Battery charging with reused inductor for boost

Patent metadata

Field	Value
Publication number	US-2015372526-A1
Application number	US-201514749466-A
Country	US
Kind code	A1
Filing date	Jun 24, 2015
Priority date	Jun 24, 2014
Publication date	Dec 24, 2015
Grant date	—

Abstract

The disclosed embodiments provide a system that manages use of a battery in a portable electronic device. During operation, the system provides a charging circuit for converting an input voltage from a power source into a set of output voltages for charging the battery and powering a low-voltage subsystem and a high-voltage subsystem in the portable electronic device. Upon detecting discharging of the battery in a low-voltage state, the system uses the charging circuit to directly power the low-voltage subsystem from a battery voltage of the battery and up-convert the battery voltage to power the high-voltage subsystem.

First claim

What is claimed is:

1 . A method for managing use of a battery in a portable electronic device, comprising:
providing a charging circuit for converting an input voltage from a power source into a set of output voltages for charging the battery and powering a low-voltage subsystem and a high-voltage subsystem in the portable electronic device; and upon detecting discharging of the battery in a low-voltage state, using the charging circuit to:
directly power the low-voltage subsystem from a battery voltage of the battery; and
up-convert the battery voltage to power the high-voltage subsystem.

2 . The method of claim 1 , further comprising:
upon detecting the input voltage from an underpowered power source and the low-voltage state in the battery, using the charging circuit to:
power the low-voltage subsystem from a target voltage of the battery; and
power the high-voltage subsystem from the underpowered power source.

3 . The method of claim 2 , further comprising:
upon detecting a voltage of the low-voltage subsystem below an open-circuit voltage of the battery, using the charging circuit to power the high-voltage subsystem from a sum of currents from the input voltage and the up-converted battery voltage.

4 . The method of claim 1 , further comprising:
upon detecting the input voltage from an underpowered power source and a high-voltage state in the battery, using the charging circuit to power the low-voltage subsystem and the high-voltage subsystem from a target voltage of the battery that is higher than a voltage requirement of the high-voltage subsystem.

5 . The method of claim 4 , further comprising:
upon detecting a voltage of the low-voltage subsystem below an open-circuit voltage of the battery, using the charging circuit to power the high-voltage subsystem from a sum of currents from the input voltage and the up-converted battery voltage.

6 . The method of claim 1 , further comprising:
upon detecting the input voltage from an underpowered power source and an undervoltage state in the battery:
powering off the portable electronic device; and
using the charging circuit to charge the battery from the input voltage.

7 . The method of claim 1 , further comprising:
upon detecting the input voltage from the power source and a low-voltage state in the battery, using the charging circuit to:
power the high-voltage subsystem from the power source;
down-convert the input voltage to a target voltage of the battery; and
charge the battery and power the low-voltage subsystem from the target voltage.

8 . The method of claim 1 , further comprising:
upon detecting the input voltage from the power source and a fully charged state in the battery, using the charging circuit to:
discontinue charging of the battery; and
power the low-voltage subsystem and the high-voltage subsystem from a target voltage that is higher than the battery voltage of the battery in the fully charged state.

9 . The method of claim 1 , wherein the charging circuit comprises:
an inductor with an input terminal and a load terminal; a first switching mechanism configured to couple the input terminal to either the power source or a reference voltage; a second switching mechanism configured to couple the load terminal to the battery, the high-voltage subsystem, and the low-voltage subsystem; and a third switching mechanism configured to couple the input voltage to the high-voltage subsystem.

10 . The method of claim 1 , wherein the battery voltage in the low-voltage state is lower than a voltage requirement of the high-voltage subsystem.

11 . A charging system for a portable electronic device, comprising:
a bidirectional converter; and a control circuit configured to use the bidirectional converter to convert an input voltage from a power source into a set of output voltages for charging a battery in the portable electronic device and powering a low-voltage subsystem and a high-voltage subsystem in the portable electronic device.

12 . The charging system of claim 11 , wherein the control circuit is further configured to:
convert a battery voltage from the battery into the set of output voltages for powering the low-voltage subsystem and the high-voltage subsystem.

13 . The charging system of claim 12 , wherein the set of output voltages is produced by:
down-converting the input voltage from the power source; or up-converting the battery voltage from the battery during discharging of the battery.

14 . The charging system of claim 12 , wherein the control circuit is configured to produce the set of output voltages during:
standard charging from the power source; charging from an underpowered power source; and discharging of the battery.

15 . The charging system of claim 12 , wherein the control circuit is configured to produce the set of output voltages during:
an undervoltage state in the battery; a low-voltage state in the battery; a high-voltage state in the battery; and a fully charged state in the battery.

16 . The charging system of claim 11 , wherein the bidirectional converter comprises:
an inductor with an input terminal and a load terminal; a first switching mechanism configured to couple the input terminal to either the power source or a reference voltage; a second switching mechanism configured to couple the load terminal to the battery, the high-voltage subsystem, and the low-voltage subsystem; and a third switching mechanism configured to couple the input voltage to the high-voltage subsystem.

17 . The charging system of claim 16 , wherein the first, second, and third switching mechanisms comprise field-effect transistors (FETs).

18 . A portable electronic device, comprising:
a first set of components in a high-voltage subsystem; a second set of components in a low-voltage subsystem; a battery; and a charging circuit configured to convert an input voltage from a power source into a set of output voltages for charging the battery and powering the low-voltage subsystem and the high-voltage subsystem.

19 . The portable electronic device of claim 18 , wherein the control circuit is further configured to:
convert a battery voltage from the battery into the set of output voltages for powering the low-voltage subsystem and the high-voltage subsystem.

20 . The portable electronic device of claim 19 , wherein the set of output voltages is produced by:
down-converting the input voltage from the power source; or up-converting the battery voltage from the battery during discharging of the battery.

21 . The portable electronic device of claim 18 , wherein the charging circuit comprises:
an inductor with an input terminal and a load terminal; a first switching mechanism configured to couple the input terminal to either the power source or a reference voltage; a second switching mechanism configured to couple the load terminal to the battery, the high-voltage subsystem, and the low-voltage subsystem; and a third switching mechanism configured to couple the input voltage to the high-voltage subsystem.

22 . The portable electronic device of claim 21 , wherein the first, second, and third switching mechanisms comprise field-effect transistors (FETs).

Assignees

• Apple Inc

Inventors

• Greening Thomas C
• Liu Qing
• Athas William C

Classifications

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H02J7/96

  in response to battery voltage · CPC title

• H02J9/061

  for DC powered loads · CPC title

• G06F1/263

  Arrangements for using multiple switchable power supplies, e.g. battery and AC (G06F1/30 takes precedence) · CPC title

• H02M3/1582 Primary

  Buck-boost converters (H02M3/1584 takes precedence) · CPC title