Power management system for computer device interconnection bus

• US 5,752,046 A
• Filed: 12/18/1996
• Issued: 05/12/1998
• Est. Priority Date: 01/14/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Teener, Michael D., Oprescu, Florin
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US08/769,583
• Time in Patent Office: 510 Days
• Field of Search: 395/750, 395/182.2, 395/750.01, 395/750.03, 395/750.08, 364/707, 364/492, 365/227, 307/29, 307/38
• US Class Current: 713/300
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/305 in the event of power-supply fluctuations
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: G06F 1/3253 Power saving in bus
• CPC Class Codes: G06F 13/36 for access to common bus or bus system
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

The power management system tracks the total amount of power drawn from a bus by devices connected to the bus and to the bus itself, based on the individual operational status of each device. The power manager system also tracks the total amount of power supplied to the bus. From this information the power manager system determines whether a power surplus exists sufficient to allow an additional device to operate or to allow a currently operating device to draw more power. Power usage requests received from devices connected to the bus are granted or denied by the power management system based on the determination of available power. The power management system additionally is capable of sequencing the use of several devices to allow the devices to each operate while maintaining the total power draw within an acceptable range. The system provides for efficient use of a limited amount of power to allow operation of more devices than conventionally allowed with a bus. The system also can activate power supply devices which are off-line via soft-power-on commands to increase the total amount of power available. The system is advantageously implemented with any bus system having devices drawing power from the bus from power supplies providing limited power.

Claims

1. An electronics system comprising:

an interconnection bus;

a plurality of devices coupled to the interconnection bus, each of the plurality of devices being operative to transmit power requests via the interconnection bus and at least a first device of said plurality of devices being capable of supplying power to said interconnection bus; and

a power manager receiving the power requests from the plurality of devices, said power manager further including;

a database that contains (i) a priority level corresponding to each of the plurality of devices, (ii) power draw information on different operating states of each of the plurality of devices, and (iii) power output capabilities of at least said first device,

a processor that grants the power requests based on the power draw information and the priority information.

2. The electronics system of claim 1, wherein the power manager grants and denies power requests based on a maximum amount of power available.

3. The electronics system of claim 2, wherein the power manager grants a power request for a first amount of power if supplying the first amount of power would result in an amount of power used by the plurality of devices being less than or equal to a maximum amount of power available, and wherein the power manager denies the power request if supplying the first amount of power would result in the amount of power used by the plurality of devices exceeding the maximum amount of power available.

4. The electronics system of claim 2, wherein the peripheral device is a mouse.

5. The electronics system of claim 1 wherein the power manager controls operation of the plurality of devices.

6. The electronics system of claim 1 wherein the power manager determines the actual amount of power utilized by each device of the plurality of devices.

7. The electronics system of claim 1 wherein the power manager determines the actual amount of power consumed by each device of the plurality of devices and controls the actual amount of power consumed by each device of the plurality of devices.

8. The electronics system of claim 1 wherein logical operations of the power manager are implemented using a computer program executing within a processing unit.

9. The electronics system of claim 1, wherein the database further includes a device status table indicating the current power status of each device of the plurality of devices.

10. The electronics system of claim 1, wherein the power draw information includes information on power consumption of a peripheral device operating in an active mode and the peripheral device operating in a standby mode.

11. A method for determining whether to grant a power request from a signaling device being one of a plurality of devices coupled to an interconnection bus, the method comprising the steps of:

obtaining power draw information for each of the plurality of devices connected to the interconnection bus;

calculating a total amount of power drawn at a particular point in time by summing the power draw information of each of the plurality of devices;

obtaining from a table power output capabilities for each of the plurality of devices connected to the interconnection bus;

calculating a total amount of power supplied to the interconnection bus by summing the power output capabilities of each of the plurality of devices;

computing a surplus power available by subtracting the total amount of power drawn from the total amount of power supplied;

receiving a power request for a first amount of power via the interconnection bus from the signaling device;

granting the power request if supplying the first amount of power would not exceed the surplus power available; and

denying the power request if supplying the first amount of power would exceed the surplus power available.

12. The method of claim 11, wherein prior to the receiving step, the method further comprises the step of transmitting the power request containing information on a target device and a requested operational state of the target device.

13. The method of claim 12 wherein the signaling device is a target device which receives increased power if the power request is granted.

14. The method of claim 11, wherein prior to the receiving step, the method further comprises the step of transmitting a packet of data including the power request over the interconnection bus from the signaling device.

15. An electronics system comprising:

an interconnection bus including a data line and a power line;

a plurality of devices coupled to the interconnection bus, each of the plurality of devices being operative to transmit power requests via the data line, wherein the plurality of devices can request a total amount of power that exceeds a maximum amount of power available; and

a power manager coupled to the data line, said power manager configured to receive the power requests from the plurality of devices, to coordinate supplying power to the plurality of devices by increasing power supplied to the power line up to said maximum amount when insufficient power is available to satisfy pending power requests, said power manager further configured to grant and revoke power requests according to priority, thereby keeping the total amount of power used by the plurality of devices less than or equal to the maximum amount of power available.

16. The electronics system of claim 15 wherein the power manager further coordinates the supply of power by controlling the operation of the plurality of devices.

17. The electronics system of claim 16 wherein the power manager coordinates the supplying of power by tracking a difference between the maximum amount of power available and the total amount of power utilized by the plurality of devices.

18. The electronics system of claim 15 wherein the maximum amount of power available is the sum of maximum power outputs of all devices coupled to the bus.

19. A method for managing power consumption in an electronics system including a plurality of devices coupled to an interconnection bus, the method comprising the steps of:

receiving a power request for a first amount of power via the interconnection bus from a requesting device, said requesting device being one device in the plurality of devices;

granting the power request if a first surplus power is sufficient to satisfy the power request;

activating at least one power supply device to generate a second surplus power if said first surplus power is insufficient to satisfy the power request, said at least one power supply device being one of the plurality of devices; and

determining whether said second surplus power is sufficient to satisfy the power request, wherein if the second surplus power is insufficient to satisfy the power request,

generating a third surplus power by deactivating at least one device of the plurality of devices, said at least one device having a lower priority than the requesting device.