Power supply for electronic device, and electronic device system

• US 5,465,039 A
• Filed: 09/09/1993
• Issued: 11/07/1995
• Est. Priority Date: 09/16/1992
• Status: Expired due to Fees

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Tsurukawa, Noboru, Suzuki, Keiji, Narita, Izuru, Mito, Toshitsugu
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/118,899
• Time in Patent Office: 789 Days
• Field of Search: 320/22, 320/31, 320/32
• US Class Current: 320/164
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: Y10S 320/10 Nonbattery load controls charging

Abstract

To make it possible to supply to a battery a charging current having a sufficient capacity which enables a short-time charge while supplying a drive current for usual operation to a battery operable electronic device, without making construction large-sized and complicated.

The present invention is intended to be able to delicately vary a charging current of a battery according to the variation of power consumption of load on an electronic device, by providing constant power feedback control means for performing feedback control of the outputted power so as to cause a constant power or a nearly constant power, based on a current feedback value and a voltage feedback value.

Claims

1. A power supply apparatus for an electronic device which is powered by either a drive current or a battery, said power supply apparatus comprising means for supplying said drive current for driving the electronic device and a charging current for charging said battery, said power supply apparatus having constant power feedback control means for performing feedback control of an outputted power based on a current feedback value and a voltage feedback value, such that the outputted power is substantially constant.

2. The power supply apparatus for an electronic device according to claim 1, wherein said constant power feedback control means performs substantially constant power feedback control based on a value obtained by adding said current feedback value and said voltage feedback value.

3. The power supply apparatus for an electronic device according to claim 2, wherein said constant power feedback control means disregards said voltage feedback value and performs constant current feedback control based on said current feedback value if the voltage feedback value is smaller than a predetermined value.

4. The power supply apparatus for an electronic device according to claim 3, wherein said predetermined value can be selected from a plurality of predetermined values.

5. The power supply apparatus for an electronic device according to claim 1, wherein said constant power feedback control means performs constant power feedback control based on a value obtained by multiplying said current feedback value by said voltage feedback value.

6. A power supply apparatus for an electronic device which is powered by either a drive current or a battery, said power supply apparatus comprising means for supplying a drive current for driving the electronic device and a charging current for charging said battery, the power supply apparatus having constant power feedback control means for performing feedback control of an outputted power based on a current feedback value and a voltage feedback value such that the outputted power is substantially constant and constant voltage feedback control means for performing feedback control of the outputted power based on a voltage feedback value so as to cause a constant voltage, said power supply apparatus being constructed such that the voltage feedback control means is operative if a Load impedance is higher than a first predetermined value and such that the power feedback control means is operative if the Load impedance is less than a second predetermined value.

7. The power supply apparatus for an electronic device according to claim 6, wherein said constant power feedback control means disregards said voltage feedback value and performs constant current feedback control based on said current feedback value if the voltage feedback value is smaller than a third predetermined value.

8. An electronic apparatus system comprising a battery operable electronic device, a battery for supplying a drive current to said electronic device, and a power supply apparatus for supplying a charging current to said battery during supplying a drive current to said electronic device, wherein said power supply apparatus has constant power feedback control means for performing feedback control of an outputted power based on a current feedback value and a voltage feedback value such that the outputted power is substantially constant.

9. An electronic apparatus system comprising a battery operable electronic device, a battery for supplying a drive current to said electronic device, and a power supply apparatus for supplying a charging current to said battery during supplying a drive current to said electronic device, wherein said power supply apparatus has constant power feedback control means for performing feedback control of an outputted power such that the outputted power is substantially constant, said constant power feedback control means including a current feedback control means for performing feedback control of the outputted power based on a current feedback value and a voltage feedback value such that the outputted power is substantially constant and constant voltage feedback control means for performing feedback control of the outputted power so as to cause a constant voltage based on a voltage feedback value, said voltage feedback control means being operative if a load impedance is higher than a first predetermined value and said power feedback control means being operative if the Load impedance is less than a second predetermined value.

10. An electronic apparatus system comprising a battery operable electronic device, a battery for supplying a drive current to said electronic device, and a power supply apparatus for supplying a charging current to said battery during supplying a drive current to said electronic device, wherein said power supply apparatus has a first differential amplifier for amplifying a difference between a current feedback value and a reference current value, a second differential amplifier for amplifying a difference between a voltage feedback value and a reference voltage value, and a feedback path which is operative such that a difference between a reverse input and a non-reverse input of the first and second differential amplifiers is minimized, and is constructed such that the feedback by the second differential amplifier is operative when an output current value is less than a first predetermined value and such that the feedback by the first differential amplifier is operative when the output current value reaches a second predetermined value, and a voltage feedback value is added to a current feedback value inputted to said first differential amplifier when said electronic device is operating.