Apparatus and method for power distribution

• US 20060103356A1
• Filed: 12/28/2005
• Published: 05/18/2006
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kodner, Lionid, Gurevich, Vitaliy, Edry, Isaac
• Granted Patent: US 7,425,817 B2
• Time in Patent Office: Days
• US Class Current: 320/150
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence

Abstract

The present invention provides a circuit arrangement wherein in operation a radio frequency power amplifier is supplied by the battery when charging is progressing normally, but switches supply to the charger if the charging process is interrupted. Thus the RF power amplifier receives approximately 4.2V from the battery, or approximately 4.4V±5% from the charger if charging of the battery is suspended. This also allows operation solely from the charger in the absence of a battery. Thus the present invention enables continuing operation of the device if charging is suspended, whilst limiting the voltage level to the RF power amplifier to approximately 4.4V±5%.

Claims

1. Apparatus to control a lithium-ion battery charging process, comprising;

a lithium-ion battery (250);

a power controller (240);

a device controller (230);

a radio frequency (RF) power amplifier (220);

a first voltage operated switch (VOS)(274) operable to control connection between the battery (250) and device (210);

a thermal detection means (254), operably coupled to the power controller (240);

a battery feedback means (242) operable to couple the power controller (240) to a charger (260); and

the charger (260) operable to respond to the battery feedback means (242), so relating charger output to battery state, wherein the charger (260) produces a default minimum

output voltage in response to a suspension in battery charging when battery temperature exceeds a threshold,

characterised by;

logic circuitry (410, 420, 230, 240) operable to indicate that battery charging has been suspended;

a first switching means (442) depending from said

logic circuitry operable to disconnect the negative

terminal of battery (250) from ground (290) if charging has been suspended;

a second switching means (432, 434) depending from said logic circuitry operable to connect the RF power amplifier (220) to the charger (260) if charging has been suspended.

2. Apparatus according to claim 1, wherein said logic

circuitry comprises at least a first NAND gate (410) operably coupled to both the input to the gate channel of

a first FET (274) from the power controller (240) and to an output channel of the device controller (230), wherein:

said input to the first VOS (274) is set ‘

on’

whilst the charger (260) is providing a voltage, and said output channel of the device controller (230) is set ‘

on’

in the event that battery charging is suspended.

3. Apparatus according to claim 1, wherein said logic circuitry comprises at least a first NAND gate (410) operably coupled to an output MOBPORTB (546) from power controller (240) and to an output channel of the device controller (230), wherein:

said input to the first VOS (274) is set ‘

on’

whilst the charger (260) is providing a voltage, and said output channel of the device controller (230) is set ‘

on’

in the event that battery charging is suspended.

4. Apparatus according to claim 1, wherein said first switching means (442) comprises a second VOS arranged with its drain node operably coupled to the negative terminal of the battery (250), its source node operably coupled to ground and its gate node operably

coupled to aforesaid logic circuitry.

5. Apparatus according to claim 1, wherein said second switching means (432, 434) comprises two additional VOSs with their source nodes connected to each other, a first drain node operably coupled to the charger, a second drain node operably coupled to the RF power amplifier and their gate nodes operably coupled to said logic circuitry.

6. Apparatus according to claim 1, wherein any or all of the VOSs are field effect transistors (FETs).

7. Apparatus according to claim 6, wherein any or all of the FETs are Metal oxide semiconductor FETs (MOSFETs).

8. Apparatus according claim 7, wherein any MOSFETs are P-channel MOSFETs.

9. Apparatus according to claim 1, wherein the default minimum voltage for the charger (260) is 4.4V±

5%.

10. Apparatus according to claim 1, wherein a suspension in battery charging is due to thermal detection means (254) detecting that the battery (250) temperature has exceeded approximately 45°

C.

11. A method of controlling a lithium-ion battery charging process, the method comprising;

using a thermal detection means (254) to detect a threshold temperature in the battery (250);

using a power controller (240) top provide battery feedback via a battery feedback means (242) to a charger (260);

regulating the output of the charger (260) in response to the battery feedback; and

suspending charging of the battery (250) when the battery temperature exceed a threshold,

characterized by;

indicating by logical operation that battery charging has been suspended;

upon suspension, regulating the charger output to maintain a default minimum output voltage;

switching, in dependence from said logical operation, of a first switching means (442) to disconnect the negative terminal of battery (250) if charging has been suspended; and

switching, in dependence from said logical operation, of a second switching means (432, 434) to connect RF power amplifier (220) to charger (260) if charging has been suspended.