Power supply arrangement and connector

A power supply arrangement for a main unit of a portable, battery operated information processing apparatus including at least a microprocessor and a battery. The power supply arrangement comprising an expansion unit for the portable information processing apparatus for expanding the operation capability of the main unit of the information processing apparatus upon connection therewith. The expansion unit includes a power circuit for converting an a.c. voltage to a d.c. voltage, the power circuit enabling supply of power to the main unit when the expansion unit is connected with the main unit. Also, a connection arrangement is provided for the expansion unit and main unit.

BACKGROUND OF THE INVENTION 
The present invention relates to a power supply arrangement for a portable 
information processing apparatus such as a laptop computer. 
Due to recent advanced semiconductor integration technology and packaging 
technology, hand-held and portable information processing apparatuses such 
as laptop computers or the like are becoming more prevalent. Such 
apparatuses, as described in Japanese Laid-Open Patent Application No. 
61-218326, are basically battery operated, and are designed to connect 
with an a.c. adapter so that they operate by an a.c. power source or for 
connection with an external battery charging unit, as shown in FIG. 2 
which is representative of the prior art. 
FIG. 2 illustrates a main unit 1 of the information processing apparatus 
(hereinafter termed the "main unit"), an a.c. adapter 2, an a.c. cable 4, 
and a d.c. power cord 5 which supply power to the main unit. An expansion 
unit 3, such as a floppy disk unit is connected externally to the main 
unit 1, and a signal cable 6 connects the expansion unit 3 to the main 
unit. Conventionally, when the main unit 1 is used as a stand-alone 
equipment, it operates by the internal battery, or when it is used in 
connection with the expansion unit 3, it is further connected with the 
a.c. adapter 2 so that power is supplied from the a.c. adapter 2 instead 
of the battery in the main unit 1. The reason for this operational 
condition is that equipping the main unit 1 with a battery having 
sufficient power to drive the expansion unit 3 increases the weight and 
also the cost of a main unit 1. Since the weight and price of a portable 
apparatus are crucial factors for the user in choosing a model, 
conventionally, the battery built in the main unit 1 has its capacity 
limited to the minimum requirement. 
The foregoing conventional technique, when the expansion unit is connected 
to the main unit, necessitates supply of power from the main unit to the 
expansion unit through the connection of an a.c. adapter. As a result, the 
number of cables running out of the main unit increases, which not only 
spoils the look of the operational environment, but also compels the user 
to labor in connecting and disconnecting the a.c. adapter to the main unit 
each time the apparatus is transported for use. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a power 
supply arrangement for a portable information processing apparatus which 
eliminates the need for a separate a.c. adapter in using the expansion 
unit, thereby relieving the user of the labor of cable connection while 
retaining the good look of the apparatus installation. 
It is another object of the present invention to provide a connector 
arrangement for a portable information processing apparatus. 
In order to achieve the above objects, the present invention provides a 
power supply arrangement for the main unit of a portable information 
processing apparatus having at least a microprocessor and a battery, and 
an expansion unit which expands the function or operation capability of 
the main unit of the information processing apparatus and which includes a 
power circuit which converts an a.c. voltage into a d.c. voltage, so that 
when the apparatus is used with the expansion unit connected to the main 
unit, power is supplied from the expansion unit to the main unit. 
In accordance with a feature of the present invention, the main unit 
comprises a switching device which selects the output of the battery or 
the output of the power circuit, and a switching controller which operates 
on the switching device to act upon detecting that the expansion unit is 
connected to the main unit. The switching controller is constructed, for 
example, to detect the connection of the expansion unit in a mechanical 
manner, or to detect the connection of the expansion unit to the main unit 
by detecting that the supply voltage from the expansion unit is within the 
prescribed voltage range. 
