401 results about "Voltage overshoot" patented technology

A multiple-phase DC—DC converter adds at least one additional phase to an N-phase DC—DC converter to improve the converter's response to changes in load. In one embodiment, an additional phase operates at a switching frequency greater than that of the N phases, to generate a current which is added to the N phase currents to improve the converter's response to changes in load. In another embodiment, an additional phase is configured to improve the converter's response to a load release. Here, the additional phase is kept off during load increase and steady-state conditions. However, when a load release occurs, the additional phase is turned on and acts to extract current from the converter's output terminal while the N phase currents slowly fall, to reduce the magnitude of output voltage overshoot that occurs on load release.

A voltage positioning technique allows a power supply controller to more fully exploit active voltage positioning as a way of maintaining supply voltage within the limits defined for an associated electrical load. The supply voltage is allowed to "droop" as a function of load current. Droop may be implemented in linear proportion to load current, or as a discrete droop function once load current exceeds a given threshold. In either case, the droop circuitry of the supply controller implements a bounding function that establishes an accurately known maximum droop voltage magnitude. This maximum droop voltage limit establishes a reliable lower limit for the supply voltage independent of increasing load current. This accurately set lower bound for the droop voltage enables the controller to more aggressively position the supply voltage at the lower voltage limit of the load, which minimizes voltage overshoot and load power consumption.

A voltage regulator may be configured to detect variation in load current and control transient response when the load current has a high slew rate or varies at high repetition rates. A linear control circuit may be employed to control charging of an output capacitor and a load of the regulator. Upon detection of high load current step-up change at high slew rates, a non-linear control circuit may be activated. The fast load current step change may be detected by comparing an output voltage of the regulator to a feedback input of an error amplifier of the linear control circuit. The output of the error amplifier may be clamped to prevent output voltage ring-back when using the non-linear control circuit or to control load release dip. Output voltage overshoot may be controlled by turning OFF a top switch that charges the output capacitor before the inductor current becomes zero.

A power module employs at least one capacitor electrically coupled across the input terminals to reduce voltage overshoot. The capacitor may be surface mounted to a high side collector plating area and a low side emitter plating area. The power module may employ a lead frame and terminals accessible from an exterior of a module housing, for making electrical couplings to externally located power sources and/or loads.

The invention discloses a transient enhancement circuit applied to a full-integration LDO. The transient induction situation of the LDO is obtained by detecting the transient voltage of an LDO error amplifier output node. When load current changes suddenly from low current to high current or from high current to low current, output voltage is descended or ascended, at the moment, feedback voltage of a loop changes as well, and thus the output transient voltage of an error amplifier changes. When the output node voltage of the error amplifier is far lower than the grid voltage of an adjusting pipe, a buffer stage inserted between the error amplifier and a transistor provides large drop-down current for the grid of the adjusting pipe. When the output node voltage of the error amplifier is far higher than the grid voltage of the adjusting pipe, the current boosts, a feedback circuit is started, and sufficient charging current is provided for the grid of the adjusting pipe, so that the breakover current is controlled to meet the load requirement, and the effect of lowering the output voltage overshooting is achieved. The simulation result indicates that the transient enhancement circuit can remarkably improve the load transient response ability of the LDO.

The invention discloses a synchronous rectification anti-backflow circuit and method of parallel synchronous rectifier converter, including auxiliary power supply, voltage detection and comparison circuit, PWM drive circuit and transfer switch, where the voltage output end of the auxiliary power supply is connected to the input end of the voltage detection and comparison circuit, the output end of the voltage detection and comparison circuit is connected to the control end of the transfer switch, PWM drive signal in the PWM drive circuit is coupled to the input end of the transfer switch, and the output end of the transfer switch is coupled to the control end of the synchronous rectifier tubes. It makes the synchronous rectifier converter have no problems of prestarting, output voltage overshoot and depression, etc., as parallel working and the parallel efficiency of the converter is high. The invention has simple and reliable circuit, low cost, and good effect after tested.

A freewheeling DC/DC step-down converter includes a high-side MOSFET, an inductor and an output capacitor connected between the input voltage and ground. A freewheeling clamp, which includes a freewheeling MOSFET and diode, is connected across the inductor. When the high-side MOSFET is turned off, a current circulates through the inductor and freewheeling clamp rather than to ground, improving the efficiency of the converter. The converter has softer diode recovery and less voltage overshoot and noise than conventional Buck converters and features unique benefits during light-load conditions.

The invention discloses a successive approximation type analog/digital converter, wherein a capacitor array digital/analog conversion circuit comprises a capacitor array, an auxiliary capacitor is connected between the capacitor array and the output end of a comparer, and the oscillation amplitude between the capacitor array and the output end of the comparer ranges from 0V to power voltage when the capacitance value of the auxiliary capacitor is selected in a range enabling the oscillation amplitude of the input voltage to be from 0V to the power voltage. A measure of carrying out limiting and compression on a quantification range or increasing complicated circuits, which is adopted for preventing voltage overshoot in the traditional scheme, is avoided. According to the circuit structure provided by the invention, the requirements on input offset of the comparer in the ADC (analog/digital converter) and performance of other internal circuits are reduced, so that higher resolution ratio can be achieved under the condition of not increasing power consumption of the ADC using the circuit structure.

