Power supply with controlled shunting element

A method for providing an AC input to a rectifying device comprising:

• monitoring an output of a rectifier;
• connecting a common ground to an input circuit and an output circuit of the rectifier;
• determining if the output of the rectifier is within a first threshold range of a desired output;
• monitoring an instantaneous voltage across an input of the rectifier;
• determining if an absolute difference of the instantaneous voltage across the input of the rectifier from zero voltage is less than a second threshold;
• and
• when the output of the rectifier is within the first threshold range of the desired output and the absolute difference of the instantaneous voltage across the input of the rectifier from zero voltage is less than the second threshold, then shunting the input of the rectifier;
• providing a second DC output;
• determining when the AC input is in a first polarity and wherein the shunting is when said AC input is in the first polarity;
• determining if the output of the rectifier is within a third threshold range of the second DC output;
• and
• when the output of the rectifier is within the third threshold range of the second DC output, the AC input is not in the first polarity and the absolute difference of the instantaneous voltage across the input of the rectifier from zero voltage is less than the second threshold, then further shunting the input of the rectifier.

A device comprising:

• a rectifier connected to an AC input;
• a first output circuit connected to the rectifier, for providing a desired DC output;
• a switch for shunting the AC input to the rectifier;
• a first capacitor for charging to a first voltage of the desired DC output wherein the AC input and a channel of the first output circuit are referred to a common ground;
• a controller comprising:
• a first connection to the first output circuit for the controller to determine a measured output of the first output circuit;
• a second connection to the AC input for the controller to determine voltage across the AC input;
• and
• a command output for the controller to provide a command signal to a switch to shunt the AC input,
• wherein the controller is configured for:
• monitoring the measured output of the first output circuit;
• determining if the measured output is within a first threshold range of the desired DC output;
• monitoring an instantaneous AC voltage across the AC input;
• determining if an absolute difference of the AC input from zero voltage is less than a second threshold value;
• providing the command signal to the switch to shunt the AC input when the measured output is within the first threshold range of the desired DC output, and the absolute difference of the instantaneous AC voltage from zero voltage is less than the second threshold value.