JPH01150394A - Erroneous operation preventive circuit for electronic device - Google Patents

Abstract

PURPOSE:To prevent the function of an electronic device from being stopped at the time of insertion and pulling-out of units by a method wherein an erroneous operation preventive circuit for preventing an erroneous operation at the time of delivery and receipt of the signal between the units at the time of insertion and pulling-out of the units in and from the device is mounted in the units. CONSTITUTION:A power supply is supplied to an enable signal reception circuit 11 and an input/output signal control circuit 12 by a power (f) from an external power supply (x) before the unit 30 is inserted. Here, as an enable signal (d) is not received, the circuit 12 is set in a reception mode. In this state, when the unit 30 is inserted in a shelf 20, the circuit 12 does not bring an erroneous operation to a device because the circuit 12 is set in the reception mode. When the unit 30 is mounted to the device, a mounting state signal (h) made in a mounting state informing circuit 14 is informed to the device and as the device side transmits a signal (d), the circuit 12 is released from the reception mode and the unit performs a normal delivery and receipt of signal between other mounting finished units and the unit. Reversely, in case the unit 30 is pulled out of the device, the circuit 12 is never operated erroneously if the external power supply is ready-connected to the unit 30.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a malfunction prevention circuit for electronic devices.

[Conventional technology]

Conventionally, when inserting or removing a unit, the power to the electronic device has usually been stopped, and the functions of the electronic device have been temporarily stopped. However, due to the expansion of the scale of electronic devices and the diversification of their functions, this temporary stop is no longer acceptable. Therefore, in the past, the terminal dimensions of the connector section that connects to the electronic device of the unit were differentiated, such as long and short. 2
When inserting the unit into an electronic device, the long terminal is connected first, followed by the short terminal, and the unit is inserted and connected in stages.

[Problem that the invention seeks to solve]

In the conventional unit insertion/removal method described above, depending on the timing of unit insertion/removal when the electronic device is activated, there are problems in guaranteeing the power supply and guaranteeing the state level of the output signal during the transition period of unit insertion/removal. However, this method does not go so far as to prevent malfunctions of the system, and has the disadvantage that the function of the entire system may be temporarily stopped.

[Means for solving problems]

A malfunction circuit for an electronic device according to the present invention includes a mounting state notification circuit that notifies the mounting state of each unit constituting the electronic device;
an enable signal receiving circuit that receives the enable signal issued from the electronic device in response to the mounting state to control execution or stop of the unit operation; and signal input/output between another unit that is not inserted or removed from the electronic device. an input/output signal control circuit that controls the input/output direction control signal from the electronic device using the input/output direction control signal and the enable signal; and an input/output signal control circuit that controls the input/output direction control signal from the electronic device using the input/output direction control signal and the enable signal; and a power supply integrated circuit that performs a logical sum with electric power and supplies power to the unit,
Malfunction of the electronic device is prevented when the unit is inserted into and removed from the electronic device.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a state in which a unit to which the illustrated embodiment is applied is inserted and removed from a shelf of an electronic device.

In FIG. 1, a malfunction prevention circuit 1 of an electronic device according to the present embodiment is an enable signal receiving circuit comprising an inverter circuit that receives an enable signal d from a unit (not shown) in which the malfunction prevention circuit 1 is mounted and inverts the logic. 11 and
An input/output signal that controls the input and output of the input/output signals a and b by the AND of the signal element obtained by logically inverting the enable signal d from the enable signal receiving circuit 11 and the input/output direction control signal C from the unit. Control circuit 12, power e from the unit's internal power supply, and external power supply (not shown)
The power supply integration circuit 13 outputs the supplied power g by logical sum with the power f from the mounting state, and the mounting state notification circuit 14 outputs the mounting state signal when receiving the supplied power g.

Note that the input/output signal control circuit 12 receives the input/output direction control signal C.
AND circuit (hereinafter referred to as AND) 124 which takes the logical product of the logic inversion signal of the enable signal d, and the AND12
An inverter circuit that logically inverts the output signal of 4 (hereinafter referred to as I
(denoted as NV) 123 and receives the input/output signal a and AND
A gate circuit (hereinafter referred to as GAT) 122 outputs an inverted signal of the input/output signal a by the gate signal of the output signal of the input/output signal a, and an INV123 receives the input/output signal a.
The GAT 121 outputs an inverted signal of the input/output signal S as an output signal a by a gate signal of the output signal of the GAT 121.

