Current control circuitry and methodology for controlling current from current constrained source
AssigneeLinear Technology Corporation
InventorsRoger A. Zemke, David B. Bell, Samuel Nork, Trevor Barcelo
Life of this patent
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Abstract
Current control circuitry for controlling current supplied from a source, that may be a current-constrained source, to a load and a battery. A current limit control circuit limits current supplied by the source to the load in accord with a programmed current limit. Load current is measured, and an input charger control circuit controls magnitude of current to the battery based on the difference between measured load current and battery current programmed to be supplied to the battery, such that the sum of load current and battery current is maintained within the programmed current limit.
Claims13
Current control circuitry for controlling current supplied to a load and a battery from a source external to the battery, the circuitry comprising:
- a current limit control circuit configured for limiting current to the load from the source within a programmed current limit;
- a load current measurement circuit configured for measuring the load current from the source;
- and an input charger control circuit coupled to the load current measurement circuit and configured for controlling magnitude of current to the battery as a function of the measured load current so that the sum of the load current and the battery current is within the programmed current limit;
- and wherein the source is a universal serial bus (USB) power supply, and the load and battery constitute a USB powered device.
Current control circuitry for controlling current supplied to a load and a battery from a source external to the battery, the circuitry comprising:
- a current limit control circuit configured for limiting current to the load from the source within a programmed current limit;
- a load current measurement circuit configured for measuring the load current from the source;
- and
- an input charger control circuit configured for controlling current to the battery from the source based on programmed magnitude for the battery charge current and the measured load current magnitude, wherein
- when the source is a current constrained source whose capacity of supplying current is limited, the input charger control circuit controls magnitude of the battery charge current based on the measured load current so that the sum of the load current and the battery current is within the programmed current limit, and
- when the source is not such a current constrained source, the input charger control circuit provides to the battery the battery charge current having magnitude equivalent to the programmed magnitude.
Dependencies are inferred from the claim text.