KR20100023365A - Protection circuit for intelligent power module - Google Patents

Abstract

The present invention is a protection circuit used in an intelligent power module (IPM), and the user can change the reference size, and when the current flows above the reference size, it is a protection circuit that detects it and informs the entire system.

The protection circuit of the present invention determines the abnormality of the intelligent power module by measuring the electrical information in the intelligent power module and converting it into a voltage, a storage unit storing a variable reference value, and a voltage and a reference value of the measurement unit, and determining the abnormality of the intelligent power module. It includes a determination unit for transmitting to the power module.

Description

PROTECTION CIRCUIT FOR INTELLIGENT POWER MODULE}

The present invention is a protection circuit of an intelligent power module (IPM), and a user can change a reference size, and when a current of the reference size or more flows, it detects this and informs the entire system.

IPM is a power module that supplies power, and is mounted in various electronic devices (such as home appliances and PDPs) to reduce power consumption. Intelligent power modules, also called smart power modules, have their own protection. Specifically, when it is determined that an abnormality has occurred by detecting an overheat, an overcurrent, a short circuit, a control power supply abnormality, and the like, safety measures such as stopping the operation may be taken. This IPM has its own protection circuit to generate its own protection signal as described below. Since the protection circuit of the IPM is only a technology that is naturally recognized by those skilled in the art to which the present invention pertains, its illustration and description are omitted.

1 is a diagram illustrating a protection function in a conventional IPM and IPM. 1 is an intelligent power module that assumes a three-phase circuit and aids in power supply. The information is shown at each point (input points of P, U, V, W, N and IC chips, etc.) (voltage, current, temperature). The measurement itself determines whether the protection function should be activated. The self-protection signal is judged to be normal when the maximum voltage that can be output (this is called High) and is not normal when it is the lowest voltage that can be output (called Low). When operating the protection function, each IC chip receives a low self-protection signal as an input (a protection signal is applied to Fo in FIG. 1), and the power supply to the electronic device connected to the IPM is cut off by stopping the operation. do.

For example, the self-protection signal is changed to Low when the amount of current flowing from one point (N) to the terminal on the right side is higher than the reference, and the IC chip stops receiving the signal from Fo of FIG. Therefore, the power supplied to the electronic device connected to the IPM can be cut off. Since the protection function based on the self-protection signal is judged according to the value set in the circuit, it is difficult to perform the protection function in consideration of the specifications of each home appliance connected to the IPM, and the specifications of each home appliance in the IPM In order to perform the protection function, it is inconvenient to separately manufacture the IPM that performs the protection function according to the value considering the specifications of each home appliance.

It is an object of the present invention to provide a protection circuit which protects an IPM by comparing a measured value separately with a reference size which can be varied.

In addition, since the present invention detects overcurrent, an object of the present invention is to provide a protection circuit that can be changed to an IPM having a current limit desired by a user only with conventional IPMs and commercial components.

In addition, an object of the present invention is to provide a protection circuit that can be changed to IPM, which can change the value set by the user when the variable resistor or the like is used.

The protection circuit of the present invention determines the abnormality of the intelligent power module by measuring the electrical information in the intelligent power module and converting it into a voltage, a storage unit storing a variable reference value, and a voltage and a reference value of the measurement unit, and determining the abnormality of the intelligent power module. It includes a determination unit for transmitting to the power module.

In addition, the electrical information includes a current, and the measurement unit preferably includes a shunt resistor through which the current flows, and measures the voltage value of the shunt resistor.

In addition, the measurement unit preferably includes an amplifier circuit or attenuation circuit that varies the voltage value of the shunt resistor.

In addition, the storage unit is preferably provided with a variable resistor to vary the stored reference value.

In addition, the storage unit may change the maximum current value allowed by the intelligent power module by changing the reference value.

In addition, the determination unit is a comparator for comparing the voltage of the measurement unit and the voltage of the storage unit, and the comparator preferably determines that an error occurs in the intelligent power module when the voltage of the measurement unit is greater than the voltage of the storage unit.

The present invention has the effect of protecting the IPM compared to the reference size that can be changed by comparing the measured values separately through this configuration.

In addition, since the overcurrent is sensed through a separate protection circuit, only the existing IPM and commercial components can be changed into an IPM having a current limit desired by the user.

In addition, in the case of using a variable resistor, there is an effect that can be changed to IPM that can change the value set by the current limit.

In the following, the invention is explained in detail in conjunction with the drawings.

