Electrical power supply with floating current source suitable for providing bias voltage and current to an amplified transducer

摘要

An electrical power supply is described which includes a floating current source. The floating current source includes a current source providing a selected amount of electrical current to a first terminal, and a current sink receiving the selected amount of electrical current from a second terminal. The current source is adapted for coupling to a first electrical voltage level which is positive with respect to a reference potential. The current sink is adapted for coupling to a second electrical voltage level which is negative with respect to the reference potential. The selected amount of current may be proportional to a reference current flowing through both the current source and the current sink. The current source and sink may each include a pair of transistors coupled together such that a flow of electrical current through one of the pair of transistors produces a proportional flow of electrical current through the other transistor. The electrical power supply may also include two line-powered voltage sources producing the first and second electrical voltage levels. During operation, the first and second electrical voltage levels may be adjusted by varying the first and second voltage sources, and a desired electrical voltage may be developed between the first and second terminals. The power supply is thus capable of supplying a bias voltage and current to an amplified transducer (e.g., an amplified piezoelectric transducer).