Maxim Integrated Products, Inc.

Volterra Semiconductor Corporation

Brett A Miwa

Serhii Mikhailovich Zhak

Xin Zhou

David Harrington

Mark Anthony Belch

Justin Michael Burkhart

Michael Warren Baker

Jonathan King

Alexandr Ikriannikov

Ilija Jergovic

Jizheng Qiu

Rui Liu

Marco A Zuniga

Andrew J Burstein

Aleksandar Prodic

Michael D McJimsey

Oscar Blyde

Urs H Mader

Karl Richard Volk

Nenad Vukadinovic

Cory Brent Arnold

Sean Lai

Kevin Wendell Dowdy

David Stearns

Jeffrey Lewis Amram Summit

Chi-Teh Chiang

A multiphase DC-DC converter includes a coupled inductor, N phases of the multiphase DC-DC converter, and a controller, where N is an integer greater than 2. The coupled inductor includes a plurality of inductors. Each inductor is coupled to two neighboring inductors or to rest of the inductors. The N phases of the multiphase DC-DC converter are respectively connected to the plurality of inductors. The controller operates the multiphase DC-DC converter in continuous conduction mode and in discontinuous conduction mode. Body diodes of switches in the N phases do not conduct when the multiphase DC-DC converter operates in discontinuous conduction mode.

Method and apparatus for multi-phase DC-DC converters using coupled inductors in discontinuous conduction mode

A current sense device includes a reference transistor for electrically coupling to a power transistor, a sense transistor for electrically coupling to the power transistor, and control circuitry. The control circuitry is configured to (a) control current through the sense transistor such that a voltage at the sense transistor has a predetermined relationship to a voltage at the power transistor, and (b) control current through the sense transistor according to one or more operating conditions at the reference transistor, to compensate for aging of the power transistor.

Current sense devices and associated methods

A logic level shifter interface including a string of logic components communicating between a first power domain and a second power domain; a first string of resistive components connecting a first power rail of the first power domain to a first power rail of the second power domain and having a plurality of intermediate first power rails at nodes between adjacent resistive components of the first string of resistive components; and a second string of resistive components connecting a second power rail of the first power domain to a second power rail of the second power domain and having a plurality of intermediate second power rails at nodes between adjacent resistive components of the second string of resistive components, where at least one logic component is powered by an intermediate first power rail of the first string of resistive components and an intermediate second power rail of the second string of resistive components.

Logic level shifter interface between power domains

A method for discontinuous conduction mode operation of a multi-phase DC-to-DC converter includes (a) forward biasing a first inductor being magnetically coupled to a second inductor, (b) reverse biasing the first inductor after forward biasing the first inductor, (c) while reverse biasing the first inductor and before magnitude of current through the first inductor falls to zero, forward biasing the second inductor.

DC-to-DC converters capable of discontinuous conduction mode, and associated methods

A converter includes first and second coupled inductors. A first phase includes first high side and low side switches connected to the first inductor. A second phase includes second high side and low side switches connected to the second inductor. In discontinuous conduction mode, the controller determines, in response to the first high side switch being turned on and the second low side switch being turned off, that coupling between the first and second inductors is strong or weak based on whether body diode of the second low side switch will conduct if not prevented from conducting. The controller prevents second low side switch body diode conduction in response to the first high side switch being turned on when the coupling is strong, and does not prevent second low side switch body diode conduction in response to the first high side switch being turned on when the coupling is weak.

A low-profile coupled inductor includes a magnetic core and first and second windings. The magnetic core includes first and second end flanges, a winding form element, a first outer plate, and a first leakage post. The winding form element is disposed between and connects the first and second end flanges in a first direction. The first outer plate is disposed over and faces the first and second end flanges in a second direction. The first leakage post is disposed between the winding form element and the first outer plate in the second direction. The first winding is wound around the winding form element, between the first end flange and the first leakage post, and the second winding is wound around the winding form element, between the first leakage post and the second end flange. Each of the windings is wound around a common axis extending in the first direction.

Low-profile coupled inductors with leakage control

In various embodiments described in the present disclosure, various methods and systems are introduced, that may reduce and/or eliminate the voltage spikes on the power switches by avoiding operation at zero-ripple duty ratios. In a first aspect, a method for reducing voltage spikes across switches in a multi-level converter is provided, the method comprising: receiving an error value associated with a difference between a measured output voltage and a reference output voltage; determining a target duty cycle value based at least on a control feedback loop adapted to minimize the error value; if the target duty cycle value is equal or approximately equal to one or more critical duty ratio values, controlling the operation of the multi-level converter to operate the multi-level converter with an averaging sequence, the averaging sequence adapted to, on average, result in, or sufficiently approximate, the one or more critical duty ratio values, but not operate at the one or more critical duty ratio values; and generating one or more pulse-width modulated signals to control the operation of the multi-level converter based on at least one of the target duty cycle and the averaging sequence.

