Apparatus for supplying power from portable computer to extended station

Abstract: An apparatus for supplying electric power from a portable computer (1) to an extended station (docking unit) (2), the portable computer having an electric power source (7,8), and being detachably mountable to the extended station. The apparatus includes means (11) for detecting whether or not the portable computer (1) is connected to the extended station (2) and power supplying means (3) for supplying electric power from the electric power source (7,8) of the portable computer (1) to the extended station (2) when the detecting means (11) detect that the portable computer is connected with the extended station.

Description: This invention relates to a power source apparatus of portable computer such as a notebook type personal computer, a word processor, and so forth. More specifically, this invention relates to an apparatus for supplying electric power from a portable computer to an extended station (for example, a base station or docking unit) provided for the portable computer. The present invention relates also to an apparatus for supplying electric power from a portable computer to an extended station when the portable computer has an add-on battery and/or an AC adaptor that can be connected to the portable computer. Recently, portable computers constructed to have a small size and a light weight have become widespread in consideration of portability, such as notebook-type personal computers and wordprocessors, and extended stations for portable computers, for extending various functions of the portable computers, are fitted mechanically and electrically to the portable computers. When a portable computer and an extended station are connected, their electric circuits are connected with each other through connectors. These sensitive and delicate circuits must be protected from an excessive load or damage due to short-circuit that may occur if the connectors are fitted incorrectly, e.g. obliquely, and so forth. In general, batteries have life characteristics such that, if the power consumption per battery cell is great, battery life becomes short. However, power consumption is increased when an extended station is connected to the computer. In conventional type portable computers and extended stations according to the prior art, it has been necessary to stop the system when the portable computer and the extended station are connected, and to turn off a power source, so as to prevent damage to the sensitive electric circuits, and to activate the system again by turning on the power source. A battery mounted in a conventional portable computer supplies power from the same number of cells even when power consumption changes due to the extended station, etc. JP-A-08-076879 by Citizen Watch Co. Ltd, for example, describes the use of a peripheral device while it is superposed with, and below, the portable computer. JP-A-08-076889 by the same applicant, on the other hand, discloses a connection structure between an information processing apparatus and a peripheral apparatus, wherein a pair of connector shell portions for the connection with a computer are formed on the housing of an extended unit connected to the information processing apparatus, these shell portions and the housing on which the shell portions are formed are integrally molded from a resin material, and metallic plating is applied to the entire surface. JP-A-07-84689 by IBM Corporation discloses that, in a portable computer of a type which is put on a docking apparatus for a portable computer and which has a signal transmission electric connection portion for transmission with the docking apparatus, a portable computer, including a contact portion which is disposed on the main body of the portable computer, is connected to a reference potential portion of the computer main body and is brought into contact with a portion to be connected to the reference potential portion of the main body of the docking apparatus at a position spaced apart from the signal transmission electric connection portion, in order to reduce an electromagnetic wave noise resulting from the potential difference between the portable computer and its docking apparatus. The prior art technologies involve a problem that, if the power consumption quantity per cell of the battery becomes great due to fitting of the extended station, the battery life is shortened. EP-A-0 421 361 discloses an apparatus according to the preamble of accompanying claim 1. In this apparatus, although a second battery is provided in addition to a main battery, no detecting means is provided for detecting whether the second battery is present. Power to the whole system is made regardless of whether the second battery is present or not. JP 56 016219A discloses an apparatus in which a status output of a peripheral unit is monitored and, if the status output is not active, no power is fed from a main unit to the peripheral unit. An embodiment of the present invention may provide an apparatus for supplying power from a portable computer to an extended station which, when a power consumption quantity per cell of a battery increases, can prevent the battery life from becoming short. According to a first aspect of the present invention, there is provided an apparatus for supplying electric power from a portable computer to an extended station, which is adapted to be removably attached to said computer, said computer comprising: a built-in power supply; and an add-on battery removably attached on and connected to said portable computer; and said apparatus comprising: power supplying means for supplying electric power from said portable computer to said extended station; characterised by: detecting means for detecting whether said add-on battery is connected to said portable computer; wherein said power supplying means is operable to supply electric power to said extended station in response to detection by said detecting means that said add-on battery is connected to said portable computer. According to a second aspect of the invention, there is provided a portable computer to which an extended station can be removably attached, said computer comprising: a built-in power supply; an add-on battery removably attached on and connected to said portable computer; and power supplying means for supplying electric power from said portable computer to said extended station; characterised by: detecting means for detecting whether said add-on battery is connected to said portable computer; wherein said power supplying means is operable to supply electric power to said extended station in