Patent Publication Number: US-2012030487-A1

Title: Information processing apparatus and power control method

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2010-172737 filed on Jul. 30, 2010, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to an information processing apparatus such as a battery-operable personal computer and a power control method applied to the information processing apparatus. 
     BACKGROUND 
     In recent years, various kinds of notebook-type or laptop-type portable personal computers have been developed. Many of such personal computers are driven by receiving power supply from an AC adapter or a secondary battery. 
     AC adapters provided in related-art portable personal computers are set at a rated power not less than the maximum power of the system. Recent portable personal computers are frequently placed under high load because of image processing and the like, and consume an increasing amount of power. Therefore, the rated power of AC adapters tends to be high. 
     On the other hand, with the size reduction of portable personal computers in recent years, the AC adapters provided in the portable personal computers are also required to be reduced in size. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A general configuration that implements the various features of the invention will be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
         FIG. 1  is an exemplary perspective view showing an appearance of an information processing apparatus according to an embodiment 
         FIG. 2  is an exemplary block diagram showing a system configuration of the information processing apparatus; 
         FIG. 3  is an exemplary circuit view showing a structure of a power supply system in the information processing apparatus; 
         FIG. 4  is a view for explaining the power supply from an AC adapter and a battery of the information processing apparatus; and 
         FIG. 5  is an exemplary flow chart showing the power control procedure of the information processing apparatus 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, an information processing apparatus includes a first circuit, a second circuit, and a controller. The first circuit is configured to detect consumed power of the information processing apparatus. The second circuit is configured to supply power received from a battery or an external power supply device, to a component in the information processing apparatus. The controller is configured to control the second circuit to receive the power from both of the battery and the external power supply device when the consumed power detected by the first circuit is higher than a capacity of the external power supply device. 
     An exemplary embodiment will be described with reference to the drawings. 
     First, referring to  FIG. 1 , the structure of an information processing apparatus according to an embodiment will be described. This information processing apparatus is implemented, for example, as a battery-operable notebook-type portable personal computer  10 .  FIG. 1  is a perspective view of the computer  10  with the display unit being opened, viewed from the front side. 
     The computer  10  includes a computer main body  11  and a display unit  12 . The display unit  12  incorporates a display device constructed of an LCD (liquid crystal display)  16 . 
     The display unit  12  is supported by the computer main body  11 , and attached to the computer main body  11  so as to be pivotable between an opened position where the top surface of the computer main body  11  is exposed and a closed position where the top surface of the computer main body  11  is covered by the display unit  12 . The computer main body  11  has a thin box-form housing, and on the top surface thereof, a keyboard  13 , a power switch  14  for powering on and off the computer  10 , and a touch pad  15  are disposed. 
     A battery  17  is, for example, removably fitted in a rear end portion of the computer main body  11 . The battery  17  may be, for example, a lithium-ion battery (high capacity battery) intended for higher capacity. 
     The computer main body  11  is provided with a power connector  20  (not shown in  FIG. 1 ). The power connector  20  is provided on the back surface of the computer main body  11 . An external power supply device is detachably connected to the power connector  20 . As the external power supply device, an AC adapter  40  can be used. The AC adapter  40  is a power supply device that converts commercial power (AC power) to DC power. In other words, the AC adapter  40  is a device that supplies external direct current to the computer  10 . 
     The power connector  20  is constructed of a jack to which a power plug drawn from the external power supply device such as the AC adapter  40  is detachably connectable. 
     The computer  10  is driven by the power from the AC adapter  40  or the power from the battery  17 . The power from the external power supply device can be used also for charging the battery  17 . The battery  17  may be charged not only while the power of the computer  10  is on but also while the power of the computer  10  is off. While the AC adapter  40  is not connected to the power connector  20  of the computer  10 , the computer  10  is driven by the power from the battery  17 . 
     The system maximum load power (consumed power) of the computer  10  is provided by the power from the AC adapter  40  and the power from the battery  17 . The system maximum load power of the computer  10  is the sum total of the consumed power when the components in the computer  10  operate at the highest throughput. 
     Normally, as the external power supply device provided in an information processing apparatus, a device of a rated power that corresponds to the maximum load of the system of the information processing apparatus is provided. That is, setting is made so that the maximum load power of the system can be provided only by the power supplied from the external power supply device. 
     However, in the computer  10 , power can be simultaneously supplied from both the AC adapter  40  and the battery  17 . Therefore, it is unnecessary that the AC adapter  40  correspond to the system maximum load power of the computer  10 . Consequently, the AC adapter  40  can be replaced with an adapter of a rated power lower than normal. 
