Abstract: A PWM controller with output current limitation makes the over-current limitations almost the same even though the input voltages are different. The designer does not need to use high specification components or add an output current limiting circuit against the over-current condition. Costs are reduced and the layout is simplified. The switch power supply includes a transformer, a power switch, a first detecting circuit for generating a first detecting signal, a second detecting circuit for generating a second detecting signal, and a controller. The transformer converts the power and outputs the power to the secondary side. The power switch has a first terminal, a second terminal, and a controlled terminal. The controller has a control terminal, a first detecting terminal for receiving the first detecting signal, and a second detecting terminal for receiving the second detecting signal. The controller performs a protecting operation according to the received signals.

Abstract: A regulator with a high side pass device and a low side pass device coupled in series to the high side pass device is disclosed. The apparatus further includes a control module coupled to the high side pass device and the low side pass device. The control module is coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device. The control module is operable to lock out the high side pass device under certain conditions.

Abstract: The invention presents a control circuit and a control method of DC-DC converter capable of suppressing subharmonic oscillation of coil current even if the on-duty is over 50%. An error amplified signal V1 is an output voltage of an error amplifier ERA1. An offset voltage unit Ve2 outputs a lower limit set voltage V2 obtained by subtracting offset voltage e2 from error amplified signal V1. A voltage comparator COMP2 compares lower limit set voltage V2 output from offset voltage Ve2, and output voltage signal VIL. When the voltage value of output voltage signal VIL is decreased to lower limit set voltage V2 (region E2), the output of voltage comparator COMP2 changes from low level to high level. As a result, main transistor FET1 is set in conductive state. On the other hand, when the voltage value of output voltage signal VIL reaches an error amplified signal V1 (region E1), main transistor FET1 is set in non-conductive state.

Abstract: In accordance with the present invention, a power converter transformer for suppressing conduction EMI (ElectroMagnetic Interference) includes a primary winding positioned at a primary side; a secondary winding positioned at a second side and coupled with the primary winding; a parasitic capacitor connected between one end of the primary winding and one end of the secondary winding; a switching unit connected to the other end of the primary winding; a Y-capacitor connected between the switching unit and a ground terminal; an auxiliary winding positioned at the secondary side and coupled with the secondary winding; and an auxiliary capacitor connected between the one end of the primary winding and the auxiliary winding.

Abstract: An amplifier having improved distortion characteristics is set forth. The amplifier includes an interleaved PWM amplifier that generates interleaved PWM pulses in response to a modified input signal and one or more carrier signals. The interleaved PWM pulses of the amplifier are used to drive a power stage, such as an opposed current power stage. The amplifier also includes an interleaved PWM generator that provides interleaved PWM pulses in response to the modified input signal and one or more further carrier signals. The carrier signals used by the PWM generator may differ in phase from the carrier signals used by the interleaved PWM amplifier to generate its interleaved PWM pulses. One or more feedback circuits are employed in the generation of the modified input signal. More particularly, the feedback circuit(s) generates the modified input signal based on an input signal that is to be amplified and the interleaved PWM pulses of the interleaved PWM generator.

Abstract: Techniques for near zero light-load supply current in switching power supply are described. In one embodiment, a switching power supply comprises sub-circuits, a capacitor/inverter circuit, and a standby control circuit. The sub-circuits comprise a feedback resistor that supplies a fraction of an output voltage of the power supply, an integrator that provides an integrator output, a comparator that provides a pulse width modulated signal, a switching element that receives the pulse width modulated signal and modulates current such that the power supply provides a regulated voltage, and a monitoring circuit that provides a logic low signal when the pulse width modulated signal is absent over a period of time. The standby control circuit disables the sub-circuits when the logical low signal is detected permitting the switching power supply to operate at a minimum current, an re-enables the sub-circuits when an out of regulation signal from the capacitor/inverter circuit is detected.

Abstract: A measurement system with selectable feedback paths includes a DUT interface including a first and a second DUT sensor, the first sensor being connected to a first feedback path for providing a measure of a first DUT characteristic, the second sensor being connected to a second feedback path for providing a measure of a second DUT characteristic, the sensors having a shared reference path and each feedback path including a set point adjustment; a differential amplifier system including differential inputs and differential outputs, the differential outputs being applied to the DUT interface; and a multi-pole switcher for connecting the differential inputs to either the first feedback path and the reference path or to the reference path and the second feedback path, respectfully. The first feedback path is selected to produce a desired first DUT characteristic or the second feedback path is selected to produce a second desired DUT characteristic.

Abstract: In one embodiment, a power supply includes a flyback transformer having a primary winding and at least two secondary windings. An output voltage is developed across a first one of the secondary windings. The power supply includes a transistor coupled to the first one of the secondary windings. The output voltage is regulated about a nominal output voltage by operating the transistor in a linear mode when current is flowing through the first one of the secondary windings and by operating the transistor in an off mode when current is not flowing through the first one of the secondary windings.

Abstract: A circuit provides a voltage reference using very low power. It can also be used as a shut regulator for a quiescent current as low as 1.5 ?A. It includes a transconductance amplifier, a gain stage, and a power transistor. One embodiment of this invention utilizes a work function difference between p+ gate and n+ gate to generate a predetermined reference voltage. In another embodiment of this invention, the predetermined reference voltage can be pre-adjusted using gate materials with different work functions.

Abstract: A device for delivering a desired power to a load comprises a voltage detection module, a comparator module, a power regulation module, and a current source. The voltage detection module generates a voltage signal based on a voltage across the load. The comparator module compares a first value based on the voltage signal to a power reference signal. The power reference signal is based on the desired power. The power regulation module generates a digital code based on the comparison. The current source provides a current to the load. The current is based on a predetermined constant current and a second value. The second value is based on the digital code.

