# US 8,541,983 B2 · Circuit and method of operation for an electrical power supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,983 B2 - Document ID: US8541983B2 - Status: Granted - Kind: B2 - Application number: 13/175,541 - Filed: 2011-07-01 - Published: 2011-10-27 - Granted: 2013-09-24 - Earliest claimed: 2003-02-21 - Assignees: BlackBerry Limited - Applicants: Dusan Veselic; Martin George Albert Guthrie - Inventors: Dusan Veselic; Martin George Albert Guthrie - Web page: https://patentgrep.com/patent/US8541983B2 ## CPC - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - H02J 7/92: with prioritisation of loads or sources - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A battery charging circuit comprising: a semiconductor switch having an output connected to a rechargeable battery; a battery charge controller for receiving power from an external source, and supplying output power to a portable device and the input of the semiconductor switch, the current output of the battery charge controller being controllable; and a voltage sensing circuit for: measuring the voltage drop across the battery charge controller; and responding to the voltage drop across the battery charge controller by modulating the semiconductor switch to reduce the quantity of current supplied to the rechargeable battery when the voltage drop is too great; whereby the total power dissipated by the battery charge controller is controlled, the portable device receiving the power it needs to operate and the rechargeable battery receiving any additional available power. ## Claims ### Claim 1 A portable electronic device, comprising: a switch configured to control a supply of power to a rechargeable battery; a controller configured to receive USB power from an external source and supply power to the portable electronic device; and a sensing circuit configured to determine power supplied to the portable electronic device, the controller responsive to the sensing circuit and configured to control the switch to limit battery charging from the external source such that sufficient power is provided for operation of the portable electronic device. ### Claim 2 (depends on 1) The portable electronic device of claim 1, wherein sufficient power is power required to meet the dynamic needs of the portable electronic device. ### Claim 3 (depends on 1) The portable electronic device of claim 1, wherein the supply of power is limited by limiting current. ### Claim 4 (depends on 1) The portable electronic device of claim 1, wherein the supply of power is limited by limiting voltage. ### Claim 5 (depends on 1) The portable electronic device of claim 1, wherein total power consumed by the device is provided by the USB source. ### Claim 6 (depends on 1) The portable electronic device of claim 1, wherein the controller comprises an external driving semiconductor for carrying supply current to the device and the switch, whereby load current passes through the external driving semiconductor in lieu of the controller. ### Claim 7 (depends on 1) The portable electronic device of claim 1, wherein the voltage sensing circuit comprises: an operational amplifier for receiving a voltage signal from an output of the controller and a reference signal, and responds to the voltage signal being less than the reference voltage by reducing flow through the switch. ### Claim 8 (depends on 1) The portable electronic device of claim 1, wherein the voltage sensing circuit comprises an operational amplifier for comparing a voltage on an output of the controller to a reference value. ### Claim 9 A portable electronic device including a graphical user interface and an interface for communicating with a communications network, comprising: a switch configured to control a supply of power to a rechargeable battery; a controller configured to receive USB power from an external source and supply power to the portable electronic device; and a sensing circuit configured to determine power supplied to the portable electronic device, the controller responsive to the sensing circuit and configured to control the switch to limit battery charging from the external source such that sufficient power is provided for operation of the portable electronic device. ### Claim 10 (depends on 9) The portable electronic device of claim 9, wherein the controller is configured to control the switch in response to the voltage drop to provide sufficient power for operation of the device. ### Claim 11 (depends on 9) The portable electronic device of claim 9, wherein the supply of power is limited by limiting current. ### Claim 12 (depends on 9) The portable electric device of claim 9, wherein the supply of power is limited by limiting voltage. ### Claim 13 (depends on 9) The portable electronic device of claim 9, wherein total power consumed by the device is provided by the USB source. ### Claim 14 (depends on 9) The portable electronic device of claim 9, wherein the controller comprises an external driving semiconductor for carrying supply current to the device and the switch, whereby load current passes through the external driving semiconductor in lieu of the controller. ### Claim 15 (depends on 9) The portable electronic device of claim 9, wherein the voltage sensing circuit comprises an operational amplifier. ### Claim 16 (depends on 9) The portable electronic device of claim 9, wherein the voltage sensing circuit comprises: an operational amplifier for receiving a voltage signal from an output of the controller and a reference signal, and responds to the voltage signal being less than the reference voltage by reducing the flow through the switch. ### Claim 17 (depends on 9) The portable electronic device of claim 9, wherein the voltage sensing circuit comprises an operational amplifier for comparing a voltage on an output of the controller to a reference value. ### Claim 18 A circuit for a portable electronic device comprising: a switch configured to control a supply of power to a rechargeable battery; a controller configured to receive USB power from an external source and supply power to the portable electronic device; and a sensing circuit configured to determine power supplied to the portable electronic device, the controller responsive to the sensing circuit and configured to control the switch to limit battery charging from the external source such that sufficient power is provided for operation of the portable electronic device. ### Claim 19 (depends on 18) The circuit of claim 18, wherein the controller limits power consumption by the device and is configured to control the switch in response to the voltage drop to provide sufficient power for operation of the device. ### Claim 20 (depends on 18) The circuit of claim 18, wherein the supply of power is limited by limiting current. ### Claim 21 (depends on 18) The circuit of claim 18, wherein the supply of power is limited by limiting voltage. ### Claim 22 A method for controlling a USB power supply to a rechargeable battery, comprising the steps of: sensing a voltage drop across a controller; and responsive to the voltage drop, limiting battery charging from the USB power supply such that sufficient power is provided for operation of a device by modulating a switch to control a quantity of power to the rechargeable battery. ### Claim 23 (depends on 22) The method of claim 22, wherein the power is limited by limiting current. ### Claim 24 (depends on 22) The method of claim 22, wherein the power is limited by limiting voltage. ### Claim 25 (depends on 22) The method of claim 22, wherein total power consumed by the device is provided by the USB source. ### Claim 26 (depends on 22) The method of claim 22, wherein the rechargeable battery is associated with a portable electronic device.