Power supply circuit for portable battery powered device
AssigneeWolfson Microelectronics plc
InventorsPeter Frith, David Sinai
Life of this patent
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Abstract
The present invention relates to battery power peripheral devices such as MP3 players which are also periodically connected to another power source such as a mains wall socket or USB cable power bus. In particular, but not exclusively, the present invention relates to regulation of these voltage sources. In general terms the present invention provides a multiple supply rail for the load regulators of a power supply circuit for a battery powered device. One supply rail is coupled to the battery, and another is coupled to a non-battery source such as an external mains regulated source and/or a bus power wire from a USB cable or similar. The regulators have multiple inputs, each for taking their input voltage from one of these supply rails.
Claims23
A portable power supply circuit for a portable battery powered device, the circuit comprising:
- a number of inputs for receiving respective voltage supplies and coupled to respective power supply buses, one of the voltage supplies being a non-battery voltage supply coupled to a first power bus and another of the voltage supplies being a battery voltage supply coupled to a second power bus;
- and a common multiple input regulator for providing a regulated power supply to said battery powered device, the common regulator having a plurality of input pass devices, at least one of said pass devices connected directly to a respective power bus, the common regulator arranged to independently control said input pass devices to derive the regulated power supply from one of said power buses.
A multiple input regulator adapted for providing a regulated power supply to a portable battery powered device, the regulator having:
- regulator circuitry for regulating an input power supply from one of two or more power supply buses;
- a corresponding number of input MOS-based transistors pass devices each connected directly to a respective power supply bus;
- and switching means independently for switching the pass devices in and out of the regulation circuitry in order to derive the power supply for regulation from the respective power supply buses.
A multiple input regulator for providing a regulated power supply to a portable battery powered device, the regulator having:
- boost regulator circuitry comprising an input inductor and for regulating an input power supply from one of two or more power supply buses;
- and a plurality of input MOS-based transistor pass devices each connected directly to a respective power supply bus, the regulator arranged such that the input pass devices are coupled to the input inductor and independently switched in order to derive the power supply for regulation from the respective power supply buses.
Dependencies are inferred from the claim text.