Apple Inc.

Marvellworld Trade Ltd.

Inhwan Oh

Manisha P Pandya

Bharat K Patel

Nicholas Ainsley Sims

Abby Cherian

Wanfeng Zhang

Bogdan Tudor Bucheru

Pantas Sutardja

Zaki Moussaoui

Weihong Qiu

Shimon Elkayam

Marco Soldano

Behzad Mohtashemi

Rohan Dayal

Malhar V Bhatt

A power converter can include a half bridge comprising a high side auxiliary switch and a low side main switch, the half bridge having an input coupled to a DC voltage source, a series resonant circuit coupled to the output of the half bridge, the series resonant circuit comprising a resonant capacitor and a primary winding of a transformer, an output coupled to a secondary winding of the transformer by a rectifier, the output delivering a regulated output voltage to a load, and control circuitry that operates the main switch and the auxiliary switch substantially complementarily as a forward converter with zero voltage switching of the main and auxiliary switches to regulate the output voltage delivered to the load.

Forward mode soft switching power converter

An AC-DC power converter can include an AC-DC converter stage, such as a flyback converter, configured to receive an AC input voltage and deliver a DC output voltage. The converter can include an active capacitor bank (ACB) coupled to the output of the AC-DC stage. The ACB can include an energy storage capacitor and a plurality of switching devices operable as a bidirectional converter to alternately charge the capacitor from the DC output or discharge the capacitor to maintain output DC voltage regulation. The converter can also include control circuitry responsive to the AC input voltage to selectively: (1) enable the AC-DC stage and operate the switching devices to charge the capacitor from the DC output voltage; (2) and disable the AC-DC stage and operate the switching devices to discharge the capacitor to maintain DC output voltage regulation.

AC/DC converter with active capacitor bank

A power converter can be implemented as a series of power conversion stages, including a wireless power conversion stage. In typical embodiments, the power converter receives power directly from mains voltage and outputs power to a battery within an electronic device. A transmitter side of the power converter converts alternating current received from a power source (e.g., mains voltage) to an alternating current suitable for applying to a primary coil of the wireless power conversion stage of the power converter.

Low-profile power converter

A power converter can include an input boost converter stage having an input configured to receive a rectified AC input voltage and an output configured to deliver a DC bus voltage and a second switching converter stage having an input configured to receive the DC bus voltage and an output configured to deliver a regulated output voltage. The input boost converter may be configured to be operated in a flat current mode to maintain a substantially constant DC bus voltage over a broad range of AC input voltages. The input boost converter may be further configured to be operated in an active blanking mode, wherein operation of the boost converter is prevented during a controlled blanking interval of each cycle of the rectified AC input voltage. The controlled blanking interval may be increased responsive at least in part to an increase in the AC input voltage and/or may be decreased responsive at least in part to a decrease in the AC input voltage.

AC-DC converter with boost front end having flat current and active blanking control

A power converter can be configured to convert an AC input voltage into a regulated DC output voltage while maintaining the input current in phase with the rectified AC input voltage. A control circuit of the power converter may be configured to selectively enable switching of at least one switching device of the power converter responsive to a determination that the input voltage is greater than a threshold voltage and to selectively disable switching of the at least one switching device responsive to a determination that the rectified AC input voltage is less than the threshold voltage. The control circuit may be configured to selectively enable and disable switching using an active burst mode signal having a frequency lower than a switching frequency of the converter. The control circuit may be still further configured to operate at least one switching device of the converter in a zero voltage switching condition.

Active burst ZVS boost PFC converter

A frequency doubling resonant converter can include a dual half bridge resonant converter configured to receive an input DC voltage and convert it to an frequency doubled AC voltage having a frequency twice the switching frequency of the dual half bridge resonant converter. The converter can further include a step down transformer configured to reduce the frequency doubled AC voltage to a stepped down AC voltage. The converter can further include a rectifier configured to convert the stepped down AC voltage into a DC output voltage for delivery to a load. The converter may optionally include an interphase transformer coupled between the step down transformer and the rectifier and configured to increase an output current of the converter. The frequency doubling resonant converter may be configured, for example, to double an output current received from the step down transformer.

