Method for controlling a power stage
AssigneeIDT Europe GmbH
InventorsAnthony Kelly, Adrian Ward
Life of this patent
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Abstract
In a control method for a power converter, an output voltage is generated according to a control law controlling a switched power stage. During ramp up of the power converter, at least one parameter of the power stage is identified, and the control law is adapted to the identified at least one parameter of the power stage for operating the power converter.
Claims11
A control method for a power converter wherein an output voltage is generated according to a control law controlling a switched power stage, wherein during a soft start ramp up of the power converter prior to the output voltage reaching its desired set-point at least one parameter of the power stage is identified and wherein said control law is adapted to said identified at least one parameter of said power stage for operating said power converter,
- wherein said control law is defined by a transfer function having a plurality of zeros and poles,
- wherein the power stage comprises an inductor and an output capacitor and wherein the parameter of the power stage to be identified is the capacitance C or the ESR of the output capacitor or the inductance of the output inductor,
- wherein the plurality of zeros and poles of said transfer function is determined on the basis of a expected value for the capacitance C or the ESR or the inductance,
- wherein the capacitance C is determined by measuring an average inductor current iL,AVG during ramp up time Δt and a voltage drop of said capacitance C at the start of the ramp up and at the end of the ramp up and computing C=iL,AVG*Δt/ΔV, wherein ΔV is the difference between the voltage drop of said capacitance C between the start of the ramp up and the end of the ramp up, and
- wherein the average inductor current iL,AVG is corrected by measuring the average inductor current when ramp up has finished and subtracting said average inductor current measured after ramp up from the average inductor current during ramp up.
A power converter comprising a switched power stage controlled by a control law implemented by a compensator, means for identifying at least one parameter of said power stage during a soft start ramp-up of the power converter prior to the output voltage reaching its desired set-point and means for adapting the control law of the compensator according to the identified at least one parameter of said power stage, wherein the means for adapting the control law comprise means for adapting, means for normalizing and means for scaling a parameter of the control law,
- wherein said control law is defined by a transfer function having a plurality of zeros and poles,
- wherein the power stage comprises an inductor and an output capacitor and wherein the parameter of the power stage to be identified is the capacitance C or the ESR of the output capacitor or the inductance of the output inductor,
- wherein the plurality of zeros and poles of said transfer function is determined on the basis of a expected value for the capacitance C or the ESR or the inductance,
- wherein the capacitance C is determined by measuring an average inductor current iL,AVG during ramp up time Δt and a voltage drop of said capacitance C at the start of the ramp up and at the end of the ramp up and computing C=iL,AVG*Δt/ΔV, wherein ΔV is the difference between the voltage drop of said capacitance C between the start of the ramp up and the end of the ramp up, and
- wherein the average inductor current iL,AVG is corrected by measuring the average inductor current when ramp up has finished and subtracting said average inductor current measured after ramp up from the average inductor current during ramp up.
Dependencies are inferred from the claim text.