Switching regulator with transient recovery circuit
First Claim
1. A method for responding to a transient output voltage in a multiphase switching regulator, the method comprising:
- comparing an output voltage with a plurality of reference voltages to generate a plurality of control voltages for respective phases of a multiphase switching regulator;
detecting changes in output current;
generating at least one inject signal when the output current changes by more than a predetermined amount within a predefined duration; and
overriding at least one of the control voltages with the inject signal to operate at least one of the phases at a predetermined duty cycle during an output voltage transient.
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Accused Products
Abstract
A transient recovery circuit in a switching regulator responds to relatively quick changes in load currents to suppress output voltage overshoots or undershoots. The transient recovery circuit operates independently of a regular feedback circuit. The transient recovery circuit can be used in a single phase or a multiphase switching regulator. In one embodiment, the transient recovery circuit overrides a control voltage from the regular feedback circuit to control the duty cycle of a pulse-width modulation circuit in the switching regulator during transient conditions. In another embodiment, the transient recovery circuit controls a dedicated transient phase in a multiphase switching regulator. The transient recovery circuit is inactive during non-transient conditions.
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Citations
10 Claims
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1. A method for responding to a transient output voltage in a multiphase switching regulator, the method comprising:
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comparing an output voltage with a plurality of reference voltages to generate a plurality of control voltages for respective phases of a multiphase switching regulator;
detecting changes in output current;
generating at least one inject signal when the output current changes by more than a predetermined amount within a predefined duration; and
overriding at least one of the control voltages with the inject signal to operate at least one of the phases at a predetermined duty cycle during an output voltage transient. - View Dependent Claims (2, 3, 4)
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5. A method of responding quickly to output transients for a multiphase switching regulator comprising:
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comparing an output voltage of the multiphase switching regulator to a reference comparing voltage;
providing a reduced-load signal to turn on a first semiconductor switch in a dedicated phase of the multiphase switching regulator to drain a portion of the output current when the output voltage is greater than the reference comparing voltage; and
providing an increased-load signal to turn on a second semiconductor switch in the dedicated phase of the multiphase switching regulator to provide additional output current when the output voltage is less than the reference comparing voltage. - View Dependent Claims (6, 7, 8, 9)
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10. A switching regulator comprising:
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means for bypassing a feedback circuit of the switching regulator in response to an overshoot in an output voltage of the switching regulator by operating the switching regulator at a first predetermined duty cycle; and
means for alternately bypassing the feedback circuit in response to an undershoot in the output voltage of the switching regulator by operating the switching regulator at a second predetermined duty cycle.
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Specification