Compensation of errors in current limiters
AssigneeDialog Semiconductor (UK) Limited
InventorGuillaume de Cremoux
Life of this patent
Estimating the term…
Abstract
The present disclosure applies to peak current limitation and also to ensuring that a minimum current condition is not exceeded, that is, that the current through a component remains at or above a desired minimum level. A current limitation circuit compensates for time-induced errors by sampling and holding a current or voltage value at the time when a power switch changes state, deriving a rate of change of the electrical parameter and extrapolating the value over time. The extrapolated value is used for subsequent post-processing such as duty cycle modification of a switching mode DC-DC converter.
Claims21
A method of measuring a current through a circuit component which is coupled between an input supply and an output node, and whereby a power switch is provided which selectively couples the component with the input and/or the output;
- the method comprising:
- extracting an electrical parameter associated with the component at a time of changing the state of the power switch;
- storing information about the rate of change of the extracted electrical parameter;
- extrapolating a measured electrical parameter value based on the stored rate of change information;
- and
- determining a boundary current value based on an extrapolated electrical parameter value.
A DC-DC converter comprising an input supply;
- an output node;
- a circuit component coupled between said input supply and output node;
- a power switch which selectively couples the component with the input and/or the output;
- and a peak current detector arranged to:
- extract an electrical parameter associated with the component at a time of changing the state of the power switch;
- store information about the rate of change of the extracted electrical parameter;
- extrapolate a measured electrical parameter value based on the stored rate of change information;
- and determine a boundary current value based on an extrapolated electrical parameter value.
A current detector circuit comprising:
- an extraction module arranged to extract an electrical parameter associated with a circuit component;
- a slope extractor module arranged to store information about the rate of change of the extracted electrical parameter and to extrapolate a measured electrical parameter value based on the stored rate of change information;
- a converter module arranged to determine a boundary current value based on an extrapolated electrical parameter value.
Dependencies are inferred from the claim text.