Electronic control systems and methods

• US 7,859,815 B2
• Filed: 04/05/2010
• Issued: 12/28/2010
• Est. Priority Date: 07/06/2001
• Status: Expired due to Fees

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Leichliter, Shawn L., Black, Richard L, Wu, Chenming, Johnson, Benjamin Aaron, Newman, Robert C. Jr.
• Primary Examiner(s): Nguyen; Danny
• Application Number:
  US12/754,266
• Publication Number:
  US 20100231055A1
• Time in Patent Office: 267 Days
• Field of Search: 361/170, 361/173, 361/174, 307/116, 307/131, 307/139, 315/291
• US Class Current: 361/173
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 5/293 using semiconductor devices only
• CPC Class Codes: H02M 7/538 in a push-pull configuration H02M7/5375 takes precedence ; with oscillating arrangements H02M7/53832, H02M7/53846
• CPC Class Codes: H03K 17/00 Electronic switching or gating, i.e. not by contact-making and –breaking gated amplifiers H03F3/72; switching arrangements for exchange systems using static devices H04Q3/52
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches
• CPC Class Codes: H03K 17/6874 in a symmetrical configuration
• CPC Class Codes: H03K 2017/0806 against excessive temperature
• CPC Class Codes: H03K 3/00 Circuits for generating electric pulses; Monostable, bistable or multistable circuits H03K4/00 takes precedence; for digital function generators in computers G06F1/02
• CPC Class Codes: H05B 39/048 with reverse phase control
• CPC Class Codes: H05B 39/08 by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices in converters H02M5/00; with regulation G05F1/44
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs'"'"' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared. Lockout circuitry is used to prevent one protection circuit from tripping after the other circuit has already tripped from a fault condition. The protection circuitry output is desirably configured such that it can bypass and override the normal turn on and turn off impedance and act virtually directly on the gates of the MOSFETs. Preferably, the system has a high efficiency switching type power supply in parallel with a low frequency controllably conductive device.

Claims

1. An electronic control system automatically operable in a two wire mode and a three wire mode, the system comprising:

a hot terminal;

a neutral terminal; and

a detector coupled to the hot terminal and to the neutral terminal for sensing whether there is a neutral wire connection to the electronic control system, the detector comprising a hot zero cross detector coupled to the hot terminal to generate a hot zero cross detection signal and a neutral zero cross detector coupled to the neutral terminal to generate a neutral zero cross detection signal, the hot zero cross detection signal and the neutral zero cross detection signal responsive to the sensing to automatically determine whether to operate the electronic control system in a selected one of the two wire mode and the three wire mode.

2. The system of claim 1, further comprising a microprocessor coupled to the detector to monitor an output signal and to select between the two wire mode and the three wire mode responsive to the output signal.

3. The system of claim 1, wherein the electronic control system is connectable to a power supply and a load, the system further comprising:

a dimmed hot terminal connectable to the load,

wherein the hot terminal is connectable to a hot wire of the power supply, and

wherein the neutral terminal is connectable to a neutral wire of the power supply.

4. The system of claim 3, wherein the electronic control system operates in the two wire mode when there is not a neutral wire connection to the neutral terminal such that current flows between the hot terminal and the dimmed hot terminal and does not flow to the neutral terminal in the two wire mode, and wherein the electronic control system operates in the three wire mode when there is a neutral wire connection to the neutral terminal such that current flows to the neutral terminal in the three wire mode.

5. The system of claim 3, wherein the electronic control system operates in the two wire mode when there is not a neutral wire connection to the neutral terminal such that current flows between the hot terminal and the dimmed hot terminal and does not flow to the neutral terminal in the two wire mode.

6. The system of claim 5, wherein the power supply operates in one of the two wire mode or the three wire mode.

7. The system of claim 5, wherein the power supply is operable only in the two wire mode.

8. The system of claim 3, wherein the electronic control system operates in the three wire mode when there is a neutral wire connection to the neutral terminal such that current flows to the neutral terminal in the three wire mode.

9. The system of claim 8, wherein the power supply operates in one of the two wire mode or the three wire mode.

10. The system of claim 8, wherein the power supply is operable only in the three wire mode.

11. An electronic control system connectable to a source of electric power and a load, and is automatically operable in one of a two wire mode or a three wire mode, the system comprising:

a hot terminal connectable to a hot wire of the source of electric power;

a dimmed hot terminal connectable to the load;

a neutral terminal connectable to a neutral wire of the source of electric power; and

a power supply, the power supply drawing a power supply current from the source of electric power, wherein the power supply current flows only between the hot terminal and the dimmed hot terminal when the electronic control system is operating in the two wire mode, and wherein a portion of the power supply current flows between the hot terminal and the neutral terminal when the electronic control system is operating in the three wire mode, wherein the electronic control system operates in the two wire mode when there is not a neutral wire connection, and wherein the electronic control system operates in the three wire mode when there is a neutral wire connection.

12. The system of claim 11, wherein the source of electric power comprises a high frequency switching power supply.

13. The system of claim 11, further comprising a detector for sensing whether the power supply current flows only between the hot terminal and the dimmed hot terminal.

14. The system of claim 11, further comprising a detector for sensing whether the power supply current flows between the hot terminal and the neutral terminal.

15. An apparatus for controlling an amount of power delivered from a source of power to a load the apparatus comprising:

a first main terminal and a second main terminal, wherein the first main terminal is connectable to the source of power and the second main terminal is connectable to the load to allow current to flow from the source of power to the load;

a power supply that draws a power supply current from the source of power through the load, wherein the power supply current flows only between the first main terminal and the second main terminal when the apparatus is operating in a two wire mode; and

a third terminal connectable to the source of power, wherein, when the third terminal is energized by the source of power, a portion of the power supply current flows through the third terminal instead of through the load when the apparatus is operating in a three wire mode,

wherein the apparatus operates in the two wire mode when there is not a connection to the third terminal, and wherein the apparatus operates in the three wire mode when there is a connection to the third terminal.

16. The apparatus of claim 15, wherein the first main terminal is connectable to a hot terminal of the source of power.

17. The apparatus of claim 15, wherein the third terminal is connectable to a neutral connection of the source of power.

18. The apparatus of claim 15, further comprising a diode that steers the portion of the power supply current through the third terminal instead of through the load.

19. The system of claim 15, further comprising a detector for sensing whether the power supply current flows only between the first main terminal and the second main terminal.

20. The system of claim 15, further comprising a detector for sensing whether the power supply current flows through the third terminal.

21. The system of claim 15, further comprising a microprocessor coupled to a detector to monitor an output signal and to select between the two wire mode and the three wire mode responsive to the output signal.