KR101335370B1 - Over Current Protection Apparatus - Google Patents

Abstract

Generates a current sensor that converts an input current into a voltage signal and outputs it, an overcurrent detector driven according to the voltage signal output from the current sensor, and a switching unit drive signal whose logic level is determined according to the duration of the output signal of the overcurrent detector. An overcurrent prevention device including an overcurrent determination unit is provided.

Description

{Over Current Protection Apparatus}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric system protection device, and more particularly, to an overcurrent prevention device.

In general, a switching mode power supply employing a pulse width modulation (PWM) method converts a DC input voltage into a square wave voltage by using a semiconductor device such as a power MOSFET as a switch, To obtain a DC output voltage. This is advantageous in that it is higher in efficiency and durability than conventional linear power supply devices, and is advantageous in size and weight by controlling the flow of electric power using a switching processor of a semiconductor device.

In the switching mode power supply, when an overcurrent is detected, various control methods such as limiting the continuous increase of the current at the output side, reducing the current supply amount, or increasing the current supply amount can be applied.

However, in the case of a switching mode power supply adopting a constant current supply method, a current mode method, a voltage mode method, and a gap oscillation method, the output current continuously flows when the state is continuously maintained even after an overcurrent is detected.

* If the current flows continuously, unnecessary power is supplied or the switching device or other parts are kept in a heat state, and the parts may be damaged, resulting in fire, circuit, or equipment. Normal operation of the system becomes difficult.

Republic of Korea Patent Publication No. 10-2008-0099417 Republic of Korea Utility Model Registration No. 20-0321222

An object of the present invention is to provide an overcurrent prevention device capable of immediately shutting off an overcurrent when an overcurrent that may cause a system malfunction is detected.

An overcurrent prevention device according to an embodiment of the present invention for achieving the above technical problem is a current sensor for converting the input current into a voltage signal and outputs; An overcurrent detector driven according to a voltage signal output from the current sensor; And an overcurrent determination unit configured to generate a switching unit driving signal whose logic level is determined according to the duration of the output signal of the overcurrent detection unit.

According to another aspect of the present invention, there is provided an overcurrent prevention apparatus comprising: a current sensor for converting an input current into a voltage signal and outputting the voltage signal; And a plurality of overcurrent control circuits connected in parallel between the current sensor and the switching unit formed in the current supply line of the device to be protected.

According to another aspect of the present invention, there is provided an overcurrent prevention apparatus comprising: a current sensor for converting an input current into a voltage signal and outputting the voltage signal; A first overcurrent control circuit for detecting the overcurrent on the forward current path of the first current sensor and controlling the first switching unit; And a second overcurrent control circuit for detecting the overcurrent on the reverse path of the second current sensor and controlling the second switching unit.

In the present invention, the current flow can be blocked as soon as the overcurrent is detected, so that the target device can be efficiently protected.

Furthermore, when a Hall sensor is used as a sensor for current sensing, the amount of current can be sensed in both directions by the voltage at the Hall sensor output terminal. Therefore, when the present invention is applied to a power supply system utilizing a charge / discharge element such as a secondary battery, overcharge and over discharge can be simultaneously detected.

Further, in the present invention, an optical switching element can be applied to detect an overcurrent. Since an optical switching element transmits and receives signals only between light input and output, it can have an optical isolation state because no current flows between the input and output. Thus, it is of course possible to more effectively protect the internal device.

In addition, when a plurality of optical switching elements as an overcurrent sensing unit are connected in parallel and the amount of current flowing in the input terminal of each optical switching element is varied, the amount of the overcurrent to be detected can be changed as desired by the operator, There is also an advantage of being able to detect the overcurrent.

1 is a configuration diagram of an overcurrent prevention apparatus according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of the overcurrent prevention device shown in FIG. 1,
3 is an example of an optical switching element applied to the present invention,
4 is another example of an optical switching element applied to the present invention,
5 is a configuration diagram of an overcurrent prevention device according to another embodiment of the present invention,
6 is a configuration diagram of an overcurrent prevention apparatus according to still another embodiment of the present invention,
7 is a diagram for explaining an application example of the overcurrent prevention device shown in Fig.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

1 is a configuration diagram of an overcurrent prevention apparatus according to an embodiment of the present invention.

