36results about How to "Avoid reverse current" patented technology

A switching power circuit in which a synchronous rectification circuit of the winding voltage detection system by use of a resistance device is provided on the secondary side of a compound resonance type converter, whereby a high power conversion efficiency can be obtained, and a reduction in the circuit scale through circuit simplification can be had. The gap length of an insulated converter transformer is enlarged to set the coupling coefficient at about 0.8, and the numbers of turns of the primary winding and the secondary windings are so set that the induced voltage level in the secondary winding is not more than 2 V / T. This causes the secondary-side rectified current to be in a continuous mode even under a heavy load condition by setting the magnetic flux density of the core in the insulated converted transformer to be not more than a predetermined value. Further, with inductors inserted into each rectified current circuit on the secondary side, the back electromotive forces in the inductors suppress a backward current generated in the rectified current, whereby a further reduction in the reactive power can be obtained.

A switching power circuit in which a synchronous rectification circuit of the winding voltage detection system by use of a resistance device is provided on the secondary side of a compound resonance type converter, whereby a high power conversion efficiency can be obtained, and a reduction in the circuit scale through circuit simplification can be had. The gap length of an insulated converter transformer is enlarged to set the coupling coefficient at about 0.8, and the numbers of turns of the primary winding and the secondary windings are so set that the induced voltage level in the secondary winding is not more than 2 V / T. This causes the secondary-side rectified current to be in a continuous mode even under a heavy load condition by setting the magnetic flux density of the core in the insulated converted transformer to be not more than a predetermined value. Further, with inductors inserted into each rectified current circuit on the secondary side, the back electromotive forces in the inductors suppress a backward current generated in the rectified current, whereby a further reduction in the reactive power can be obtained.

The invention discloses a diagnosis electric circuit for relays. A plurality of relays is in series connected between a power supply terminal of an electric vehicle and a load / charging terminal. The diagnosis electric circuit for relays includes multiple common-ground bleeder branches, an isolation unit and a judgment unit. Each bleeder branches is used for obtaining a terminal voltage of each relay and performing voltage sharing then outputting; the isolation unit is used for performing isolation transition and transition to multiple shared voltage output by the multiple shared voltage and then outputting the shared voltage to the judgment unit; the judgment unit is used for performing a comparison between the comparison information of the shared voltage on two ends of each relay and thedrive state of the corresponding relay, and the diagnosis results of each relay is obtained. Compared with the prior art, two reference ground of a crossover voltage sampling scheme are merged to onereference ground, through optimizing a resistance typology of the scheme, so that the problem of latent reverse current is avoided.

A converter with synchronous rectification is driven in such a way so that the reverse currents do not build up and cause damage or limit the efficiency of the circuit. Negative currents are self-adjusted to very small percent of load current, so the converter will not have problem when in parallel with other modules. An auxiliary winding is used to allow an output inductor to drive the secondary side rectifiers thereby limiting their conduction time as reverse currents increase. The primary side conduction timer are extended by operation of their anti-diodes so that reverse currents are limited naturally without the use of dedicated load sensing and shutdown circuits.

The invention provides a voltage regulator which can prevent reverse current from an output terminal (122) with low current consumption regardless of the voltage of a VDD terminal (121). Low current consumption can be realized through a circuit structured in such a manner that no resistor voltage divider is used in a comparison circuit which compares the voltage of the VDD terminal (121) of the voltage regulator with the voltage of the output terminal (122).

The invention provids a thin film transistor and an organic electro luminescent display device to restrict an occurrence of an optical current due to outer light, and also to reduce variations of a characteristic (for example, a threshold value) of the thin film transistor. An active layer 2 (semiconductor layer) is formed by poly-crystalizing amorphous silicon on an insulating substrate 1 by laser annealing, and a drain region 2d and a source region 2s are formed so as to face each other in the active layer 2. The drain region 2d and the source region 2s have a structure that an n<-> layer is adjacent to an n<+> layer, respectively. A p-type channel region 2c is formed between the n<-> layer of the drain region 2d and the n<-> layer of the source region 2s. A shading layer 3d is formed so as to coat only a boundary region of the n<-> layer of the drain region 2d and the channel region 2c, for shading the outer light incident on the boundary region through the insulating substrate 1.

The direction of flow of purged fuel reactant gas (20) is sensed (38, 39, 44, 53, 54) to ensure it flows outwardly from a fuel cell stack (9) towards the ambient (21). If the purged fuel reactant. gas is not flowing outwardly, a signal (39) causes a controller (26) to open the circuit (35) thereby disconnecting the electrical load (33) from the fuel cell stack.

