Alpha and Omega Semiconductor (cayman) Ltd.

Idt Europe Gmbh

Alpha and Omega Semiconductor International LP

Chris M Young

Amir Babazadeh

Eric Marschalkowski

Richard Schmitz

Kevin Finke

Cameron Jue

Tom Udd

Emmett Barton

Richard Maria Schmitz

Demetri Giannopoulos

N Tim Salazar

Apparatus and associated methods relate to dynamic bandwidth control of a variable frequency modulation circuit by selective contribution of a crossover frequency tuning engine (XFTE) in response to a transient in a switching frequency. In an illustrative example, the XFTE may generate a transient control signal (C) in response to a transient in a control output signal (C) indicative of switching frequency and received from a feedback control circuit. The XFTE may generate C, for example, according to a predetermined relationship between a crossover frequency and the switching frequency of the modulation circuit. The feedback control circuit may, for example, generate Cfrom a predetermined reference and a control input signal. Cmay, for example, correspond to a pulse-width modulated output delivered to a load through an inductor. Various embodiments may advantageously increase the effective bandwidth of the modulation circuit while maintaining desired frequency response characteristics.

High bandwidth constant on-time PWM control

Apparatus and associated methods relate to dynamic bandwidth control of a variable frequency modulation circuit by selective contribution of a crossover frequency tuning engine (XFTE) in response to a transient in a switching frequency. In an illustrative example, the XFTE may generate a transient control signal (C) in response to a transient in a control output signal trans, (C) indicative of switching frequency and received from a feedback control circuit. The XFTE may generate C, for example, according to a predetermined relationship between a crossover frequency and the switching frequency of the modulation circuit. The feedback control circuit may, for example, generate Cfrom a predetermined reference and a control input signal. Cmay, for example, correspond to a pulse-width modulated output delivered to a load through an inductor. Various embodiments may advantageously increase the effective bandwidth of the modulation circuit while maintaining desired frequency response characteristics.

Apparatus and associated methods relate to providing an integrated circuit package having (a) a bypass circuit in parallel with an inductor and (b) a logic circuit configured to control the bypass circuit for conductivity modulation. In an illustrative example, in response to a corresponding load transient, the logic circuit may include a state machine configured to generate different control signals for the bypass circuit to control the timing and/or quantity of energy transfer from the inductor to a load. The bypass circuit may include a first semiconductor switch and a second semiconductor switch connected in anti-series. In some implementations, the power stage and the bypass circuit may be operated, for example, in numerous operational modes to dynamically modulate conductivity across the terminals of the inductor in a power supply to advantageously result in a smaller undershoot and overshoot.

Methods and apparatuses for auxiliary transient control system

Apparatus and associated methods relate to providing a power stage having an auxiliary power switch coupled to a high-side switch or a low-side switch in parallel and turning on the auxiliary power switch earlier than turning on the high-side switch. In an illustrative example, the auxiliary power switch may be connected with the high-side switch in parallel. The on-resistance of the auxiliary power switch may be greater than the on-resistance of the high-side switch. A gate drive engine may be configured to generate gate driving signals for the switches in the power stage such that the auxiliary power switch is turned on a predetermined time duration earlier than the high-side switch. Thus, the ringing at a switch node of the power stage may be advantageously reduced or eliminated.

Switch circuit with reduced switch node ringing

A system power monitor circuit and method implemented in a system including multiple power supplies measures and scales the power supply output current value at each power supply as a ratio of the power supply output voltage and a reference voltage. Scaled power supply output current values are combined to provide a single system current signal that is referenced to the same reference voltage value being the system voltage signal. The system power is determined from the system current signal and the system voltage signal. In some embodiment, a power supply output voltage of a selected power supply is used as the reference voltage.

System power monitor

Apparatus and associated methods relate to providing a piecewise loadline having a number of segments with different slopes and selecting a segment of the piecewise loadline based on an output current of a power supply. In an illustrative example, the piecewise loadline may include a segment that has a negative slope. When the output current is less than a predetermined threshold, the segment with the negative slope may be selected to improve power efficiency. In some embodiments, the piecewise loadline may have several segments with different positive slopes. Different segments may be selected to make the load work in different modes. For example, by selecting an overcurrent loadline, the load (e.g., a processor) may be informed to throttle back its performance. Having a piecewise loadline may allow independent optimization of the loadline resistances, voltage thresholds, and current limits.

Voltage regulator with piecewise linear loadlines

Some apparatus and associated methods relate to conductivity modulation apparatus for active operations with an inductive element in a packaged circuit module formed with a bypass switch for configuration in parallel with an inductor. In an illustrative example, the bypass switch may be a controllable bidirectional switch formed of, for example, two anti-series connected MOSFETs. In some embodiments, the packaged module may include a main switch and/or a freewheeling rectifier (e.g., synchronous rectifier) operable as a buck-derived switched mode power supply. The bypass switch may, in operation, selectively circulate inductor current through the bypass switch, for example, to control the timing and/or quantity of energy transfer from the inductor to a load. In some implementations, the bypass switch may be operated, for example, to dynamically modulate conductivity across the terminals of an inductor in a buck-derived switched mode power supply to enhance circuit performance in numerous operational modes.

