Electronic Apparatus With Detachable Member Arranged to Detect Erroneous Mounting of the Detachable Member

1. Field of the Invention

The present invention relates to a method of power supply, and more particularly to such method wherein a part of a connector is formed as power supply control elements to interrupt the power supply in case of an erroneous connection of the connector.

2. Description of the Prior Art

A memory pack in which a memory module or the like is enclosed in a metal or conductive case for mechanical reinforcement and noise shielding, the case having an aperture installing a connector is known in the art. Such a memory pack, if erroneously mounted, may cause short-circuiting of the contacts of the connector which are connected to a main apparatus by the metal case of the metal pack, thus eventually damaging the circuits in the main apparatus.

In consideration of the foregoing, an object for supplying the present invention is to provide a method of power wherein designated connector contacts are formed as power supply control elements thereby interrupting the supply of power if the connector is mounted incorrectly.

Another object of the present invention is to provide a detachable member and an electronic apparatus utilizing such detachable member, comprising means for detecting erroneous mounting of the detachable member on the electronic apparatus, and means for disabling selected functions of the electronic apparatus in response to the detection of incorrect mounting by the detecting means.

Still another object of the present invention is to provide an electronic apparatus with a detachable member, comprising control means provided on the detachable member for controlling the power supply of the electronic apparatus, and means for activating said power supply by the control means.

Still another object of the present invention is to provide an electronic apparatus with a detachable member, comprising means for detecting erroneous mounting of the detachable member, and means for disabling the function of the electronic apparatus in response to the detection by the detecting means, wherein the disabling means comprises means for activating the electronic apparatus while the detachable member is detached from the electronic apparatus.

FIG. 1 is an external perspective view of a memory pack;

FIG. 2 is a schematic view showing the structure of a connector on the electronic apparatus; and

FIG. 3 is a circuit diagram showing a power supply control circuit.

FIGS. 4 and 5 are schematic sectional views of the proper and improper connection, respectively, between the metal case housing the memory pack and the connector element of the present invention.

The present invention is described in greater detail by an embodiment thereof shown in the attached drawings. FIG. 1 is a perspective view showing a memory pack, wherein a memory pack MC having a metal case encloses a memory element such as a read-only memory or a random access memory mounted on a printed circuit board, and an aperture C of the case is provided with contacts P1, P2-Pn for signal exchange with an electronic apparatus. Among the contacts, the contacts P1 and P2 are electrically insulated.

FIG. 2 shows a connector to be provided on the electronic apparatus corresponding to the contacts of memory pack MC, wherein pins CN-1, CN-2-CN-n respectively correspond to and are brought into contact with the contacts P1, P2-Pn when memory pack MC is correctly mounted on the electronic apparatus. Among these pins, the pins CN3-CNn are used for making access to the memory in memory pack MC and supplying, power to memory pack MC. Pins CN1 and CN2 are used for detecting whether memory pack MC is correctly mounted on the electronic apparatus. Pin CN2 is grounded in the circuit of the electronic apparatus while pin CN1 is maintained open. When pins CN1 and CN2 are shortcircuited as illustrated in FIG. 5, a signal line S1 connected to pin CN1 is grounded to control a power supply control circuit thereby interrupting the power supply in the circuit of the electronic apparatus.

FIG. 3 shows a power supply control circuit wherein a battery B supplies electric power to the circuit of the electronic apparatus through a transistor Tr2. When a transistor Tr1 is rendered conductive, a base current flows to transistor Tr2 through a resistor R3 to supply electric power to the circuit of the electronic apparatus. When transistor Tr1 is non-conductive, transistor Tr2 is turned off to interrupt the power supply to the circuit of the electronic apparatus. The conductive or non-conductive state of transistor Tr1 is determined by the potential of line S1 connected to the base. When signal line S1 is open, a base current flows to transistor Tr1 through a pull-up resistor R2 to render transistor Tr1 conductive. Transistor Tr1 is non-conductive when signal line S1 is grounded.

When memory pack MC is correctly mounted as illustrated in FIG. 4, contacts P1 and P2 are maintained in contact with connector pins CN1, CN2 of the electronic apparatus which are electrically insulated so that contact CN1 remains open. Signal line S1 remains open, so that transistor Tr1 is rendered conductive by a base current supplied through resistor R2. Thus, transistor Tr2 receives a base current through resistor R3 to supply electric power to the load from the battery B. If memory pack MC is mounted in the wrong direction, as shown in FIG. 5 pins CN1 and CN2 are short-circuited by the metal case of memory pack MC to ground the signal line S1, whereby the supply of base current to transistor Tr1 is terminated. Thus transistor Tr1 is rendered non-conductive to turn off transistor Tr2, thereby interrupting the supply of power from the battery B to the load. In this manner the electronic apparatus is protected from damage resulting from an excessive current caused by the short-circuiting of a power supply connector.

As explained in the foregoing, the present invention enables to prevent damage to a circuit resulting from short circuiting of the connector of a detachable memory. Designated connector terminals are so constructed as to detect an erroneous mounting of the connector and to interrupt the supply of power to the load.