KR19980038346A - Alarm sound generation circuit when excessive voltage is applied to high and low voltage electronic devices - Google Patents

Abstract

According to the present invention, in the case of using a 110V / 220V combined electronic device, the overvoltage is detected when 220V voltage is applied to the device due to user's carelessness while the power supply voltage selection switch of the device is in the 110V position. A circuit for generating an alarm sound to a user.

The present invention provides a power input unit for receiving commercial power; A voltage selection switching unit that selects a power input from the power input unit as low voltage (eg 110V) or high voltage (eg 220V); An electronic device having a power supply section comprising conversion means for converting a commercial voltage value input through said voltage selection switching section into a low voltage direct current value for use in an apparatus, wherein said voltage selection switching section is selected in a selected position. Has an interlocking contact to which the following overvoltage sensing circuitry is connected when in the low pressure position; Has an overvoltage detecting means connected to the circuit by connecting the interlocking contact; It is connected to the over-voltage detecting means is provided with an alarm sound generating circuit when the over-voltage applied in the low-voltage, high-voltage electronic device, characterized in that it comprises an alarm sound generating means for generating an alarm sound when the over-voltage is detected, An alarming effect is achieved to prevent damage to the circuit arrangement due to this input.

Description

Alarm sound generation circuit when excessive voltage is applied to high and low voltage electronic devices

The present invention relates to an overvoltage application alarm circuit in a 110V / 220V combined device, and more particularly, when a 110V / 220V combined electronic device is used as the power supply voltage, the power supply voltage selector switch of the device is in the 110V position. The present invention relates to a circuit for detecting an overvoltage and generating an alarm sound to a user when 220V voltage is applied to the device due to user's carelessness.

A power source is required for the operation of various electrical and electronic devices. For example, as a power source for a computer monitor circuit, an AC 110V or 220V commercial power is received as an input power source, converted into various DC values required in the monitor, and supplied to each part of the circuit.

As the power supply unit of the electronic device, a power supply unit is usually configured by using a rectifier circuit that converts a high voltage of an AC into a low voltage AC using a transformer and rectifies it to generate a required DC voltage.

1 shows an example of the power supply unit. Fig. 1A shows the switch section as the rear side of the monitor device with an input voltage selection switch. 1 (B) is a simplified circuit example of a 110V / 220V combined power supply circuit.

The rectifier circuit of the power supply unit includes a power transformer 130 for obtaining a low voltage AC voltage required by a high voltage AC power supply, a rectifying element 140 for converting AC into DC, and a pulsation powder included in the rectified DC voltage and current. It consists of a smoothing circuit for reducing the voltage, a stabilization circuit for preventing the output voltage and current from being changed by the load. In the stabilization circuit, a control circuit is inserted between the DC output and the load in order to prevent stabilization by changing the output voltage. This is used to detect power fluctuations with transistors and to control the output continuously.

In addition to the conventional power supply unit, a power supply configuration using a switching power supply has also been made in recent years. The switching power supply unit changes the value of the output power by changing the on time and the off time of the input power, respectively.

In the above-described power supply unit, there is a problem that the input voltage selection switch attached to the outside of the device must be selected in accordance with the input voltage value due to the difference in the supply voltage of the power company in the region where the electric and electronic devices are used. .

When the input voltage of 220 V is applied in the state where the position of the input voltage selection switch is 110 V, for example, an excessive current is generated in the power supply unit. Normally, when the impedance of the power supply is Z, according to Ohm's law, when the impedance is constant, the current flowing in the circuit is proportional to the voltage. Therefore, overcurrent twice as much as the normal current flows in the circuit, which damages the characteristic elements of the circuit.

As a device for preventing damage to the circuit due to the excessive current described above, a fuse element is usually used, thereby protecting against the abnormal current caused by the above-described abnormal voltage. The fuse simulates an impedance at the time of an accident and selects the current at the time of an accident impedance according to Ohm's law.

When overcurrent flows through the fuse, Joule heat is generated, and when the fuse exceeds the allowable melting point, the fuse is blown. These fuses can be divided into fast blow fuses, time lag blow fuses and ordinary blow fuses according to blow characteristics.

However, since the basic operation principle of the fuse is a melting action due to heat generation due to overcurrent, a long time is elapsed until the fuse is overheated and blown, thereby avoiding a fatal damage to the circuit element. none.

On the other hand, in the power supply unit of the recent technology, a power supply unit employing a free volt function capable of automatically obtaining a constant output voltage value regardless of the variation of the input voltage value is used. It has a circuit configuration in which the output voltage is automatically controlled without the operation of the input voltage selection control switch of the electric device even in the region where the commercial power supply voltage is 110V or 220V. In this case, even if the input voltage value varies within a range from 90V to 240V, the output voltage is automatically adjusted.