2 is a diagram illustrating the protection circuit of the present invention. The protection circuit is connected to the intelligent power module by receiving the value of the part to be measured (for example, the current value), comparing it with a predetermined value stored in advance, and transmitting the output value depending on the magnitude to the intelligent power module. Protect electronic devices For example, by attaching a shunt resistor to the N portion of FIG. 1, measuring the current through the voltage value of the shunt resistor, and connecting the output of the protection circuit to the position Fo to which the self-protection signal is applied, the protection circuit is connected thereto. You can decide whether to power the connected electronics. The location where the input and output of the protection circuit is connected to the intelligent power module will be described in more detail in FIG. 3.

The measurement unit 20 includes a shunt resistance (R _shunt ), and measures the current where the shunt resistance is to be measured by attaching the shunt resistance to a conductive wire. For example, if the shunt resistor is 0.05 Ohm and the voltage of the shunt resistor R _shunt is 0.3 Volt, the current flowing in the N part is 0.3 (V) ÷ 0.05 (Ω) = 6 (A You can see that. Of course, it is also possible to measure the current value directly by attaching a sensor for measuring the current, but this method is preferable because it is economical. That is, when the value to be measured is a current value, it can be changed to a voltage value through a shunt resistor.

The measurement unit 20 may further include an amplifier circuit or attenuation circuit, so that the changed voltage value may be changed to a size comparable with the value of the storage unit 30. The amplifier circuit illustrated in FIG. 2 is a conventional non-inverting amplifier circuit using an op-amp, and its amplification ratio is 1+ (R2 / R1). For example, if the value of resistor R1 is 1 kiloohm (kΩ) and the value of resistor R2 is 7.5 kiloohms (kΩ), the amplification ratio is 8.5, and the voltage of the shunt resistor is 0.3 volt (V). ), The voltage V1 at the op amp output is 0.3 (V) x 8.5 = 2.55 (V).

The storage unit 30 stores a reference value for comparing with the voltage measured and amplified (or attenuated) by the measuring unit 20. The example illustrated in FIG. 2 reduces a voltage of a voltage source to output a predetermined value. It is a circuit. If the voltage of the voltage source is 5 (V) and the values of the resistors R3 and R4 are both 10 kiloohms (kΩ), then the output value is 5 (V) × {10 (kΩ) ÷ (10 ( kΩ) +10 (kΩ))} = 2.5 (V). In FIG. 2, the protection function operates according to whether or not overcurrent exists, and a criterion for determining whether the overcurrent is overcurrent is 2.5 (V) ÷ 8.5 ÷ 0.05 (Ω) = 5.88 (A). The DC voltage source provided in the storage unit 30 may be a 5V voltage source that can be generally drawn from the intelligent power module.

The reference value 2.5V of the protection circuit illustrated in the storage unit 30 in FIG. 2 reflects a requirement that a current value flowing through a conductor line provided with a shunt resistor should not exceed 5.88 (A). Since the value stored by the storage unit 30 can be changed by setting at least one of the resistor R3 and the resistor R4 as a variable resistor, the range allowed by the intelligent power module when the protection circuit of the present invention is used. And user requirements, for example, a maximum current value (reference value of current).

The comparator 40 compares the output of the measuring unit 20 with a reference value stored in the storage unit 30. One of the input terminals of the op-amp receives the output of the measuring unit 20, and the other The page receives a value stored in the storage unit 30. In FIG. 2, the output of the measuring unit 20 is connected to the negative terminal of the op amp, and a value stored in the storage unit 30 is input to the + terminal of the op amp. In this case, when the output of the measuring unit 20 is larger than the value stored in the storage unit 30, the output value of the op-amp and the output value V2 of the protection circuit give Low, and the low voltage of the IPM itself Logic coupling with the guard signal signal allows the output voltage (V _out ) to be determined and delivered to the entire intelligent power module. Since the IPM determines that the low signal is applied to the Fo receiving the self-protection signal, the output signal V _out should be low when the output of the comparator 40 or the self-protection signal is the low signal. In FIG. 2, it can be seen that the output voltage V _out outputs Low even if only one of the output self-protection signal of the self-protection circuit and the output value from the comparator 40 goes low. When at least one of the output of the self-protection circuit and the output value from the comparator 40 is low, the configuration in which the output voltage V _out is low can be implemented through the AND gate of the IC chip as well.

