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US 8,044,611 B2Granted
LED control device
AssigneeTexas Instruments Incorporated
InventorSinichi Tanaka
Life of this patent
Estimating the term…
Abstract
An LED controller is provided that can easily control light-on testing of LEDs. A super voltage can be added to a signal including a low voltage and a high voltage. When the super voltage is not detected, LED driving circuit is operated in normal mode. When the super voltage is detected, LED driving circuit is operated in test mode. In test mode, the LEDs are turned on by a test signal directly input to LED driving circuit instead of by light emission data sent from shifter register to storage circuit. Accordingly, light-on testing of LEDs can be carried out easily.
Claims12
An apparatus comprising:
- a shift register that sequentially stores light emission data input from a data input terminal and overflows the light emission data exceeding the storage capacity;
- a switch terminal that is adapted to receive a switch voltage;
- a detector that is coupled to the switch terminal and that compares the switch voltage to a predetermined voltage;
- a plurality of current output terminals, wherein each current output terminal is adapted to be coupled to an LED;
- and
- a plurality of LED drivers, wherein each LED driver is coupled to at least one of the current output terminals and to the detector, and wherein each LED driver that includes:
- a storage circuit that is coupled to the shift register and that stores light emission data from the shift register;
- a pulse width modulation (PWM) circuit that is coupled to the storage circuit;
- a selection circuit that is coupled to the storage circuit;
- a control circuit that is coupled to PWM circuit and the selection circuit;
- and
- a variable current circuit that is coupled to the control circuit and to its associated current output terminal.
9 more elements
An apparatus comprising:
- a plurality of light emitting diode (LED) sets, wherein each set includes a plurality of LEDs;
- a plurality of LED controllers arranged in a plurality of rows, wherein each LED controller is coupled to the LEDs associated with at least one of LED sets, and wherein the LED controllers of each row are coupled in series to one another, and wherein each LED controller includes:
- a shift register that sequentially stores light emission data input from a data input terminal and overflows the light emission data exceeding the storage capacity;
- a switch terminal that is adapted to receive a switch voltage;
- a detector that is coupled to the switch terminal and that compares the switch voltage to a predetermined voltage;
- a plurality of current output terminals, wherein each current output terminal is adapted to be coupled to at least one of the LEDs;
- and
- a plurality of LED drivers, wherein each LED driver is coupled to at least one of the current output terminals and to the detector, and wherein each LED driver that includes:
- a storage circuit that is coupled to the shift register and that stores light emission data from the shift register;
- a pulse width modulation (PWM) circuit that is coupled to the storage circuit;
- a selection circuit that is coupled to the storage circuit;
- a control circuit that is coupled to PWM circuit and the selection circuit;
- and
- a variable current circuit that is coupled to the control circuit and to its associated current output terminal.
11 more elements
Dependencies are inferred from the claim text.