Inductor with bypass switch

Apparatus and associated methods relate to modulating the frequency of a switch signal to achieve a fast transient response while holding the average frequency constant over a predetermined number of N cycles. In an illustrative example, a quantum charge modulator may include a compensation processor configured to compensate an error signal and generate a compensation signal by performing operations to maintain an average switching frequency over the N cycles in response to the transient. The compensation signal may be a function of a real phase deviation &#x394;Tbetween a stable pulse modulated signal having a cycle period Tbefore the transient and a measured pulse modulated signal having a cycle period Tafter the transient. A forgetting factor may be used to calculate the phase deviations. The quantum charge modulator may provide a compensation free, stable, and high performance response over power stage component changes.

Methods and apparatuses for stable control in power converters

Some apparatus and associated methods relate to a three quarter bridge (TQB) applied across an output inductor of a buck-derived power converter, the TQB operated in a first mode such that when a high-side switch of the power converter is turned on, the TQB configured to pass a first controlled current to combine with a first output inductor current to a load, the TQB configured to control the first controlled current to minimize a negative voltage transient on the load, the TQB operated in a second mode such that when the high-side switch of the power converter is turned off the TQB configured to divert a second controlled current away from the load and to circulate the second controlled current through the output inductor, the TQB configured to control the second controlled current to minimize a positive voltage transient on the output of the power converter.

Three quarter bridge for buck-derived switch-mode power supplies

Thermal immersion circulator

Some apparatus and associated methods relate to a buck-derived switched mode power supply with three-quarter bridge (TQB) formed with a bypass switch in parallel with an inductor. In an illustrative example, the bypass switch may be configured to, in response to a decrease in average load demand, operate in a first mode to turn on the bypass switch to selectively circulate inductor current through the bypass switch while a high-side switch and a low-side switch are off. In a second mode, the bypass switch may be turned off to circulate the inductor current through, for example, an output capacitor and the low-side switch. In some implementations of the TQB, the bypass switch may be operated, for example, to selectively transfer a controlled amount of energy stored in the inductor to the output capacitor in response to a decrease in average load demand.

Multifunction three quarter bridge

Some apparatus and associated methods relate to a buck-derived switched mode power supply with constant on-time and configured to substantially maintain a steady-state average switch period in a time interval between a start of a load transient and the time when the inductor current returns to a steady state. In an illustrative example, the time interval may include a first and a second predetermined number of cycles after the start of the load transient. The switch period may be modulated, for example, by an amount calculated to supply a change in additional energy demand in the first number of cycles and an opposite amount in the subsequent second number of cycles calculated to maintain the average steady-state switch period over the time interval. In various examples, maintaining average switching period with constant on-time may minimize transient response times without sacrificing stability and without the need for complex compensation networks.

Self-stabilized constant on-time control

Methods and apparatus relate to a minimizing ripple in a polyphase power supply by modulating a voltage pre-regulator output setpoint to minimize ripple performance. In an illustrative example, the modulation may include incrementally adjusting the pre-regulator output setpoint supplied, for example, to a multiphase controller. Some examples may reverse the increment direction in response to determining that the prior incremental adjustment yielded increased ripple. Each phase of the polyphase power supply may include a buck-derived switch-mode power supply connected, for example, to a common output node. Various embodiments may advantageously maximize reduce bulk capacitance requirements for active loads by dynamically seeking a duty cycle of the polyphase power supply with substantially minimal ripple.

Switched-mode ripple optimization

A switched power converter includes a power stage for generating an output voltage according to a switching signal and an input voltage via a switching element. The switching signal is generated by a variable timing generator which is controlled by a compensator. The pulses of the switching signal are generated on a 'need to have basis'. Hence, theses pulses may be generated independently of a PWM period. The pulses can be generated such that switching losses are minimized. A switching pattern can be matched to the load current pattern. Thus, the behavior of the compensator can be synchronized to a regular pattern of the load current. A high resolution variable timing generator may be employed.

Non PWM digital DC-DC converter

A switched power converter includes a switchable power stage for generating an output voltage according to a switching signal and an input voltage via a switching element. The switching signal is generated by a multi-mode controller. The multi-mode controller controls a digital control path for generating a pulse width modulation switching signal and a constant-on-time control path for generating a constant-on-time switching signal. The switching signal for controlling the switching element is generated in the digital control path when the multi-mode controller is run in a high load mode. The switching signal is generated in the constant-on-time control path when the multi-mode controller is run in a light load mode.

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Round Rock, TX, United States of America

Chris M Young