Here, the value stored by the storage unit 30 may be changed when the resistor R3 or R4 is a variable resistor. If the electronic device connected to the intelligent power module flows more than a certain current, the protection function is activated to cut off the power supplied to the electronic device. The user sets the intelligent power by setting or changing the value of the resistor (R3 or R4). You can set or change the reference value that best protects the electronics connected to the module and allow the intelligent power module to actuate its protection if it exceeds the set or changed reference value.

In a general intelligent power module, the self-protection signal is normal when it is high and abnormal when it is low. The self-protection signal of the inventors and the original self-protection signal in the original intelligent power module are ANDed together to receive the original self-protection signal. If connected to Fo, the whole intelligent power module can stop the operation of the electronic device connected to the intelligent power module not only when it determines that its protection signal is abnormal, but also when the protection circuit outputs a low signal. have.

3 is a circuit for explaining a position where the protection circuit of FIG. 2 is connected to a conventional IPM. In the protection circuit of FIG. 2, the measurement section 20 receives information of the circuit between the points 101 and 102, and the shunt resistor R instead of the lead of the portion between the points 101 and 102. _shunt ) can be connected to measure the current value. By connecting the shunt resistor R _shunt between the point 101 and the point 102, the current flowing through the N portion of FIG. 1 may be measured. Where Fo received the output of the self-protection circuit in the conventional IPM was connected to the output of the self-protection circuit. However, in the present invention, the connection between Fo and the output of the self-protection circuit is cut off, and at the point 103, the output voltage V _out logically combining the output of the self-protection circuit and the output voltage V2 of the protection circuit is To be authorized. Alternatively, a voltage passing through the comparator 40 in FIG. 2 is applied to the point 103 and a diode or an AND gate is connected between the voltage of the point 103 and the signal of the protection circuit applied to the Fo part. It is also possible to apply the resulting output (V _out ) to each IC chip using (not shown).

4 is a graph showing results of experiments with the protection circuit of FIG. 2. The embodiment tested in FIG. 4 is intended to make the output of the protection circuit low when the current flowing in the N portion of FIG. 1 is 5 amperes (A) or more. Therefore, the maximum value (reference value) of the current flowing in the N portion of FIG. 1 is set to 5 amps (A), and accordingly, the value stored by the storage unit 30 indicates that the current flowing through the shunt resistor is 5 amps (A). It sets to the voltage value input into the comparator 40 at the time. The output voltage V _out of the protection circuit of FIG. 2 is a voltage value indicated by a dotted line in FIG. 4. It shows the output voltage when instantaneous overcurrent flows. When the amount of current exceeds 5 amperes (A), it can be seen that the output voltage changes after a certain time since the voltage value in the measuring unit 20 becomes larger than the voltage value in the storage unit. However, due to the delay of the circuit, the output voltage changes after a predetermined time passes from the point t1 where the amount of current exceeds the reference value (t2). These results show that the output voltage changes to Low only when the current through the protection circuit is above the reference value. In addition, as described above, the reference value may be adjusted through a variable resistor or the like.

In the above, the present invention has been described in detail based on the embodiments of the present invention and the accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the contents described in the claims below.

1 is a diagram illustrating a protection function in a conventional IPM and IPM.

2 is a diagram illustrating the protection circuit of the present invention.

3 is a circuit for explaining a position where the protection circuit of FIG. 2 is connected to a conventional IPM.

4 is a graph showing the results of experiments performed with the protection circuit of FIG. 2.

Claims (6)

A measuring unit measuring electrical information in the intelligent power module and converting the electrical information into a voltage; A storage unit which stores a variable reference value; A determination unit comparing the voltage of the measurement unit with a reference value to determine whether the intelligent power module is abnormal and transferring the same to the intelligent power module; The protection circuit of the intelligent power module comprising a. The method of claim 1, The electrical information includes a current, and the measuring unit includes a shunt resistor through which the current flows, and measures the voltage value of the shunt resistor. The method of claim 2, And the measuring unit includes an amplifying circuit or attenuating circuit for varying a voltage value of the shunt resistor. The method of claim 1, The storage unit has a variable resistor to protect the intelligent power module, characterized in that for varying the stored reference value. The method of claim 4, wherein The storage unit changes the maximum current value allowed by the intelligent power module by changing the reference value. The method according to any one of claims 1 to 5, The determining unit is a comparator for comparing the voltage of the measuring unit and the voltage of the storage unit, and the comparator determines that an error has occurred in the intelligent power module when the voltage of the measuring unit is greater than the voltage of the storage unit.

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