The present invention provides a LC series resonance high frequency chain matrix-type inverter topology and a resonance modulation method thereof. The topology comprises of a full bridge LC series resonance inverter, a high-frequency transformer T, a matrix converter and a CL-type filter which are connected in order. The modulation method is configured to process the SPWM wave through separation and link semi-excitation modulation logics to obtain driving signals of a transformer pre-stage LC series resonance inverter and a transformer post-stage matrix converter so as to allow the work duty ratio of the transformer pre-stage resonance circuit excitation resonance work state in the resonance half period to be controllable and realize the control of energy side transmission to the output load. The transformer post-stage matrix converter is modulated and decoupled to two common current-type inverters for controlling, a switch tube performs switching during the zero current outputting to realize zero current switching to avoid causing voltage overshoot problems and realize energy bidirectional flow and four-quadrant operation. The power transformation grades are few, the control method is simple, the circuit stability is high, and the like.

The invention belongs to the technical field of air conditioner controlling and provides a frequency-conversion air conditioner operation control method and device. The frequency-conversion air conditioner operation control method includes: acquiring a frequency threshold; judging whether a shutdown instruction is received or not during operation of a compressor, and judging whether current operation frequency of the compressor is larger than the frequency threshold or not when the shutdown instruction is received; if yes, reducing operation frequency of the compressor according to preset frequency reduction rate and continuously judging whether the current operation frequency of the compressor is larger than the frequency threshold or not, if not, controlling an inverter to stop outputting. Therefore, the operation frequency of the compressor can be sustained in the preset frequency threshold during shutdown, problems about voltage overshoot of a direct-current bus and overlarge stress impact upon a system pipeline when the compressor is shut down during high-frequency operation are solved, reliability of the high-frequency-conversion air conditioner can be beneficially improved, and service lives of internal electronic devices and cooling/heating system components of the frequency-conversion air conditioner can be favorably prolonged.

Switching regulator Burst Mode control circuitry is provided for limiting voltage overshoot at the output of a switching regulator operating in power saving Burst Mode. The Burst Mode control circuitry may include regulator load current sensing circuitry which may be operative to put and maintain the regulator in the SLEEP state when the load current amplitude is below a threshold. The control circuitry may also include gated over-voltage comparator circuitry operative to reduce regulator output overshoot and to eliminate erroneous deactivation of the regulator switch circuitry when the regulator is not operating in Burst Mode. The gated over-voltage circuitry may include a one-shot timer circuit.

A hybrid electric vehicle includes a traction battery, traction motor and power inverter therebetween. The power inverter converts the DC power of the traction battery to AC power to drive each phase of the traction motor. The power inverter includes Insulated Gate Bipolar junction Transistors (IGBTs) to modulate the power to the traction motor. The speed at which the IGBTs are modulated impacts the system performance including power loss, voltage overshoot and current overshoot. Using a dual emitter IGBT to provide a current mirror of the drive current, circuitry may be used with the gate drive circuitry such that the gate drive speed may be dynamically adjusted based on characteristics including temperature and traction motor rotational speed.

A voltage regulator includes a transistor, a comparator, and a compensation circuit. The comparator has a first input terminal coupled to receive a clock signal, a second input terminal, and an output terminal coupled to a control electrode of the transistor. The compensation circuit has a first input terminal coupled to receive a reference voltage, a second input terminal coupled to the output terminal of the voltage regulator, and an output terminal coupled to the second input terminal of the comparator. The compensation circuit has a filter circuit. The filter circuit has a first RC time constant during startup of the voltage regulator, and the filter circuit has a second RC time constant during normal operation. Changing the RC time constant for startup prevents an overshoot of an output voltage of the voltage regulator.

A liquid crystal (LC) display device includes a LC panel and a driving circuit. The LC panel exhibits, in its voltage-transmittance characteristics, an extreme transmittance at a voltage equal to or lower than a lowest gray-level voltage. The driving circuit supplies to the LC panel a predetermined driving voltage overshooting a gray-level voltage corresponding to an input image signal of a current vertical period, according to a combination of an input image signal of an immediately preceding vertical period and the input image signal of the current vertical period.

The invention discloses an isolated bidirectional DC-DC (direct current) converter realized by a coupling inductor, which comprises four power switch tubes with reverse parallel diodes and parallel capacitors, two auxiliary switch tubes with reverse parallel diodes, two clamping capacitors, a switch capacitor and two two-winding coupling inductors. The invention reduces the ripples of the low-voltage side current through the low-voltage side parallel structure, realizes the zero voltage shutoff of the power switch tubes through the parallel capacitors on the power switch tubes, realizes the zero voltage conduction of the power switch tubes through the leakage inductance of the coupling inductors, realizes lossless transfer of the leakage inductance energy through the auxiliary switch tubes and an active clamping circuit consisting of the reverse parallel diodes of the auxiliary switch tubes and the clamping capacitors, and increases/decreases the voltage of the converter through the serial structure of the high-voltage side windings of the two coupling inductors. The circuit has simple structure, all power switches work in a soft switch state, no energy consumption element is arranged in the circuit, and the converter efficiency is improved; and moreover, during the current conversion, the switch device does not experience voltage overshoot.

