612 results about "Voltage clamp" patented technology

A voltage limiting device (15) for constant current circuits (10) comprises input terminals (153) for connecting the voltage limiting device to a current supply (11) of a constant current circuit, output terminals (154) for connecting the voltage limiting device to a load, a voltage clamping circuit (151), and a switching circuit (152). The input terminals (153) are connected to the output terminals (154) under a normal operating condition. The voltage clamping circuit (151) is configured to clamp a voltage across the output terminals to a first voltage threshold and the switching circuit is configured to short-circuit the output terminals when a second voltage threshold across the output terminals is exceeded longer than a predetermined time period.

The invention discloses a slew rate enhancement circuit of an operational amplifier, which comprises a comparison module used for comparing a positive input voltage and a negative input voltage of the operational amplifier and generating a first comparison signal and a second comparison signal according to a comparison result; the slew rate enhancing module is used for enhancing the slew rate of the falling edge of the output voltage of the operational amplifier according to the first comparison signal and enhancing the slew rate of the rising edge of the output voltage of the operational amplifier according to the second comparison signal; the common-mode feedback module is used for clamping the common-mode voltage of the first comparison signal and the common-mode voltage of the second comparison signal to a reference voltage when the operational amplifier is in a steady state, so that the slew rate enhancing module is in a closed state; therefore, the slew rate of the output voltage of the operational amplifier can be quickly enhanced when the operational amplifier has large step signal output, so that the output of the operational amplifier is quickly responded and established.

The invention provides a junction temperature measuring circuit of a vehicle inverter power device and a design method and application thereof. The junction temperature measuring circuit comprises two measuring circuits and a clamping power supply, wherein the two measuring circuits are respectively used for measuring two power devices of an upper bridge and a lower bridge; each measuring circuit comprises a self-adaptive switch and a clamping module, and the self-adaptive switch is configured to enable the potential of the measuring end to track the potential of the drain electrode or the source electrode of the measured power device when the measured power device enters a conducting state; when the tested power device is in the off state, the micro-conduction state between the drain electrode or the source electrode of the tested power device and the measuring end is kept; the clamping module realizes positive clamping voltage and negative clamping voltage through a clamping power supply, and the positive clamping voltage and the negative clamping voltage are respectively used for voltage clamping of a measuring end when the measured power device is in a turn-off state. According to the junction temperature measuring circuit provided by the invention, the working junction temperature of the power device of the high-speed switch can be measured timely and accurately.

The invention discloses a short-wave strong electromagnetic pulse suppression circuit with direct current and control functions. The short-wave strong electromagnetic pulse suppression circuit comprises an I-stage transient protection circuit, a three-signal circuit and an II-stage transient protection circuit, the I-stage transient protection circuit is formed by connecting two stages of gas discharge tubes in series and is used for protecting a low-frequency part in the lightning electromagnetic pulse or the nuclear power electromagnetic pulse, and the output end of the I-stage transient protection circuit is connected with the three-signal circuit; the three-signal circuit provides a path for transmission of the short-wave signal, the direct-current signal and the control signal and carries out transient protection, and the output end of the three-signal circuit is connected with the II-stage transient protection circuit; and the II-stage transient protection circuit is a voltage clamping circuit consisting of a low-capacitance diode and a bidirectional transient suppression diode, and is used for protecting a high-frequency part in the lightning electromagnetic pulse or the nuclear power electromagnetic pulse and clamping the residual voltage at a relatively low level. The device can effectively protect thunder and lightning and nuclear power electromagnetic pulses, has the characteristics of small insertion loss, low residual voltage and the like, and can greatly improve the strong electromagnetic environment viability and anti-interference capability of a short-wave radio station.

An image sensor may include an array of imaging pixels arranged in rows and columns. Each column of pixels can be coupled to a column analog-to-digital converter (ADC) via a pixel output line. The column ADC can include a first low noise single-ended comparison stage, a second low noise single-ended comparison stage, a latch circuit, and a counter. The first low noise single-ended comparison stage may include one or more current source transistors, a voltage ramp generator, a common source amplifier transistor, one or more autozero components, one or more capacitors such as a noise filtering capacitor, and a voltage clamping circuit. The voltage ramp generator can output an increasing voltage ramp or a decreasing voltage ramp.

