Circuits and methods for synchronizing non-constant frequency switching regulators with a phase locked loop
AssigneeLinear Technology Corporation
InventorsChristopher B. Umminger, Randy G. Flatness
Life of this patent
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Abstract
Methods for synchronizing non-constant frequency switching regulators with a phase locked loop are disclosed. The methods enable non-constant frequency switching regulators to be synchronized with a phase locked loop to achieve constant frequency operation in steady state while retaining the advantages of non-frequency operation to improve transient response and operate over a wider range of duty cycles. In addition, the methods enable multiple non-constant frequency regulators to be synchronized and operated in parallel to deliver higher power levels to the output than a single switching regulator.
Claims73
A method for synchronizing a non-constant frequency switching regulator that generates a regulated voltage output at an output node, the method comprising:
- providing a source voltage at an input node;
- providing control circuitry coupled to the output node that controls the duty cycle of the switching regulator;
- and
- providing a phase locked loop comprising a phase detector circuitry to control a parameter of the switching regulator, causing the switching frequency of the switching regulator to be constant.
A method for synchronizing a plurality of non-constant frequency switching regulators, the method comprising:
- providing a source voltage at a plurality of input nodes;
- providing a regulated voltage at a plurality of output nodes;
- providing control circuitry coupled to the plurality of output nodes to control the duty cycles of the plurality of regulators;
- and
- providing a plurality of phase locked loops, each phase locked loop from the plurality of phase locked loops coupled between a first and a second switching regulators selected from the plurality of switching regulators, wherein each phase locked loop comprises phase detector circuitry to control the on-time of the first switching regulator, causing the switching frequency of the first and second switching regulators to be equal.
A method for adjusting the switching frequency of a non-constant frequency switching regulator, the method comprising:
- providing a one shot timer in the switching regulator comprising ION and VON inputs and an output to control the duty cycle of the switching regulator;
- providing a phase locked loop connected to the ION or VON input and the output of the one shot timer to control the on-time of the one shot timer, causing the steady state switching frequency of the switching regulator to be constant.
A circuit for adjusting the switching frequency of a non-constant frequency switching regulator having a one shot timer comprising ION and VON inputs and an output to control the duty cycle of the switching regulator, the one shot timer coupled between an input voltage and a regulated output voltage, the circuit comprising:
- a phase locked loop connected to the ION or VON input and the output of the one shot timer to control the on-time of the one shot timer, causing the steady state switching frequency of the switching regulator to be constant.
A circuit for synchronizing a plurality of non-constant frequency switching regulators, each switching regulator from the plurality of switching regulators having a one shot timer comprising ION and VON inputs and an output to control the duty cycle of the switching regulator, the one shot timer coupled between an input voltage and a regulated output voltage, the circuit comprising:
- a plurality of phase locked loops, each phase locked loop from the plurality of phase locked loops coupled between the one shot timer of a first switching regulator and the one shot timer of a second switching regulator selected from the plurality of switching regulators, wherein each phase locked loop controls the on-time of the first switching regulator, causing the switching frequency of the first and second switching regulators to be equal.
Dependencies are inferred from the claim text.