The present invention also provides an apparatus connection arrangement for 
connecting the main unit of a portable information processing apparatus 
having at least a microprocessor, a battery and a display panel to an 
expansion unit which expands the function or operation capability of the 
main unit, wherein the connection arrangement includes a first connector 
provided on the upper side of the expansion unit and a second connector 
provided on one end of the main unit for direct connection with the first 
connector so that the main unit is connected electrically and mechanically 
to the expansion unit in such a state that the display panel is inclined 
by using the expansion unit as a support stage therefor. 
In the apparatus connection arrangement, the expansion unit may be provided 
with an air flow generator, and a path for conducting the air flow from 
the expansion unit to the main unit may be provided. The expansion unit 
may be provided therein with a power circuit which converts the a.c. 
voltage into a d.c. voltage, so that when the expansion unit is connected 
to the main unit, power is supplied from the expansion unit to the main 
unit. 
The expansion unit for expanding the function or operation capability of 
the main unit of a portable information processing apparatus having at 
least a microprocessor and a battery comprises any of an input/output 
device, an external storage unit or a memory element, a power circuit 
which receives an a.c. voltage from an a.c. power source through a power 
cable and converts the a.c. voltage into a d.c. voltage, and an 
arrangement for supplying the d.c. voltage from the power circuit to the 
main unit. 
The connector arrangement in accordance with the present invention 
comprises a male connector housing, a female connector housing, a circuit 
opening/closing device having normal-open or normal-closed contacts 
provided on one or both of the connector housings, and an actuator which 
turns on the normal-open contacts or turns off the normal-closed contacts 
when the connector housings are coupled completely. 
The conventional a.c. adapter has its power output intended to supplement 
the power for the expansion unit which cannot be provided by the main 
unit. On this account, the output of the a.c. adapter is supplied to the 
expansion unit by way of the main unit. Namely, when the expansion unit is 
used, a power source other than the battery of the main unit is required, 
and its power is consumed by the expansion unit. The present invention is 
constructed so as to build a power circuit in the expansion unit so that 
power is supplied from the expansion unit to the main unit, instead of 
supplying power from main unit to the expansion unit. This not only 
eliminates the need for an a.c. adapter in adding an expansion unit, but 
also relieves the user of the labor of connecting and disconnecting only 
the main unit in the device configuration including the main unit and 
expansion unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, FIG. 1 shows an embodiment of the present 
invention wherein the main unit 1 of a portable information processing 
apparatus such as a laptop computer which incorporates a battery, and an 
expansion unit 7 which expands the function or operation capability of the 
main unit incorporates a power circuit and is provided with an a.c. cord 4 
and a connection cable 8 for connecting the main and expansion units. 
When the user carries and uses the main unit 1, it is operated on its 
built-in battery. When the user uses a peripheral device which is not 
included in the main unit 1, e.g., an expansion unit 7 such as an external 
storage unit, the expansion unit 7 is connected to the main unit 1 using 
the connection cable 8. In this case, the power circuit in the expansion 
unit 7 supplies power not only to the components in the expansion unit 7, 
but also to the components in the main unit 1 through the connection cable 
8. It is also possible to charge the battery in the main unit 1 in this 
arrangement. 
Next, an example of the internal block arrangement of this invention will 
be explained with reference to FIG. 3 which shows the arrangement of the 
internal blocks of the embodiment of FIG. 1, for example. In FIG. 3, the 
main unit 1 incorporates a microprocessor 10 (hereinafter termed CPU), a 
memory 11, a display panel 12 such as a liquid-crystal, 
electroluminescence, or plasma display panel, a display interface 13 for 
operating the display panel 12, and a basic input/output (I/O) device 14, 
such as a keyboard, printer or communication device. The basic 1/O device 
14 may include an external storage unit, e.g., a floppy disk unit. The 
main unit also includes a battery 15, and a power switching controller 16 
which operates on a switching device 17 to select the battery 15 or 
external power source 80 by monitoring the power supply status from the 
expansion unit 7 to the external power source 80. The main unit further 
includes an internal signal bus 18, a first interface (hereinafter termed 
IF1) between signal lines 81 of the peripheral devices of the expansion 
unit 7 and the internal bus 18, and a connector 20 which connects the 
cable 8 to the main unit 1. The expansion unit 7 includes a power circuit 
70, an extended I/O section 71 including card slots and network interface, 
for example, a file 72 for an external storage device such as a floppy 
disk unit, hard disk unit, tape cartridge unit or optical disk, an 
extended memory 73, a second interface 74 (hereinafter termed IF2) for 
connecting an internal bus 75 of the expansion unit 7 to the IF1 in the 
main unit 1, and an a.c. cord 4. 
