1043 results about "Switching cycle" patented technology

A dual output buck-boost power converter operates with a single inductor to achieve high efficiency with automatic or inherent load balancing. Switches associated with the opposite polarity outputs are driven based on feedback signals, with one feedback signal being a reference voltage and another feedback signal being related to an opposite polarity output. The opposite polarity feedback signal is provided to a comparator with a reversed polarity to achieve a simple balanced control that maintains polarity outputs. The power converter delivers power to each output with each switching cycle and uses a single inductor to achieve high efficiency performance.

A DC power supply device includes transformers that operate with an enhanced efficiency and can reduce the factors that generate ripples in the output voltage to make it possible to downsize the transformers and the smoothing filters of the device, reduce the loss attributable to the switching elements during its constant power output operation and also downsize the heat sink fins so that the overall dimensions of the power supply device may be reduced. The DC power supply device also comprises a pair of switching changers, two output transformers and two rectifying/smoothing sections for rectifying the respective outputs of the switching changers. Each of the two switching changers has the same switching cycle period and the striking phases of the switching elements of one of the switching changers and those of the switching elements of the other switching changer are made variable. Then, a constant power output level is achieved by utilizing the difference of the striking phases of the two switching changers in order to isolate the switching changers from each other for operation and connect them in series or in parallel for operation.

A method and apparatus to implement parallel current mode control that is suitable for digital and analog implementation. A duty cycle algorithm is composed of a voltage term and a parallel current term which depends on the inductor current change between the inductor current value at the beginning of a switching cycle and the reference inductor current value at the end of that switching cycle. Parallel current mode control can be applied to all DC-DC converters, including both non-isolated and isolated topologies. It can also be applied to AC-DC converters with power factor correction.

A switching power converter and method of controlling an output voltage thereof using predictive sensing of magnetic flux provides a low-cost switching power converter via primary-side control using a primary-side winding. The power converter has improved immunity to parasitic phenomena and other variations within the power converter components. An integrator is used to generate a voltage analog that represents magnetic flux within a power magnetic element via an integration of a voltage on a primary-side winding of the power magnetic element. A detection circuit detects the end of a half-cycle of post-conduction resonance that occurs in the power magnetic element subsequent to the energy level in the power magnetic element reaching zero. The voltage of the integrator is stored at the end of the post-conduction resonance half-cycle and is used to determine a sampling point prior to or equal to the start of post-conduction resonance in a subsequent switching cycle of the power converter (which is the predicted zero-energy storage point of the power magnetic element). The primary-side winding voltage is then sampled at the sampling point, providing an indication of the output voltage of the power converter. By predicting the zero-magnetic-energy storage point, the output voltage of a power converter operating in discontinuous or boundary conduction mode can be accurately controlled without being affected by parasitic phenomena or variations in circuit performance over time, input voltage and temperature.

A synchronous rectifier PWM (SR-PWM) controller controls a MOSFET in response to the value of a secondary current and the status of a synchronous signal for both discontinuous and continuous operation mode. The secondary current is generated in a secondary circuit and is detected by two threshold-detection terminals of the SR-PWM controller. The SR-PWM controller produces the synchronous signal by detecting a switching signal of the transformer via a detection terminal of the SR-PWM controller. Furthermore, a delay-time is inserted after the MOSFET is turned off and before the next switching cycle starts to ensure a proper operation of the MOSFET. In one embodiment, an equivalent series resistance (ESR) of an output capacitor can be used as a sensor to detect the secondary current. Therefore, no additional current sensor is required and the efficiency can be improved.

The invention discloses a PFC circuit which is provided with an average current control module, comprising a first boosting circuit, a second boosting circuit and the average current control module. The average current control module comprises a sampling unit, a difference value operating unit, a proportion integral unit and a duty ratio regulating unit which are connected one by one. The duty ratio regulating unit realizes the average current of the inductance current mean in a switch cycle. The invention also discloses an average current control method used for the PFC circuit, and the method comprises the following steps: A. a reference current is produced; B. the current is sampled and the difference value is operated to obtain the inductance current difference value of two parallel branches; C. control signal one of the first boosting circuit is produced through operation; D. control signal two of the second boosting circuit is produced through operation; E. the duty ratio of the two branches is obtained by regulating the duty ratio.

An adjustable compensation offset voltage is applied to a comparator to vary turn-off timing of a synchronous rectifier. A comparator output indicates when current through an inductor coupled to the synchronous rectifier should be approaching zero. If the synchronous rectifier is turned off before the current through the inductor reaches zero, the compensation offset voltage is adjusted to delay the synchronous rectifier turn-off for the next switching cycle. If the synchronous rectifier is turned off after the current through the inductor reaches zero, the compensation offset voltage is adjusted to advance the synchronous rectifier turn-off for the next switching cycle. An up/down counter, in conjunction with a digital to analog converter, may be used to provide the adjustment to the compensation offset voltage. The adjustable compensation offset voltage improves the accuracy of synchronous rectifier turn-off in relation to a zero inductor current, thereby improving power converter efficiency.

A buck switching regulator receives an input voltage and provides a switching output voltage on a switch output node using a minimum on-time, variable off-time feedback control loop. The buck switching regulator includes an on-time control circuit for generating a first signal for turning off the high-side switch at the expiration of a first on-time duration or at the expiration of a maximum on-time. The first on-time duration is at least a minimum on-time and is allowed to expand to a maximum on-time when the feedback voltage remains less than a reference voltage. The maximum on-time includes a first maximum on-time and a second, extended maximum on-time. The second maximum on-time is applied when a minimum off-time was used for the high-side switch during the previous switching cycle. In another embodiment, the second maximum on-time is applied only when the switching regulator is not being current limited.

