Current mode control DC-DC converter with single step load transient response
AssigneeVirginia Tech Intellectual Properties, Inc.
InventorsVirginia Li, Pei-Hsin Liu, Qiang Li, Fred C. Lee
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Abstract
A power converter using constant on-time (COT) or ramp pulse modulation (RPM) control achieves more rapid resumption of steady-state operation after a step-up load transient by extending an on-time of a switching pulse by interrupting a ramp voltage waveform that is compared with a threshold that equals a threshold voltage at the termination of a switching pulse or increasing a voltage with which the ramp voltage is compared. These techniques are applied to both single-phase and multi-phase power converters.
Claims20
A power converter comprising
- a pulse generator for generating switching pulses for controlling duration of connection of said power converter to a power source based on a comparison of an output voltage of said power converter with a reference voltage,
- a circuit for developing a control voltage corresponding to a combination of signals representing a reference voltage, output voltage and inductor current of said power converter,
- a detector receiving a threshold voltage bounding said control voltage during steady-state operation of said power converter for determining when said control voltage corresponding to said combination of threshold voltage, output voltage and inductor current of said power converter represents a step-up load transient by comparison of said control voltage with said threshold voltage, and
- a control circuit responsive to an output of said detector for maintaining a switching pulse state from said pulse generator and connection of said power converter to said power source for a duration that said output of said detector indicates said step-up load transient.
A method of operating a power converter, said method comprising steps of
- generating pulses for controlling a switch to connect said power converter to a power source,
- detecting a duration of a step-up load transient in said power converter, and
- extending a pulse for controlling said switch for said duration of said step-up load transient wherein said extending step is performed by substituting a high voltage for a threshold voltage for comparison with a ramp voltage for a duration of said step-up load transient to terminate said pulse.
A method of operating a power converter, said method comprising steps of
- generating pulses for controlling a switch to connect said power converter to a power source,
- detecting a duration of a step-up load transient in said power converter, and
- extending a pulse for controlling said switch for a said duration of said step-up load transient wherein said extending step is performed by interrupting a ramp voltage generated concurrently with said pulses during steady state operation.
Dependencies are inferred from the claim text.