Described embodiments include a gate drive circuit with a first transistor coupled between an input voltage terminal and a switching terminal, and having a first control terminal. A second transistor is coupled between the switching terminal and ground, and has a second control terminal. A first driver circuit has a first driver output coupled to the first control terminal, a first positive supply input coupled to a bootstrap voltage terminal, and a first negative supply input coupled to the switching terminal. A second driver circuit has a second driver output coupled to the second control terminal, a second positive supply input coupled to a driver supply, and a first negative supply input coupled to ground. An active clamp circuit is coupled between the driver supply and ground, and prevents a voltage between the driver supply and ground from exceeding a threshold voltage.

The invention discloses a self-adaptive power adjusting method and system for power receiving equipment, and the method comprises the steps: adjusting a voltage clamping circuit through obtaining power matching information of target power supply equipment, obtaining a voltage control signal, carrying out the real-time sampling, and obtaining a current signal of the target power receiving equipment, performing differential adjustment on the current signal according to the power matching information to obtain a current control signal; and adjusting the duty ratio of the initial determination signal according to the voltage control signal and the current control signal, and then adjusting the initial output power of the target powered device according to the adjusted driving signal to obtain the adjusted output power. Corresponding current control signals and voltage control signals are determined according to the power matching information, and then the output power of the powered device is limited and adjusted according to the determined control signals, so that the stability and reliability of the output power of the device and the adaptability and compatibility of the device to different POE standards are improved. And the limitation of the equipment in the aspect of power limitation is reduced.

The present disclosure concerns a method for measuring a degradation of thermal characteristics of a power module comprising sequences of: - injecting current pulses (Pinj), having a voltage-clamped constant amplitude (IInj), between an emitter and a gate of a power semiconductor of such power module, a duration of said voltage-clamped constant amplitude (Iinj) current pulses (Pinj) being modulated periodically with a modulation frequency (Fmod), said current pulses causing losses modulated with said modulation frequency (Fmod), - measuring a parameter (k.Tj) dependent of a junction temperature (Tj) of such power semiconductor at the beginning of said current pulses, - measuring a phase shift (Δφ) between said modulation frequency (Fmod) and said parameter (k.Tj), said phase shift (Δφ) providing a health indicator for the power module.　

The invention discloses a voltage fault detection device of a three-phase alternating current power supply, a motor controller and a voltage fault detection method thereof, and the device comprises a sampling unit which carries out the separation sampling of each phase of current in three-phase current from a rectification front end, and obtains the sampling voltage of each phase; the step-down unit is used for carrying out step-down on the sampling voltage of each phase to obtain the step-down voltage of each phase; the clamping unit is used for clamping the reduced voltage of each phase to obtain clamping voltage of each phase; the filtering unit is used for filtering the clamping voltage of each phase to obtain filtering voltage of each phase; and the control unit determines whether the phase voltage of each phase of the three-phase alternating-current power supply has a fault according to the filtering voltage of each phase so as to protect the three-phase alternating-current power supply and a load thereof. According to the scheme, the three-phase input current of the three-phase alternating-current power supply is separated and sampled from the rectification front end of the input side of the three-phase alternating-current power supply to obtain the sampling voltage, and fault detection is performed after voltage reduction, clamping and filtering, so that the accuracy of fault detection is improved.

A switch device includes: a first power transistor die including a normally-on power transistor; a second power transistor die including a normally-off power transistor having a drain electrically connected to a source of the normally-on power transistor to form a cascode device; and a capacitor electrically connected between a gate of the normally-on power transistor and a source of the normally-off power transistor. Both power transistors have at most half a maximum rated drain-to-source voltage as the switch device. The second power transistor die further includes a voltage clamp circuit having a normally-off clamp transistor with a drain electrically connected to the gate of the normally-on power transistor and a source electrically connected to the source of the normally-off power transistor, and diode(s) between the drain and a gate of the normally-off clamp transistor. Additional switch devices embodiments are described.

