Switching converter for lighting with light intensity as feedback and light emitting apparatus using the same

• US 7,965,048 B2
• Filed: 10/16/2008
• Issued: 06/21/2011
• Est. Priority Date: 10/16/2008
• Status: Active Grant

• Current Assignee: Capella Microsystems, Corp.
• Original Assignee: Capella Microsystems, Corp.
• Inventors: Shih, Cheng-Chung, Lin, Yuh-Min
• Primary Examiner(s): Le; Don P
• Application Number:
  US12/252,699
• Publication Number:
  US 20100097009A1
• Time in Patent Office: 978 Days
• Field of Search: 315/127, 315/294, 315/297
• US Class Current: 315/297
• CPC Class Codes: H05B 45/12 using optical feedback

Abstract

A light emitting apparatus comprises a light emitting element and a switching converter comprising a conversion circuit for converting an operating electric signal to generate the driving electric signal, a feedback circuit having a light detecting element for detecting a luminous intensity of the light emitting element and generating a feedback signal, and a control circuit for receiving the feedback signal, comparing the received feedback signal with a reference electric signal, and controlling the conversion circuit based on comparison results to adjust the driving electric signal. Alternatively, the light detecting element detects ambient light and the control circuit controls the conversion circuit based on comparison results to stop or enable outputting of the driving electric signal.

Claims

1. A switching converter for lighting with light intensity as feedback, comprising:

a conversion circuit capable of converting an operating electric signal to generate an output electric signal;

a feedback circuit including a light detecting element capable of detecting an external light to generate a feedback signal; and

a control circuit capable of receiving the feedback signal, and comparing the received feedback signal with a reference electric signal, and controlling the conversion circuit based on comparison results to adjust the output electric signal;

wherein the conversion circuit of the switching converter is a voltage-current converter, the operating electric signal is a voltage signal, and the output electric signal is a current signal.

2. The switching converter as claimed in claim 1, wherein the switching converter is a voltage converter, and the operating electric signal and the output electric signal each are a voltage signal.

3. The switching converter as claimed in claim 1, wherein the control circuit comprises at least a PWM signal generating circuit and a switching element.

4. The switching converter as claimed in claim 1, wherein the light detecting element comprises a silicon photodiode or a CdS photoresistor.

5. A light emitting apparatus, comprising:

a light emitting element capable of receiving a driving electric signal to thereby emit light; and

a switching converter comprising;

a conversion circuit capable of converting an operating electric signal to generate the driving electric signal;

a feedback circuit including a light detecting element capable of detecting a luminous intensity of light emitted from the light emitting element and generating a feedback signal; and

a control circuit capable of receiving the feedback signal, and comparing the received feedback signal with a reference electric signal, and controlling the conversion circuit based on comparison results to adjust the driving electric signal;

wherein the conversion circuit of the switching converter is a voltage-current converter, the operating electric signal is a voltage signal, and the output electric signal is a current signal.

6. The light emitting apparatus as claimed in claim 5, wherein the switching converter is a voltage converter, and the operating electric signal and the output electric signal each are a voltage signal.

7. The light emitting apparatus as claimed in claim 5, wherein the control circuit comprises at least a PWM signal generating circuit and a switching element.

8. The light emitting apparatus as claimed in claim 5, wherein the light detecting element comprises a silicon photodiode or a CdS photoresistor.

9. The light emitting apparatus as claimed in claim 5, wherein the light emitting element comprises a light emitting diode (LED) or a cold cathodic fluorescent lamp (CCFL).

10. A light emitting apparatus, comprising:

a light emitting element capable of receiving a driving electric signal to thereby emit light beams;

a switching converter comprising;

a conversion circuit capable of converting an operating electric signal to generate the driving electric signal;

a feedback circuit including a light detecting element capable of detecting a luminous intensity of ambient light and generating a feedback signal; and

a control circuit capable of receiving the feedback signal, and comparing the received feedback signal with a reference electric signal, and controlling the conversion circuit based on comparison results to stop or enable outputting of the driving electric signal;

wherein the conversion circuit of the switching converter is a voltage-current converter, the operating electric signal is a voltage signal, and the output electric signal is a current signal.

11. The light emitting apparatus as claimed in claim 10, wherein the switching converter is a voltage converter, and the operating electric signal and the output electric signal each are a voltage signal.

12. The light emitting apparatus as claimed in claim 10, wherein the control circuit comprises at least a PWM signal generating circuit and a switching element.

13. The light emitting apparatus as claimed in claim 10, wherein the light detecting element comprises a silicon photodiode or a CdS photoresistor.

14. The light emitting apparatus as claimed in claim 10, wherein the light emitting element comprises a light emitting diode (LED) or a cold cathodic fluorescent lamp (CCFL).