       FIG. 2  shows the system configuration of the computer  10 . The computer  10  includes a CPU  111 , a northbridge  112 , a main memory  113 , a graphics controller  114 , a southbridge  115 , a hard disk drive (HDD)  116 , an optical disk drive (ODD)  117 , a BIOS-ROM  118 , an embedded controller (EC)  119 , a charger circuit  120  and the AC adapter  40 . 
     The CPU  111  is a processor that controls the operations of the components of the computer  10 . The CPU  111  executes various pieces of software, for example, the operating system (OS) and various application programs loaded from the HDD  116  to the main memory  113 . The CPU  111  also executes the BIOS (basic input output system) stored in the BIOS-ROM  118  which is a nonvolatile memory. The BIOS is a system program for hardware control. 
     The northbridge  112  is a bridge device that connects between the local bus of the CPU  111  and the southbridge  115 . The northbridge  112  also has the function of executing communication with the graphics controller  114 . Further, the northbridge  112  incorporates a memory controller that controls the main memory  113 . The graphics controller  114  is a display controller that controls the LCD  16  used as the display monitor of the computer  10 . 
     The southbridge  115  is connected to a PCIe bus  1 , and executes communication with devices on the PCIe bus  1 . The southbridge  115  incorporates an IDE (integrated drive electronics) controller and a serial ATA controller for controlling the HDD  16  and the ODD  17 . 
     The EC  119  and the battery  17  are interconnected through a serial bus (I 2 C bus  2 ). The EC  119  is a power management controller for managing the power of the computer  10 , and implemented, for example, as a one-chip microcomputer incorporating a keyboard controller that controls the keyboard (KB)  13 , the touch pad  15  and the like. The EC  119  has the function of powering on and off the computer  10  in response to an operation of the power switch  14  by the user. The control of the power-on and power-off of the computer  10  is executed by the EC  119 . When an ON signal is received, the EC  119  controls the charger circuit  120  to power on the computer  10 . When an OFF signal is received, the EC  119  controls the charger circuit  120  to power off the computer  10 . The EC  119  and the charger circuit  120  also operate by the power from the battery  17  or the AC adapter  40  while the power of the computer  10  is off. 
     The charger circuit  120  generates power (operating power supply) to be supplied to the components, by using the power from the battery  17  attached to the computer main body  11  or the power from the AC adapter  40  connected to the computer main body  11  as the external power source. When the AC adapter  40  is connected to the computer main body  11 , the charger circuit  120  generates the operating power supply to the components by using the power from the AC adapter  40 , and can charge the battery  17 . 
     In the present embodiment, for example, the output voltage of the AC adapter  40  is higher than that of the battery  17 . In this case, the AC adapter  40  is preferentially used as the power source. 
     Next, referring to  FIG. 3 , an example of the structure of the power supply system in the computer  10  will be described. The power supply system of  FIG. 3  includes switches S 1  and S 2 , a resistor R 1 , the battery  17 , the EC  119 , the charger circuit  120  and a switching power source  121 . 
     The EC  119  connects with the battery  17  through the I 2 C bus  2 . The EC  119  communicates with the microcomputer in the battery  17  via the I 2 C bus  2 , and receives information representative of the detection and charging condition of the battery  17  or the like. 
     The EC  119  also controls the charger circuit  120 . The EC  119  determines whether the AC adapter  40  is connected or not through the AD port of the charger circuit  120 . That is, when a voltage not less than a certain value is detected at the AD port, the EC  119  determines that the AC adapter  40  is connected. 
     The charger circuit  120  controls the switches S 1  and S 2  and the switching power source  121  under the control of the EC  119 . The charger circuit  120  also detects the current outputted to the system load based on the voltage across the resistor R 1 . 
     The EC  119  detects the load power of the system based on the current value detected by the charger circuit  120 . The EC  119  classifies the load power of the system into three conditions (conditions A, B and C), and controls the charger circuit  120  according to each condition. 
     Next, the operations of the components in the three conditions will be described by using  FIG. 4 .  FIG. 4  is a view for explaining the power supply from the AC adapter  40  and the battery  17  of the computer  10 . As shown in  FIG. 4 , from T 0  to T 3 , the load power of the system increases with the lapse of time. From T 3 , the system load power is held at the adapter rated capacity. 
     The condition A is a condition in which the system load power is not more than the rated power of the AC adapter  40 . In the condition A, the charger circuit  120  turns on the switch S 1  and turns off the switch S 2 . That is, the system load is provided by the power from the AC adapter  40 . The charger circuit  120  also calculates the surplus power by subtracting the system load power value from the value of the power from the AC adapter  40 . The charger circuit  120  charges the battery  17  by the surplus power. The charger circuit  120  performs conversion from the AC voltage to the battery voltage by using the switching power source  121 , and charges the battery  17 . 
