LIGHT EMITTER DRIVING DEVICE AND LIGHTING APPLIANCE THEREWITH
First Claim
1. A light emitter driving device comprising:
- a decoder portion that monitors a rectified voltage and generates a dimming signal; and
a drive current control portion that controls a drive current for the light emitter in accordance with the dimming signal;
whereinthe decoder portion includes;
a comparator that compares the rectified voltage with a predetermined threshold voltage to generate a comparison signal;
a sampling counter that measures a high level time span and a low level time span of the comparison signal;
a duty calculation portion that calculates a duty of the rectified voltage in accordance with an output from the sampling counter;
a filter operation portion that applies a digital filter process to an output from the duty calculation portion to remove a sudden duty change; and
a dimming signal generation portion that generates the dimming signal based on an output from the filter operation portion.
1 Assignment
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Accused Products
Abstract
A light emitter driving device has a decoder portion which monitors a rectified voltage and generates a dimming signal, and a drive current control portion which controls a drive current to a light emitter according to the dimming signal. The decoder portion has a comparator which compares the rectified voltage with a predetermined threshold voltage to generate a comparison signal, a sampling counter which measures high-level and low-level periods of the comparison signal, a duty calculation portion which calculates the duty of the rectified voltage based on the output of the sampling counter, a filter calculation portion which excludes sporadic variation in duty by applying digital filtering to the output of the duty calculation portion, and a dimming signal generation portion which generates the dimming signal based on the output of the filter calculation portion.
63 Citations
12 Claims
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1. A light emitter driving device comprising:
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a decoder portion that monitors a rectified voltage and generates a dimming signal; and a drive current control portion that controls a drive current for the light emitter in accordance with the dimming signal;
whereinthe decoder portion includes; a comparator that compares the rectified voltage with a predetermined threshold voltage to generate a comparison signal; a sampling counter that measures a high level time span and a low level time span of the comparison signal; a duty calculation portion that calculates a duty of the rectified voltage in accordance with an output from the sampling counter; a filter operation portion that applies a digital filter process to an output from the duty calculation portion to remove a sudden duty change; and a dimming signal generation portion that generates the dimming signal based on an output from the filter operation portion. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A lighting appliance comprising:
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a light emitter; a rectification circuit that rectifies an a.c. voltage to generate a rectified voltage; a smoothing circuit that generates a d.c. voltage from the rectified voltage and supplies the de voltage to the light emitter; a switch device that opens/closes an electric current route in which a driving current for the light emitter flows; and a light emitter driving device that performs on/off control of the switch device; wherein the light emitter driving device includes; a decoder portion that monitors the rectified voltage and generates a dimming signal; and a drive current control portion that controls a drive current for the light emitter in accordance with the dimming signal;
whereinthe decoder portion includes; a comparator that compares the rectified voltage with a predetermined threshold voltage to generate a comparison signal; a sampling counter that measures a high level time span and a low level time span of the comparison signal; a duty calculation portion that calculates a duty of the rectified voltage in accordance with an output from the sampling counter; a filter operation portion that applies a digital filter process to an output from the duty calculation portion to remove a sudden duty change; and a dimming signal generation portion that generates the dimming signal based on an output from the filter operation portion. - View Dependent Claims (9, 10, 11, 12)
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Specification