The expansion unit 7 in accordance with this invention includes at least 
the extended I/O section 71, file 72 and extended memory 73. The power 
circuit 70 supplies power not only to the expansion unit 7, but also to 
the main unit 1 through the external power line 80. The connection cable 8 
may be combined with the power line 80 so that the expansion unit 7 can 
easily be connected or disconnected with the main unit through a single 
connection. Alternatively, the signal line 81 and power line 80 may have 
independent connectors, in accordance with features of the present 
invention which enable supply of power from the expansion unit 7 to the 
main unit 1. The power switching controller 16 in the main unit 1 may 
operate by mechanically detecting the connection of the connector 20 on 
the connection cable 8, or may operate by monitoring the voltage of the 
power line 80. Accordingly, the power switching device 17 can employ 
various schemes including a mechanical switch and electrical switch such 
as a semiconductor switching device. Adoption of a mechanical switch will 
reduce the cost, or adoption of an electrical switch will enable the main 
unit 1 to operate on the built-in battery 15 when the power circuit within 
the expansion unit 7 is turned off. Any of the switching schemes may be 
utilized in accordance with the present invention. 
Another embodiment of the present invention will be described with 
reference to FIGS. 4A and 4B wherein FIG. 4A shows the main unit 1' of a 
portable information processing apparatus incorporating a battery, a 
display panel 12 equipped on the main unit, an external keyboard 9, an 
expansion unit 7' which incorporates a power circuit, a connector block 
82, and an a.c. cord 4. In this embodiment, the main unit 1' is operative 
by itself based on its built-in battery. Instead of connecting the 
external keyboard 9 as shown, another input device such as a touch panel 
may be equipped on the display panel 12. The main unit 1' is connected to 
the connector block 82 as shown in FIG. 4B and this configuration allows 
the use of a larger, more convenient keyboard 9'. This embodiment enables 
the connection of the main unit 1' and expansion unit 7' through the 
connector block 82 instead of using the connection cable 8 used in the 
embodiment in FIG. 1, and provides the following effectiveness: 
(1) The component devices can more easily be connected or disconnected by 
the user. 
(2) The distance between the main unit 1' and the expansion unit 7' can be 
reduced, allowing the signal lines to run separately, whereby the 
apparatus can be operated stably at a higher clock frequency. 
(3) The connector block 82 can be shielded easily, and the electromagnetic 
characteristics (EMC) can be enhanced. 
The arrangement of FIGS. 4A and 4B can be modified as shown in FIG. 5, 
which shows another embodiment of the present invention. An information 
processing apparatus using a CPU has its power dissipation increased when 
the CPU is operated at a higher frequency, resulting in an increased heat 
dissipation requirement for the CPU and associated control circuit. In the 
arrangement of FIG. 4B, when the main unit 1' is operated at a clock 
frequency higher than the case of operating it alone, sufficient power can 
be supplied from the expansion unit 7', but a remaining problem is how to 
deal with internal heat of the main unit 1. The embodiment of FIG. 5 is 
suitable for heat removal due to an increase of the CPU clock frequency of 
the main unit 1' when it is connected with the expansion unit 7'. 