However, there is a current limiting resistor for limiting excessive current for proper operation of a circuit element caused by a change in input voltage even in the power supply of the prevolt function. The current limiting resistor has a current value flowing through the resistor as the input voltage is changed. Therefore, with a fixed resistance value, the proper operation value for overcurrent control cannot be matched.

In more detail, when the resistance value of the overcurrent limiting resistor is set on the assumption that the input voltage value is 110V, the set resistance value is not appropriate when the input voltage value is changed to 220V. In this case, various problems occur due to a temperature increase due to an increase in power consumption of the integrated circuit performing the prevolt function.

Therefore, in the power supply apparatus of the conventional free voltage function, the resistance value of the current limiting resistor is treated as an option, so that the resistance value of the current limiting resistor is changed according to the commercial voltage value of the region to be used. The above problem is also solved by the method.

The present invention has been made to solve the above problems, and prevents damage to the circuit due to overcurrent when the power plug is inserted into the outlet in a state where the input position of the input voltage selection switch of the electrical and electronic device is different from the input voltage value. To this end, it is an object of the present invention to provide a circuit capable of quickly alerting a user of the apparatus to a state in which an overvoltage is applied.

FIG. 1 is a schematic circuit diagram showing an example of a voltage change select switch of a 110V / 220V combined electronic device and a circuit thereof, and FIG. 1 (A) shows an input voltage selector switch and a power outlet on the rear of the monitor device.

Figure 2 is a configuration diagram showing the connection of the overvoltage detection means and the alarm means as an example of the present invention is applied,

3 is a block diagram showing a configuration between circuit means of the present invention;

Figure 4 is an embodiment of the present invention, Figure 4 (A) is an example of the configuration of the overvoltage detection means, Figure 4 (B) is an example of the configuration of the alarm sound generating means.

* Explanation of symbols for main parts of the drawings

100; Power input unit 110; Voltage selector

130; Power conversion means 140; Rectifier circuit

200; Overvoltage sensing means 210; Alarm sound generating means

220; Input voltage selector switch 221; Input voltage switching contact

222; Interlocking contacts 223; Rectification means

224; Zener diode 230; Shutdown Relay Contacts

In order to achieve the above object, the present invention, the power input unit for receiving commercial power; A voltage selection switching unit that selects a power input from the power input unit as low voltage (eg 110V) or high voltage (eg 220V); An electronic device having a power supply section comprising conversion means for converting a commercial voltage value input through said voltage selection switching section into a low voltage direct current value for use in an apparatus, wherein said voltage selection switching section is selected in a selected position. Has an interlocking contact to which the following overvoltage sensing circuit is connected when in the low pressure position; Has an overvoltage detecting means connected to the circuit by connecting the interlocking contact; It is connected to the over-voltage detecting means provides an alarm sound generating circuit when the over-voltage applied in the low-voltage, high-voltage electronic device, characterized in that it comprises an alarm sound generating means for generating an alarm sound when the over voltage is detected.

According to a preferred embodiment of the present invention, the overvoltage sensing means uses a zener diode, and when the voltage across the zener diode is greater than or equal to a predetermined zener voltage, the configuration is made by detecting that current starts to flow in the zener diode.

In addition to the above configuration, an oscillation sound generator may be used as the alarm means, and the oscillation sound generator may be mounted on the electronic device.

In accordance with the above configuration, the circuit of the present invention performs an alarm sound generating action that automatically alerts in advance to prevent the element in the apparatus from being damaged due to carelessness of the user.

Example

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 2 is an example of a power supply unit of the apparatus to which the present invention is applied, the power input unit 100 receiving a commercial power source; A voltage selection switching unit 110 for selecting a power input from the power input unit 100 as a low voltage (eg 110V) or a high voltage (eg 220V); An electronic device having a power supply unit including conversion means 130 for converting a commercial voltage value input through the voltage selection switching unit 110 into a low voltage direct current value for use in a device is shown.

In the above electronic device, the voltage selection switching unit (110) has an interlocking contact (222) to which the following overvoltage detecting means (200) circuit is connected when the selection position is a low voltage position; The interlocking contact 222 has an overvoltage detecting means 200 connected to a circuit; It is connected to the overvoltage detecting means 200 is configured to include an alarm sound generating means 210 for generating an alarm sound when the overvoltage is detected.

Typically, the voltage syntax changer 110 includes an input voltage selector switch, which is formed by using a toggle switch or a slide switch, and mounting the switch in an appropriate position on the side panel of the electronic device.

When an electronic device is damaged by an overcurrent in an electronic device, an input voltage of 220V is applied when the input voltage selection switch is 110V. On the contrary, when a voltage of 110V is applied while the position of the input voltage selection switch is 220V, circuit damage due to overcurrent does not generally occur as described above.

Accordingly, the circuit of the present invention relates to an alarm sound generating circuit for alarming a voltage when 220V is applied to the input inadvertently while the user switches the position of the input voltage selection switch to the position of 110V.

