43results about How to "Current limit" patented technology

The invention discloses an anti-thunder overvoltage protection device. The anti-thunder overvoltage protection device comprises a piezoresistor, a positive temperature coefficient thermistor and a gas discharge tube, wherein the positive temperature coefficient thermistor is connected with the gas discharge tube in parallel and then connected with the piezoresistor in series; the positive temperature coefficient thermistor and the piezoresistor form a thermal coupling relationship. The piezoresistor, the positive temperature coefficient thermistor and the gas discharge tube can be packaged into a whole, or the piezoresistor and the positive temperature coefficient thermistor are packaged into a whole, thus a packaged body is formed, and the gas discharge tube is located outside the packaged body. The anti-thunder overvoltage protection device not only can restrain operation overvoltage and fault power frequency overvoltage, but also can have the protection function of a normal voltage-sensitive element when lightning stroke pulse overvoltage occurs.

The invention provides a current control method, a current control system and an air conditioner. The current control method is used for the air conditioner and comprises the following steps: determining the maximum current value, which corresponds to the environmental temperature of an environment where the air conditioner is placed, of a compressor in the air conditioner and operation current of the compressor; if the operation current is greater than the maximum current value, controlling the working rotating speed of the compressor to be reduced to a first rotating speed at a first rate; and after the compressor operates for a first time length at the first rotating speed, increasing the working rotating speed at a second rate till the rotating speed reaches the maximum safety rotating speed. According to the technical scheme provided by the invention, when the operation current detected of the compressor is greater than a safety range, the operation current of the compressor is reduced to be within the safety range; and after temperatures of a power module and an element for controlling a computer board are reduced to be within the safety range, the compressor operates at the maximum power, so that the system reliability of the air conditioner is improved, the refrigeration effect of the air conditioner is enhanced, and the user experience is increased.

To convert the first DC voltage to the second DC voltage, a first bridge circuit included in the power converter is controlled to convert the first DC voltage to the first AC voltage. This first AC voltage is transformed into a second and possibly further AC voltage. The second and any possible further AC voltages are converted into DC voltages by respective bridge circuits. In order to increase the efficiency of the power converter, the switches of the power converter are controlled to operate in soft switching. In addition, the duty cycle of each AC voltage is controlled. In one embodiment, the half cycle voltage-time integrals of each AC voltage are controlled to be substantially equal.

The invention discloses a magnetic coupling commutation type transfer circuit and a use method thereof. The magnetic coupling commutation type transfer circuit comprises a main current circuit and a transfer current circuit, wherein the main current circuit is formed by connecting a mechanical switch, a power electronic device, a current limiter, a resistor and one or more of conducting wires in series or parallel; the transfer current circuit comprises a first circuit and a second circuit; the first circuit is formed by connecting an inductor L1 at a secondary side and a resistor in series; the second circuit is formed by connecting a third circuit A3, power semiconductor devices or triggering gaps B1-B4, and an inductor L0 at a primary side in series, and the third circuit consists of a precharging capacitor or a superconduction inductor. The magnetic coupling commutation type transfer circuit has the advantages that the voltage produced by a voltage transformer is used for directly transferring current to the resistor, the process of transferring the current into the capacitor or the power electronic device is not needed, and compared with the prior art, the current limiting speed and reliability are higher; a capacitor charging unit can be isolated from a direct current system, the voltage class and size of the charging unit are obviously reduced, and the action reliability is improved.

The invention discloses a starting overshoot suppression circuit used for an LDO. The circuit comprises a first overshoot suppression circuit connected between a power end and an output end of an error amplifier of the LDO; the first overshoot suppression circuit comprises a first switch control unit and a voltage clamp unit which are in series connection, moreover, an enabling signal of the firstswitch control unit is obtained through inverting the enabling signal of the LDO and delaying for first predetermined time, thus, within the first predetermined time of starting of the LDO, through the voltage clamp unit, grid voltage of a power tube of the LDO is clamped to a first predetermined value, and grid source voltage of the power tube is maintained at a second predetermined value, so, current output to a load by the LDO is limited. With simpler circuit design, smaller circuit area and ultralow circuit power consumption, the starting overshoot suppression circuit provided by the invention realizes suppression of overshoot generated when the LDO starts, and thus, relatively small starting overshoot is realized.

