Current Limit Control with Current Limit Detector
AssigneeAdvanced Analogic Technologies, Inc.
InventorJohn So
Life of this patent
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Abstract
Devices, such as mobile devices, may be exposed to short circuit and output overload events. To protect against such events, mobile devices typically include circuitry to limit currents so as not to exceed a pre-programmed current limit. Various embodiments of the present invention include devices and methods for detecting pre-programmed current limits and for limiting currents in response to such detection. In some embodiments, both the current limit detector and the current limit controller circuitry include scaled current switches. The scaling may be substantially similar between the programmed-current limit detector and the current limit controller circuitry.
Claims25
A device for controlling current limits with a current limit detector, comprising:
- a current limit controller including a current switch;
- a current limit detector adapted to detect a user-defined current limit and to generate a signal associated with the user-defined current limit;
- and
- a current limit portion including an amplifier, a large scale transistor of a predetermined large scale and a small scale transistor of a predetermined small scale, wherein a ratio between the predetermined large and small scales is preset to control a ratio between a small scale current and a large scale current flowing to the small and large scale transistors, respectively, the small and large scale transistors and the current switch being responsive to the signal from the current limit detector, the amplifier being adapted to regulate the large and small scale currents in response to a control signal from the current switch.
A method for controlling current limits with a current limit detector, comprising:
- receiving, at a current limit controller, a signal from a current limit detector, the signal being associated with a user-defined current limit;
- and
- controlling a current to maintain it substantially below the user-defined current limit by regulating a large scale current and a small scale current flowing to, respectively, a large scale transistor and a small scale transistor and combining to produce the current, wherein the regulating is performed by operating one or more current switches in the current limit controller in response to the received signal.
A device for controlling current limits, comprising:
- a current switch;
- a small scale transistor of a predetermined small scale adapted to conduct a small scale current and operative to interrupt conduction of the small scale current when turned OFF;
- a large scale transistor of a predetermined large scale adapted to conduct a large scale current and operative to interrupt conduction of the large scale current when turned OFF, wherein a ratio between the predetermined large and small scales is preset to control a ratio between the small and large scale currents, the small and large scale transistors and the current switch being responsive to a signal from a current limit detector associated with a user-defined current limit;
- and
- an amplifier adapted to regulate the large and small scale currents in response to a control signal from the current switch.
Dependencies are inferred from the claim text.