Integrated power supply with wide input supply voltage range

摘要

A novel integrated switched mode power supply circuit that provides supply voltages to an integrated circuit may be of minimal complexity and have the capacity for a wide range of input supply voltages. The novel power supply may include cascaded, unregulated step-down charge pumps (e.g. unregulated voltage splitters), one or more linear regulators coupled to the output of the cascaded voltage splitters, and a start-up current source to provide the IC supply current until the input supply voltage is sufficiently high for the voltage splitter(s) to be functional to provide the IC supply current. Furthermore, each voltage splitter may be activated or disabled depending on the value of the input supply voltage, and the input of a disabled voltage splitter may be shorted to its output via an integrated power switch. Using (cascaded) voltage splitters to provide the IC supply current reduces overall power dissipation in the IC.

主权项

1. A power supply comprising:
one or more voltage splitters configured to provide a supply current at a supply node, based on an input voltage; one or more linear voltage regulators coupled to the supply node and configured to provide one or more respective regulated output voltages responsive to the supply current; and a current source configured to provide a start-up current at the supply node until the input voltage is of sufficient value for the one or more voltage splitters to provide the supply current; wherein the one or more linear voltage regulators are configured to provide the one or more respective regulated output voltages responsive to:
the start-up current when the current source is providing the start-up current; andthe supply current when the one or more voltage splitters are providing the supply current.