The utility model discloses a lightning protection circuit and a power converter, and relates to the technical field of power electronics. According to the lightning protection circuit, for the condition that a capacitor parallel branch in a bus capacitor circuit comprises a first capacitor, a second capacitor and an inductor, and the first capacitor is connected with the inductor in series and then connected with the second capacitor in parallel, a lightning protection device is arranged to be connected with the inductor in parallel; in the lightning stroke process, the voltage at the two ends of the inductor exceeds the action voltage of the lightning protection device, so that the lightning protection device is broken down, and the voltage at the two ends of the inductor is clamped at the voltage drop after the lightning protection device is broken down, so that overlarge voltage cannot be formed on the second capacitor; therefore, the problem of voltage oscillation caused by current backflow at the lightning stroke moment can be weakened, the voltage stress borne by a corresponding power device in a post-stage circuit is reduced, and the corresponding power device is effectively protected.

The invention discloses a high-precision alternating-current voltage direct-current component detection circuit which comprises a capacitance-resistance voltage division circuit, a differential amplification circuit, a second-order RC filter circuit, a voltage following and lifting circuit and an AD voltage clamping circuit which are arranged in sequence. The invention aims to improve the detection precision of the direct-current voltage in the alternating-current output voltage of the energy storage converter and feed back the detected accurate direct-current voltage amplitude to the CPU to carry out closed-loop control on the system output voltage so as to achieve the purpose of reducing the direct-current component in the alternating-current output voltage of the energy storage converter.

In an audio amplifier circuit, a power supply terminal receives a power supply voltage. A voltage source generates an internal power supply voltage obtained by multiplying the power supply voltage by a first gain and a bias voltage obtained by multiplying the power supply voltage by a second gain. An input gain circuit amplifies an analog audio signal with reference to the bias voltage. The input gain circuit has an input stage and a gain stage. A phase compensation capacitor is connected to the gain stage. A withstand voltage protection circuit clamps an output voltage of the gain stage to a predetermined clamp voltage.

The present invention provides a negative voltage protection circuit, which includes a voltage clamping module, which is arranged between the gate terminal and the drain terminal of an NMOS tube, and is used to clamp the voltage between the drain terminal and the source terminal of the NMOS tube to a protection threshold voltage when the NMOS tube is turned off, so that the voltage between the drain terminal and the source terminal of the NMOS tube can be clamped within a safe range, avoiding the problem that the NMOS tube is broken down due to excessive current between its source terminal and the drain terminal. In this process, the power supply voltage for the inductive load, the NMOS tube and the inductive load form a demagnetization path, so that the inductive load can be demagnetized faster. On this basis, since the protection threshold voltage of the voltage clamping module is negatively correlated with the temperature of the voltage clamping module, when the NMOS tube is overheated during demagnetization, the voltage between the drain terminal and the source terminal of the NMOS tube will decrease, so that the NMOS tube will not produce thermal failure during demagnetization.

Embodiments of the disclosure provide a level shift circuit, a chip and a display device. By setting first and second voltage clamping modules, and by adjusting first clamping voltage by controlling bias voltage input to the first voltage clamping module and adjusting second clamping voltage by controlling bias voltage and second bias voltage input to the second voltage clamping module, respective operating and output voltages of the first and the second voltage clamping modules and the shift module are within small range. Therefore, even the level shift circuit is designed by using devices with breakdown voltage lower than the difference between the first and second power supply voltages, the devices in the level shift circuit may be avoid being breakdown. Accordingly, some process platforms that cannot produce high-breakdown voltage devices may produce chips including the level shift circuit in the embodiment, and the restrictions on the process platform are reduced.

The invention discloses a gallium nitride driving circuit which is used for generating driving voltage for driving a gallium nitride transistor. The circuit comprises a gallium nitride switching tube, an upper switching tube, a lower switching tube, a clamping module, an energy collection module, a diode, a capacitor, a clamping and logic driving module and a bias voltage generation module. The gallium nitride switch tube is connected with the drain electrode of the gallium nitride transistor and clamps the drain electrode voltage to a first voltage; the clamping module receives the first voltage and clamps the first voltage to a second voltage; the energy collection module receives the second voltage and the PWM signal and generates a power supply voltage and a stable voltage. The clamping and logic driving module receives a power supply voltage and a PWM signal and generates a pull-down driving signal. The bias voltage generation module receives the stable voltage and the pull-down driving signal and outputs a bias voltage. When the PWM signal is at a high level, the pull-down driving signal is at a low level, the bias voltage is at a high level, and the driving voltage is at a high level; when the PWM signal is at a low level, the pull-down driving signal is at a high level, the bias voltage is at a low level, and the driving voltage is at a low level.

