Patent ID: 6462524
Filing Date: 2002-10-08
Classification: H02M

Abstract:
An apparatus that is arranged to receive an input voltage that is provided between an input terminal and a circuit ground, and provide an output voltage to a load that is coupled to the circuit ground, wherein the circuit ground has an associated circuit ground voltage, the apparatus comprising:a first coil circuit that is arranged to conduct a first current and provide the output voltage to the load; a switch control circuit that is arranged to provide a control signal in response to the output voltage; a switching circuit that is arranged to cooperate with the first coil circuit such that the output voltage is regulated by selective activation of the switching circuit in response to the control signal, wherein the switching circuit has an associated open circuit voltage when the switching circuit is in an open position; a first rectifier circuit that is arranged to conduct the first current when the switching circuit is in the open position; a second coil circuit that is coupled to a circuit ground and inductively coupled to the first coil circuit; and a second rectifier circuit that is arranged to conduct a second current that is provided by the second coil circuit, wherein the second coil circuit and the second rectifier circuit are arranged to provide a virtual ground, wherein the virtual ground has an associated virtual ground voltage that is different from the circuit ground voltage, and the open circuit voltage associated with the switching circuit is determined by a difference between at least the input voltage and the virtual ground voltage.