Systems and methods for reducing switch stress in switched mode power supplies

A control circuit for a step-up converter includes a soft start module configured to control states of N transistor pairs of the step-up converter, where N is an integer greater than two. A driver module is in communication with the soft start module and configured to generate a first signal when N transistor pairs of the step-up converter are ready to switch. A first charging circuit is configured to charge (N-1) capacitors of the step-up converter to an input voltage of the step-up converter in response to the first signal and to generate a second signal when charging is complete. A second charging circuit is configured to sequentially charge the (N-1) capacitors of the step-up converter to (N-1) predetermined voltage values in response to the first signal and the second signal and before operation of the step-up converter begins.

Soft start systems and methods for multi-level step-up converters

The present disclosure eliminates the unwanted conduction of the body diode of the low side switch or the unwanted conduction of the low side switch in coupled phases of DC-DC converters operating in DCM to increase efficiency. Specifically, in one implementation, by detecting strong or weak coupling, the present disclosure eliminates body diode conduction in strong coupling by turning on the low side switch and eliminates negative body diode current in weak coupling by turning off the low side switch. Further, for multiphase switching DC-DC converters with coupled inductors operating at light load (i.e., in DCM), when a high side switch of a first phase is turned on, the body diode of a low side switch of a second phase is adaptively bypassed if needed, blocked by specific design, or prevented from conducting by reducing forward voltage across the body diode.

A multi-level, step-up converter circuit includes an inductor including one terminal in communication with an input voltage supply. N transistor pairs are connected in series, where N is an integer greater than one. First and second transistors of a first pair of the N transistor pairs are connected together at a node. The node is in communication with another terminal of the inductor. Third and fourth transistors of a second pair of the N transistor pairs are connected to the first and second transistors, respectively. (N&#x2212;1) capacitors have terminals connected between the N transistor pairs, respectively. An output capacitor has a terminal in communication with at least one transistor of the N transistor pair.

Multi-level step-up converter topologies, control and soft start systems and methods

A method of regulating voltage includes closing first and second switching devices during first and second periods in response to first and second signals, respectively. The first and second switching devices open and close to connect and disconnect first ends of first and second inductors of first and second phases of a voltage regulator to and from an input voltage, respectively. The method includes selectively generating one of the first and second signals when a third signal is in a first state; selectively setting the third signal to the first state based on a ramp voltage; resetting the ramp voltage to a predetermined reset voltage when the third signal transitions from a second state to the first state; maintaining the ramp voltage at the predetermined reset voltage for a predetermined ramp reset period after the resetting; and increasing the ramp voltage after the predetermined ramp reset period.

Methods for multi-phase voltage regulator control

Multi-level step-up converter topologies, control and soft start systems and  methods

A control circuit for a step-up converter includes a soft start module configured to control states of N transistor pairs of the step-up converter, where N is an integer greater than two. A driver module is in communication with the soft start module and configured to generate a first signal when N transistor pairs of the step-up converter are ready to switch. A first charging circuit is configured to charge (N&#x2212;1) capacitors of the step-up converter to an input voltage of the step-up converter in response to the first signal and to generate a second signal when charging is complete. A second charging circuit is configured to sequentially charge the (N&#x2212;1) capacitors of the step-up converter to (N&#x2212;1) predetermined voltage values in response to the first signal and the second signal and before operation of the step-up converter begins.

Soft start systems and methods for multi-stage step-up converters

A voltage regulator includes at least two phases, where each phase includes an inductor connected at one end to a load, a switching device that opens and closes to connect another end of the inductor to and from an input voltage; and a pulse generator that selectively closes the switching device. A phase manager module selectively triggers a pulse generator to close its switching device for a closed period when a third signal is in a first state. A comparator module selectively sets the third signal to the first state based on a ramp voltage. A ramp generator module maintains the ramp voltage at a predetermined reset voltage for a predetermined ramp reset period after the third signal transitions to the first state. The predetermined ramp reset period is less than a minimum value of the closed period. This allows the switching devices of multiple phases to be closed simultaneously.

Multi-phase voltage regulator control systems and methods

A coupled inductor array has length, width, and height. The coupled inductor array includes a monolithic magnetic core formed of a magnetic material having a distributed gap, and a plurality of windings embedded in the monolithic magnetic core. Each winding forms a respective winding loop of one or more turns around a respective winding axis, and each winding axis extends in the height direction. Areas of the monolithic magnetic core enclosed by the winding loops are greater than areas of the monolithic magnetic core outside of the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction. One possible application of the coupled inductor array is in a multi-phase switching power converter.

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Wellesley, MA, United States of America

Brett A Miwa