Patent ID: 8488349

Claim:
A method for tracking power supplies, comprising: receiving, by a controller, a signal to be tracked; outputting, by the controller, according to the signal to be tracked, a control signal for: controlling at least two sets of voltage level selection circuits for selecting at least one tracking voltage level, wherein the selected at least one tracking voltage level comprises at least two groups of isolation voltage levels selected from the at least two sets of voltage level selection circuits, wherein an isolation power supply provides to the at least two sets of voltage level selection circuits the at least two groups of isolation voltage levels according to a voltage level interval of the signal to be tracked, wherein each of the at least two groups of isolation voltage levels comprises at least two tracking voltage levels, and controlling each set of the voltage level selection circuits for selecting at most one tracking voltage level out of a corresponding group of isolation voltage levels from each set of the voltage level selection circuits; wherein one of the at least two sets of voltage level selection circuits is connected with an output reference end of the other of the at least two sets of voltage level selection circuits through an output end thereof; and providing, by the voltage level selection circuits, the selected at least one tracking voltage level being connected in series to supply power to a load circuit.