Known junction boxes set the alignment of the external connection cables of the photovoltaic module, which are rigidly connected with a box lid. In the junction box (01) according to the invention, the box lid (04) can be placed on the box receptacle (03) in two or more different fitting positions, wherein a positive contact (05) and a negative contact (08) in the box receptacle (03) are provided for each fitting position. A positive mating contact (23) and a negative mating contact (24) are arranged in the box lid (04). According to the invention, the contacts (05, 08) and mating contacts (23, 24) are situated in such a way that, in each fitting position of the box lid (04) on the box receptacle (03), the positive mating contact (23) can be electrically contacted with one of the positive contacts (05), and the negative mating contact (24) can be electrically contacted with one of the negative contacts (08). According to the invention, the final fitting position of the box lid (04) on the box receptacle (03) is selected based on a prescribed alignment of the connection cables (30, 32) relative to the photovoltaic module (02). The invention makes it possible to preassemble junction boxes (01) and adjust them to each photovoltaic module (02) by selecting the fitting position, and hence alignment of the connection cables (30, 32).

A switching circuit with reverse current prevention for use in a Buck converter includes a power switch coupled to a coupling node, which is an interconnection point of a power switch, an inductor and a freewheeling diode of the Buck converter. The inductor is coupled between the coupling node and an output of the Buck converter, and the freewheeling diode is coupled between coupling node and an output return of the Buck converter. A controller is coupled to receive a feedback signal to control switching of the power switch to regulate a transfer of energy from the input to the output of the Buck converter. A reverse current prevention circuit is coupled to detect a reverse current condition of the power switch to generate an inhibit signal to inhibit the power switch from receiving a drive signal to prevent a reverse current through the power switch.

The invention relates to the field of battery energy storage conversion power supply, in particular to a device and a method for improving charging and discharging performance of a power battery pack.In order to solve the technical problem, the controlled battery pack device is provided, a charging input / discharging output electric type controlled unit is connected in series in a battery pack toform an electric type controlled charging and discharging battery pack; the electric type controlled charging and discharging battery pack is limited in the charging and discharging electric type parameters, namely the basic electrical parameters are controlled, charging input / discharging output voltage works within an effective preset range, and the charging input / discharging output current within an effective preset range is limited. The device and the method have the beneficial effects that the power battery pack is in a straight-through charging and discharging state within a protection limit, volt-ampere impedance electrical parameters are in an uncontrolled and unadjustable free state, and intelligent internal control modular operation cannot be achieved are overcome.

The invention provides an electronic system. The electronic system comprises a display device and a data processing device, wherein the display device is connected with the data processing device and is provided with an antenna and a metal framework; the data processing device is provided with a coaxial cable extending to the display device; the coaxial cable is coupled with the antenna and feeds a signal in the antenna from the data processing device; and a part of a metal shielding layer of the coaxial cable is stripped and exposed and electrically connected with the metal framework to inhibit reverse current so as to improve the radiation efficiency of the antenna. When the electronic system is implemented, the metal shielding layer and the metal framework are electrically connected through a conductive adhesive tape or in a welding mode.

A power converter includes a power conditioning circuit to receive input power and set operating voltages of the power converter, a current sensing circuit to determine an input current of the power converter, a voltage regulation circuit to step down a voltage level of the input power, a charge pump circuit to store charge delivered by the voltage regulation circuit and output to a load a currentlarger than the input current, and a power path controller to control switching and provide feedback within the power converter.

A switching circuit with the circuit protection function comprises a current-limiting resistor R1, a photoelectric coupler, a resistor R2, a resistor R3, a triode, a diode and a relay. One end of the current-limiting resistor R1 is connected with input signals and the other end of the current-limiting resistor R1 is connected with one input end of the photoelectric coupler. One input end of the photoelectric coupler is connected with the current-limiting resistor R1, the other input end of the photoelectric coupler is grounded, one output end of the photoelectric coupler is connected with a power source Vcc through the resistor R2, and the other output end of the photoelectric coupler is connected with the base electrode of the triode. The collector electrode of the triode is connected with the positive electrode of the diode, the emitting electrode of the triode is grounded, and the resistor R3 is further connected between the base electrode and the emitting electrode of the triode. The negative electrode of the diode is connected with the power source Vcc and a coil J of the relay is connected with the diode in parallel. The triode is adopted for controlling the relay to achieve the switching function, the reverse current is prevented through the photoelectric coupler, the circuit is protected, the switching circuit with the circuit protection function is obtained through less devices, and the circuit is easy to obtain and low in cost.

