Electronic control systems and methods
View Patent ↗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.
1. A method for supplying power to control circuitry of a power control device, the power control device including at least one controllably conductive device, the method comprising:
charging a capacitor through a load to a predetermined high voltage only when said controllably conductive device is in a non-conductive state, wherein the controllably conductive device is connectable to the load in a two wire mode and controls whether or not the load is being energized; and
drawing current from said capacitor using a converter having a predetermined efficiency to provide a power supply voltage for operation of said control circuitry both when the load is being energized and when the load is not being energized,
wherein the controllably conductive device controls the load to be energized when the controllably conductive device is in a conductive state and not to be energized when the controllably conductive device is in the non-conductive state.
2. The method of claim 1 , wherein said converter is a switch mode type converter.
3. The method of claim 1 , wherein said converter is a flyback type converter.
4. The method of claim 1 , wherein said converter is at least about 50% efficient.
5. The method of claim 1 , wherein said converter is a buck converter.
6. The method of claim 1 , wherein said converter is at least about 75% efficient.
7. The method of claim 1 , wherein an efficiency of the converter is reasonably independent of a difference between a voltage across the controllably conductive device when the controllably conductive device is in the non-conductive state and the power supply voltage.
8. The method of claim 1 , wherein the capacitor may be charged through the load throughout a duration of an AC line voltage half cycle.