The present invention belongs to the technical field of protecting single-phase grounding short-circuit which results from insulation failure of single-phase and three-phase power consuming equipment in a low-voltage power network, and in particular relates to a current-limiting, arc-eliminating and excitation-dividing tripping type grounding short-circuit protection device. The technical proposal consists of a circuit breaker actuating device, a circuit breaker starting mechanism, and a short-circuit detection actuating mechanism. Because the current or voltage signals which are used for actuating the protection device is not related to the short-circuit current of the original grounding short-circuit loop, the protection device solves the problem of dependence on the fuse for the grounding short-circuit failure in the long term and the problem that the short-circuit switch with current as a parameter can not easily generate the maximum allowable temperature rise (igniting fire) in the loop wire within the protective range, and in particular in the terminal insulating wire of the power consuming equipment, so as to timely cut off the circuit.

The embodiment of the invention discloses a current limiting charging circuit comprising a transformer, an oscillation switch and a current limiting module. The current limiting module comprises a current limiting resistor and a current limiting switch. A primary coil of the transformer, the oscillation switch and the current limiting resistor are in series connection in order and then are connected between an anode of a power supply and the ground. A control end of the oscillation switch is communicated with pulse voltage. The current limiting switch is connected between the control end of the oscillation switch and the ground. A control end of the current limiting switch is connected with a common node of the current limiting resistor and the oscillation switch. By employing the current limiting charging circuit, the current of the charging circuit can be effectively limited, the burning of a component due to overcurrent is prevented, and the service life of the charging circuit is prolonged.

The invention discloses a high-input-voltage double-loop stable linear voltage regulator. The linear voltage regulator comprises an error amplification unit (1), an overcurrent protection unit (2), acompensation circuit unit (3), a secondary amplification unit (4), a current sampling unit (5), a first PMOS transistor P1 and a second PMOS transistor P2. The error amplification unit (1) is used forcompleting conversion from double-end input to single-end output; the overcurrent protection unit (2) is used for realizing an over-current protection function; the compensation circuit unit (3) is used for ensuring the stability of a loop under various loads; and the secondary amplification unit (4) is used for converting the output of an error amplifier into two paths of control signals relatedto the power supply voltage. There are an error amplification unit main loop and an over-current protection loop, the two loops are both provided with frequency compensation circuits, and frequency compensation does not interfere with each other. The voltage regulator is suitable for a power supply environment with high power supply voltage and a large load change range.

The invention relates to the technical field of integrated circuits, in particular, to a voltage-controlled oscillator, an integrated chip, and an electronic device. The voltage-controlled oscillatorcomprises a resistor unit, a current mirror unit, a bias unit, and an oscillating unit. The current mirror unit responds to a first bias voltage provided by the bias unit to carries out bias processing on a voltage of a first node at a first current path and a voltage of a third node at a third current path to generate a first bias voltage and is also used for responding to resistance configuration of the resistor unit and adjusting a third current flowing through the third current path, wherein the first current flowing through the first current path is equal to the third current. Therefore,with configuration of the resistance corresponding to the resistor unit, the charging and discharging time of the capacitor of the oscillating unit can be indirectly adjusted to change the oscillationperiod of the oscillating unit and thus the changed oscillation period is closer to a desired oscillation period, so that the output accuracy of the oscillation period is improved.

Provided is a power converter which suppresses a current that flows to a capacitor due to a direct current link voltage increase generated by parasitic inductance when a switching a converter is switched in the normal operation. The converter (4) has switching elements, which are connected between a plurality of input terminals (Pr, Ps, Pt) and a direct current power supply line (LH), and switching elements, which are connected between the plurality of input terminals (Pr, Ps, Pt) and a direct current power supply line (LL). A capacitor (C1), a resistor (R1), and a diode (D1) are connected to each other in series between the direct current power supply lines (LH, LL).