Frequency doubling resonant converter

A power converter includes a current-monitoring on-state controller that is configured to adjust the timing of a switch-mode voltage conversion stage of the power converter. For example, the timing of the turn-on of a MOSFET associated with a buck converter operated in a discontinuous conduction mode (e.g., quasi-resonant) can be adjusted based on a zero crossing of current through a tank inductor also associated with the buck converter. More particularly, the MOSFET may be turned on after a predetermined delay is initiated after current through the tank inductor reaches zero. The predetermined delay is based on a resonance period defined by the characteristic capacitance of the MOSFET and the inductance of the tank inductor.

Quasi-resonant power converter with reduced dynamic switching losses

A wireless power transfer circuit can include an interphase transformer operatively coupled to a receiver coil, a rectifier, and a load. The receiver coil can be configured to have an alternating current induced therein by a transmitter coil. The interphase transformer can be configured to deliver a current to the load that is twice the current induced in the receiver coil, and the rectifier can be configured to rectify the current delivered to the load. The interphase transformer may be constructed with a center tapped winding structure or a bifilar winding structure, and may be constructed as a planar transformer. The rectifier may be made up of diodes (which may be Schottky diodes) or may be a synchronous rectifier comprised of switching devices such as MOSFETs.

Interphase transformer based rectifier for wireless power transfer

A half bridge power converter can be coupled to, or included in, a wireless transmitter device. The half bridge power converter includes an upper switching element connected between a direct current supply voltage and a lower switching element. A duty controller is coupled to the upper and the lower switching elements and is configured to asymmetrically control the duty cycles of the upper and lower switching elements based on a voltage level of the direct current supply voltage. In general, the duty cycle of the lower switching element is different than the duty cycle of the upper switching element. Additionally or alternatively, the duty controller is configured to determine and control the duty cycles of the upper and lower switching elements to adjust a direct current gain of a wireless energy transfer system that includes the wireless transmitter device.

Asymmetric duty control of a half bridge power converter

A variable-output power converter includes a switch-mode voltage conversion stage operating in a peak-current control mode. For example, the timing of the turn-off of a MOSFET associated with a buck converter can be adjusted based on a measurement of current conducted through the by MOSFET. When the current through the MOSFET exceeds a threshold, the MOSFET is turned off, thereby defining the peak current that can be output by the variable-output power converter. The peak-current threshold can be adjusted by changing one or more characteristics of a compensation network configured to provide positive feedback to the variable-output power converter. In many examples, the peak-current threshold is adjusted using a pulse-width modulated signal.

Power converter with output voltage control

A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The primary resonant flyback converter may include one or more of: (a) output voltage sensing across the resonant capacitor; (b) a full bridge switch configuration; and (c) lossless current sensing using a current sensing circuit coupled in parallel with the resonant capacitor.

Primary side control of primary resonant flyback converters

A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The switching frequency may be varied as a function of output load, input voltage and/or voltage ripple on a DC bus of the converter. Switching may also be temporarily disabled responsive to a decrease in output load and re-enabled responsive to an increase in output load.

Variable frequency and burst mode operation of primary resonant flyback converters

A power converter includes a buck converter with a low-side switch. During a discharge mode, current passes through the low-side switch to form a current loop. The low-side switch is typically closed synchronously with the opening of a high-side switch coupled to an input voltage level to the buck converter. The power converter also includes a high-side controller and a low-side controller, which together are configured to adjust the timing of the operation mode of the high-side controller between a storage mode and the discharge mode.

Synchronous buck converter with current sensing

An electronic device has an I/O port, a bus connector and a transistor that is connected between the I/O port and a communications contact of the bus connector. A control circuit is connected to the transistor to maintain a gate voltage of the transistor independent of power supply voltage on a power supply contact of the connector. Other embodiments are also described and claimed.

Over voltage protection for a communication line of a bus

A power converter controller controls a power stage to produce a regulated voltage at a converter output node, using an input signal. A circuit uses an opto-coupler circuit that has an input node connected to a compensation circuit, to generate the input signal. The compensation circuit has a shunt regulator having an output that is connected to the opto-coupler circuit through series-connected first and second current limiting elements. An input of the shunt regulator is connected to the converter output node. A feedback element has one end connected between the series-connected current limiting elements and another end connected to the input of the regulator. Other embodiments are also described and claimed.

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Cupertino, CA, United States of America

Inhwan Oh