Circuit for connecting a low current lighting circuit to a dimmer

• US 8,664,885 B2
• Filed: 05/28/2010
• Issued: 03/04/2014
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Silergy Semiconductor (Samoa) Ltd. (Silergy Corporation)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Koolen, Gert-Jan, Zwanenberg, Victor, Bonarius, Jochem
• Primary Examiner(s): LE, DON P
• Application Number:
  US13/320,547
• Publication Number:
  US 20120056553A1
• Time in Patent Office: 1,376 Days
• Field of Search: 315/209.R, 315/224, 315/225, 315/291
• US Class Current: 315/291
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/3575 by means of dummy loads or bleeder circuits, e.g. for dimmers
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 47/10 Controlling the light source

Abstract

A circuit for connecting to a dimmer, the circuit configured to receive an input signal from the dimmer. The circuit comprises a first load and a switch. The switch is operable to automatically engage the first load at a predetermined time from a zero-crossing of the input signal and automatically disengage the first load at other times.

Claims

1. A circuit for a dimmer, the circuit configured to receive an input signal from the dimmer, the circuit comprising:

a first load; and

a switch;

wherein the switch is operable to automatically engage the first load when the input signal drops below a first threshold voltage and automatically disengage the first load when the input signal reaches zero.

2. The circuit of claim 1, wherein the input signal is derived from a generally sinusoidal mains supply signal.

3. The circuit of claim 1, wherein the first load is a resistive load.

4. The circuit of claim 1, wherein the dimmer is a trailing edge dimmer.

5. The circuit of claim 1, wherein the dimmer is a transistor dimmer.

6. The circuit of claim 1, wherein the first threshold voltage is adjustable in accordance with a dimming level of the dimmer.

7. A circuit for a dimmer, the circuit configured to receive an input signal from the dimmer, the circuit comprising:

a first load; and

a switch;

wherein the switch is operable to automatically engage the first load at a predetermined time from a zero-crossing of the input signal and automatically disengage the first load at other times; and

wherein the predetermined time is adjustable in accordance with a dimming level of the dimmer.

8. The circuit of claim 7, further comprising an in-rush current limiter being provided as a damper for the dimmer, wherein the in-rush current limiter has a limit level that is controllable in accordance with a dimming level of the dimmer.

9. A circuit for a dimmer, the circuit configured to receive an input signal from the dimmer, the circuit comprising:

a first load; and

a switch;

wherein the switch is operable to automatically engage the first load at a predetermined time from a zero-crossing of the input signal and automatically disengage the first load at other times;

a second load; and

a second switch;

wherein the second switch is operable to automatically engage the second load at a second predetermined time from a zero-crossing of the input signal, and automatically disengage the second load at other times.

10. The circuit of claim 9, wherein the second predetermined time is different from the first predetermined time.

11. The circuit of claim 9, wherein the second switch is configured to disengage the second load when the first switch engages the first load.

12. A method of operating a circuit for a dimmer, the circuit comprising a first load, the method comprising:

receiving an input signal from a dimmer;

automatically engaging the first load when the input signal drops below a first threshold voltage; and

automatically disengaging the first load when the input signal reaches zero.

13. A circuit for a dimmer, the circuit configured to receive an input signal from the dimmer, the circuit comprising:

a first load; and

a switch;

wherein the switch is operable to automatically engage the first load at a predetermined time from a zero-crossing of the input signal and automatically disengage the first load at other times; and

an in-rush current limiter being provided as a damper for the dimmer, and

wherein the in-rush current limiter has a limit level that is controllable in accordance with a dimming level of the dimmer.