Method and a system for producing a power supply voltage for controlling an electronic switch

• US 20020113584A1
• Filed: 01/10/2002
• Published: 08/22/2002
• Est. Priority Date: 01/10/2001
• Status: Active Grant

• Current Assignee: Legrand France SA (Legrand SA)
• Original Assignee: Legrand (Legrand SA), Legrand Snc (Legrand SA)
• Inventors: Pelletier, Laurence, Delaporte, Alain
• Granted Patent: US 6,690,150 B2
• Time in Patent Office: Days
• US Class Current: 323/324
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H03K 17/725 for ac voltages or currents H03K17/722, H03K17/735 take precedence
• CPC Class Codes: H03K 2217/0081 Power supply means, e.g. to the switch driver
• CPC Class Codes: H05B 47/10 Controlling the light source

Abstract

A direct current supply voltage for controlling an electronic switch, for example a triac, is obtained from a residual voltage at the terminals of the switch when it is conducting. The electrical energy needed to produce an auxiliary power supply voltage is taken from the terminals of the electronic switch while it is conducting. The residual voltage is rectified and stepped up, for example using a regulated switch-mode power supply circuit as a rectifier/voltage step-up system.

Claims

1. A method of producing an auxiliary power supply voltage for controlling an electronic switch connected in series with a load to a single-phase alternating current mains supply, which method uses a residual voltage drop between said terminals so that the electrical energy needed to produce said auxiliary power supply voltage while said electronic switch is conducting is taken from the terminals of said electronic switch.

2. The method claimed in claim 1 wherein said voltage drop is rectified and stepped up to obtain said auxiliary power supply voltage.

3. The method claimed in claim 1 wherein said auxiliary power supply voltage is produced from the voltage of said mains supply while said electronic switch is turned off.

4. An electronic system for controlling an electrical power supply for a load, said system including an electronic switch adapted to be connected in series with said load to supply it with power from a single phase alternating current mains supply, control means for said switch, and a first auxiliary direct current power supply circuit connected to supply power to said control means, wherein said first auxiliary direct current power supply circuit has an alternating current electrical energy input and said control means are adapted to connect said alternating current electrical energy input to said electronic switch when it is conducting.

5. The system claimed in claim 4 wherein said first auxiliary power supply circuit includes a rectifier/voltage step-up system.

6. The system claimed in claim 5 wherein said rectifier/voltage step-up system is a regulated switch mode power supply.

7. The system claimed in claim 4 wherein said control means include a connection interface between said electronic switch and said alternating current electrical energy input.

8. The system claimed in claim 7 wherein said connection interface includes an electromagnetic relay including a first switch connected between said electrical energy input and said electronic switch.

9. The system claimed in claim 4 wherein said electronic switch is a triac.

10. The system claimed in claim 8 wherein said electronic switch is a triac and said electromagnetic relay includes a second switch connected between said phase and the control electrode of said electronic switch.

11. The system claimed in claim 8 wherein said electromagnetic relay is a bistable relay.

12. The system claimed in claim 11 wherein said electromagnetic relay has two coils respectively energized by two switches forming part of a control circuit which is controlled via a user interface.

13. The system claimed in claim 4 including a second direct current auxiliary power supply circuit with its input connected to said alternating current mains supply and adapted to supply power to said control means when said electronic switch is not conducting.

14. The system claimed in claim 13 wherein said second auxiliary power supply circuit is a rectifier connected to said mains supply via a resistor and a capacitor.