Fairchild Semiconductor Corporation

Semiconductor Components Industries, LLC

Hangseok Choi

Sangcheol Moon

Jintae Kim

Cheng-Sung Chen

Lei Chen

Chih-Hsien Hsieh

Taesung Kim

Zhibo Tao

Li Kuei Lin

Jung-Sheng Chen

Yue-Hong Tang

Kai-Fang Wei

Chi Chen Chung

SangCheol Moon

Dibyendu Rana

Demon Hsu

Wei-Hsuan Huang

A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of &#x394;tclose to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.

Power supply with near valley switching in near valley window time period

A circuit for controlling a power converter includes a transient detector that generates a transient detection signal in response to a feedback signal indicating an output signal of the power converter, a gain selector that generates a gain selection signal in response to the transient detection signal, and an amplifier circuit that generates a comparison signal based on the value of the feedback signal, a value of a reference signal, and a gain value of the amplifier circuit, the gain value being adjusted in response to the gain selection signal. The transient detection signal indicates that a value of the feedback signal is in a first range and a specific condition of the feedback signal is detected.

System and method for controlling voltage control loop in power converter

Provided is a power factor correction circuit including an inductor having one end to which an input voltage is applied; a power switch connected between another end of the inductor and the ground, and configured to control an output of the power factor correction circuit; and a power factor correction controller configured to calculate a duty of the power switch on the basis of an output detection voltage corresponding to the output and an inductor current flowing through the inductor, calculate conduction-period information regarding a conduction period in which the inductor current flows in one switching cycle of the power switch, and compensate the calculated duty on the basis of the conduction-period information.

Power factor correction circuit with calculated duty compensation and driving method thereof

According to an implementation, a resonant converter for short-circuit protection includes an oscillator, a short-circuit detector configured to detect a short-circuit condition in a component of the resonant converter, and a pulse width modulation (PWM) controller configured to control the oscillator in a PWM mode before short-circuit protection is triggered. The oscillator, when in the PWM mode, is configured to generate a first clock signal for driving a first power switch and a second clock signal for driving a second power switch.

Short-circuit protection using pulse width modulation (PWM) for resonant converters

A Power Factor Correction (PFC) circuit includes an oscillator circuit. The oscillator circuit receives a valley detect signal indicating a zero current condition, determines a blanking time according to an operational cycle of the PFC circuit, and determines to initiate the operational cycle according to the valley detect signal and the blanking time. Determining the blanking time includes selecting one of a plurality of predetermined blanking times according to a count of operational cycles of the PFC circuit. The PFC circuit may operate in a Boundary Conduction Mode or a Discontinuous Conduction Mode depending on whether a charge-discharge period is greater than the blanking time. The PFC circuit may determine, according to its output voltage, a first duration of a charging period, determine a delay time according to zero current times of previous operational cycles, and extend the first duration of the charging period by the delay time.

Power factor correction circuit and method

A Synchronous Rectifier (SR) controller circuit includes a dead time evaluation circuit, an offset voltage controller circuit, an off threshold control circuit, and a comparator circuit. The dead time evaluation circuit produces an indication of whether a measured dead time of an SR switching device is less than a target dead time. The offset voltage controller circuit determines an offset count using the indication, an offset voltage using the offset count, and high and low saturation indicators according to the offset count. The off threshold control circuit determines a threshold count using the high and low saturation indicators and an off threshold voltage using the threshold count. The comparator circuit determines whether a measured voltage of the SR switching device is greater than a virtual off threshold voltage, the virtual off threshold voltage corresponding to the off threshold voltage minus the offset voltage.

Automatic control of synchronous rectifier turn-off threshold

A circuit comprises an Inductor-Inductor-Capacitor (LLC) tank circuit and an energizing circuit. The LLC tank circuit includes first and second inductors, a capacitor, and a primary coil of a transformer. The first inductor is coupled in series with the second inductor, the second inductor is coupled in series with the capacitor, and the primary coil is coupled in parallel with the second inductor. The energizing circuit supplies power to the LLC tank circuit according to a switching period, and detects a power limit condition according to a value of an integrated current sense signal and a duration of the switching period. The integrated current sense signal corresponds to an integration over time of a current supplied to the LLC tank circuit. The circuit may be incorporated into a power converter to provide power limit detection according to an accurate real-time estimation of the power converter's output power.

Power limit protection for resonant power converter

A power adapter includes a protocol integrated circuit (IC) on a secondary side of a transformer and a controller IC on a primary side of the transformer. The power adapter has an output voltage that changes depending on the charging voltage requirement of an electronic device (e.g., mobile device) connected to receive power from the power adapter. The power adapter includes an adaptive overvoltage protection mode that sets an overvoltage protection threshold to a low level during startup and thereafter sets the overvoltage protection threshold to a higher level after detecting proper operation of the protocol IC.

Adaptive overvoltage protection for adaptive power adapters

According to an implementation, a resonant converter for detecting non-zero voltage switching includes an oscillator configured to generate a first clock signal to drive a first power switch, and a second clock signal to drive a second power switch. The resonant converter includes a non-zero voltage switching (non-ZVS) detection circuit configured to receive an integrated current sense signal sensed on a primary side of a transformer of a resonant network, and determine a polarity of a voltage of the integrated current sense signal at a predetermined point in the first clock signal or the second clock signal during a switching cycle. The non-ZVS detection circuit is configured to detect a non-ZVS event based on the polarity of the voltage of the integrated current sense signal at the predetermined point in the first clock signal or the second clock signal during the switching cycle.

Non zero-voltage switching (ZVS) detection in resonant converters

A method for controlling a power converter includes determining whether a value of a feedback signal is in a first range, detecting a plurality of points of the feedback signal, and decreasing one or both of a proportional coefficient and an integral coefficient of a first control loop of the power converter at a first plurality of times corresponding to the detected plurality of points of the feedback signal when the value of the feedback signal is in the first range. The feedback signal indicates an output signal of the power converter. A circuit for controlling a power converter includes a transient detector that generates a transient detection signal in response to a feedback signal indicating an output signal of the power converter and a gain selector that generates a gain selection signal in response to the transient detection signal.

Power supply with near valley switching

According to an implementation, a resonant converter for resonant capacitance stabilization during start-up includes an oscillator configured to generate a first clock signal to drive a first driver for a first power switch, and a second clock signal to drive a second driver for a second power switch during switching operations, and a resonant capacitor stabilizer configured to control the second driver to periodically activate the second power switch to discharge a resonant capacitor of a resonant network during initialization of the switching operations of the resonant converter.

Resonant capacitor stabilizer in resonant converters

According to an implementation, a resonant converter for burst mode control includes an oscillator configured to control switching operations of at least one power switch, and a burst mode controller configured to control a burst mode by determining a start of a burst pulse of the burst mode using a first internal signal and determining an end of the burst pulse of the burst mode using a second internal signal. The burst mode controller is configured to stop the switching operations during the burst pulse.

Burst mode control in resonant converters

A method for controlling a power converter includes generating a load detection signal in response to a conduction signal and a driver input signal, and generating a gate control signal in response to the load detection signal. The gate control signal is delayed by a delay amount in response to the load detection signal. An apparatus for controlling a power converter includes a gate signal control circuit generating a load detection signal in response to a conduction signal and a driver input signal, and a synchronous rectifier (SR) driver generating a gate control signal in response to the load detection signal.

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Bedford, NH, United States of America

Hangseok Choi