LED brightness control system for a wide-range of luminance control
First Claim
1. An LED brightness control system for a wide range of luminance control, comprising:
- a brightness control module for providing a pulse width modulation (PWM) control signal and a peak current control signal;
a pulse width modulation (PWM) converter circuit for receiving said PWM control signal and converting it to a PWM signal;
a multiplier for receiving said PWM signal and said peak current control signal from said brightness control module and for multiplying the same to provide a light emitting diode (LED) current control signal with a variable “
on”
time as well as variable “
on”
level;
a voltage-controlled current source for utilizing said LED current control signal and an LED current feedback signal for providing an LED current;
an LED illuminator array for receiving said LED current; and
,a current sensing element connected to said LED illuminator array for providing an LED current feedback signal representing LED peak current,wherein said voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level.
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Accused Products
Abstract
The LED brightness control system for a wide range of luminance control includes a brightness control module that provides a pulse width modulation (PWM) control signal and a peak current control signal. A pulse width modulation (PWM) converter circuit receives the PWM control signal and converts it to a PWM signal. A multiplier receives the PWM signal and the peak current control signal from the brightness control module and multiplies the same to provide a light emitting diode (LED) current control signal with a variable “on” time as well as variable “on” level. A voltage-controlled current source utilizes the LED current control signal and an LED current feedback signal for providing an LED current. An LED illuminator array receives the LED current. A current sensing element connected to the LED illuminator array for providing an LED current feedback signal representing LED peak current. The voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level.
407 Citations
20 Claims
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1. An LED brightness control system for a wide range of luminance control, comprising:
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a brightness control module for providing a pulse width modulation (PWM) control signal and a peak current control signal; a pulse width modulation (PWM) converter circuit for receiving said PWM control signal and converting it to a PWM signal; a multiplier for receiving said PWM signal and said peak current control signal from said brightness control module and for multiplying the same to provide a light emitting diode (LED) current control signal with a variable “
on”
time as well as variable “
on”
level;a voltage-controlled current source for utilizing said LED current control signal and an LED current feedback signal for providing an LED current; an LED illuminator array for receiving said LED current; and
,a current sensing element connected to said LED illuminator array for providing an LED current feedback signal representing LED peak current, wherein said voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A head-up display (HUD) system, comprising:
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a HUD computer for providing control and data signals; an overhead unit (OHU), comprising; a communication interface for receiving said control and data signals and providing desired communication with other portions of said HUD system; an LED brightness control system, comprising; a brightness control module for providing a pulse width modulation (PWM) control signal and a peak current control signal from said control and data signals received from said communication interface; a pulse width modulation (PWM) converter circuit for receiving said PWM control signal and converting it to a PWM signal; a multiplier for receiving said PWM signal and said peak current control signal from said brightness control module and for multiplying the same to provide a light emitting diode (LED) current control signal with a variable “
on”
time as well as variable “
on”
level;a voltage-controlled current source for utilizing said LED current control signal and an LED current feedback signal for providing an LED current; an LED illuminator array for receiving said LED current; and
,a current sensing element connected to said LED illuminator array for providing an LED current feedback signal representing LED peak current, wherein said voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level; and
,an LCD driver for receiving display signals from said communication interface and for providing an LCD drive signal; an LCD for generating a display image in response to said LCD drive signal; and
,a power source for providing power to said communication interface;
LED brightness control system, LCD driver, and LCD; and
,a combiner including an ambient light sensor (ALS) that detects ambient light and sends an ambient light signal, brightness and contrast control signals to said OHU for processing. - View Dependent Claims (17, 18)
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19. A method for providing a wide range of luminance control of an LED illuminator array, comprising the steps of:
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providing a pulse width modulation (PWM) control signal and a peak current control signal; receiving said PWM control signal and converting it to a PWM signal; multiplying said PWM signal and said peak current control signal to provide a light emitting diode (LED) current control signal with a variable “
on”
time as well as variable “
on”
level;utilizing said LED current control signal and an LED current feedback signal with a voltage-controlled current source for providing an LED current; receiving said LED current with an LED illuminator array; and
,utilizing a current sensing element connected to said LED illuminator array for providing an LED current feedback signal representing LED peak current, wherein said voltage-controlled current source controls a drive voltage to the LED illuminator array at a commanded level. - View Dependent Claims (20)
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Specification