The invention discloses an anti-thunder overvoltage protection component which comprises a piezoresistor disc, a positive temperature coefficient thermistor disc and a gas discharge tube, wherein the piezoresistor disc, the positive temperature coefficient thermistor disc and the gas discharge tube are integratedly packaged; the first common terminal of the positive temperature coefficient thermistor disc and the gas discharge tube is a first leading-out terminal; the second common terminal of the positive temperature coefficient thermistor disc and the gas discharge tube is connected with one end of the piezoresistor disc; the other end of the piezoresistor disc is a second leading-out terminal. The anti-thunder overvoltage protection component can restrain the switching overvoltage and fault power frequency overvoltage, and can play the protective role of a normal pressure cell in case of a thunderstrike pulse overvoltage.

The invention discloses a thunder-prevention overvoltage protection device. The thunder-prevention overvoltage protection device comprises a piezoresistor sheet, a positive temperature coefficient thermistor sheet and a gas discharge tube, wherein the piezoresistor sheet and the positive temperature coefficient thermistor sheet are encapsulated integrally to form an encapsulation body. One end of the positive temperature coefficient thermistor sheet is a first leading-out end. The other end of the positive temperature coefficient thermistor sheet is connected with one end of the piezoresistor sheet to form a public end, and the public end serves as a third leading-out end. The other end of the piezoresistor sheet serves as a second leading-out end. The gas discharge tube is located outside the encapsulation body, and two ends of the gas discharge tube are connected with the first leading-out end and the third leading-out end respectively. The thunder-prevention overvoltage protection device can inhabit operation overvoltage and fault power frequency overvoltage and can play a protecting role of a normal voltage-sensitive element when lightning stroke pulse overvoltage occurs.

The invention relates to a driving circuit comprising a driver control circuit, a first and a second driving transistor and a current limiting device. In order to limit the current flowing through the driving transistor, said current limiting device controls the voltage at the gate of said first driving transistor. A control input of the current limiting device is used to adjust the current-limitation application point to the load to be controlled by a negative feedback. According to a second embodiment, a driving circuit having one of its two transistors designed as a MOSFET and the other one as a bipolar transistor is produced in such a way that diodes of the two driving transistors block the switched-off supply voltage or transmit the voltage according to a voltage applied on the output of said driving circuit.

The invention relates to the field of light-emitting diode (LED) illuminating lamps, in particular to an LED ground lamp with a self protection function. The LED ground lamp comprises a lamp, an LED driving power supply and LED lamp beads packaged in the lamp. The LED ground lamp is characterized by also comprising at least one self-restoring fuse tube which is packaged in the lamp, forms an electric loop with the LED lamp beads and the LED driving power supply and is high in resistance when the current or the temperature is abnormal; and the plurality of LED lamp beads can be connected in series or in parallel, and can be connected in series and in parallel, or can be connected crossly. The LED ground lamp has the advantages that: when the current in a circuit is overhigh or the temperature in the LED lamp is overhigh, the resistance of the self-restoring fuse tube is very high, so the current of a main circuit or sub-circuits is limited, and the LED lamp beads of the LED ground lamp are prevented from being damaged; the operation of the LED ground lamp is kept and the LED ground lamp is effectively protected by limiting the current of a part of sub-circuits but not affecting other sub-circuits.

An emergency lighting device comprises an illumination lamp for illuminating an area and an energy storage unit for providing electrical energy for powering the lamp. According to the invention, the energy storage unit comprises an ultra-capacitor for storing the electrical energy. As the ultra-capacitor shows hardly any deterioration over time, extensive, e.g. periodical testing of the emergency lighting device during its lifetime can be omitted. A charging arrangement for charging the ultra-capacitor in the emergency lighting device is described.