response to detection by said detecting means that said add-on battery is connected to said portable computer. According to a third aspect of the present invention, there is provided a method of supplying electric power in a portable computer to which an extended station can be removably attached, said portable computer comprising a built-in power supply; an add-on battery removably attached on and connected to said portable computer; and power supplying means for supplying electric power from said portable computer to said extended station; characterised by the steps of: automatically detecting whether said add-on battery is connected to said portable computer; and operating said power supplying means to supply electric power to said extended station in response to detection that said add-on battery is connected to said portable computer. According to the construction described above, when the built-in battery of the portable computer is the only power source under the state where the portable computer is fitted to the extended station, the power is not supplied to the extended station, and when the add-on battery is connected to the portable computer or when the other, third power source, such as the AC adaptor, is connected, the power is supplied from the portable computer to the extended station. Therefore, since the power is not supplied to the exteneded station when only the built-in battery of the portable computer is the power source, the extended station cannot be used, and the power consumption per cell of the built-in battery by the use of the extended station can be prevented. In this way, shortening of life of the internal power source (built-in battery) can be prevented. Reference is made, by way of example, to the accompanying drawings in which: Fig. 1 is an explanatory view of an embodiment of the present invention; Fig. 2 shows connection portions between a portable computer and an extended station; Fig. 3 shows the connection procedures between the portable computer and the extended station; Fig. 4 is an explanatory view of the principle of a connection confirmation circuit; Fig. 5 is an explanatory view of the principle of a power supply detection circuit; Fig. 6 is a perspective view showing the state where the portable computer, an add-on battery and the extended station are not yet fitted; Fig. 7 is a perspective view showing the state where the add-on battery is fitted to the portable computer main body; and Fig. 8 is a perspective view showing the state where the portable computer and the add-on battery are further fitted to the extended station from the state shown in Fig. 7. Fig. 1 is an explanatory view of an embodiment of the present invention, showing a portable computer 1 together with an extended station 2 for the portable computer, which may be a docking unit to which the portable computer is docked, or alternatively a peripheral unit (such as a printer) to which the portable computer is connected via a cable. In this embodiment, the apparatus of the invention is incorporated into the personal computer. Reference numeral 3 denotes a power source switch for the extended station, reference numeral 4 denotes a battery protection switch, reference numeral 5 denotes a DC-IN connector of the portable computer, reference numeral 6 denotes a DC-IN connector of the extended station, reference numeral 7 denotes a built-in battery of the portable computer, reference numeral 8 denotes an add-on battery of the portable computer, reference numeral 9 denotes a capacity detection circuit, reference numeral 10 denotes a system circuit, reference numeral 11 denotes a connection confirmation circuit, reference numeral 12 denotes a power supply detection or judgement circuit, reference numeral 13 denotes a contact portion for confirming the connection on the portable computer side, reference numeral 14 denotes a contact portion for confirming the connection on the extended station side, reference numeral 15 denotes a connection connector on the portable computer side, and reference numeral 16 denotes a connection connector on the extended station side. The power supply switch 3 for the extended station is turned ON or OFF in accordance with the signal from the current supply detection circuit 12, and controls whether or not the power should be supplied from the portable computer 1 to the extended station 2. The system circuit and the portable computer 1 send the signals, which vary depending on the resume state or suspend state, to the power supply detection circuit 12. The connection judgement circuit 11 sends the signal, which varies depending on whether or not fitting of the extended station 2 to the portable computer 1 is finished, to the power supply judgement circuit 12. The power supply detection circuit 12 sends the ON command of the power supply switch 3 for the extended station only when the signal from the system circuit 10 represents the resume state and the signal from the connection confirmation circuit 11 represents that fitting of the extended station 2 to the portable computer 1 is completed, and sends the OFF signal at other times. Whether or not fitting of the extended station 2 to the portable computer 1 is finished is judged by the connection confirmation circuit 11 as described above. Hereinafter, judgement as to whether or not fitting of the extended station 2 to the portable computer 1 is finished will be explained. Fig. 2 shows the mechanical connection portion between the portable computer 1 and the extended station 2, and Figs. 3(a) to 3(c) show the mechanical connection procedures between the portable computer 1 and the extended station 2, that is, the separation state, the incomplete connection state and the connection completion state, respectively. Fig. 4 shows the connection confirmation circuit 11 on the portable computer side 1 and Fig. 5 shows an AND gate of the power supply detection circuit 12. As shown in Figs. 2 and 3, whether or not the portable computer 1 and the extended station 2 are reliably connected, that is, whether or not the connection between them is completed, is confirmed by a mechanical method. The contact portion 13 for confirming the connection is disposed adjacent to the connection connector 15 on the portable computer 1 side, and the contact portion 14 for confirming the connection is disposed adjacent to the connection connector on the extended station side 2, too (Fig. 2). As shown in Fig. 3 at (c), the contact portion 13 for confirming the connection on the side of the portable computer 1 and the contact portion 14 for confirming the connection on the side of the extended station are