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US 8,912,732 B2Granted
Current sensing for LED drivers
AssigneeMaxim Integrated Products, Inc.
InventorSuresh Hariharan
Life of this patent
Estimating the term…
Abstract
Embodiments of the present invention provide a system and method for determining a magnitude of current driving LEDs by sensing a current through a switching transistor and extracting the information of the LED current based on a relationship between the current through the switching transistor and the current driving the LEDs.
Claims20
An LED driving apparatus comprising:
- an LED driver and regulator coupled to receive an input power signal from a power source, the LED driver and regulator converts the input power signal into a regulated current signal for an LED array;
- a current sense circuit coupled to the LED driver and regulator, the current sense circuit comprises:
- a first switch that receives a first current from a low-current side of the LED array;
- and
- a second switch coupled to the first switch, the second switch carries a second current representative of but relatively smaller than the first current,
- the current sense circuit generates a control signal based on the second current;
- and
- a control block coupled to the LED driver and regulator and the current sense circuit, the control block receives the control signal and controls the regulated current signal based at least in part on the control signal.
5 more elements
An LED system comprising:
- an interface on which a power signal is received;
- an LED driver and regulator coupled to the interface and that converts the power signal into a regulated current signal;
- an LED array coupled to the LED driver and regulator, the LED array comprising a plurality of LEDs;
- a current sense circuit coupled to the LED driver and regulator, the current sense circuit comprises:
- a first switch that receives a first current from a low-current side of the LED array;
- and
- a second switch coupled to the first switch, the second switch carries a second current representative of but relatively smaller than the first current,
- the current sense circuit generates a control signal based on the second current;
- and
- a control block coupled to the LED driver and regulator and the current sense circuit, the control block receives the control signal and controls regulates the regulated current signal based at least in part on the control signal.
7 more elements
A method for regulating a current signal driving an LED array, the method comprising:
- receiving an input current from a current source;
- regulating the input current to generate a first current, the first current drives an LED array;
- sensing a second current at a low-current side of the LED array, the second current having a relationship to the first current;
- calculating a value of the first current based on a feedback signal derived from of the second current;
- and
- adjusting the regulated first current so that a power delivered to the LED array falls within a preferred power range.
3 more elements
Dependencies are inferred from the claim text.