FIG. 5 is a schematic side cross-sectional view of FIG. 4(B). The expansion 
unit 7' is provided therein with a cooling fan 103, and a blower duct 105 
is provided inside the connector block 82. Parts 100, 101 and 102 
represent components of the main unit 1' in which heat dissipation 
requirements increase as the clock frequency is raised. In operation, in 
response to the connection of the main unit 1' with the expansion unit 7', 
the power switching controller 16 of FIG. 3, for example, switches the 
power supply from the battery 15 in the main unit 1' to the external power 
line 80. At this time, the control output of the power switching 
controller 16 is used to raise the clock frequency of the CPU 10 as 
described hereinafter. Then, the main unit 1' which is now supplied with 
sufficient power from the expansion unit 7' operates at a higher speed 
than the operation based on the built-in battery 15. Consequently, heat 
dissipation requirements of the parts 100, 101 and 102 also increase, 
resulting in a rising internal temperature of the main unit 1'. The 
temperature rise is responded to by the activation of a cooling fan 103 in 
the expansion unit 7', and cooling air flows along the path shown by arrow 
104 through the blower duct 105 in the connector block 82 and passes out 
through a vent 51 formed in the upper section of the main unit 1'. The 
parts 100, 101 and 102 are then cooled by the air. The air flow direction 
may be opposite to that shown. It is also possible to support the 
connector block 82 pivotably about a shaft 53 so that the tilt angle of 
the display panel 12 can be varied. In this case, a sealing arrangement 
(not shown) is provided if necessary so that the entirety of the air flow 
does not pass out at the linkage of the connector block 82 on the upper 
surface of the expansion unit 7'. According to this embodiment, as 
described, the expansion unit 7' supplies not only power but also air 
flow, allowing the apparatus to operate at a higher speed when the 
expansion unit is used. The apparatus is thus up-graded regardless of the 
capacity of the battery 15 built in the main unit 1'. 
FIGS. 6A, 6B and 7A, 7B illustrate different arrangements for providing a 
higher CPU clock frequency. FIG. 6A shows an embodiment, in which a pair 
of oscillators 200, 201 respectively generate clocks having different 
oscillating frequencies f1, f2 (f1&gt;f2), and these clocks are switched by a 
clock switching controller 203, and a clock having a frequency fc is 
supplied to the CPU 10. FIG. 6B shows another embodiment, in which a 
single oscillator 200 generates a clock having a frequency f1 which is 
supplied to a divider 202 and the clock switching controller 203. The 
divider 202 produces a clock of a frequency f2' (f1&gt;f2') by dividing the 
clock delivered from the oscillator 200, and the clock (fc) is provided to 
the CPU 10 through the clock switching controller 203. In both 
embodiments, when the main unit is powered by the battery 15, the lower 
frequency f2 or f2' is selected as the clock (fc) by the clock switching 
controller 203, and when the power is supplied from the expansion unit, 
the higher frequency clock (f1) is selected as the clock (fc) by the clock 
switching controller 203. 
FIGS. 7A and 7B show examples of the clock switching controller 203 of 
FIGS. 6A, 6B. In FIG. 7A, the clock switching controller 203 includes a 
switching device 204, and an I/O register 205. The I/O register 205 can be 
set through the internal signal bus 18 with a program executed by the CPU 
10, and the switching device 204 is controlled by the output of the I/O 
register 205 to change the clocks having the frequencies f1 and f2. In 
FIG. 7B, with the function of the above mentioned power switching 
controller 16, the clock switching controller 203 changes the clocks 
having the frequencies f1 and f2 (f2') at the same timing as the 
controller 16 controls the power switching device 17 to select the battery 
15 or the external power circuit 70. 
In the operation shown in FIG. 7A, although it is necessary to control the 
switching device 204 with the program, the CPU can change the operation 
frequency at a voluntary timing, so that if necessary, it becomes possible 
to execute a low power operation with a lowering of the operation 
frequency during the operation with the external power circuit 70. As 
such, it becomes possible to reduce the total power of the system during 
the waiting state of the system, for example, the duration of waiting for 
an input from a keyboard. 
In the operation shown in FIG. 7B, it is not necessary to control the 
switching device 204 with the program, and it is possible to automatically 
raise the operation frequency of the CPU 10 when the power is supplied 
from the external power line 80. Therefore, it is not necessary to change 
the basic program of the CPU. Further, since it is possible to commonly 
use the function of the power switching controller 16, it becomes possible 
to simplify the hardware structure of the system. 
