JPH01150392A - Erroneous operation preventive circuit in electronic device - Google Patents

Abstract

PURPOSE:To prevent the functional stoppage of an electronic device from occurring in case of inserting and pulling out an unit by a method wherein an erroneous operation preventive circuit C for preventing any erroneous operation during transmitting and receiving signals between units in case of inserting and pulling out the unit in and from the electrode device is made in the unit. CONSTITUTION:Before inserting an unit 30, an enable signal receiving circuit 12 and an output signal control circuit 11 are supplied with power (f) from an outer power supply A. At this time, the unit 30 is not yet inserted into a shelf 20 of the device not to receive the enable signal (c). Consequently, the circuit 12 transmits a data disabling an output signal (b) to the circuit 11. When the output signal (b) is being disabled, the output part of the circuit 11 provides the disabled output signal (b) with high impedance. Next, the unit 30 is inserted into the shelf 20. The signal (b) provided with the high impedance can prevent the device from causing any erroneous operation. Reversely, when the unit 30 is drawn out of the shelf 20, the circuit 11 can be prevented from causing any erroneous operation by connecting the outer power supply A to a power supply integrating circuit 13.

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 a unit is inserted into or removed from an electronic device, the power to the electronic device is usually stopped, and the functions of the electronic device are 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. Two types of terminals are used, and when inserting the unit into an electronic device, the long terminal is inserted first, followed by the short terminal, so that the unit is inserted and connected in stages.

[Problem that the invention attempts to solve]

In the conventional unit insertion/removal method described above, depending on the timing of unit insertion/removal when the electronic device is active, 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. It is not possible to prevent all malfunctions of the entire system! There is a drawback that 1!1 structure may stop temporarily.

[Means for solving problems]

A malfunction prevention circuit for an electronic device according to the present invention includes an enable signal receiving circuit that receives an enable signal for controlling execution or stopping of the operation of each unit constituting the electronic device, and other units that are not inserted or removed from the electronic device. an output signal control circuit that controls a signal output to the electronic device using the enable signal; and an output signal control circuit that performs a logical sum of power supplied from an internal power source of the electronic device and power supplied from an external power source of the electronic device; and a power integrated circuit for supplying power to the electronic device to prevent malfunctions when signals are exchanged between the units when the unit is inserted or removed from the electronic device.

〔Example〕

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

Figure 1 is a circuit diagram showing one 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 for an electronic device according to the present embodiment includes an enable signal receiving circuit 12 consisting of an inverter circuit that receives an enable signal C and inverts the logic thereof, and a controlled output signal a that is the logic inversion of the enable signal C. An output signal control circuit 11 consisting of a two-person NAND circuit that outputs an output signal S under the control of a signal LOW, and a logical sum of an external power f from an external power source and an internal power e from an internal power source, calculates a supply power d. The power supply integrated circuit 13 outputs the power.

In FIG. 2, the unit 30 in which the malfunction prevention circuit 1 of the present embodiment shown in FIG. 1 is mounted is receiving power f from an external power source from the shelf 20 of an electronic device (not shown). , indicates that it will be inserted or removed.

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

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

Power f from the external power supply is sent to the power supply integration circuit 13, passes through this, and is consumed within the unit 30 as supplied power d.

Next, before the unit 30 is inserted, power is supplied to the enable signal receiving circuit 12 and the output signal control circuit 11 using electric power f from an external power source.

Here, since the unit 30 has not yet been inserted into the shelf 20 of the device, the enable signal C has not been received. Therefore, the enable signal receiving circuit 12 transmits information to the output signal control circuit 11 to disable the output signal.

The output section of the output signal control circuit 11 is made to have a high impedance when disabled by using a device such as an oven collector or a three-state device.

Next, the unit 30 is inserted into the shelf 20 in the above state. Since the output signal of the unit 30 is high impedance, it will not cause any malfunction to the device.

After the unit 30 is mounted on the shelf 20, an enable signal C is sent from the device, and this is received by the enable signal receiving circuit 12. In accordance with this enable signal C, the enable signal receiving circuit 12 transmits an enable information meter obtained by logically inverting the enable signal C to the output signal control circuit 11. The output signal control circuit enables the controlled output signal a according to the enable information stone.

Thereafter, the unit 30 can perform normal signal exchange with other mounted units.

Furthermore, when the unit 30 is mounted on the device, power e is supplied from the device's internal power source to the power supply integrated circuit 13. From now on, it is only necessary to operate the unit 30 using the internal power source. You can disconnect it from the power supply.

Conversely, when removing the unit 30 from the shelf 20, if you first connect the external power supply to the power supply integrated circuit 13,
Since the power supply is guaranteed even during the transitional period of extraction, the output signal control circuit 11 will not malfunction.

〔Effect of the invention〕

As explained above, the present invention implements the malfunction prevention circuit according to the present invention in a unit constituting an electronic device, thereby eliminating a factor that causes malfunction of the electronic device when the unit is inserted or removed, thereby preventing the electronic device from stopping functioning. Since the unit can be inserted and removed without malfunction even when the electronic device is activated, it is possible to eliminate the temporary stoppage of the entire system's function when inserting or removing a unit, which conventionally occurred. .

[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... Output signal control circuit, 12... Enable signal receiving circuit, 13... Power supply integration circuit, 20... Shelf, 30... Unit. Agent Patent Attorney Uchihara Oto 1 tack production prevention times I L J/1° boka inrenal archery ゛ 1 wisdom times 34 7'?・Ihan-'ful Buddha name zu auspicious times each/3・
・Electrical bed adjustment circuit Figure 1, Figure Z

Claims (1)

[Claims] an enable signal receiving circuit for receiving an enable signal for controlling execution or stopping of the operation of each unit in each unit constituting the electronic device; and using the enable signal to output a signal to other units that are not inserted or removed from the electronic device. an output signal control circuit for controlling the electronic device; and a power supply integration circuit that performs a logical sum of power supplied from an internal power source of the electronic device and power supplied from an external power source of the electronic device and supplies power to the unit. 1. A malfunction prevention circuit for an electronic device, characterized in that the circuit is configured to prevent malfunctions when signals are exchanged between the units when the unit is inserted or removed from the electronic device.