A two-stage power converter that dynamically adjusts to output current requirements includes a first stage regulator that provides power to a second stage regulator. The first stage can be a buck converter, and the second stage can be a multiple-phase buck converter. The output voltage of the first stage (intermediate bus voltage Vbus) is varied according to the load current to optimize conversion efficiency. To provide maximum efficiency, the Vbus voltage is increased as load current increases. The Vbus voltage provided by the first stage can be varied by duty cycle or operating frequency control. In another embodiment, the switching frequency of the second stage is varied as output current changes so that output current ripple is held constant. In an embodiment employing a multiple-phase buck converter in the second stage, the number of operating phases are varied as output current changes.

Two-stage voltage regulators with adjustable intermediate bus voltage, adjustable switching frequency, and adjustable number of active phases

A supply circuit (1) comprising an inductor (2) coupled to switching means (7) and comprising a capacitor (4) is provided with an impedance (3) located between the inductor (2) and the capacitor (4) , with a current injector (5) and with a feedback loop comprising a converter (6) for controlling the current injector (5) for compensating a ripple in an output voltage across the capacitor (4) . The impedance (3) allows injection of acompensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor (4) . The converter (6) detects a detection signal via the impedance (3) by measuring a voltage across the impedance (3) or across a serial circuit comprising the impedance (3) and the capacitor (4) . The impedance (3) comprises a resistor or a further inductor.

Supply circuit with ripple compensation

Embodiments of a current sensing circuit for a multi-phase DC-DC converter are disclosed. In one embodiment, an integrated circuit (IC) may be provided that has high- and low-side switch arrays being coupled to an output terminal as well as being coupled between high and low voltage terminals. The switch arrays may also include at least one bonding pad and at least one bonding wire. The IC may also include a driver coupled to the switch arrays for driving the switch arrays and a sensing circuit that coupled to the bonding pad for detecting a signal passing through the bonding wire.

Current sensing circuit for a multi-phase DC-DC converter

A method for controlling a variable of a switching electrical circuit detects values for each of a first waveform and of a second waveform in the switching circuit at a beginning of and at a predetermined instant during a switching interval of a switching operation of the electrical circuit, both of the first and second waveforms are perturbed by the switching operation, and evaluates the variable based on the corresponding values of both the first waveform and the second waveform detected at the beginning and at the predetermined instant during the switching interval. The method further adjusts an operating point of the circuit based on a change in the variable between the two evaluations so as to maximize the variable.

Ripple correlation control based on limited sampling

Systems and techniques for performing power conversion operations in a portable device are used to convert an input voltage to a voltage at an output. The conversion operations use a two-stage conversion to convert the input voltage to a first voltage and to convert the first voltage to a second voltage. A switching frequency is altered with changes in the input voltage. The switching frequency is selected based on the input voltage level and/or to maintain a substantially consistent ripple at the output, which can correspond to the first voltage and/or the second voltage.

Power Converters Having Varied Switching Frequencies

In a method for a DC-DC power conversion performed by a switching mode buck voltage converter, the power conversion is split into two or more stages, and a feed-forward signal is generated by one of the stages and sent to another stage prior thereto. The feed-forward signal is generated by responding to a load current transient, such as output voltage drop, ON-duty increment or decrement occurred in the PWM control loop, error amp output swinging, and any other detectable signals in response to load current transient of the voltage converter. As a result, the performance of the DC-DC voltage converter is improved due to the prior stage modulated early in time, and both lower ripple current and peak current in steady state operations and fast response to load current transient conditions could be simultaneously obtained.

Jing-Meng Liu

Papers

Feed-forward method for improving a transient response for a DC—DC power conversion and DC—DC voltage converter utilizing the same