In the above description, it is assumed that there are no changing hazards 
in the switching device 204. The changing hazards may be considered, for 
example, a transient signal having waveforms, the minimum period of which 
is smaller than t1 wherein t1 is the period of the clock having the 
frequency f2. Since the structure of the switching device 204 with no 
changing hazards is apparent to a person having ordinary skill in this 
art, it is not described herein. 
Now, in FIG. 6A, although it is necessary to use two oscillators 200, 201, 
it is possible to determine any values for the frequencies f1, f2. In 
contrast, in FIG. 6B, the frequency f2' is selected by f1/n, where n is an 
integer and represents the divider value. However, since it needs only one 
oscillator, it is possible to reduce the cost of the system. Further, the 
clock switching controller 203 of FIG. 6A, and the divider 202 and the 
clock switching controller 203 of FIG. 6B could be also included in the 
CPU 10. 
FIGS. 8A-8C and 9A, 9B show details of the structure of a connection unit 
of the main unit 1' and the connector block 82 as shown in FIGS. 4A, 4B. 
FIG. 8A shows positions of connection units 300, 300' of the main unit 1' 
to be connected to the expansion unit 7'. In FIG. 8A, two connection units 
300, 300' are illustrated which, respectively, correspond to horizontally 
and vertically oblong screens of the display. Needless to say, it is 
possible to form only one of the connection units 300, 300'. FIG. 8B 
illustrates a side sectional view of an embodiment of the connection unit 
300. A connector 301 is provided for transmitting signals from the main 
unit 1' to the expansion unit 7'. Further, a shutter 310 is provided for 
protecting the interior of the main unit 1' and the connector 301. The 
shutter 310 is opened into the interior of the main unit 1' and, for 
example, attached with a spring (not shown). 
FIG. 8C illustrates a side sectional view of a state, in which the 
connection unit 300 of the main unit 1' is connected with the connector 
block 82. A connector 302 of the connector block 82 pushes and opens the 
shutter 310, so that the connector block 82 is connected to the main unit 
1'. In this state since there exists a passage 311 for air flow, as 
previously described, it becomes possible to air-cool the main unit 1' in 
a case that the power is supplied to the main unit 1' from the expansion 
unit 7', and the main unit 1' is operated at high speed. 
FIGS. 9A-9C show other embodiments, in which a thin main unit 1' or a thick 
main unit 1" is connected with the connector block 82 by using holder 
units 303, 304. There may be different types of main units since one of 
the main units may have a back light for the display panel 12, and another 
of the main units may not have such a back light. However, it is 
preferable to commonly use the expansion unit 7' for all of the different 
types of main units. FIGS. 9A and 9B illustrate views of the holder units 
303, 304 respectively attached to the main units 1', and 1" having 
different thicknesses. FIG. 9C illustrates a side sectional view of the 
connector block 82, and the holder units 303, 304. The holder unit 303 
corresponds to the thin main unit 1', and the holder unit 304 corresponds 
to the thin main unit 1". It becomes possible to connect the same 
connector block 82 and the main units 1', 1" having the different 
thicknesses by way of the respective holder units 303, 304, as shown. 
FIGS. 10A, 10B show further embodiments of the present invention, wherein 
the power supply system serves to charge the battery built in the main 
unit 1 when the expansion unit 7 is used. In FIG. 10A, a charging 
controller 150 for charging the battery 15 is provided in the main unit 1 
whereas FIG. 10B shows an arrangement wherein the charging controller 150 
is provided in the expansion unit 7. In any case, during the period when 
the battery 15 is charged by the charging controller 150, the main unit 1 
is supplied with power from the power circuit 70 in the expansion unit 7. 