     The condition B is a condition in which the system load power is higher than the rated power of the AC adapter  40  and there is power left in the battery  17 . The charging information of the battery  17  is obtained by the EC  119  through the I 2 C bus  2 . In the condition B, the charger circuit  120  turns off the switch S 1  and turns on the switch S 2 . In the circuit in the condition B, the system load power is supplied by the power from the AC adapter  40  and the battery  17 . From times T 1  to T 2 , the system load power increases, and reaches the maximum load power of the system at the time T 2 . After the maximum load capacity of the system is reached, the maximum load of the system is handled by the power from the AC adapter  40  and the power form the battery  17 . Therefore, the AC adapter  40  can be reduced in size compared with when the maximum load of the system is handled only by the AC adapter  40 . 
     The condition C is a condition in which the system load capacity is reduced forcibly and maintained at the rated capacity of the AC adapter  40 . That is, it is a condition in which no power is left in the battery  17  although the system load capacity is higher than the rated capacity of the AC adapter  40 . The EC  119  accesses the battery  17  through the I 2 C bus  2 , and detects that the remaining power of the battery  17  is zero. Then, the EC  119  controls the charger circuit  120  to turn on the switch S 1  and turn off the switch S 2 . In the circuit in the condition C, the system load power is supplied by the power from the AC adapter  40 . 
     The EC  119  also transmits an SMI (system management interrupt) signal to the CPU  111 . The SMI signal transmitted to the CPU  111  is processed by the BIOS. For example, this SMI signal provides an instruction to switch the computer  10  to the power saving mode. An example of the power saving mode is a slot ring. The slot ring is to reduce the operating frequency of the CPU  111  or the like or to intermittently operate the CPU  111  or the like. 
     Next, the method of power control performed by the EC  119  will be described by using  FIG. 5 . First, the EC  119  determines whether the computer  10  is driven by the battery  17  or not (step S 11 ). 
     When determining that the computer  10  is driven by the battery  17  as a result of the determination at step S 11  (Yes of step S 11 ), the EC  119  ends the power control procedure. When determining that the computer  10  is not driven by the battery  17  as a result of the determination at step S 11  (No of step S 11 ), the EC  119  determines whether the system load power is higher than the rated power of the AC adapter  40  or not (step S 12 ). 
     When determining that the system load power is not more than the rated power of the AC adapter  40  as a result of the determination at step S 12  (No of step S 12 ), the EC  119  charges the battery  17  by the surplus power with the AC adapter  40  as the power source (step S 13 ). The operation mode of the computer  10  is kept the normal operation mode. 
     On the other hand, when the system load power is higher than the rated power of the AC adapter  40  as a result of the determination at step S 12  (Yes of step S 12 ), the EC  119  determines whether there is power left in the battery  17  or not (step S 14 ). When determining that there is power left in the battery  17  as a result of the determination at step S 14  (Yes of step S 14 ), the EC  119  sets the AC adapter  40  and the battery  17  as the power sources (step S 15 ). When determining that there is no power left in the battery  17  as a result of the determination at step S 14  (No of step S 14 ), the EC  119  sets the AC adapter  40  as the power source, and sets the operation mode of the computer  10  to the power saving mode (step S 16 ). 
     As mentioned above, in the present embodiment, power can be simultaneously supplied from both the AC adapter  40  and the battery  17 . Therefore, the AC adapter  40  can be set at a rated power lower than the system load power of the computer  10 . That is, size reduction of the AC adapter  40  can be realized. 
     Moreover, when the system load power of the computer  10  is not more than the rated power of the AC adapter  40 , the battery  17  can be charged by using the surplus power. With this structure, when the system load is low, the driving time when the computer  10  is driven by the battery  17  can be prolonged by charging the battery  17  while driving the computer  10 , so that convenience improves. 
     Moreover, when the system load power of the computer  10  is higher than the rated power of the AC adapter  40  and there is no power left in the battery  17 , the computer  10  is set in the power saving mode. An example of the power saving mode is to reduce the operating frequency of the CPU  111 , the graphics controller  114  or the like or to intermittently operate the CPU  111 , the graphics controller  114  or the like. With this structure, size reduction of the AC adapter  40  is realized while user operability is hardly affected. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. Indeed, the novel apparatus and method described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the apparatus and method, described herein may be made without departing from the sprit of the invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and sprit of the invention.