FIG. 2 shows a state in which the unit 30 in which the malfunction prevention circuit 1 of this embodiment is mounted is inserted and removed from the shelf 20 of an electronic device (not shown).

Next, the operation of this embodiment will be explained using FIG. 1 and FIG. 2 together.

When the unit 30 is inserted into the shelf 20 of an electronic device (hereinafter referred to as the device) and when the unit 3 is inserted from the shelf 20
When extracting 0, the power f from the external power supply is always supplied to the power supply integrated circuit 13.

The power from the external power supply is sent to the power supply integration port 1113, passes through this port, and is consumed within the unit 30.

First, before inserting the unit 30, the power f from the external power source is
As a result, power is supplied to the enable signal receiving circuit 11 and the input/output signal control circuit 12.

Here, since the unit 30 has not yet been inserted into the shelf 20, the enable signal d has not been received. Therefore, the enable signal receiving circuit 11 sends information to the input/output signal control circuit 12 to enter the receiving mode. do. The input/output signal control circuit 12 sets the reception mode according to this information.

Next, the unit 30 is inserted into the shelf 20 in the above state. Since the input/output signal control circuit 12 of the unit 30 is in the reception mode, it will not cause any malfunction to the device.

When the unit 30 is mounted on a device, the mounting state signal created by the mounting state notification circuit 14 is first notified to the device, and the device side transmits an enable signal d in response to this mounting state signal. This is received by the enable signal receiving circuit 11. In accordance with this enable signal d, the enable signal receiving circuit 11 transmits an enable information part obtained by logically inverting the enable signal d to the input/output signal control circuit 12.

Since the input/output signal control circuit 12 is released from the forced reception mode in the enable information section, the unit 3
The direction of the signal is determined according to the input/output direction control signal C in 0, and thereafter this unit 30 performs normal signal exchange with other mounted units.

Furthermore, when the unit 30 is mounted on the device, the internal power supply of the device supplies power e to the power supply integrated circuit 13, so from now on, it is only necessary to operate the unit 30 using the internal power supply. You can disconnect it.

Conversely, when the unit 30 is removed from the device, if the external power supply is connected to the unit 30 first, power supply is guaranteed even during the transition period when the unit 30 is removed, thereby preventing the input/output signal control circuit 12 from malfunctioning. There isn't.

〔Effect of the invention〕

As explained above, by implementing the malfunction prevention circuit according to the present invention in a unit constituting an electronic device, the cause of malfunction of the electronic device when the unit is inserted or removed is eliminated, and the function of the electronic device is prevented. It is possible to insert and remove the unit without malfunction even when the electronic device is active, and in particular, it is reliably enabled by the mounting status signal from the mounting status notification circuit that indicates that power is being supplied to the unit. Since the signal is output, it is possible to eliminate the temporary suspension of the function of the entire system when a unit is inserted or removed, which conventionally occurs.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a state in which a unit to which the illustrated embodiment is applied is inserted and removed from a shelf of an electronic device. DESCRIPTION OF SYMBOLS 1... Malfunction prevention circuit, 11... Enable signal receiving circuit, 12... Input/output signal control circuit, 13... Power supply integration circuit, 14... Mounting status notification circuit, 121,1
22... Gate circuit (GAT), 123... Inverter circuit (INV), 124... AND circuit (AN
D). Agent Patent Attorney Oto Uchihara Figure 1

Claims (1)

[Claims] a mounting state notification circuit that notifies the mounting state of each unit constituting the electronic device; and an enable signal that receives an enable signal issued from the electronic device in response to the mounting state and controlling execution or stop of the operation of the unit. an input/output signal control circuit that controls signal input/output between a receiving circuit and other units that are not inserted or removed from the electronic device using an input/output direction control signal from the electronic device and the enable signal; and a power supply integration circuit that performs a logical OR of the power supplied from the power supply and the power supplied from the external power supply of the electronic device and supplies the power to the unit, and the unit is inserted and removed from the electronic device. A malfunction prevention circuit for an electronic device, characterized in that the circuit prevents malfunction of the electronic device when the electronic device is malfunctioned.