JP2771421B2 - High voltage protection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage protection circuit for safely handling a detachable electronic device from a high voltage.

[0002]

2. Description of the Related Art In many cases, an electronic device is provided with a connector for attaching a detachable unit in order to extend its function. In some cases, a high voltage is applied to the pins of the connector on the electronic device main body side with no unit attached. Therefore, conventionally, when a dangerous voltage is used for the human body in the connector for unit connection, the connector on the main body side is made a female type so that the pins are not directly contacted with the human body.

[0003] By the way, labor saving of mounting and wiring of connectors has been attempted, and a structure hitting the backboard by a press has attracted attention. However, when this structure is adopted, the connector on the main body side of the electronic device becomes a male type, and the pins protrude. Therefore, when this structure is adopted, it becomes impossible to apply a high voltage to the connector for unit connection.

With respect to such a problem, for example, Japanese Patent Application Laid-Open No. 63-292924 provides one solution. Although this publication relates to a control device for an electric hot plate, an open / close element is connected in series to each of a plurality of heaters incorporated in a heating plate to control energization to the heaters and to open the heaters. The attachment / detachment state of the heating plate is detected by detecting the voltage at both ends of the switching element. When the heating plate is not mounted on the main body of the apparatus, the control operation for the switching element is stopped so that a high voltage of a different polarity is not applied to the exposed terminal portion.

Further, Japanese Patent Publication No. 62-12635 discloses a connection device in which an additional unit is connected at an arbitrary timing to a main unit with a power supply turned on, to prevent a malfunction caused by noise generated when the additional unit is removed. Preventing. The connection device disclosed in this publication is provided with a switch for detecting the attachment / detachment state of the receptacle with respect to the plug, and the switch is closed after all the terminals have been inserted into the terminals of the plug. When the receptacle is removed, the switch is opened before the terminals are separated from each other. The output of the switch is transmitted to the main unit via a logic circuit. As a result, for example, when the receptacle is pulled out from the plug, when the receptacle is slightly separated from the plug, that is, with all the terminals still connected, the control circuit cuts off signal transmission to the connector, Prevent the generation of noise when the terminal leaves,
Malfunction on the main unit side is prevented.

[0006]

In the former technique disclosed in Japanese Patent Application Laid-Open No. 63-292924, the voltage at both ends of the open / closed switching element is detected to detect the state of attachment / detachment of the heating plate. Therefore, a special detection circuit is required, and not only is the apparatus expensive, but also in the event that any failure occurs in the detection circuit, a high voltage may be applied, and there is a problem in reliability.

Further, in the latter technique disclosed in Japanese Patent Publication No. 62-12635, the purpose is to prevent malfunction of the main unit due to noise, so that all terminals of the switch are still connected when the receptacle is removed. In such a state, it is necessary to detect the extraction operation and cut off the circuit leading to the connector, which makes the circuit complicated and expensive, and also poses a reliability problem.

Accordingly, an object of the present invention is to prevent a high voltage from being applied to exposed pins in a state where a detachable unit is detached from a male connector of an apparatus main body, and to realize a highly reliable high voltage with a simple configuration. To provide a protection circuit.

[0009]

According to the invention described in claim 1, (a) a connector provided on the apparatus main body side;
A switch which is also provided on the apparatus body side and is turned on in conjunction with this only when the detachable unit to be attached to this connector is mounted, and is also turned off in conjunction with the removal when it is removed; , This switch
Has a switching contact of the switch is the off contact is closed only when turned on, before the high voltage is supplied
The high voltage protection circuit is provided with a high voltage application line to be applied to the high voltage application pin of the connector.

That is, according to the first aspect of the present invention, a switch that performs an on / off operation in conjunction with the mounting and removal of the detachable unit is used, and the high voltage supplied to the main unit is changed by the switch. The high voltage is applied to the high voltage application pin of the connector via the open / close contact , and the high voltage is not applied to the high voltage application pin with the detachable unit removed. Moreover, the switch is a detachable unit
It will be ON only when mounted, so operator safety is
It is planned.

In the invention according to claim 2, it has been clarified that, for example, an optical switch can be used as the switch.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows a main part of an electronic apparatus using a high-voltage protection circuit according to an embodiment of the present invention. A press hit connector 13 is attached to a predetermined position of the back board 12 on the electronic device main body 11 side of the electronic device. A switch 15 is mounted on the back board 12 at a position slightly away from the pin 14 of the press hit connector 13. The connector section 17 of the detachable unit 16 includes a press hit connector 13
To be fitted. Press hit connector 1
A pair of pins 14A, 14B arranged at the bottom of
This is a pin to which a high voltage is applied.

