configured to deliver power to a plasma chamber to ignite a plasma. The apparatus also includes a shunt switch in parallel with the output port and a processor configured to receive an indicator of an arc in the plasma. The processor is configured to close the shunt switch for a period of time to divert current away from the arc. The processor is also configured to trigger a pulse of the shunt switch to limit a voltage of an increasing voltage condition associated with the arc.

A downhole measurement tool circuit and method to balance fault current in a protective inductor, which keeps an alternating current balanced in a protective choke during a phase-to-ground fault condition in a power cable or a downhole motor of an electrical submersible pump. The downhole measurement tool circuit and method cause a conducting of current during the negative polarity voltage portions of a phase-to-ground fault condition, but do not cause a conduction of negative polarity voltage during use of a negative polarity megger.

An input-side protective circuit for protecting an intermediate circuit of an inverter against overvoltages, wherein the input-side protective circuit includes an upstream element for limiting the voltage of the intermediate circuit connected upstream of the intermediate circuit and which is bridgeable by a mechanical switching device that is controllable such that it opens in a feed-in operation of the inverter when an intermediate circuit voltage is greater than a specified voltage limit. The protective circuit also includes an electronic voltage limiter connected downstream of the upstream element and connected in parallel to the intermediate circuit.

A power subsystem for a computer system allows a voltage regulator module (VRM) to be removably connected to a system board, while limiting disturbances on the voltage rails of the system board. The electrical disturbances are prevented by charging voltage outputs of the DC/DC circuit of the VRM prior to directly connecting the voltage outputs to the voltage rails. To ensure that the voltage outputs are properly charged, a VRM connector may be used in which the voltage output pins are shorter than charge pins which are coupled to respective capacitors and to the voltage outputs of the DC/DC circuit. In this manner, as the connector is mated with a corresponding connector on the system board, the capacitors are first charged via resistive paths connected to the voltage rails, prior to directly connecting the voltage outputs to the voltage rails. The VRMs are thus "hot-pluggable," enabling a user to upgrade or service the system with no interruption.

A data access arrangement (DAA) having improved surge protection. The DAA incorporates a high voltage clamping device functioning to protect line side circuitry from signal paths created by EMI capacitors. In one embodiment of the invention, EMI capacitors are added between the “plus” and “minus” terminals of the diode bridge of the DAA to balance and reduce noise injection onto the TIP and RING lines. These EMI capacitors also reduce EMI interference. However, by adding EMI capacitors on this side (the “rectified side” or “line side”) of the diode bridge, a high voltage signal path to earth ground is created that may have deleterious effects on the line side circuitry. To effectively negate undesirable signal paths through the EMI capacitors, the DAA includes a high voltage clamping device (e.g., a MOV, SIDACTor™, gas discharge tube or similar device) disposed between the plus and minus terminals of the diode bridge for suppressing high voltage spikes. The high voltage clamping device limits the voltage seen by the line side circuitry as a result of high voltage longitudinal surges by providing a current path from the plus terminal to the minus terminal of the diode bridge, thereby effectively bypassing the line side circuitry. The present invention recognizes and takes advantage of the fact that the diodes of a typical diode bridge are capable of withstanding the peak currents associated with most voltage surges.

Level shift circuits are disclosed for level shifting an input signal corresponding to a first voltage domain, to generate a pair of complementary output signals corresponding to a second, higher-voltage domain. Snap-back sensitive devices in a discharge circuit for a high voltage output node are protected, irrespective of the loading on the output node, and without requiring precise transistor sizing as a function of the output loading. The snap-back sensitive devices are protected by a voltage shifter circuit in series with the sensitive devices, to limit the voltage across the sensitive devices, even for a high capacitance output node at its highest output voltage. The voltage shifter circuit is then bypassed to provide for an output low level that fully reaches the lower power supply rail.

Level shift circuits are disclosed for level shifting an input signal corresponding to a first voltage domain, to generate a pair of complementary output signals corresponding to a second, higher-voltage domain. Snap-back sensitive devices in a discharge circuit for a high voltage output node are protected, irrespective of the loading on the output node, and without requiring precise transistor sizing as a function of the output loading. The snap-back sensitive devices are protected by a voltage shifter circuit in series with the sensitive devices, to limit the voltage across the sensitive devices, even for a high capacitance output node at its highest output voltage. The voltage shifter circuit is then bypassed to provide for an output low level that fully reaches the lower power supply rail.

A surge clamp circuit that may be implemented with DAA circuitry to limit the total voltage developed across one or more line side capacitors due to charge pumping phenomenon during a multi-transient events such as lightning strikes. The surge clamp circuit is capable of electronically sensing a transient event (e.g., lightning strike) and of momentarily turning on one or more components of a DAA hookswitch circuit during on hook mode to discharge the voltage developed across one or more line side capacitors before it reaches critical breakdown levels. The surge clamp circuit may be configured with a clamping sensitivity selected so that the DAA hookswitch circuitry is only activated or turned on upon occurrence of relatively large and potentially damaging transient events, and not upon occurrence of non-damaging transient events, such as operational signals.

A method and apparatus for providing ESD event protection for a circuit using a source or bulk pump to increase the bulk and/or source potential level during an ESD event. The apparatus comprises a protection circuit that, in response to an ESD event, limits the voltage formed between two terminals of a transistor by adjusting a potential level on the second terminal.

Stacked SCR's are disclosed with a resistor connecting an internal portion of the upper SCR to an internal portion of the lower SCR. The anode of the protective circuit is connected to a contact on a target circuit to be protected and the cathode of the protective circuit is connected to ground or a reference voltage on the target circuit. The anode voltage is directed to the lower SCR via the resistor such that when the voltage on the anode reaches the triggering voltage of the lower SCR, that SCR triggers and that triggering triggers the upper SCR, such that the stacked SCR's both trigger and thereby limit the voltage between the anode and the cathode and thereby protecting the target circuit.