POWER MANAGEMENT UNIT FOR BATTERY-OPERATED DEVICES

• US 20080278002A1
• Filed: 05/07/2008
• Published: 11/13/2008
• Est. Priority Date: 05/07/2007
• Status: Active Grant

• Current Assignee: Stmicroelectronics France (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV), STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Nebon, Jerome, Platania, Giuseppe, Balmefrezol, Alexandre, Polisi, Vincenzo, Milazzo, Patrizia
• Granted Patent: US 7,768,150 B2
• Time in Patent Office: Days
• US Class Current: 307/49
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 2310/22 The load being a portable electronic device
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

A power management unit for a battery-operated electronic device having a bus interface for the interconnection with another electronic device, the power management unit including an electric energy storage element coupled between a battery of the battery-operated electronic device and a voltage supply line of the bus interface, the electric energy storage element being operable to charge/discharge electric energy; a drive circuitry arranged to control a charge/discharge of the electric energy storage element. The drive circuitry is operable to cause an electric power supplied by the other electronic device through the voltage supply line to re-charge the battery; or, in case the other electronic device does not supply electric power, cause the battery supply electric power to the other electronic device through the voltage supply line. The power management unit is particularly adapted for battery-operated, mobile USB OTG devices.

Claims

1. A power management unit for a battery-operated electronic device having a bus interface for the interconnection with another electronic device, the power management unit comprising:

an electric energy storage element coupled between a battery of the battery-operated electronic device and a voltage supply line of the bus interface, the electric energy storage element being operable to charge/discharge electric energy;

a drive circuitry arranged to control a charge/discharge of the electric energy storage element,

wherein the drive circuitry is operable to;

cause an electric power supplied by said another electronic device through the voltage supply line to re-charge the battery;

or

in case said another electronic device does not supply electric power, cause the battery supply electric power to said another electronic device through said voltage supply line.

2. The power management unit of claim 1, wherein:

said electric energy storage element includes at least one inductor having a first terminal coupled between a battery of the battery-operated electronic device and a second terminal coupled to a voltage supply line of the bus interface; and

said drive circuitry is arranged to control a charge/discharge of the inductor.

3. The power management unit of claim 2, adapted to convert a first voltage received from said voltage supply line into a second voltage of said battery.

4. The power management unit of claim 3, wherein said first voltage is higher than said second voltage.

5. The power management unit of claim 4, wherein said drive circuitry is a switched-mode circuitry.

6. The power management unit of claim 5, wherein the switched-mode drive circuitry comprises:

a first switch coupled between the voltage supply line and the second terminal of the inductor;

a second switch coupled between the second terminal of the inductor and a reference voltage terminal of the battery;

a switch control circuit operable to control the first and second switch.

7. The power management unit according to claim 6, wherein said switch control circuit is operable to generate PWM control signals for controlling the opening and closing of the first and second switch.

8. The power management unit of claim 7, wherein said switch control circuit is operable to generate first and second PWM control signals in phase opposition for controlling the first and second switch.

9. The power management unit of claim 1, wherein said bus interface is a USB interface.

10. A battery-operated electronic device having a bus interface for the connection to another electronic device and a power management unit according to claim 1.