1, the overcurrent prevention apparatus 10 according to the embodiment of the present invention includes a current sensor 110 for converting an input current into a voltage signal and outputting the voltage signal, And an overcurrent judging unit 130 for determining whether the overcurrent detecting unit 120 and the overcurrent detecting unit 120 are driven in response to a signal outputted in response to the driving of the overcurrent detecting unit 120 and the overcurrent detecting unit 120.

The output signal of the overcurrent judging unit 130 controls the switching unit connected to the current supply line of the system to be protected to determine the ON / OFF state of the switching unit.

The current sensor 110 detects the amount of current flowing through the protection target device, for example, the power supply system, and converts it into a voltage. The current sensor 110 may be selected from a Hall sensor, a current transformer, a resistor, and the like. In particular, when the Hall sensor is adopted, the overcurrent can be detected in both directions, which will be described later.

The overcurrent sensing unit 120 may be a switching device that is determined to be driven according to a voltage signal, which is an output signal of the current sensor 110, and may preferably adopt an optical switching device. An optical switching element, which is usually composed of a photodiode and an electronic switch, can be optically isolated since signals are transmitted and received only between the input and output ends. Thus, the internal device can be protected more efficiently.

On the other hand, the overcurrent judging unit 130 regards the overcurrent which is maintained in less than the designated time as an instant pulse in response to the output signal of the overcurrent detecting unit 120, and judges that the overcurrent which is maintained over the designated time is an overcurrent to be cut off . When the overcurrent to be cut off is detected, the switching unit is turned off.

That is, the switching unit maintains the ON state when an overcurrent is not detected, or when an overcurrent handled as an instantaneous pulse is detected, and when an overcurrent to be blocked is detected, the switching unit cuts off the current supply to the protection target device.

Fig. 2 is a circuit diagram of the overcurrent prevention device shown in Fig. 1. Fig.

2, the overcurrent sensing unit 120 includes a current amount control unit 122, an optical switching device 124, and a pull-down unit 126. [

The amount of current input to the optical switching element 124 is adjusted according to the output voltage of the current sensor 110 so that the reference value of the overcurrent detection is set to .

The optical switching element 124 can be formed using a photo coupler or a photo MOS. By applying the optical switching element 124, it is possible to block the formation of a current path between power sources having different ground states. In other words, since the optical switching element 124 sends and receives signals only between the input terminal and the output terminal, no current flows between the input terminal and the output terminal. That is, the internal device can be more reliably protected through optical insulation.

FIG. 3 is a view showing an example of an optical switching device applied to the present invention, showing a case using a photocoupler, FIG. 4 is a view illustrating another example of an optical switching device applied to the present invention, Respectively.

3 and 4, the optical switching element 124 is connected to the input terminal (terminal 1) and the first ground terminal (AGND) (terminal 2) in response to an input signal whose voltage level is determined by the current- The first power voltage terminal VDD (terminal 4) and the output terminal (terminal) are driven when the amount of current flowing through the light emitting elements 1241 and 1245 and the light emitting elements 1241 and 1245 forming the current path between the first power voltage terminal VDD 3 which form a current path between the light receiving elements 1243, 1247.

A pull-down section 126 is provided between the output terminal (terminal 3) of the optical switching element 124 and the second ground terminal DGND, so that the output signal can be outputted quickly.

When the input current amount of the optical switching element 124 adjusted by the current amount adjusting section 122 connected to the input terminal (terminal 1) is equal to or higher than a certain level, the terminal 4 and the terminal 3 are electrically connected to each other, 3 < / RTI >

Although the pull-down unit 126 is shown in FIGS. 2 to 4, the present invention is not limited thereto, and it is also possible to form a pull-up unit between the first power voltage terminal DVDD and the terminal 4.

4 also has a switching element 1249 for electrically connecting the first power supply voltage terminal VDD (terminal 4) and the output terminal (terminal 3) to the light receiving unit side, As shown in FIG.

The optical switching elements shown in Figs. 3 and 4 are only one embodiment, but are not limited thereto.