In addition, the embodiment of the conversion means 130 of the electronic device is a method of obtaining a low voltage AC by using a power transformer, rectifying it to obtain a DC voltage, or using a switching transistor to quickly turn on and off the input power and integrate it. It is also possible to use a method of obtaining the required low pressure.

The input voltage selection switch 220 used as an embodiment of the present invention is connected to the overvoltage detecting means 200 of the present invention in addition to the contact 221 used for the tap change switch of the power transformer as the conventional conversion means 130. An interlocking contact 222 of a single pole double throw (SPDT) having a contact configured to be added is configured. The interlocking contact 222 of this switch is operated in conjunction with the operation of the voltage selection contact 221 of the input voltage selection switch.

When the input voltage selection switch 220 is selected as the position of 110V, the overvoltage detecting means 200 of the present invention is connected by the single pole double throw (SPDT) interlocking contact 222. This sensing means does not operate because the interlocking contact 222 is open when a normal voltage of 110V is applied, and thus the circuit is not connected.

An embodiment of the configuration of the sensing means 200 is shown in FIG. 4.

The sensing means 200 may be configured in a circuit using a zener diode. In the embodiment of Fig. 4A, after the circuit is configured via the contact 222, the rectifier element 223 is used to generate a DC voltage, and the zener diode 224 is connected to the voltage in the reverse direction.

When a reverse voltage is applied to the zener diode 224, there is no current flow until the zener voltage VZ is reached, but when both terminal voltages of the zener diode 224 exceed the zener voltage VZ, the current rapidly increases. Will flow.

When the power supply voltage E ≥ zener voltage VZ, even when the power supply voltage E changes, the voltage across the zener diode 224 is almost constant, and when the power supply voltage EVZ, the zener diode 224 exhibits an extremely large resistance value so that current does not flow very much. .

The zener voltage of the zener diode is set to a predetermined value between 110V and 220V.

When the 220V voltage is applied to the sensing means 200, the sensing means 200 detects the abnormal voltage and outputs it to the alarm sound generating means 210.

Figure 4 (B) shows an alarm sound generating means as an embodiment of the present invention.

As an embodiment of the present invention, the alarm sound generating means 210 may be configured using a buzzer for generating a warning sound.

The alarm sound buzzer uses a buzzer operated by an AC voltage of 220V and is connected to a rear end of the sensing means 200 so that the buzzer operates as a result of the sensing of the sensing means 200.

The present invention can be connected to the automatic cut-off device, etc. instead of the alarm sound generating means (210). The overvoltage detecting means 200 detects the overvoltage, and accordingly, a current flows in a specific circuit to operate the relay contacts 230 and the like to automatically cut off the input power.

In the electronic device to which the circuit of the present invention is applied, when an input voltage of 220V is applied to the device while the position of the input voltage selection switch is selected as 110V, an alarm sounds through the alarm sound generating device to alert the user of an abnormal state. An overvoltage alarm is triggered to immediately disconnect the power plug or disconnect the power switch.

As described above, the overvoltage alarm circuit of the present invention achieves the effect of alarming to prevent damage to the circuit device due to the overvoltage input when the position of the input voltage selection switch of the device is inappropriately selected.

In addition, the circuit of the present invention achieves the effect of automatically blocking the circuit and preventing its damage when overvoltage is applied when the position of the input voltage selection switch of the device is inappropriately selected.

While the invention has been shown and described with respect to certain preferred embodiments, it will be appreciated that the invention can be modified and modified in various ways without departing from the spirit or scope of the invention as set forth in the claims below. One of ordinary skill in the art will readily know.

Claims (3)

A power input unit 100 for receiving commercial power; A voltage selection switching unit 110 for selecting a power input from the power input unit 100 as a low voltage (eg 110V) or a high voltage (eg 220V); An electronic device having a power supply comprising a conversion means (130) for converting a commercial voltage value input through the voltage selection switching unit (110) into a low voltage direct current value for use in a device. The selection switching unit 110 has an interlocking contact 222 to which the following overvoltage sensing circuit 200 is connected when the selection position is a low pressure position; The interlocking contact (222) has an overvoltage detecting means (200) to which a circuit is connected; Alarm sound generation when excessive voltage is applied in the low-voltage, high-voltage dual-purpose electronic device, characterized in that it is connected to the over-voltage detecting means 200 and comprises an alarm sound generating means 210 for generating an alarm sound when the over-voltage is detected. Circuit. The zener diode 224 according to claim 1, wherein the overvoltage detecting means 200 uses a zener diode 224, and a current starts to flow in the zener diode 224 when the voltage across the zener diode 224 is equal to or higher than a predetermined zener voltage. And an overvoltage detecting means is configured, so that an alarm sound generation circuit is applied when an excessive voltage is applied to a high-voltage and low-voltage electronic device. The overvoltage of the high-voltage and low-voltage combined electronic device according to claim 1 or 2, wherein an oscillation sound generator is used as the alarm means 210 and the oscillation sound generator is mounted on the electronic device. Authorized alarm circuit.