The switch 14 is pressed by the detachable unit housing near the connector 17 when the detachable unit 16 is attached to the electronic device body 11, and in this state, the pins 14A and 14B are connected to the pins 14A and 14B. A high voltage is applied. This switch 15 is arranged relatively above the backboard 12. Therefore, it is sufficiently away from the positions of the pins 14A and 14B. Therefore, even if the operator accidentally presses the switch 15 with one hand, the other finger of the hand is pressed by the pin 14A or 14A.
B cannot be touched at the same time.

FIG. 2 shows a circuit portion of a high voltage application path. High-voltage line 21A on the electronic device body side,
21B is connected to the corresponding pins 14A and 14B via the contacts of the switch 15, respectively. Therefore, when the switch 15 is not pressed, the high voltage lines 21A, 21A
B is electrically disconnected from the pins 14A and 14B, and no high voltage is applied even if the operator touches the pins 14A and 14B. That is, the operator does not receive an electric shock due to the high voltage when the detachable unit 16 is not attached to the electronic device main body 11.

When the detachable unit 16 is mounted on the electronic device main body 11, the switch 15 is in a pressed state.
A high voltage is supplied to the pins 14A and 14B, and the electronic device can perform a predetermined operation. Of course, as described above, even if the operator presses the switch 15 by mistake, his / her hand simultaneously presses the pin 14 of the press hit connector.
Touching can prevent electric shock.

In the above embodiment, the switch is described as a push-button mechanical switch. However, another switch such as an optical switch in which a light emitting element and a light receiving element are opposed to each other at a very small interval, or a magnetic sensor. to use the
More protection circuit for the operator
be able to. When this optical switch is used, a plate-shaped protruding portion may be provided on the detachable unit 16 side, and the plate-shaped portion may block an optical path when the detachable unit 16 is mounted on the electronic device main body 11. In this embodiment,
Since the light emitting element and the light receiving element is opposed with a very narrow interval, without the operator's finger is or enters the meantime, wear
There is no possibility that the switch will be operated accidentally except when mounting the detachable unit . Also, in the case of the magnetic sensor, the operation is not performed only by touching the operator's hand, so that the safety of the operator can be achieved.

As described above, according to the first aspect of the present invention, a switch that performs an on / off operation in conjunction with mounting and detaching of the detachable unit is used, and the main unit is used.
Since as applied to the pins of the high-pressure application of a high voltage being supplied via the switching contact of the switch, there is no a high voltage is applied thereto when not implement the detachable unit. In addition, the high power supplied to the
The high-voltage application line that applies pressure to the high-voltage application pin
Switch only, so only the main unit side
To turn on / off high-voltage application and supply power
The side does not need to be aware of the need for on / off
There is an advantage that the configuration is simplified. In addition,
The switch is only activated when the detachable unit is mounted on the main unit.
Switch, there is no risk of the switch operating accidentally.
To provide the operator with a safe protection circuit mechanism.
You.

[0019]

According to the second aspect of the present invention, the optical switch
Since the high voltage application control is performed using the switch , a high voltage protection circuit with sufficiently high safety can be configured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an electronic apparatus using a high-voltage protection circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a high-voltage protection circuit according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electronic device main body 12 Backboard 13 Press hit connector 14 Pin 14A, 14B (High voltage is applied) pin 15 Switch 16 Detachable unit 21A, 21B High voltage line

Claims (2)

(57) [Claims] 1. A connector provided on an apparatus main body side, which is also provided on the apparatus main body side and turned on only in conjunction with mounting of a detachable unit attached to the connector, and also turned off in conjunction with removal when removing. A switch which is also provided on the apparatus main body side, and is a switching contact of the switch.
The opening and closing only when the switch is turned on
A high-voltage applying circuit , wherein a contact is closed and a high-voltage applying line for applying the supplied high voltage to the high-voltage applying pin of the connector. 2. The switch has a light emitting element and a light receiving element.
Optical switch facing each other at a narrow interval.
When the unit is attached to the connector of the main unit, the optical switch
2. The high-voltage protection circuit according to claim 1, further comprising a plate-shaped protrusion that blocks an optical path of the switch .