Adaptive power control for hysteretic regulators
AssigneeLinear Technology Corporation
InventorDavid Salerno
Life of this patent
Estimating the term…
Abstract
A hysteretic regulator may be set to an active mode when voltage at an output falls to a first threshold level. In the active mode, charge is applied to an output node by a current having a set limit value. The regulator is set to an inactive mode when the voltage at the output node rises to a second threshold level. The current limit value is automatically adjusted as a function of average regulator current. An indication of average regulator current may be obtained by charging a sense capacitor during the active mode and discharging the sense capacitor during the inactive mode. The voltage of the sense capacitor, which is representative of the average regulator current, is used to generate an offset adjustment applied to a regulator controller.
Claims17
A method for controlling a DC/DC regulator comprising the steps of:
- setting the regulator to an active operational mode in which charge is applied to an output node of the regulator by a current having a set limit value when the voltage at the output falls to a first threshold level;
- setting the regulator to an inactive operational mode when the voltage at the output node rises to a second threshold level;
- and
- automatically adjusting the current limit value as a function of a duty cycle of the operational modes.
A method for controlling a DC/DC regulator comprising the steps of:
- setting the regulator to an active operational mode in which charge is applied to an output node of the regulator by a current having a set limit value when the voltage at the output falls to a first threshold level;
- setting the regulator to an inactive operational mode when the voltage at the output node rises to a second threshold level;
- and
- automatically adjusting the current limit value as a function of a characteristic of regulator current.
A DC/DC regulator having an input node coupled to a power source and an output node coupled to a load, the converter comprising:
- an inductor;
- an output capacitor;
- a power controller coupled to the converter input and to the inductor, the power controller configured to assume an active operational mode to apply charge to the capacitor via current through the inductor in response to the output voltage falling to a first threshold level, and to assume an inactive operational mode in response to the output voltage rising to a second threshold level, the active mode current limited to a set value;
- and
- an adjustment controller coupled to the power controller for adjusting the current limit value as a function of average load current.
Dependencies are inferred from the claim text.