Illumination controlling circuit and illumination system

• US 8,716,951 B2
• Filed: 06/25/2012
• Issued: 05/06/2014
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Lextar Electronics Corporation
• Original Assignee: Lextar Electronics Corporation
• Inventors: Chen, Chun-Kuang, Chen, Hui-Ying, Chen, Po-Shen, Lin, Feng-Ling
• Primary Examiner(s): Le, Tung X
• Application Number:
  US13/531,603
• Publication Number:
  US 20130147354A1
• Time in Patent Office: 680 Days
• Field of Search: 315/119, 315/246, 315/247, 315/291, 315/294, 315/297, 315/299, 315/300, 315/306, 315/307, 315/308
• US Class Current: 315/291
• CPC Class Codes: H05B 39/044 continuously H05B39/042 takes precedence
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The invention discloses an illumination controlling circuit coupled between a household electricity input and an illumination lamp. The illumination controlling circuit includes a dimmer module, a sampling-and-holding circuit, a differential circuit, an integrator circuit and a clamping circuit. The dimmer circuit is used for generating a dimming signal which includes a plurality of waveform pulses. The sampling-and-holding circuit samples from the dimming signal, so as to obtain an average waveform pulse. The differential circuit is used for extracting a voltage difference of the average waveform pulse. The integrator circuit performs integration on the average waveform pulse according to the voltage difference, so as to generate a direct current voltage signal. When a level of the direct current voltage signal exceeds a threshold voltage level of the clamping circuit, the direct current voltage signal is used for driving the illumination lamp.

Claims

1. An illumination controlling circuit, coupled between a household electricity input and an illumination lamp, the illumination controlling circuit comprising:

a dimming module, coupled with the household electricity input, configured for modulating an alternating current input signal from the household electricity input and generating a dimming signal, the dimming signal comprising a plurality of waveform pulses;

a sampling-and-holding circuit, coupled with the dimming module, configured for continuously sampling the waveform pulses of the dimming signal to obtain an average waveform pulse from sampled waveform pulses;

a differential circuit, coupled with the sampling-and-holding circuit, configured for extracting a voltage difference of the average waveform pulse;

an integrator circuit, coupled with the differential circuit, configured for performing integration on the average waveform pulse according to the voltage difference, so as to generate a direct current voltage signal; and

a voltage-clamping circuit, coupled between the integrator circuit and the illumination lamp, having a threshold voltage level, the voltage-clamping circuit applying the direct current voltage signal to the illumination lamp so as to light up the illumination lamp when a level of the direct current voltage signal exceeds the threshold voltage level of the clamping circuit.

2. The illumination controlling circuit as claimed in claim 1, wherein the respective waveform pulses of the dimming signal have a conduction angle which is adjustable.

3. The illumination controlling circuit as claimed in claim 2, wherein the conduction angle, the level of the direct current voltage signal is in proportion to a luminance of the illumination lamp.

4. The illumination controlling circuit as claimed in claim 1, wherein the voltage-clamping circuit blocks the direct current voltage signal to turn off the illumination lamp when the level of the direct current voltage signal is below the threshold voltage level of the clamping circuit.

5. An illumination system, coupled with a household electricity input, the illumination system comprising:

an illumination lamp emitting light with a luminance according to an operative current flowing through the illumination lamp; and

an illumination controlling circuit, coupled with the household electricity input, the illumination controlling circuit comprising;

a dimming module, coupled with the household electricity input, configured for modulating an alternating current input signal from the household electricity input and generating a dimming signal, the dimming signal comprising a plurality of waveform pulses;

a sampling-and-holding circuit, coupled with the dimming module, configured for continuously sampling the waveform pulses of the dimming signal to obtain an average waveform pulse from sampled waveform pulses;

a differential circuit, coupled with the sampling-and-holding circuit, configured for extracting a voltage difference of the average waveform pulse;

an integrator circuit, coupled with the differential circuit, configured for performing integration on the average waveform pulse according to the voltage difference, so as to generate a direct current voltage signal; and

a voltage-clamping circuit, coupled between the integrator circuit and the illumination lamp, having a threshold voltage level, the voltage-clamping circuit applying the direct current voltage signal to the illumination lamp so as to light up the illumination lamp when a level of the direct current voltage signal exceeds the threshold voltage level of the clamping circuit, wherein the operative current flowing through the illumination lamp is correspondingly varied with the level of the direct current voltage signal.

6. The illumination system as claimed in claim 5, wherein the respective waveform pulses of the dimming signal have a conduction angle which is adjustable.

7. The illumination system as claimed in claim 6, wherein the conduction angle, the level of the direct current voltage signal is in proportion to a luminance of the illumination lamp.

8. The illumination system as claimed in claim 5, wherein the voltage-clamping circuit blocks the direct current voltage to turn off the illumination lamp when the level of the direct current voltage signal is below the threshold voltage level of the clamping circuit.

9. The illumination system as claimed in claim 5, wherein the illumination lamp further comprises a switch unit, a lamp driver and a light-emitting load, wherein a first end of the switch unit is coupled to the voltage-clamping circuit;

a second end of the switch unit is coupled to the light-emitting load;

the lamp driver is coupled between a third end of the switch unit and the light-emitting load; and

the switch unit selectively couples the first end to the second end or the third end.

10. The illumination system as claimed in claim 9, wherein the switch unit, under a dimming mode, couples the first end to the second end for applying the direct current voltage signal onto the light-emitting load, and the switch unit, under a non-dimming mode, couples the first end to the third end for applying the direct current voltage signal to the lamp driver, such that the lamp driver generates an operative current with a fixed current value to the light-emitting load.