disposed so that only when the connection connector 15 on the portable computer 1 is sufficiently fitted into the connection connector 16 on the extended station 2, do they come into contact with each other. In the connection confirmation circuit 11 (Fig. 4) on the side of the portable computer 1, a signal of CDATCH# is always detected, and the voltage of this CDATCH# becomes lower when both connection confirmation contact portions 13 and 14 are connected and becomes high when they are not connected. Therefore, when the voltage of CDATCH# is low, the connection between the portable computer 1 and the extended station is judged as being completed. The suspend/resume state of the portable computer 1 is held by the system circuit 10 as described already. A signal voltage TRIS-3V from the system circuit 10 represents the resume state when the voltage is high and represents the suspend state when the voltage is low. In the AND gate of the power supply detection circuit 12 shown in Fig. 5, the CDATCH# signal and the TRIS-3V# signal are inputted to the AND gate of the power supply judgement circuit 12, and the power supply switch 3 for the extended station is turned ON only when the CDATCH# voltage is low and the TRIS-3V# voltage is high, as shown in Table 1. TRIS-3V voltage CDATCH voltage power supply switch (3) for extended station low low OFF low high OFF high low ON high high OFF When only the built-in battery 7 of the portable computer 1 is available for supply of power to the portable computer 1 fitted to the extended station 2, the power is not supplied to the extended station, but when the add-on battery 8 is connected to the portable computer 1 or when the AC adaptor (not shown) is connected to the DC-IN connector 5 or 6, the power is supplied from the portable computer 1 to the extended station 2. The construction for accomplishing this feature will be now explained. The battery protection switch 4 is turned ON and OFF in accordance with the signal from the capacity detection circuit 9 of the add-on battery 8, and whether or not the built-in battery 7 is allowed to participate in the power supply to the extended station 2 is judged. However, the built-in battery 7 does not participate in the power supply itself to the extended station 2. The capacity detection circuit 9 of the add-on battery 8 estimates the capacity of the add-on battery 8 by measuring the voltage, and permits the battery protection switch 4 to supply power from the built-in battery 7 to the extended station 2 only when the add-on battery 8 has a capacity to accommodate power consumption under the state where the extended station 2 is fitted to the portable computer 1. When the add-on battery 8 is not connected, the capacity detection circuit 9 judges that the add-on battery 8 does not have sufficient power capacity. Fig. 6 is a perspective view of the portable computer main body 1, the add-on battery 8 and the extended station 2. Fig. 7 is a perspective view showing the state where the add-on battery 8 is fitted to the portable computer main body 1 and Fig. 8 is a perspective view showing the state where the add-on battery 8 and the computer main body 1 are fitted together and mounted on the extended station 2. As described above, the add-on battery 8 can be fitted to and removed from the portable computer 1. In the present invention, however, the portable computer 1 can be further fitted to the extended station 2 while the add-on battery 8 is fitted to the portable computer 1. To this end a recess 31 for accommodating the add-on battery 8 is disposed on the extended station 2. Since this recess 31 is not a mere opening but is a recess having a bottom portion, a wiring pattern such as a printed board for supplying and transmitting power and signals between the front and rear areas of the extended station 2 can be disposed below this recess 31, and the space can be utilized effectively. In addition, when the portable computer main body 1 is fitted to the extended station, the connector 15 (see Figs. 1 and 2) disposed on the back of the portable computer main body 1 fits to the connector 16 of the extended station 2 and electric connection is thus established between them. Audio speakers 20 are disposed on both sides of the front portion of the extended station 2. These speakers 20 are inclined downward towards both side edges. Therefore, thin speakers 20 can be effectively disposed. The back of the portable computer main body 1 keeps contact with the upper surface 21 of the extended station 2 under the state where the portable computer 1 is fitted, but because the speakers 20 on both sides are inclined, the portions of these speakers 20 define the spaces from the back of the portable computer main body 1 and for this reason, the speaker sound can be effectively diffused. According to the present invention described above, the power is not supplied from the portable computer to the extended station under the state where fitting of the extended station to the portable computer main body is not completed. Only after fitting of the extended station to the portable computer is completed, is the power supplied from the portable computer to the extended station. Therefore, the connection operation between the portable computer and the extended station can be carried out without turning off the power source of the portable computer, and moreover, sensitive electric circuits can be prevented from receiving an excessive load or damage due to a short-circuit resulting from incomplete connection of the connectors such as when the connectors are obliquely inserted. When the portable computer is fitted to the extended station in the present invention, the power is not supplied to the extended station if the built-in battery of the portable computer is the only power source. When an add-on battery or other power source, such as an AC adaptor, is connected to the portable computer, on the other hand, the power is supplied from the portable computer to the extended station. Therefore, when the built-in battery of the portable computer is the only power source, power is not supplied to the extended station and the extended station cannot be used. In other words, the excess power consumption per unit cell of the built-in battery by the use of the extended station can be prevented, and the drop of life of the built-in battery can be prevented. It should be understood by those skilled in the art that the foregoing description relates to only some preferred embodiments of the disclosed invention, and that various changes and modifications may be made to the invention without departing from the scope thereof.

