The present invention provides a pair of input terminals to which AC voltage is input, the AC voltage being phase-controlled by a dimmer for phase-controlling AC voltage of an AC source; a damping circuit which has a resistor inserted to a position, into which input current flows from the AC source via the dimmer in series, and a capacitor and an inductor which form a closed circuit together with the AC source and the dimmer, and suppresses high-frequency vibration generated in the dimmer when a phase control element of the dimmer is turned on; and an LED lighting circuit which rectifies AC voltage phase-controlled and input via the pair of input terminals, converts DC output voltage, which is obtained by rectification, so that the voltage adapts to a load, and lights the LED.

LED lighting device and illumination apparatus

The present invention relates to a method for determining drive values for driving a lighting device at a desired brightness and color. The method comprising the steps of determining a first luminous flux weight ratio based on the desired color and a first drive current for driving each of the differently colored LEDs, determining a first luminous flux for each of the differently colored LEDs based on the desired brightness and the first luminous flux weight ratio, comparing, for each of the differently colored LEDs, the first luminous flux with a nominal luminous flux for a plurality of different drive currents, selecting, for each of the differently colored LEDs, a preferred drive current that at least can produce the first luminous flux, determining a second luminous flux weight ratio based on the desired color and the selected drive currents for each of the differently colored LEDs, determining a second luminous flux for each of the differently colored LEDs based on the desired brightness and the second luminous flux weight ratio, and determining a duty cycle for each of the differently colored LEDs at the selected drive currents, wherein the selected currents at the determined duty cycles produces the second luminous flux for each of the differently colored LEDs. The present invention provides for the possibility to limit the number of necessary computational steps for determining preferred drive currents. Furthermore, an increase in number of current level and/or differently colored LEDs would only slightly increase the computational cost.

Method and driver for determining drive values for driving a lighting device

Methods and apparatuses are disclosed that provide increased control of backlit keys for a keyboard. Some embodiments may include controllers within the keyboard that are capable of dynamically programming illumination of the keyboard based upon interaction, where each key of the keyboard may be individually programmed in a dynamic manner. For example, a spell checking function may be executing on a computer system, and as the user types various words, the keyboard may dynamically program the illumination of keyboard controllers such that the next letter of the word being typed is illuminated by the keyboard. Also, different keyboard illumination schemes may be generated based upon mouse movements by the user and/or based upon which application is currently executing.

Keyboard with increased control of backlit keys

An apparatus and method for controlling the brightness and luminance of a light, such as an LED. The embodiment may vary the brightness and luminance of the LED in a variety of ways to achieve a variety of effects. The exemplary embodiment may vary the rate at which the LED's luminance changes, such that an observer perceives the change in the LED's brightness to be smooth and linear as a function of time, regardless of the ambient light level. Changes to the LED's luminance may be time-constrained and/or constrained by a maximum or minimum rate of change.

Brightness control of a status indicator light

There are provided systems, devices and methods for operating a light source to match a white point of ambient light. In one embodiment, a light control system is provided. The light control system includes a light source and a light sensor. The light sensor is configured to operate in conjunction with the light source to provide a visual effect. A controller is electrically coupled to the light source and the light sensor and configured to determine the intensity and color of light to which the light sensor is exposed and dynamically adjust the output of the light source to match the determined intensity and color of light to which the light sensor is exposed.

White point adjustment for multicolor keyboard backlight

An LED control circuit for controlling a plurality of LEDs with different emission colors comprises a counter which increments or decrements a count value at a predetermined clock in response to a count start signal externally supplied, a signal conversion circuit which converts the count value into an analog signal displaying intensity corresponding to the count value and outputs the analog signal as an output signal, a signal generation circuit which generates, based on the output signal from the signal conversion circuit and brightness data externally specified to its corresponding LED, an analog signal displaying intensity corresponding to a product of the output signal and the brightness data, and a driving circuit which drives its corresponding LED according to the analog signal output from the signal generation circuit, to gradually and simultaneously change the brightness of the LEDs in accordance with the count value.

LED control circuit

A light emitting element control circuit comprising: a variable current generation circuit configured to generate a variable current varying in a direction of increase or in a direction of decrease; a fixed current generation circuit configured to generate a fixed current smaller than a predetermined current of a light emitting element; and a mode setting circuit configured to selectively set a first mode of prohibiting supply of the variable current and the fixed current to the light emitting element, a second mode of supplying the variable current to the light emitting element, and a third mode of supplying the fixed current to the light emitting element, for the variable current generation circuit and the fixed current generation circuit.

Light emitting element control circuit

The output voltage of a charge pump 10 is monitored by a voltage monitoring circuit. The operating current of a series regulator is restricted when the output voltage of the charge pump falls below a predetermined value. A power supply circuit is provided that is capable of effectively eliminating the decline in the output voltage of the charge pump.

Power supply circuit having a plurality of voltage conversion circuits

Disclosed is a power source circuit capable of stabilizing the output of charge pump, wherein the output voltage of charge pump (10) is monitored by a monitoring circuit (20). The operation current of the series regulator (12) is limited when the output voltage of the charge pump (10) is under a predetermined value.

Power source circuit

A power voltage of a battery (including a secondary battery) mounted on a portable device drops with use or the like of the portable device. Therefore, a step-up switching voltage regulator circuit is mounted on the portable device. On the other hand, the power voltage of the battery exceeds a voltage necessary for driving the portable device sometimes when the battery is fully charged. In this case, when the step-up switching voltage regulator circuit is driven, the power is consumed in vain, and a burden is imposed on the battery. The step-up switching voltage regulator circuit of the present embodiment switches an output in accordance with the power voltage, that is, raises the power voltage supplied from the battery to a predetermined output voltage, and outputs the output voltage, when the power voltage supplied from the battery is smaller than the predetermined output voltage; on the other hand, the step-up switching voltage regulator circuit outputs the power voltage supplied from the battery as the output voltage, when the power voltage supplied from the battery is larger than the predetermined output voltage; and consequently, in the step-up switching voltage regulator circuit, the burden on the battery mounted on the portable device can be reduced.

Step-up switching voltage regulator circuit

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