KR20140073939A - Protection circuit - Google Patents

Protection circuit Download PDF

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Publication number
KR20140073939A
KR20140073939A KR1020120141988A KR20120141988A KR20140073939A KR 20140073939 A KR20140073939 A KR 20140073939A KR 1020120141988 A KR1020120141988 A KR 1020120141988A KR 20120141988 A KR20120141988 A KR 20120141988A KR 20140073939 A KR20140073939 A KR 20140073939A
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KR
South Korea
Prior art keywords
overcurrent
overvoltage
input power
reference voltage
power source
Prior art date
Application number
KR1020120141988A
Other languages
Korean (ko)
Inventor
성광희
Original Assignee
삼성전기주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 삼성전기주식회사 filed Critical 삼성전기주식회사
Priority to KR1020120141988A priority Critical patent/KR20140073939A/en
Publication of KR20140073939A publication Critical patent/KR20140073939A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16504—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed
    • G01R19/16523—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed using diodes, e.g. Zener diodes
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

To a protection circuit capable of preventing overvoltage / overcurrent of the present invention. The protection circuit of the present invention includes a driver for transmitting driving power to an output terminal according to whether a reference voltage set in advance is applied or not; An overvoltage protection unit that short-circuits the reference voltage to ground when an overvoltage of the input power source is detected; And an overcurrent protection unit for disconnecting a current path of a current applied to the driving unit by the reference voltage when an overcurrent of the input power source is detected. And a protection circuit.

Description

{PROTECTION CIRCUIT}

The present invention relates to a protection circuit capable of preventing overvoltage and overcurrent.

Generally, a power supply used in electrical and electronic equipment outputs a constant DC rated voltage. Overvoltage / overcurrent protection circuits are used in electrical and electronic equipment because the systems or components of electrical and electronic equipment are damaged or destroyed when overvoltages or overcurrents higher than rated due to malfunction of the power supply are output.

However, in the case of the overvoltage / overcurrent protection circuit provided in the IC, it is not easy to implement the circuit, and since the device used is expensive, the manufacturing cost of the overvoltage / overcurrent protection circuit increases.

In the following prior art document, Patent Document 1 relates to an overvoltage protection device, which is connected to a power supply line of a main circuit to sense a power supply voltage to prevent a main circuit from being broken due to an overvoltage exceeding an allowable voltage, And a foldback method in which the power supply voltage is instantaneously shunted. However, Patent Document 1 does not disclose the content of detecting an overcurrent.

Korean Patent Publication No. 10-2012-0058729

An object of the present invention is to solve the above problems of the prior art, and it is an object of the present invention to provide an overcurrent detection circuit which does not have an overvoltage and an overcurrent protection circuit in an IC, detects an overvoltage and an overcurrent using an external zener diode, And a protection circuit that can cut off the driving power.

According to a first technical aspect of the present invention, there is provided a plasma display apparatus comprising: a driver for transmitting driving power to an output terminal according to whether a reference voltage set in advance is applied; An overvoltage protection unit that short-circuits the reference voltage to ground when an overvoltage of the input power source is detected; And an overcurrent protection unit for disconnecting a current path of a current applied to the driving unit by the reference voltage when an overcurrent of the input power source is detected. And a protection circuit.

Also, the driving unit may include a photocoupler for transmitting the driving power to the output terminal by emitting light by the reference voltage.

The overvoltage protection unit may include: an overvoltage detection unit that detects an overvoltage of the input power supply; And an overvoltage controller for shorting the reference voltage applied to the photocoupler to ground when an overvoltage of the input power is detected by the overvoltage detector. And a protection circuit.

Further, the overvoltage detection section proposes a protection circuit including a first zener diode having a first zener threshold voltage that provides an overvoltage reference level of the input power source.

Further, the overvoltage control unit includes at least one switch element for short-circuiting the reference voltage to ground by performing a switching-on operation when an overvoltage of the input power source is detected by the overvoltage detection unit.

The overcurrent protection unit may include: an overcurrent detection unit that detects an overcurrent of the input power source; And an overcurrent controller for blocking a current path of a current applied to the photocoupler by the reference voltage when an overcurrent of the input power is detected by the overcurrent detecting unit.

Further, the overcurrent detecting section includes a second zener diode having a second zener threshold voltage for providing an overcurrent reference level of the input voltage.

The overcurrent controller may switch off the overcurrent when the overcurrent of the input power is detected by the overcurrent detector so that at least one switch element that cuts off the transfer path of the current applied to the photocoupler according to the reference voltage A protective circuit is proposed.

According to the present invention, the reference level of the overcurrent and the overvoltage can be easily set by using the Zener threshold voltage of the Zener diode provided outside the IC as the reference level of the overcurrent and the overvoltage, and an overvoltage / overcurrent protection circuit The circuit can be easily implemented and the manufacturing cost can be reduced.