Referring to FIG. 2 again, the overcurrent determining unit 130 outputs a switching unit driving signal according to the duration of the signal output from the overcurrent sensing unit 120.

The overcurrent determination unit 130 includes a logic element G1 for receiving a signal output from the output terminal (terminal 3) of the overcurrent sensing unit 120 as a first input signal, a logic circuit G1 for receiving the output signal of the overcurrent sensing unit 120, And a delay circuit (R1, C1) for providing the second input signal of the logic element (G2) with a specified time delay. The delay circuit may comprise a resistance element R1 and a capacitor C1. By using the time constant of the resistor element R1 and the capacitor C1, the overcurrent maintained for a time less than the time constant is regarded as an instantaneous pulse so that the switching unit is not turned off, and an overcurrent The switching unit driving signal is output so that the switching unit is turned off.

2, when the current sensor 110 detects the amount of current flowing in the device under protection, such as a power supply system, and outputs the detected voltage as a voltage signal, the overcurrent detecting device 10 shown in FIG. (124) is driven in accordance with the detected voltage level. The signal outputted as the optical switching element 124 is driven is supplied to the overcurrent determining unit 130. When the overcurrent is maintained for a predetermined time or more, the overcurrent determining unit 130 turns off the switching unit to prevent the overcurrent from flowing to the protection target apparatus.

The overcurrent detecting unit 120 and the overcurrent determining unit 130 that determine the on / off state of the switching unit according to the output signal of the current sensor 110 may collectively be referred to as an overcurrent control circuit.

The overcurrent detecting unit 120 and the overcurrent determining unit 130 are connected to at least two or more current sensors 130 and 130. The overcurrent detecting unit 120 and the overcurrent determining unit 130 are used to block the overcurrent, 110 and the switching unit, and will be described below.

5 is a configuration diagram of an overcurrent prevention device according to another embodiment of the present invention.

5 includes first overcurrent control circuits 120-1 and 130-1 and second overcurrent control circuits 120-1 and 120-2 connected in parallel between the current sensor 110 and the switching unit. 2, and 130-2.

The current amount control unit 1227 provided in the current amount control unit 1221 and the second overcurrent control circuits 120-2 and 130-2 provided in the first overcurrent control circuits 120-1 and 130-1 are respectively connected to resistors Device. The current amount regulating units 1221 and 1227 may be the same or different in size. In the case where resistance elements of different sizes are used, one overcurrent preventing apparatus 10-1 can detect the overcurrent of various levels have.

Further, when a plurality of the overcurrent control circuits 120-1 / 130-1 and 120-2 / 130-2 are connected and used, the amount of the output current of the current sensor 110 can be reduced. In this case, the optical switching elements 1223 and 1229 may not operate or the output voltage of the current sensor 110 may be lowered, thereby malfunctioning. Therefore, the buffer unit 150, preferably an analog buffer unit, may be additionally provided at the output terminal of the current sensor 110 to maintain the output current level of the current sensor 110 above a certain level.

5, reference numerals 1225 and 1231 denote pull-down portions, respectively. The overcurrent detection unit 120 and the overcurrent detection unit 120 shown in FIG. 2 are used to determine the overcurrent detection unit 120 and the overcurrent detection unit 120, The detailed configuration of the unit 130 will be omitted.

As mentioned above, the overcurrent prevention device of the present invention can use a Hall sensor as the current sensor 110. [

The hall sensor is a current sensor having excellent responsiveness for converting the intensity of the current magnetic field into a voltage. That is, a sensor using a Hall element having a current magnetic effect in which the output changes when a magnetic field is applied perpendicularly to the direction of the current. Since the output signal is analog, the system can be used directly without conversion process, , There is an economic advantage.

Particularly, if a reference voltage is applied to the Hall sensor and the output voltage becomes higher as the current flows more in the forward direction of the current flow with reference to the reference voltage, the voltage is reversely lowered in the opposite direction. Therefore, an overcurrent control circuit (an overcurrent detection unit and an overcurrent control unit) can be applied to both the forward direction and the reverse direction.