In FIG. 10A, only the power line 80 from the expansion unit 70 is required 
to supply power to the main unit 1 and charge the battery 15, allowing 
reduction in the number of wires in the cable 8 or connection block 82 
between the main unit 1 and expansion unit 7, whereby the reliability of 
connector which is connected and disconnected repeatedly can be enhanced 
as compared with the case of FIG. 10B. The arrangement of FIG. 10B has the 
charging controller 150, which increases the weight, size and cost of the 
main unit in FIG. 10A, included in the expansion unit 7, whereby the size, 
weight and cost of the main unit can be reduced, although a charging power 
line 83 is needed. 
FIG. 11 shows the arrangement of the connection cable in accordance with 
the present invention wherein the connection cable 8 for connecting the 
expansion unit to the main unit is provided with a connector housing 84 at 
the cable end and having contact pins 840. A connector housing is provided 
on either the main unit 1 or expansion unit 7 and includes ground pins 
800, power pins 801, and signal pins 810. In this embodiment, when the 
connector 84 is connected to the connector 85, the ground pins 800 are 
first connected to the contacts 840, and next the signal pins 810 and 
finally the power pins 801 are connected to the corresponding contacts 840 
When the connectors are disconnected, the pins are disconnected in the 
reverse order of connection, i.e., the power pins 801, signal pins 810 and 
ground pins 800. Consequently, the signal lines are left inactive until 
the power lines are connected which allows disconnection of the connection 
cable 8 during the operation. Small or portable information processing 
apparatuses are often handled by the user to connect or disconnect the 
expansion unit without suspending the job (i.e., with the power kept 
alive). This embodiment permits the user to disconnect the connector while 
the power is on, which not only enhances the usage, but also prevents 
electrical failure of the apparatus should the connector be disconnected 
accidentally. 
FIGS. 12A, 12B show an embodiment of the present invention, wherein the 
connector housing is provided with a circuit opening/closing device having 
normal-open contacts. As shown, a connector housing 84 is provided at the 
end of connection cable 8 and includes housing fixing screws 841. A 
connector housing 85 is provided on the main unit 1 and includes insulator 
springs 850, contacts 851 of the circuit opening/closing device, a power 
terminal 852 for receiving the connection cable 8, and a power line 853. 
FIG. 12A shows the state of apparatus before the connection cable is 
connected. When the connector housings 84 and 85 are coupled, the terminal 
852 is connected with the power output from the expansion unit 7, but the 
contacts 851 are kept open because the fixing screws 841 are not yet 
tightened and therefore power is not supplied to the main unit 1. FIG. 12B 
shows the state of apparatus after the fixing screws 841 are tightened to 
completely fix the housing 84 to 85. The fixing screws 841 push the 
insulator springs 850 down, resulting in the closure of the contacts 851, 
and the power output on the terminal 852 is conducted to the power line 
853. According to this embodiment, as described, the fixing screws 841 
function as an actuator, enabling power supply only after the connector is 
fixed completely, whereby the same effectiveness as of preceding 
embodiment can be attained. As apparent, a feature of this embodiment is 
the inclusion of the circuit opening/closing in part of the connector 
housing. The contacts 851 may be of normal-closed type, which open when 
the connector is connected. Although two pairs of contacts are shown in 
FIG. 12A, 12B, any number of contact pairs is possible. Further, although 
the figure shows the operation of the contacts by tightening the fixing 
screws 841, an alternative arrangement is such that the contacts are 
closed by simply inserting the connector all the way in. 
As is apparent from the above description, the present invention, in which 
power is supplied from the expansion unit to the main unit when the 
expansion unit is used, provides the following pronounced effectiveness. 
(1) The a.c. adapter is eliminated. 
(2) The main unit may be provided with a battery having the minimum 
required capacity thereby enabling reduction of weight and cost of the 
main unit. 
(3) Connection and disconnection between the main unit and expansion unit 
by the user are made easier. 
While we have shown and described several embodiments in accordance with 
the present invention, it is understood that the same is not limited 
thereto but is susceptible of numerous changes and modifications as known 
to those skilled in the art and we therefore do no wish to be limited to 
the details shown and described herein but intend to cover all such 
changes and modifications as are encompassed by the scope of the appended 
claims.