Claims: An apparatus for supplying electric power from a portable computer (1) to an extended station (2), which is adapted to be removably attached to said computer (1), said computer comprising: a built-in power supply (7); and an add-on battery (8) removably attached on and connected to said portable computer (1); and said apparatus comprising: power supplying means (3, 4) for supplying electric power from said portable computer (1) to said extended station (2); characterised by : detecting means (9) for detecting whether said add-on battery (8) is connected to said portable computer (1); wherein said power supplying means (3, 4) is operable to supply electric power to said extended station (2) in response to detection by said detecting means (9) that said add-on battery (8) is connected to said portable computer (1). An apparatus as set forth in Claim 1, wherein: another power supply (5) is connectable to said personal computer in addition to said built-in battery (7)and said add-on battery (8); said detecting means (9) is further operable to detect whether said another power supply (5) is connected to said portable computer (1); and said power supplying means (3, 4) is further operable to supply electric power to said extended station (2) in response to detection by said detecting means (9) that said another power supply (5) is connected to said portable computer (1). An apparatus as set forth in claim 2, wherein said another power supply (5) is an AC adapter. A portable computer (1) to which an extended station can be removably attached, said computer comprising: a built-in power supply (7); an add-on battery (8) removably attached on and connected to said portable computer (1); and power supplying means (3, 4) for supplying electric power from said portable computer ('1) to said extended station (2); characterised by : detecting means (9) for detecting whether said add-on battery (8) is connected to said portable computer (1); wherein said power supplying means (3, 4) is operable to supply electric power to said extended station (2) in response to detection by said detecting means (9) that said add-on battery (8) is connected to said portable computer (1). A portable computer as set forth in claim 4, wherein another power supply (5) is connectable to said personal computer (1) in addition to said built-in battery (7) and said add-on battery (8); said detecting means (9) is further operable to detect whether said another power supply (5) is connected to said portable computer (1); and said power supplying means (3, 4) is further operable to supply electric power to said extended station (2) in response to detection by said detecting means (9) that said another power supply (5) is connected to said portable computer (1). A portable computer as set forth in claim 5, wherein said another power supply (5) is an AC adapter. A method of supplying electric power in a portable computer (1) to which an extended station (2) can be removably attached, said portable computer (1) comprising a built-in power supply (7); an add-on battery (8) removably attached on and connected to said portable computer (1); and power supplying means (3, 4) for supplying electric power from said portable computer (1) to said extended station (2); characterised by the steps of: automatically detecting whether said add-on battery (8) is connected to said portable computer (1); and operating said power supplying means (3, 4) to supply electric power to said extended station (2) in response to detection that said add-on battery (8) is connected to said portable computer (1). A method as set forth in claim 7, wherein another power supply (5) is connectable to said personal computer (1) in addition to said built-in battery (7) and said add-on battery (8), and wherein: said detecting step further comprises detecting whether said another power supply (5) is connected to said portable computer (1); and said step of operating said power supplying means further comprises supplying electric power to said extended station (2) in response to detection that said another power supply (5) is connected to said portable computer (1). A method as set forth in claim 8, wherein said another power supply (5) is an AC adapter.

Inventors: SAEKI MITSUO, SHIN TAKAHIRO, TAKIMOTO TSUYOSHI, SAEKI, MITSUO, SHIN, TAKAHIRO, TAKIMOTO, TSUYOSHI, Saeki, Mitsuo, c/o Fujitsu Limited, Shin, Takahiro, c/o Fujitsu Limited, Takimoto, Tsuyoshi, c/o Fujitsu Limited
Applicants: FUJITSU LTD, FUJITSU LIMITED
Application year: 1997
Main classification: G06F1
IPC codes: G06F15, G06F3, G06F1