The invention discloses a drive circuit for inhibiting crosstalk of SiC MOSFET bridge arms, and relates to the technical field of power electronics, and the drive circuit is characterized in that a grid electrode of each bridge arm SiC MOSFET is connected with a push-pull circuit, a grid electrode voltage clamping circuit is connected in parallel between the push-pull circuit and the grid electrode of the SiC MOSFET, the G ends of two field effect transistors of the push-pull circuit are connected with PWM1 signals, and the G ends of the two field effect transistors of the grid electrode voltage clamping circuit are connected with the PWM M1 signals. An electrical isolation barrier sigma 1 exists between a PWM1 signal and the G end of the field effect transistor, the D end of the field effect transistor is connected to the grid electrode of the SiC MOSFET, the grid electrode voltage clamping circuit comprises a capacitor C and an auxiliary MOS transistor which are connected in series, and the G end of the auxiliary MOS transistor is further connected with a comparator circuit; the system is easy to integrate, the control strategy is simple, and no extra control signal is included.

The invention discloses an LED open circuit protection control system and a control method thereof. The circuit comprises a logic control module, a constant turn-on time module, a driving module, an NMOS tube MN1, an NMOS tube MN2, an inductor L, a current sampling resistor Rsense, a capacitor C2, an operational amplifier OP2, an error amplifier EA, a comparator CMP1, a loop compensation network, a switch S1, a filter network, a selector MUX, an operational amplifier OP1, a PMOS tube MP1, a minimum turn-off time detection circuit, an output overvoltage detection circuit, an AND gate AND1 and a phase inverter INV1. When the output LED is in an open circuit, the output voltage of the error amplifier EA is clamped at a proper voltage value required by normal operation of the system, so that the problem of inductive current peak during fault removal in the prior art is solved, and the reliability of the system is improved.

The utility model relates to a surge protection circuit and an automobile controller system, and relates to the technical field of automobiles. The circuit comprises at least one surge protection sub-circuit, and each surge protection sub-circuit is connected with a bus. The surge protection sub-circuit comprises a first surge sub-circuit and a second surge sub-circuit. The first end, the second end and the control end of the first surge sub-circuit are electrically connected with the bus, the first voltage end and the second voltage end respectively. The first end, the second end and the control end of the second surge sub-circuit are electrically connected with the bus, the first voltage end and the third voltage end respectively. When the difference between the voltage of the signal transmitted by the bus and the voltage of the second voltage end is greater than or equal to a first threshold value, the first surge sub-circuit clamps the voltage on the bus to a first safety voltage. And when the difference between the voltage of the third voltage end and the voltage of the signal transmitted by the bus is greater than or equal to a second threshold value, the second surge sub-circuit clamps the voltage on the bus to a second safety voltage.

A semiconductor circuit device includes a driver circuit, a pre-driver circuit, a first pad, first wiring, a second pad, second wiring, and a voltage clamp circuit. The driver circuit includes a high-side first transistor. The pre-driver circuit includes a first pre-driver that drives a gate of the first transistor. The first wiring couples the first pad to a source of the first transistor. The second wiring couples the second pad to a power supply node of the first pre-driver. The voltage clamp circuit clamps a voltage between power supplies of the first pre-driver.

Described embodiments include a voltage clamping circuit having a threshold-setting circuit with a threshold input and a threshold output. A switch has a first terminal coupled to the threshold input, a second switch terminal, and a switch control terminal. A first transistor is coupled between the threshold output and the switch control terminal, and has a first control terminal. A second transistor is coupled between the first control terminal and ground, and has a second control terminal. A first driver circuit has a first driver input and a first driver output. A second driver circuit has a second driver input coupled to the first driver input, and a second driver output. A third transistor is coupled between the threshold input and ground, and has a third control terminal that is coupled to the second control terminal and the second switch terminal.