A switched mode power supply (SMPS) includes a transformer with a primary winding, a secondary winding, an auxiliary winding, and a power switch coupled to the primary winding. During one switching cycle, the auxiliary winding provides a feedback signal which includes a first voltage pulse that is induced after the power switch is turned on and a second voltage pulse that is induced after the power switch is turned off. A control circuit includes a circuit for generating a sampling signal for sampling the second voltage pulse in a switching cycle at a time that is determined based on the first voltage pulse in the same switching cycle. A sample-and-hold circuit is configured for sampling and storing the second voltage pulse in response to the sampling signal. A switching signal generating circuit is configured to generate a switching signal for controlling the power switch based on an output of the sample-and-hold circuit.

An inductor current emulation circuit for a switched-mode power supply (SMPS) which is arranged such that its inductor current (I_L) goes to zero at least once per switching cycle. The emulation circuit includes an RC integrator connected in parallel across the inductor, and a zero reset switch (ZRS) connected in parallel across the integrator's capacitor. A control circuit operates the ZRS such that it is opened when I_L is non-zero, and is closed for a least a portion of the time during each switching cycle when I_L is zero such that the capacitor is substantially discharged. In this way, the ZRS essentially recalibrates the emulation circuit when I_L is zero. When so arranged, the voltage (V_C) across the capacitor emulates I_L. The invention may be implemented with either a discontinuous-inductor-current SMPS, or a continuous-bipolar-inductor-current SMPS.

A main circuit of a three-level active neutral point clamped voltage source converter having a pair of additional main switches provides two paths between an output node and a neutral point in which one of the paths involves only switches of an inner pair of switches that are operated at a high frequency. An auxiliary circuit operating at a high frequency for only a brief period during each high frequency switching cycle selects the path involving only the inner switches and provides operation with zero voltage switching and avoids reverse recovery of diodes connected antiparallel with the main and additional main switches. Accordingly, turn-on switching losses in the main switches is avoided and the voltage source converter can be operated at increased frequency to allow reduction in size of magnetic components and full potential power transfer to be achieved.

The object of providing a non-volatile semiconductor memory that stands out by good scalability and a high retention time as well as ensures low switching voltages at low switching times and achieves a great number of switching cycles at good temperature stability is solved by the present invention with a semiconductor memory whose memory cells comprise at least one silicon matrix material layer with open or disturbed nanocrystalline or amorphous network structures and structural voids which has a resistively switching property between two stable states, utilizing the ion drift in the silicon matrix material layer. The memory concept suggested in the present invention thus offers an alternative to the flash and DRAM memory concepts since it is not based on the storing of charges, but on the difference of the electric resistance between two stable states that are caused by the mobility of ions in the amorphous silicon matrix material with an externally applied electric field.

A control system for an electric machine having a rotor position sensor that generates a rotor position signal, a velocity module that generates an electric angular velocity value based on the rotor position signal, a random pulse width modulation module that generates a switching period and a delay for a current cycle, and a phase angle compensation module that sums a sample rate, one half of the switching period, and the delay of a previous cycle and that outputs a delay time. The phase angle compensation module further multiplies the delay time and the electric angular velocity value and generates a compensating angle.

A electric motor drive apparatus comprising a voltage control unit performing voltage control processing that determines alternating-current voltage command values serving as command values of the alternating-current voltages to be supplied to the alternating-current electric motor and generates switching control signals for the inverter; and a control mode selection unit selecting a synchronous control mode in which a cycle of electric angle of the alternating-current electric motor is synchronized with a switching cycle of the inverter, or an asynchronous control mode in which the cycles are not synchronized with each other. Current detection processing is performed to detect currents flowing in coils of the alternating-current electric motor in every standard calculation cycle that is set to a half of a cycle of the carrier.

Systems and methods are provided for regulating a power conversion system. An example system controller includes a driving component and a detection component. The driving component is configured to output a driving signal to a switch associated with a first current flowing through a primary winding of a power conversion system, the switch including a first switch terminal related to a first voltage and a second switch terminal related to a second voltage, the driving signal being associated with a plurality of switching periods. The detection component is configured to receive an input signal associated with a difference between the first voltage and the second voltage, detect at least one valley of the input signal in magnitude during a detection period for the first switching period, and output a detection signal based on at least information associated with the input signal to affect the driving signal.

A lighting device (1) comprises a plurality of LEDs (11-14) producing light (21-24) of mutually different colors. The LEDs are driven in switching cycles (63) with a duty cycle controlled supply current of constant magnitude. In each switching cycle, each LED is first switched ON (61) and then switched OFF (62).

In a measuring mode, during one switching cycle (63B), all ON phases of all LEDs are briefly interrupted, except for one LED (11), so that a light sensor (70) measures the light from this one LED. This measurement can be used to adapt the duty cycle of this one LED. In the next switching cycle (63C), the interruption of the ON phases is compensated by extending the ON phases of all LEDs except said one LED, the extension having a duration equal to the duration (τ_D) of the interruption.

An arrangement for measuring current through a phase section of a buck mode DC-DC converter includes an auxiliary integrated circuit containing an auxiliary power MOSFET and a pilot MOSFET coupled in parallel with a current path through a high side MOSFET of a half-bridge of the converter. The pilot MOSFET has a current path coupled to a current measurement terminal. The MOSFETs of the auxiliary circuit are time division multiplexed with the high side MOSFET, whereby a determination of current through the auxiliary high side MOSFET is based upon current through the pilot device and the geometric ratio of the size of the pilot device to that of the high side auxiliary MOSFET. The high side MOSFET is activated for a large number of switching cycles relative to the pilot circuitry, but the pilot circuitry is activated sufficiently often to derive a relatively accurate measure of current flow.