1 is a block diagram illustrating a protection circuit according to an embodiment of the present invention.
2 is a circuit diagram showing a protection circuit according to an embodiment of the present invention.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order that those skilled in the art can easily carry out the present invention.

1 is a block diagram illustrating a protection circuit according to an embodiment of the present invention.

Referring to FIG. 1, the protection circuit of the present invention may include a driving unit 100, an overvoltage protection unit 200, and an overcurrent protection unit 300.

The driving unit 100 may transmit the driving power to the output terminal OUT when the input power applied to the input terminal IN satisfies a preset rated range. However, when the input power exceeds the pre-set rated range, it blocks the driving power transmitted to the output terminal OUT. The driving power transmitted to the output terminal is applied to the IC element connected to the output terminal to operate the IC element.

The overvoltage protection unit 200 may include an overvoltage detection unit 210 and an overvoltage control unit 220. The overvoltage detection unit 210 detects the overvoltage of the input power source applied to the input terminal IN. The overvoltage detection unit 210 detects the overvoltage of the input power source by comparing the voltage level of the input power source with a predetermined first Zener threshold voltage. When the overvoltage of the input power source is detected by the overvoltage detector 210, the overvoltage controller 220 may control the driver 100 to prevent the drive power from being transmitted to the output OUT.

The overcurrent protection unit 300 may include an overcurrent detection unit 310 and an overcurrent control unit 320. The overcurrent detection unit 310 detects the overcurrent of the input power source applied to the input terminal IN. The overcurrent detection unit 310 detects the overcurrent of the input power source by comparing the voltage level of the input power source with the second predetermined Zener threshold voltage. The overcurrent control unit 320 may control the driving unit 100 to prevent the driving power from being transmitted to the output terminal OUT when the overcurrent detection unit 310 detects an overcurrent of the input power source.

The protection circuit of the present invention is for maintaining the rating of the driving power applied to the IC in order to protect the IC element connected to the output terminal and is connected to the overvoltage protection unit 200 and the overcurrent protection unit 300 through the input terminal IN The transmitted input power may be the same power as the driving power. However, for convenience of explanation, the input power and the driving power are expressed differently.

2 is a circuit diagram showing a protection circuit according to an embodiment of the present invention. The driving unit 100 includes a photodiode PD that emits light by a predetermined reference voltage Vref and a phototransistor PTR that includes a phototransistor PTR that is turned on and off by light emitted from the photodiode . ≪ / RTI > When the reference voltage Vref is applied to the photodiode PD, the phototransistor PTR is turned on, and when the phototransistor PTR is turned on, the voltage applied to the emitter of the phototransistor PTR is the resistance The first transistor M1 can be turned on by being divided by the elements R1 and R2. Thereby, the driving power supply Vcc can be transmitted to the output terminal OUT.

However, when the reference voltage Vref is not applied to the photodiode PD, the driving unit 100 can not transfer the driving power Vcc to the output OUT. The overvoltage protection unit 200 and the overcurrent protection unit 300 may be configured such that when the overvoltage and the overcurrent of the input power applied to the input terminal IN are detected respectively, the reference voltage applied to the photodiode PD is grounded Or the cathode of the photodiode PD is opened so that the transfer path of the current applied to the photodiode by the reference voltage is cut off so that the reference voltage Vref is not applied to the photodiode PD.

When the overvoltage protection unit 200 detects the overvoltage of the input power source, the reference voltage Vref can be prevented from being applied to the photodiode PD by shorting the reference voltage to the ground. When the overvoltage of the input power source is detected by the overvoltage detection unit 210 and the overvoltage detection unit 210 that detect the overvoltage of the input power source, the overvoltage protection unit 200 outputs the reference voltage Vref applied to the photodiode PD And an overvoltage control unit 220 short-circuited to ground.

The overvoltage detection unit 210 may include a first Zener diode ZD1 and the overvoltage control unit 220 may be switched on when the overvoltage is detected by the overvoltage detection unit 210, And at least one switch element shorting the reference voltage Vref to ground.

In addition, when the overcurrent protection unit 300 detects an overcurrent, the reference voltage Vref can cut off the transfer path of the current applied to the porter diode PD. When the overcurrent of the input power source is detected by the overcurrent detection unit 310 and the overcurrent detection unit 310 that detect the overcurrent of the input power source, And an overcurrent control unit 320 that cuts off the transmission path.

The overcurrent detection unit 310 may include a second Zener diode ZD2 and the overcurrent control unit 320 may control the overcurrent control unit 320 to detect the overcurrent of the input power by the reference voltage Vref, It is possible to cut off the propagation path of the current applied to the PD.

Hereinafter, the operation of the protection circuit of the present invention will be described in detail. The first Zener diode ZD1 and the second Zener diode ZD2 connected to the input IN provide the overvoltage reference level and the overcurrent reference level of the input power source applied to the input terminal, respectively. In this case, the Zener threshold voltages of the first Zener diode and the second Zener diode are referred to as a first Zener threshold voltage and a second Zener threshold voltage, respectively.

