| 摘要 |
A method and apparatus for over-current protection of a transformer supplying a load. The method includes periodically sampling a current supplied to the load, calculating an RMS average current using the samples collected, comparing the RMS average current to a target current, and limiting an amount of power intended for the load during a subsequent cycle to the lower of a desired power value and an RMS average power value, the RMS average power value determined by the comparison of the RMS average current to the target current. The described apparatus includes a controller capable of performing a process including each of these functions. A method for selectively enabling flow of current to a load includes storing the time between the leading edge of the supply signal and the trailing edge of the supply signal and sending a first signal enabling flow of the current according to a desired conduction angle when a subsequent leading edge of the supply signal does not occur within a second time, which is at least as long as the first time. A train controller for a model toy train can incorporate the invention.
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