The invention discloses a negative voltage clamping circuit and method. The negative voltage clamping circuit comprises a current mirroring module which is used for providing a reference current Iref and generating a corresponding reference current according to a preset current proportion mirroring; the voltage detection module is connected with the current mirror module and the negative voltage input end of the chip and is used for detecting the voltage VS of the negative voltage input end; and the clamping control module is connected with the current mirroring module and the voltage detection module, and the clamping control module is configured to be switched on when the voltage VS of the negative voltage input end exceeds a preset clamping threshold value and clamp the voltage VS of the negative voltage input end within a preset range. According to the negative voltage clamping circuit, the change of the negative voltage input end can be monitored in real time, it is ensured that the clamping control module responds rapidly when the voltage exceeds a threshold value, the negative voltage is limited within a safe range, circuit damage or performance reduction caused by too low voltage is avoided, and therefore the stability and reliability of a chip are improved.

In one example, a circuit includes a first transistor having a first terminal coupled to a first supply voltage source, a second transistor coupled between a second terminal of the first transistor and a ground terminal, and a voltage clamp circuit coupled between the first supply voltage source and the ground terminal. The circuit may further include a first switch coupled between a control terminal of the first transistor and a second supply voltage source, the first switch having a control terminal coupled to the second terminal of the first transistor, a second switch coupled between a control terminal of the second transistor and the second supply voltage source, the second switch having a control terminal coupled to the ground terminal, and a filter coupled between the control terminal of the second transistor and the ground terminal.

The utility model provides a protection circuit and a vehicle power utilization system, and relates to the technical field of electronic circuits. The protection circuit comprises a voltage clamping unit, a voltage comparison unit and a first switch unit, wherein one end of the voltage clamping unit is connected with a power supply input end, the other end of the voltage clamping unit is connected with a first input end of the voltage comparison unit, and the voltage clamping unit is used for clamping the voltage of the power supply input end to a first voltage and outputting the first voltage to the voltage comparison unit; the second input end of the voltage comparison unit is connected with a preset voltage reference point, the output end of the voltage comparison unit is connected with the control end of the first switch unit, and the voltage comparison unit is used for turning off the first switch unit when the first voltage is larger than the voltage input by the preset voltage reference point; the first end of the first switch unit is connected with the power input end, and the second end of the first switch unit is connected with the voltage output end. Therefore, when a load throwing event occurs, high voltage is clamped, overvoltage protection is realized, and damage to electric equipment is avoided.

The invention provides a feedback circuit, a DCDC conversion circuit, a chip and electronic equipment. The feedback circuit comprises a first clamping circuit, a digital-to-analog conversion circuit, a voltage and current conversion circuit and a first voltage division circuit. The first clamping circuit is used for receiving a first reference voltage and clamping the voltage of the input end of the digital-to-analog conversion circuit at the first reference voltage, and the digital-to-analog conversion circuit is used for converting the first reference voltage into a first voltage according to a received binary code value of a set output voltage; the voltage and current conversion circuit is used for converting the first voltage into first current; the first voltage division circuit is used for generating a feedback voltage according to the actual output voltage of the DCDC conversion circuit and the first current and transmitting the feedback voltage to the control circuit. According to the feedback circuit provided by the invention, the direct-current signal feedback coefficient and the alternating-current signal feedback coefficient are separately designed, the alternating-current signal feedback coefficient is reasonably designed, the problem of small alternating-current feedback quantity fed back to the control circuit in the related technology is solved, and the transient response performance of the system is improved.

The invention discloses a dual-channel voltage clamping circuit, a chip and electronic equipment, and the dual-channel voltage clamping circuit comprises a first voltage clamping circuit which is connected with a to-be-clamped position and is used for clamping the voltage of the to-be-clamped position to a positive voltage clamping value when the voltage of an input signal is in a first voltage range, and a second voltage clamping circuit which is connected with the to-be-clamped position and is used for clamping the voltage of the to-be-clamped position to a negative voltage clamping value when the voltage of the input signal is in a second voltage range; the second voltage clamping circuit is connected with the to-be-clamped position and used for clamping the voltage of the to-be-clamped position to a negative voltage clamping value when the voltage of the input signal is in a second voltage range; wherein the voltage in the first voltage range is greater than the voltage in the second voltage range, and wherein the negative voltage clamp value is full amplitude adjustable. According to the dual-channel voltage clamping circuit, at least the negative voltage clamping value can be flexibly adjusted to meet different requirements, positive and negative voltage clamping is achieved through dual channels, the positive and negative voltage clamping does not affect each other, and the accuracy of the positive and negative voltage clamping is ensured.