The voltage level of the first Zener threshold voltage may be set to be higher than the rated voltage level of the input power source and the voltage level of the second Zener threshold voltage may be set to be lower than the rated voltage level of the input power source.

When the input power source is applied to the input terminal IN in the rated range, the voltage level of the input power source is higher than the voltage level of the second Zener threshold voltage, so that the second Zener diode ZD2 is turned on and the second Zener diode ZD2 ) Is smoothed by the capacitor C3 and the fifth transistor M5 is turned on. In this case, since the voltage level of the input power source is lower than the voltage level of the first Zener threshold voltage, the first Zener diode ZD1 is turned off so that the third transistor M3 is turned on, The fourth transistors M2 and M4 are turned off. The reference voltage Vref applied to the photodiode PD is applied to the ground through the fifth transistor M5 so that the driving unit 100 transfers the driving power Vcc to the output terminal OUT do.

When the input power applied to the input terminal is an overcurrent, the voltage level of the input power source is reduced. Accordingly, the voltage level of the input power source is reduced below the second Zener threshold voltage, so that the second Zener diode ZD2 is turned off, and thus the fifth transistor M5 is turned off. In this case, the transmission path of the current applied to the photodiode PD is blocked by the reference voltage, and the driving unit 100 can not transmit the driving power Vcc to the output terminal OUT, It is possible to prevent the breakdown of the IC element connected to the output terminal.

When the input power applied to the input terminal is an overvoltage, the voltage level of the input power supply is equal to or higher than the first Zener threshold voltage, so that the first Zener diode ZD1 is turned on. The power outputted to the anode of the first Zener diode ZD1 is rectified and smoothed by the diode D1 and the capacitor C2 and is divided by the resistance elements R3 and R4 to be applied to the second and fourth transistors M2, M4, and turns off the third transistor M3 to form a path for shorting the reference voltage Vref to ground. In this case, since the reference voltage Vref is not applied to the photodiode PD, the driving unit 100 can not transfer the driving power source Vcc to the output terminal, so that the protection circuit of the present invention is connected to the output The breakdown of the IC device can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Therefore, the spirit of the present invention should not be construed as being limited to the above-described embodiments, and all of the equivalents or equivalents of the claims, as well as the following claims, I will say.

100:
200: Overvoltage protection unit
210: Overvoltage detector
220: Overvoltage control section
300: Overcurrent Protection
310: Overcurrent detection unit
320: Overcurrent control unit

Claims (8)

A driving unit for transmitting driving power to an output terminal according to whether a preset reference voltage is applied or not;
An overvoltage protection unit that short-circuits the reference voltage to ground when an overvoltage of the input power source is detected; And
An overcurrent protection unit for disconnecting a current path of a current applied to the driving unit by the reference voltage when an overcurrent of the input power source is detected; ≪ / RTI > The driving apparatus according to claim 1,
And an optocoupler for transmitting the driving power to an output terminal by emitting light by the reference voltage. 3. The overvoltage protection circuit according to claim 2,
An overvoltage detector for detecting an overvoltage of the input power supply; And
An overvoltage controller for short-circuiting the reference voltage applied to the photocoupler to ground when an overvoltage of the input power is detected by the overvoltage detector; ≪ / RTI > 4. The overvoltage detection circuit according to claim 3,
A first Zener diode having a first Zener threshold voltage providing an overvoltage reference level of the input power source. 4. The overvoltage protection circuit according to claim 3,
And at least one switching element for short-circuiting the reference voltage to ground by performing a switching-on operation when an overvoltage of the input power source is detected by the overvoltage detecting unit. 3. The overcurrent protection circuit according to claim 2,
An overcurrent detecting unit for detecting an overcurrent of the input power source; And
And an overcurrent controller for blocking a current path of a current applied to the photocoupler by the reference voltage when an overcurrent of the input power is detected by the overcurrent detecting unit. 7. The overcurrent detecting apparatus according to claim 6,
A second Zener diode having a second Zener threshold voltage providing an overcurrent reference level of the input voltage. 8. The overcurrent controller according to claim 7,
And at least one switching element for switching off the transmission path of the current applied to the photocoupler according to the reference voltage when the overcurrent detection unit detects the overcurrent of the input power source.
KR1020120141988A 2012-12-07 2012-12-07 Protection circuit KR20140073939A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020120141988A KR20140073939A (en) 2012-12-07 2012-12-07 Protection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020120141988A KR20140073939A (en) 2012-12-07 2012-12-07 Protection circuit

Publications (1)

Publication Number Publication Date
KR20140073939A true KR20140073939A (en) 2014-06-17

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Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020120141988A KR20140073939A (en) 2012-12-07 2012-12-07 Protection circuit

Country Status (1)

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KR (1) KR20140073939A (en)

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