Abstract: A switching regulator includes a first switching regulator corresponding to a master channel, and a second switching regulator corresponding to a slave channel. The first switching regulator generates first output voltage Vout1 by a constant on-time system in which on-time is constant. On the other hand, the second switching regulator monitors a first switching signal and a second on-time control circuit determines on-time of a second switching signal in accordance with lapse time from the rising time of the first switching signal to the rising time of a second switching signal.

Abstract: One embodiment relates to a control system. In one embodiment, a control system is configured to drive a load based on a set-point of the load, a measured load characteristic and a supply voltage of the load. The controller is configured to determine a duty cycle based on the load characteristic, the set-point, and the supply voltage. The controller is further configured to drive the load in response to the duty cycle.

Abstract: A reverse current stopping circuit includes a synchronous rectification device, a comparator for detecting a reverse current of an inductor, the synchronous rectification device being turned off when the reverse current is detected by the comparator, a reverse current detector circuit for detecting a switching terminal voltage after the synchronous rectification device is turned off, thereby determining a value of the inductor current to decide whether the inductor current is flowing in a reverse direction or a forward direction, and a memory unit for receiving a predetermined output signal from the reverse current detector circuit in accordance with a result of the reverse current detector circuit, and outputting a control signal for an offset voltage in accordance with the predetermined output signal. The offset voltage is changed in accordance with the control signal so as to adjust the inductor current to zero when the synchronous rectification device is turned off.

Abstract: A DC-to-DC converter includes a DC-to-DC conversion unit for converting an input voltage into an output voltage by switching operation of the switching element according to a drive signal and supplying the output voltage to a load and a control unit for generating the drive signal. The control unit includes a determination circuit for determining whether the load is in a normal operation state or a standby state, an error amplifier for generating an error signal according to the output voltage, a first drive-signal generator for generating a pulse sequence of pulses each having a pulse width according to the error signal, and a second drive-signal generator for generating a pulse having a pulse width larger than a cycle of repetition of the pulses in the pulse sequence when the voltage according to the output voltage falls below the reference voltage and the load is in the standby state.

Abstract: A system and method are disclosed for controlling a regulator circuit that outputs a plurality of radio frequency power amplifier bias voltages. A feedback loop is connected to the regulator circuit from the plurality of bias voltages that are output from the regulator circuit. The feedback loop comprises a demultiplexer circuit and a multiplexer circuit that are connected to the regulator circuit. The demultiplexer circuit and the multiplexer circuit each receive an enable signal and provide a feedback signal to the regulator circuit from the bias voltage that is associated with the received enable signal. The invention allows the regulator circuit to be configured as needed to provide different values of radio frequency power amplifier bias voltages.

Abstract: A method of controlling a DC-DC step-up converter including at least one power switch and an energy storage inductor may include comparing a converter output voltage to a first threshold and generating a first comparison flag based on the converter output voltage comparison. The method may also include comparing a voltage across the energy storage inductor to a second threshold and generating a second comparison flag based on the second energy storage inductor voltage comparison. The method may further include controlling the at least one power switch as a function of a logic state of the first comparison flag and the second comparison flag, and stepwise adjusting the second threshold as a function of the first comparison flag and the second comparison flag to limit a ripple on the converter output voltage.

Abstract: A synchronous rectifier is switched in accordance with a primary switch transition and a reference signal representing current in a current storage device to which the synchronous rectifier is coupled. A current emulator provides a signal representing current in the current storage device as a volt-second product so that current stored in the current storage device while the primary switch is on is discharged by the synchronous rectifier. The use of a current emulator provides an inexpensive solution for controlling synchronous rectifier transitions without resorting to more expensive current sensing solutions that are commercially impracticable. Blanking intervals are provided for avoiding false transitions of the synchronous rectifier when the primary switch turns on and after the synchronous rectifier turns off. The disclosed system and method can be applied to flyback converters for a synchronous rectifier on the secondary side of a transformer, or the inductor of buck converters.

Abstract: The present invention discloses a resonance circuit for use in an H-bridge DC-DC converter, the resonance circuit comprising: an H-bridge converter, capable of converting unstable DC power into stable DC power; a first resonance circuit, disposed on a buck side of the H-bridge converter for reducing the turn-off loss of a first active switching element; and a second resonance circuit, disposed on a boost side of the H-bridge converter for reducing the turn-on loss of a second active switching element. The H-bridge converter comprises: a first active switching element and a second active switching element; a coupled inductor with dual windings capable of storing energy; and a first passive switching element and a second passive switching element.

Abstract: A power supply includes: a switching amplifier including an input and an output, the amplifier input being adapted to be powered by an electrical power source; a transformer including a primary and a secondary winding on a magnetic core, the number of winding turns being chosen to limit magnetization levels to avoid magnetic saturation while maximizing winding spacing, the transformer primary winding being in communication with the amplifier output; a rectification system in communication with the transformer secondary winding, the rectification system providing a DC power output; and a controller. The controller monitors the DC power output and adjusts the switching amplifier in response to the monitoring to provide a desired power output characteristic.

Abstract: A current-sensing and correction circuit having programmable temperature compensation circuitry that is incorporated into a pulse width modulation controller of a buck mode DC—DC converter. The front end of the controller contains a sense amplifier, having an input coupled via a current feedback resistor to a common output node of the converter. The impedance of a MOSFET, the current through which is sampled by a sample and hold circuit is controlled by the sense amplifier unit. A sensed current correction circuit is coupled between the sample and hold circuit and the controller, and is operative to supply to the controller a correction current having a deterministic temperature-compensating relationship to the sensed current. The ratio of correction current to sensed current equals a value of one at a predetermined temperature, and has other values at temperatures other than at that temperature.