The present invention discloses a level conversion circuit and chip for converting an input signal in a first voltage domain into an output signal in a second voltage domain. The level conversion circuit includes: a switch unit including a first MOS transistor and a second MOS transistor, wherein the control end of the first MOS transistor and the control end of the second MOS transistor are both connected to a bias voltage; an input unit operating in the first voltage domain and connected to the second end of the first MOS transistor and the second end of the second MOS transistor; a conversion unit operating in the second voltage domain and connected to the first end of the first MOS transistor and the first end of the second MOS transistor; an output unit operating in the second voltage domain; and a clamping unit connected between the switch unit and a first low voltage. In a first state, the first high voltage is not powered off and the clamping unit is disconnected. In a second state, the first high voltage is powered off and the clamping unit is turned on to clamp the driving voltage to the second low voltage. The present invention reduces chip area and avoids power consumption caused by the DC current brought by the pull-down element.

The invention provides a method and device for increasing the rated current breaking frequency of a direct-current solid-state circuit breaker and application of the method and device, and aims to solve the problem that the breaking frequency of an existing direct-current solid-state circuit breaker is limited due to over-temperature damage caused by performance degradation after multiple current impacts of a piezoresistor and difficult measurement of the junction temperature of a power device. The system comprises a junction temperature prediction module based on a physical information neural network, an auxiliary energy absorption module and a power device voltage clamping module. The junction temperature prediction module is used for accurately predicting the junction temperature of the power device in real time by fusing a physical thermal model and a neural network; the voltage clamping module suppresses turn-off overvoltage; and the auxiliary energy absorption module is started when the junction temperature is close to the limit to absorb residual energy. According to the design, turn-off energy is reasonably distributed, the impact frequency and strength of the piezoresistor are reduced, the service life of the piezoresistor is remarkably prolonged (for example, the service life is prolonged by about 10 times under the impact of 200A), then the rated breaking frequency of the solid-state circuit breaker is greatly increased, and the solid-state circuit breaker is low in cost, high in reliability and suitable for scenes such as a direct-current power grid.

The utility model discloses an inductive load circuit of a gallium nitride device and electronic equipment, which are used in the technical field of gallium nitride. According to the utility model, when the gallium nitride device is in a turn-off state, the drain-source electrode voltage of the gallium nitride device is clamped in the maximum withstand voltage of the drain-source electrode of the gallium nitride device through the clamping circuit, so that the gallium nitride device can be effectively prevented from being broken down by the voltage and losing efficacy; the gate-source voltage of the gallium nitride device is adjusted through a potential self-building circuit, the gallium nitride device is controlled to work in a semi-conduction state, the current of the inductor is released, and the turn-off process of the gallium nitride device is completed; according to the utility model, in the turn-off process of the gallium nitride device, the clamping circuit and the potential self-building circuit are signal circuits, the power of the gallium nitride inductive load circuit is not additionally consumed, the power loss of the gallium nitride inductive load circuit can be effectively avoided, and the system efficiency of the gallium nitride inductive load circuit is improved.

The invention discloses an active clamping control method and device and a switching power supply, and the method comprises the steps: determining whether a buck-boost cascade circuit is in a no-load state or a light-load state, and enabling the working mode of the buck-boost cascade circuit to be set as a discontinuous mode, the active clamping control mode of the buck-boost cascade circuit is set as a leading edge non-complementary mode; or, the working mode of the buck-boost cascade circuit is set to be a forced continuous mode, and the active clamping control mode of the buck-boost cascade circuit is set to be a trailing edge non-complementary mode; and determining that the buck-boost cascade circuit is in a heavy load state, setting the working mode of the buck-boost cascade circuit as a continuous mode, and setting the active clamping control mode as a trailing edge non-complementary mode. Corresponding sequential logic can be matched according to different working modes, the clamping effect of peak voltage at the two ends of a switching tube is optimized, ZVS can be achieved in a continuous mode, and the efficiency of the switching power supply is improved.