The power system using the secondary battery module, which is attracting attention as the next generation fuel for solving the problems of environmental pollution, both the over discharge problem and the overcharge problem are all important issues. Therefore, if the overcurrent prevention device is constructed using the hall sensor, it is possible to detect both overdischarge and overcharge in both directions along the current flow of the secondary battery module.

6 is a configuration diagram of an overcurrent prevention device according to another embodiment of the present invention.

6, the overcurrent prevention device 20 according to the present embodiment includes a current sensor 210, a first overcurrent control circuit 220, and a second overcurrent control circuit 230. [

The first and second overcurrent control circuits 220 and 230 include overcurrent sensing units 221 and 231 and overcurrent determination units 223 and 233, It can be adopted with reference to circuit or device.

The current sensor 210 is preferably composed of a hall sensor. The current sensor 210 converts the amount of current flowing along the device under protection to a voltage level, and outputs a voltage signal to the first overcurrent control circuit 220. Assuming that the current flow from the current sensor 210 to the first overcurrent control circuit 220 is forward and a large amount of current flows along the forward path and the output voltage of the current sensor 210 becomes high, 2 overcurrent control circuit 230 is lowered.

It goes without saying that when the voltage level on the forward path is lowered, the voltage level on the reverse path rises.

Accordingly, the overcurrent flowing along the forward path is detected by the first overcurrent control circuit 220 to control the switching unit, and the overcurrent flowing along the reverse path is detected by the second overcurrent control circuit 230 so that the switching unit is controlled.

That is, it is possible to detect the overcurrent in both directions with respect to the protection target device such as the power supply system.

7 is a diagram for explaining an application example of the overcurrent prevention device shown in Fig.

7, the protection target device 100 may be a power supply system including a fuel cell module such as a secondary battery module. The protection target device 100 is connected between a power supply unit (not shown) and an external device (not shown) to charge the power supplied from the power supply unit and supply the charged power to the external device, .

When the overcurrent protection device 20 as shown in FIG. 6 is applied to such a power supply system, the overcurrent state is detected through, for example, the first overcurrent control circuit 220 to prevent the overcurrent from flowing through the secondary battery module . Similarly, overdischarge may be detected through the second overcurrent control circuit 230 to prevent an overcurrent from flowing to an external device that receives power from the secondary battery module.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10, 10-1, 20: Overcurrent prevention device
110: Current sensor
120, 120-1, 120-2, 221, and 231: an overcurrent sensing unit
130, 130-1, 130-2, 223, 233: Overcurrent judging unit
122, 1221, and 1227:
124, 1223, 1229: optical switching element
126, 1225: Pull-
150, and 1231:

Claims (7)

A current sensor for converting an input current into a voltage signal and outputting the converted voltage;
A first overcurrent control circuit for detecting whether there is an overcurrent on a forward current path of the current sensor to control a first switching unit; And
A second overcurrent control circuit configured to detect whether there is an overcurrent on a reverse path of the current sensor and to control a second switching unit;
The overcurrent protection device comprising: The method of claim 1,
And the current sensor comprises a hall sensor. 3. The method of claim 2,
Each of the first and second overcurrent control circuits,
An overcurrent detector driven according to a voltage signal output from the current sensor; And
An overcurrent determination unit configured to generate a switching unit driving signal whose logic level is determined according to a duration of an output signal of the overcurrent detection unit;
The overcurrent protection device comprising: The method of claim 3, wherein
Wherein the overcurrent sensing unit includes an optical switching device. The method of claim 3, wherein
Wherein the overcurrent determining unit outputs the switching unit driving signal for turning off the switching unit when the output signal of the overcurrent sensing unit is maintained for a predetermined time or longer. The method of claim 1,
The current sensor receives an amount of current flowing through the fuel cell module, converts it into a voltage signal, and outputs the converted voltage signal. The first overcurrent control circuit detects an overcurrent flowing through a charge path of the fuel cell module, and the second overcurrent control circuit. Is an overcurrent prevention device for detecting an overcurrent flowing through the discharge path of the fuel cell module. The method according to claim 6,
The fuel cell module is an overcurrent prevention device comprising a secondary battery module.

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