Power supply assembly for portable phone

• US 6,167,289 A
• Filed: 02/20/1998
• Issued: 12/26/2000
• Est. Priority Date: 02/20/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ball, Scott R., Peterzell, Paul E.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Mehrpour, Naghmeh
• Application Number:
  US09/027,354
• Time in Patent Office: 1,040 Days
• Field of Search: 455/572, 455/573, 455/575, 455/90, 455/127, 455/343, 455/348, 455/349, 320/119, 320/118, 320/160, 320/135, 320/138
• US Class Current: 455/572
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A portable phone has an internal battery and an external battery pack is releasably attachable to the phone. A control unit in the phone controls connection of the respective batteries to a phone power input, depending on the detection of the external battery voltage. Whenever an external battery is present with a voltage above a predetermined minimum value, the external battery will be connected to the phone power input to provide power to operate the phone, so that the internal battery lifetime is extended. When the external battery voltage falls below the minimum value, or the external battery is removed, the unit automatically switches to internal battery power, so that the external battery can be changed without interrupting power supply to the phone, if the phone is on or during a call.

Claims

1. A power supply control assembly for a portable phone, comprising:

an internal battery for mounting inside a phone housing;

an external battery for releasable mounting on the phone housing;

a control unit connected to the internal and external batteries to control connection of the batteries to a phone power line; and

the control unit including first and second detectors for detecting the output voltage of the internal and external battery, respectively, first and second switches for controlling connection of the internal battery and external battery, respectively, to the phone power line, and a signal output device connected to the first and second detectors for producing a first output signal and a second output signal dependent on the output of the external battery, the first and second output signals controlling the first and second switches, the first switch being off and the second switch being on when the output voltage of the external battery is above a predetermined minimum value, whereby power is supplied by the external battery, and the first switch being switched on and the second switch being switched off when the output voltage of the external battery falls below said predetermined minimum value, whereby power is supplied by the internal battery;

the assembly further including an external voltage input connected to the control unit for supplying a charge input to a selected battery, the control unit further including a detector for detecting when the charge input is connected to a charging device, and a selector for controlling connection of the charge input to the external and internal battery, whereby only one battery is connected to the charge input at any time, and the internal battery is charged prior to the external battery;

wherein the charge input has a fast charge input to each battery, and the charge input is connected to first and second trickle charge units having outputs connected to the internal and external battery, respectively, a third switch controlling connection of the first trickle charge unit to the internal battery, and a fourth switch controlling connection of the second trickle charge unit to the external battery, and a controller is connected to the battery outputs and to the fast charge inputs and third and fourth switches to control the speed of charging a selected battery, the controller including means for detecting the output voltage of each battery, initiating a charging cycle when a charge input is detected, connecting a fast charge input to the selected battery if the battery voltage is greater than a predetermined minimum value, and connecting a trickle charge input from the respective trickle charge unit to the selected battery if the battery voltage is below a predetermined minimum value.

2. A method of controlling the power supply to a portable phone, comprising the steps of:

mounting an external battery on a portable phone unit having an internal battery;

detecting an output voltage from an external battery and determining whether the battery output voltage is above or below a predetermined minimum value;

connecting the external battery to an input power line for the phone whenever an external battery is present and the external battery output voltage is above a predetermined value;

automatically switching from the external battery to the internal battery to connect the internal battery to the phone input power line when the external battery is removed or the battery output voltage falls below the predetermined minimum value;

detecting an external voltage input from a charging unit; and

on detection of an external voltage input, initiating a battery charging sequence, the sequence comprising connecting the external voltage input to the internal battery until the internal battery is charged, and subsequently connecting the external voltage input to the external battery until charged;

wherein the battery charging sequence further includes the steps of;

providing a fast charge input and a trickle charge input from the external voltage input to each battery;

detecting whether the output voltage of each battery is above a predetermined minimum;

connecting the trickle charge input to a respective battery if the battery output voltage is below a predetermined minimum; and

switching from the trickle charge input to the fast charge input when the battery output voltage is above the predetermined minimum.