The invention discloses a current sampling circuit based on a bridge circuit, which comprises a first rectifier bridge arm formed by connecting a first switch tube and a second diode in series, and a second rectifier bridge arm formed by connecting a second switch tube and a first diode in series, the first rectifier bridge arm and the second rectifier bridge arm are connected in parallel, a common node of the first switch tube and the second diode forms a midpoint of the first rectifier bridge arm, and a common node of the second switch tube and the first diode forms a midpoint of the second rectifier bridge arm; and the current sampling circuit also comprises a detection resistor unit, which is connected in parallel with the first rectifier bridge arm and the second rectifier bridge arm. A peak current controller is used for controlling the bridge unit and the switching tube of the rectifying circuit, so that the problem of reverse current of the primary side of a transformer caused by starting of secondary side synchronous rectification is prevented, the circuit safety is effectively protected, the current sampling interval can be controlled, the negative current of the transformer is prevented from being sampled, and the working stability of the circuit is ensured.

The invention provides a circuit device, a switching regulator, and an electronic device. The circuit device includes a first switching circuit that has one end connected to an output node, and turns on and off according to a drive signal, a second switching circuit that is connected in series with an impedance element between another end of the first switching circuit and a node having a predetermined potential, and turns off and on complementarily with the first switching circuit, a comparator circuit that outputs an output signal indicating whether or not a potential of the other end of the first switching circuit is higher than a determination level, and a control circuit that controls a level of the drive signal based on the output signal of the comparator such that the switching element enters a non-conduction state.

A low-power direct current-direct current (DC-DC) converter includes a capacitor, an inductor electrically connected to the capacitor, a first switch configured to be turned on for a first switching interval and supply energy from an input power source to the inductor for the first switching interval, a second switch configured to be turned on for a second switching interval and electrically connect the inductor and a ground terminal for the second switching interval, and a switching control circuit configured to generate first and second switching signals. The switching control circuit is further configured to generate a first sample signal by sampling the voltage level of a first node, and to determine, responding to the first sample signal in time domain, an pulse width adjustment adapted to adjust at least one of the length of a second switching interval and the length of a common blocking interval.

The invention provides a converter which comprises a plurality of parallel half-bridges. Each half-bridge comprises a first MOS transistor, a second MOS transistor and a first inductor. The gate electrode of the first MOS transistor is connected with a first control signal. The gate electrode of the second MOS transistor is connected with a second control signal. The first control signal is complementary with the second control signal for reducing cost. Alternatively, when the average current which flows over the first inductor in one period is larger than critical switching current, the firstcontrol signal and the second control signal are complementary signals. When the average current which flows over the first inductor in one period is smaller than the critical switching current, thefirst control signal and the second control signal are independent signals. Hereon, the duty ratio of the first control signal is determined by the required load voltage, and the duty ratio of the second control signal is determined by the required load voltage, the input voltage and the duty ratio of the first control signal. The converter has advantages of reducing cost, preventing reverse current in light load and improving efficiency.

A method and an arrangement for operating a photovoltaic system, and the photovoltaic system are provided. The photovoltaic system comprises a boost converter (10A, 10B) having a controllable duty ratio; at least two strings (20) of photovoltaic panels supplying an input of the boost converter (10A, 10B), wherein the strings are connected in parallel with each other; detection means (30, 31) configured to detect a reverse current in any of the strings (20); and control means (40) configured to increase, in response to the detection means detecting a reverse current in at least one of the strings (20), the duty ratio of the boost converter (10A, 10B) at least insomuch that the reverse current stops.

The invention relates to the technical field of switch time sequence control, in particular to a switch control method and a digital controller, wherein the switch control method is used for a totem pole bridge-free circuit. The switch control method comprises the following steps of obtaining the power supply voltage of a power supply, the load voltage of a load unit and the inductive current of an inductor; respectively calculating the duty ratio M of a main switch tube and a duty ratio N of a synchronous rectifier switching tube according to the power supply voltage, the load voltage and the inductive current; if the sum of M and N is smaller than 1, switching off the synchronous rectifier switching tube. Therefore the reverse current occurring during the light load of the inductive current or the reverse current in a state in a region near the zero-passing point of the net side voltage can be inhibited.

A power converter includes a power conditioning circuit to receive input power and set operating voltages of the power converter, a current sensing circuit to determine an input current of the power converter, a voltage regulation circuit to step down a voltage level of the input power, a charge pump circuit to store charge delivered by the voltage regulation circuit and output to a load a currentlarger than the input current, and a power path controller to control switching and provide feedback within the power converter.

The present invention discloses enabling readily determining which circuit, among a plurality of circuits including an optical source lighting circuit and a power supply circuit, has a failure and repairing the circuits easily in a short period. A liquid crystal television 100 comprising a power supply circuit 24 that produces and outputs various power supply voltages from an inputted commercial AC power supply, a microcomputer 22 that outputs a control signal to a plurality of circuits, respectively, including at least the power supply circuit 24 and an inverter circuit 26 that is driven by a power supply voltage output by the power supply circuit 24 to controls turning on and off of each circuit, is provided with an input terminal 53 for providing a power supply voltage from the outside of the liquid crystal television 100, and an inspection auxiliary circuit 50 connected to the power supply circuit 24 and inverter circuit 26, generating a constant voltage that starts the power supply circuit 24 and inverter circuit 26 when a power supply voltage is provided from the input terminal 53 and outputs the constant voltage as a control signal.

