A circuit and method for controlling a switching voltage regulator having (1) a switch including one or more switching transistors and (2) an output adapted to supply current at a regulated voltage to a load including an output capacitor. The circuit and method generates a control signal to turn said one or more switching transistors OFF under operating conditions when the voltage at the output is capable of being maintained substantially at the regulated voltage by the charge on the output capacitor. Such a circuit and method increases the efficiency of the regulator circuit particularly at low average current levels.

Control circuit and method for maintaining high efficiency over broad current ranges in a switching regulator circuit

A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

Distributed Power Harvesting Systems Using DC Power Sources

A general small-signal model for current-programmed switching power stages is used for design-oriented analysis of a 150 W buck regulator and a 280 W boost regulator. The model, into which the current-programming minor feedback loop is absorbed, exposes the desired tendency towards 'constant' output current. The regulator voltage loop remains the only explicit feedback loop, allowing the regulator closed-loop properties to be easily obtained from those of the open-loop current-programmed power stage. The design-oriented analytic results allow easy inference of the effects of element changes on the regulator performance functions. Results are obtained for the regulator line-to-output transfer function (audio susceptibility) and output impedance. >

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Modeling current-programmed buck and boost regulators

Method for distributed power harvesting using DC power sources

A DC to DC converter which maintains high efficiency over broad current ranges in a current mode switching regulator circuit without changing operational mode. A low ripple voltage is maintained over the entire load range and good voltage regulation is maintained with high efficiency. This is possible because the switching frequency is adjusted in accordance with the load without changing operational states, thus making it unnecessary to define plural states of operation. The timing of turning on the switch(es) varies since the switch(es) is (are) turned on when two set (ready) signals both become ready. For fixed frequency switching applications, switching pulses from a fixed frequency oscillator as a first set signal are skipped when a second set signal is not ready. On the other hand, for a variable frequency switching scheme which is implemented by driving the switching with a one-shot having a constant OFF time, the switching pulse is created after both set signals become active. A low pass filter is also used to dynamically adjust the minimum peak inductor current and to minimize ripple voltage for low load conditions so that a smaller output capacitor may be used.

DC to DC converter with high efficiency for light loads

The output impedance of current-injection-controlled (CIC) buck regulators can be significantly reduced by deriving the current control signal from the output capacitor instead of the inductor. This technique is shown to be mathematically equivalent to CIC with load-current feedforward. Performance comparisons with normally implemented CIC and voltage control are given. >

Output impedance considerations for switching regulators with current-injected control

A multiresonant DC to DC converter which operates at a substantially fixed frequency yet maintains relatively constant efficiency levels despite wide variations in input voltage. The multiresonant converter includes a first transistor switch in series with the DC voltage supply source and the load and a second transistor switch in parallel with the DC voltage supply source and the load. The switching action of the first transistor switch is controlled as a function of the supply voltage input to the converter while the duty factor of the second transistor switch is controlled in accordance with the output voltage of the converter.

Zero-voltage-switched multiresonant DC to DC converter

The output Impedance of current-Injected controlled (CIC) buck regulators can be significantly reduced by deriving the current control signal from the output capacitor Instead of the Inductor. This technique Is shown to be mathematically equivalent to CIC with load-current feedforward. Performance comparisons with normally Implemented CIC and voltage control are given.

The authors verify the validity of applying state-space averaging and linearization to the control law of current-injected switching regulators for designs with wideband first-order open-loop responses without right-hand plane (RHP) zeros. Quantitative closed-loop performance comparisons are made of current-injected versus voltage control for the boost and buck switching regulator topologies. In buck-topology regulators, current-injected control implemented using pole cancellation, does not yield categorically better closed-loop performance than what is obtained by using lead compensated voltage control. For the boost regulator, the advantages of current-injected control are greater since lead-compensation cannot usually be used due to the duty-factor-dependent complex pole and RHP zero. >

Closed-loop performance comparisons of switching regulators with current-injected control

The validity of applying state-space averaging and linearization to the control law of current-injected switching regulators for designs with wide-band, first-order, open-loop responses without RHP zeroes is verified. Quantitative closed-loop performance comparisons are made of current-injected versus voltage control for the boost and buck switching regulator topologies.

G.K. Schoneman

Papers

Output impedance considerations for switching regulators with current-injected control

Zero-voltage-switched multiresonant DC to DC converter

Output impedance considerations for switching regulators with current-injected control

Closed-loop performance comparisons of switching regulators with current-injected control

Closed-loop performance comparisons of switching regulators with current-injected control