The Voltage Sense Method is introduced and a number of its implementations using Voltage Sense Circuit are demonstrated to solve problems associated with the start-up of parallel switching converters, each converter having output synchronous rectifiers or more general Current Bi-directional Switches: prevention of the excessive reverse current, elimination of the excess voltage stress of the input switches and elimination of the voltage overshoot in the common output voltage. The Voltage Sense circuit added to each converter generates a Simulated Output Voltage, which predicts how would the output voltage of each particular unit rise during the start-up with enabled synchronous rectifiers if that particular unit were to operate alone. When the simulated output voltage of one converter reaches the actual common output voltage, synchronous rectifiers/CBS switches of that particular converter are all enabled so that their body-diodes, used up until that time to prevent reverse current flow, are by-passed eliminating all start-up problems. The introduced Voltage Sense Method and a number of its Voltage Sense Circuitries are also applicable to solve problems associated with the start-up of the current bi-directional converters with a battery load.

The invention relates to an LC series resonance high frequency chain matrix type half-bridge inverter topology and a modulation method. The topology comprises a half-bridge LC series resonance inverter, a high-frequency transformer T, a matrix converter and a CL type filter. The modulation method comprises steps that SPWM waves generated in a SPWM signal generation link are processed through series resonance modulation logics to acquire driving signals of a transformer front-level LC series resonance inverter and a transformer back-level matrix converter, a work duty ratio of an excitation resonance work state of a transformer front-level resonance circuit is made to be controllable within a half period, and output load side energy transmission control is realized; the transformer back-level matrix converter is taken as a common current type inverter to control, switching of a switch tube during a transformer zero current output period is carried out to realize a zero current switch, a voltage overshoot problem caused by break of a transformer secondary side leakage current flow path can be avoided, and bidirectional energy flow is realized. The method has advantages of small-quantity power conversion grades, small-quantity switch tubes, simple control and high circuit stability.

A current mode control buck-boost converter with improved performance utilizes separate buck and boost pulses. The buck-boost converter utilizes a buck/boost decision method with continuous control voltage for buck and boost mode, therefore eliminating transients in the control loop between operation modes and preventing voltage overshoots. If switching in Boost mode and the buck duty cycle is smaller than a set duty cycle, then in the next cycle Buck mode switching will occur. It is possible to track a Buck comparator output and the related duty cycle during Boost mode operation. Thus a mode change decision will only be dependent on a single input. A control loop will incorporate a single loop filter and error amplifier, wherein control voltages for Buck comparator and Boost comparator will be related.

An apparatus includes an inverter including a high-side switch coupled to a low-side switch, the inverter generating a time-varying drive current from a plurality of drive control signals, a positive rail voltage, and a negative rail voltage wherein controlling the switches to generate the time-varying drive current produces a potential transitory overshoot condition for one of the switches of the inverter; a drive control, coupled to the inverter, to generate the drive control signals and to set a level of each of the rail voltages responsive to a plurality of controller signals; and a controller monitoring one or more parameters indicative of the potential transitory voltage overshoot condition, the controller dynamically adjusting, responsive to the monitored parameters, the controller signals to reduce a risk of occurrence of the potential transitory voltage overshoot condition.

An apparatus includes an inverter including a high-side switch coupled to a low-side switch, the inverter generating a time-varying drive current from a plurality of drive control signals, a positive rail voltage, and a negative rail voltage wherein controlling the switches to generate the time-varying drive current produces a potential transitory overshoot condition for one of the switches of the inverter; a drive control, coupled to the inverter, to generate the drive control signals and to set a level of each of the rail voltages responsive to a plurality of controller signals; and a controller monitoring one or more parameters indicative of the potential transitory voltage overshoot condition, the controller dynamically adjusting, responsive to the monitored parameters, the controller signals to reduce a risk of occurrence of the potential transitory voltage overshoot condition.

The invention discloses a voltage converter capable of suppressing output voltage overshooting. The voltage converter is used for receiving an input voltage and adjusting the input voltage to generate an output voltage. In one embodiment of the invention, the voltage converter comprises an error amplifier, a compensation network and a selection circuit. The error amplifier has a positive-phase input end used for receiving a reference voltage, a reverse-phase input end used for receiving a feedback voltage associated with the output voltage, and an output end used for providing an error voltage. The compensation network is used for compensating the stability of the error amplifier. The selection circuit is used for selectively connecting the compensation network to the output end of the error amplifier according to the voltage level of the error voltage. In operation, when the voltage level of the feedback voltage is smaller than the voltage level of the reference voltage, the compensation network is not connected to the output end of the error amplifier; and when the voltage level of the feedback voltage is substantially equal to the voltage level of the reference voltage, the compensation network is connected to the output end of the error amplifier.