An integrated anti-reverse current electronic fuse circuit, based on the traditional electronic fuse efuse circuit, includes PMOS transistors PS1, PS2, NMOS transistor NS and output power NMOS transistor Npower and is used to detect the power supply VIN voltage and output voltage VOUT The control circuit of the reverse current protection module, the reverse current protection module outputs control signals V+, V- and substrate potentials VS and VS2 to control PS1, PS2, NS switches and the substrate potentials of Npower, PS1 and PS2. The Npower substrate potential is switched to the lowest potential of the two, forming a body diode reverse bias to avoid reverse current.

The invention discloses a circuit structure of charge pump comprising an auxiliary charge pump, a level shifter, and a main charge pump. The auxiliary charge pump provides the level shifter with a sub-high level (VDD) and can be used to improve the swing of the controlling clock of the main charge pump low level switches (P1, P2) to speed up starting of the main charge pump. The main charge pump provides the level shifter with the highest level (VCP) after starting so that the swing of the controlling clock of the main charge pump high level switches (P3, P4) can be improved eventually. The invention can effectively control the conductance of the switch tube; improve the voltage gain; overcome the defects of low efficiency and long time for starting the high level charge pump, and is characterized in high voltage gain and short time for starting, applicable for low-voltage applied environment.

The invention discloses a current sampling circuit based on a bridge circuit, which includes a first rectifier bridge arm formed by connecting a first switch tube and a second diode in series, and a bridge arm formed by connecting a second switch tube and the first diode in series. The second rectifier bridge arm, wherein the first rectifier bridge arm and the second rectifier bridge arm are connected in parallel, the common node of the first switch tube and the second diode forms the midpoint of the first rectifier bridge arm, the second switch tube and the second rectifier bridge arm The common node of a diode forms the midpoint of the second rectifying bridge arm; the detection resistance unit is connected in parallel with the first rectifying bridge arm and the second rectifying bridge arm; the present invention controls the bridge unit and the rectifying circuit through a peak current controller The switch tube is controlled to prevent the reverse current problem on the primary side of the transformer caused by the synchronous rectification of the secondary side, effectively protect the circuit safety, and control the current sampling interval, so as to avoid sampling the negative current of the transformer and ensure the circuit work stability.

The invention relates to a magnetic induction transferred DC circuit breaker. The circuit breaker comprises a main current circuit and a transfer current circuit which are connected in parallel, wherein the main current circuit is used for a current in a normal working condition to pass through, and the transfer current circuit is used for transferring the current of a short-circuit fault to the main current circuit when the short-circuit fault occurs in a circuit system where the circuit breaker is located. The transfer current circuit adopts a bridge structure, a reverse current of a high-speed switch opening of the main current circuit can be avoided by controlling an action sequence of a conductive control in the transfer circuit, and the breaking capability is improved; and a mutual inductor is used for increasing a transfer speed of the short-circuit current, and bidirectional breaking of the current is achieved by a group of full-controlled power semiconductor devices.

First and second clocks are applied to first and second capacitors respectively. First and second preceding stage clocks are applied to first and second preceding stage capacitors. The first switch is coupled to second preceding stage capacitor and first capacitor. The second switch is coupled to first preceding stage capacitor and second capacitor. First circuit of preventing countercurrent makes control pole of first switch be coupled to second capacitor and second preceding stage capacitor alternately. Second circuit of preventing countercurrent makes control pole of second switch be coupled to first capacitor and first preceding stage capacitor alternately. Trailing edges of first and second clocks are earlier than trailing edges of first and second preceding stage clocks respectively. Rising edges of first and second preceding stage clocks are earlier than trailing edges of first and second clocks respectively.

The invention discloses a new energy electric vehicle super capacitor charging device which comprises a main control chip. The main control chip is connected with a power supply bus through an input isolation switch circuit; the input isolation switch circuit is connected with an input voltage feedback circuit; the input voltage feedback circuit is connected with an input current detection circuit; and the input current detection circuit is connected with a bidirectional BUCK-BOOST converter. The bidirectional BUCK-BOOST converter is connected with an output current detection circuit; the output current detection circuit is connected with an output voltage feedback circuit; and the output voltage feedback circuit is connected with a super capacitor through an output isolation switch circuit. The input voltage feedback circuit, the input current detection circuit, the bidirectional BUCK-BOOST converter, the output current detection circuit, the output voltage detection circuit and the output isolation switch circuit are all connected with the main control chip. A super capacitor charging circuit with a buck-boost function is formed, power optimization is carried out on a charging scheme through internal digital logic, and the functions of simplifying the circuit and reducing the cost are achieved.