KR20010037871A - Circuit for protecting IPM - Google Patents

Abstract

PURPOSE: An IPM protection circuit is provided to achieve an improved operation reliability and lengthen useful life of the IPM circuit by automatically sensing convergence of micro computer. CONSTITUTION: An IPM protection circuit comprises an over temperature sensing unit for sensing over temperature of the IPM circuit and outputting an over temperature signal; an over current sensing unit for sensing over current of the IPM circuit and outputting an over current signal; a micro computer convergence sensing unit for sensing convergence of the micro computer installed at the IPM circuit and outputting a convergence signal; and an error signal generating unit for generating an error signal when at least one of the over temperature signal, over current signal and the convergence signal is output, and shutting down the IPM circuit.

Description

Circuit for protecting IPM

The present invention relates to an IPM circuit, and more particularly, to an IPM protection circuit that monitors the congestion of the microcomputer and prevents damage of the IPM due to the congestion of the microcomputer.

The IPM circuit generally includes a power device portion, a gate drive, and a protection circuit portion. 1 is a block diagram schematically illustrating a conventional IPM protection circuit, and FIG. 2 is a circuit diagram showing the protection circuit of FIG. 1 in detail.

The power supply element is generally composed of an IGBT and a diode. The size of the IGBT and the diode installed in the power supply element is adapted to the specification of the IPM circuit or the system in which the IPM circuit is to be used.

In addition, the control unit generally includes a high voltage integrated circuit (HVIC).

At this time, in the IPM circuit, the protection circuit which is not embedded in the high voltage integrated circuit includes an over current monitoring unit, a current output unit, an over temperature monitoring unit, and a fault signal output unit. ) And fault latch & clear.

At this time, the overcurrent monitoring unit is configured to suit the specifications of the power device, in particular IGBT, the current output unit is connected to the external control unit by a predetermined interface to operate. The current output unit and overcurrent monitor detects high currents due to overload and prevents damage to components. The current output unit detects a current flowing in the DC voltage line and amplifies the predetermined current by using a predetermined amplifier, in particular, OP-Amp, and outputs the voltage value between 0 volts and 5 volts. The overheat monitor protects the power supply device by stopping the operation of the gate drive when the IPM circuit is overheated above a predetermined temperature.

The error signal output unit generates an error signal when the overcurrent monitoring unit or the overheat monitoring unit operates, and the error detection correction unit operates when the cause of the error signal generated in the error signal output unit is eliminated.

However, since the protection circuit portion for protecting the conventional IPM circuit is composed of separate circuits for protecting the overcurrent monitoring portion, the overheating monitoring portion, and the current output portion, respectively, an error signal is generated when the protection circuit of each portion is operated. To work. In particular, the conventional IPM circuit operates so that the microcomputer stops the operation of the IPM circuit in software when such an error signal is transmitted to the port of the microcomputer. Therefore, the conventional IPM circuit has a problem that the IPM circuit is not properly protected when the microcomputer is congested due to electrical noise or the like.

The reason is that the microcomputer periodically checks for congestion by using a built-in watchdog and resets itself, so that the microcomputer cannot protect the IPM without detecting the congestion by the monitoring function. Because. As a result, since the IPM continues to operate in a state in which the microcomputer does not detect congestion, that is, in an unstable state, the IPM may be damaged in some cases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object thereof is to add a function of monitoring the congestion of the microcomputer to the IPM circuit so as to quickly detect the congestion of the microcomputer to prevent damage to the IPM.

1 is a block diagram schematically showing a conventional IPM protection circuit

2 is a circuit diagram showing a conventional IPM protection circuit in detail

3 is a block diagram schematically showing an IPM protection circuit of the present invention.

4 is a circuit diagram showing in detail the IPM protection circuit of the present invention;

5A and 6A are waveform diagrams showing signals when the microcomputer is in a steady state

5B and 6B are waveform diagrams showing signals when the microcomputer is in a runaway state

Symbol description for main parts of drawing

100: micom congestion detection unit 200: overheat detection unit

300: over current detection unit 400: error signal generation unit

The present invention is characterized in that it detects the congestion of the micom, and automatically generates an error signal according to the congestion of the micom.

The IPM protection circuit of the present invention includes an overheat monitoring unit for detecting whether the IPM circuit is overheated, an overcurrent monitoring unit for detecting whether the current flowing in the IPM circuit is excessive, and a microcomputer runaway monitoring unit for detecting whether the microcomputer is installed in the IPM circuit And an error signal generator for receiving an signal output from at least one of the monitoring units and generating an error signal. 3 is a block diagram schematically showing the IPM protection circuit of the present invention, Figure 4 is a circuit diagram showing in detail the IPM protection circuit of the present invention.

The overheat monitoring unit 200 is configured to detect whether the IPM circuit is overheated and output an overheat signal. As shown in FIG. 4, the overheat monitoring unit 200 includes a temperature sensor whose resistance value varies according to temperature, a first reference resistor receiving a reference voltage, a voltage applied to the reference resistance, and a voltage applied to the temperature sensor. It consists of a first comparator and the like to compare. Since the overheat monitoring unit 200 is the same as that of the conventional IPM protection circuit, the detailed description thereof will be omitted in the present invention.

The overcurrent monitoring unit 300 is configured to detect whether the current flowing in the IPM circuit is excessive and output an overcurrent signal. As shown in FIG. 4, the overcurrent monitoring unit 300 is connected to the current output unit, and includes a second reference resistor receiving a voltage flowing through the current output unit, a third reference resistor receiving a predetermined reference voltage, and a second reference resistor. And a second comparator for comparing the current by the voltage applied to the reference resistor and the third reference resistor, respectively. Since the overcurrent monitoring unit 300 is the same as that provided in the conventional IPM protection circuit, the detailed description thereof will be omitted in the present invention.

The micom congestion monitoring unit 100, which is a main feature of the present invention, is configured to detect congestion of the microcomputer installed in the IPM circuit and output a congestion signal. As shown in FIG. 4, the micom congestion monitoring unit 100 includes a first inversion unit M4 for inverting a signal applied from the microcomputer and a second half for inverting the signal output from the first inversion unit M4. A third inversion unit for smoothing and inverting the signal applied from the microcomputer, and a fourth inversion unit M1 for inverting the signal applied from the second inversion unit M2 and the third inversion unit. It is composed. In this case, at least one of the first inverting unit M4, the second inverting unit M2, and the fourth inverting unit M1 may be configured as a Darlington transistor array. Of course, all of the first inverting unit M4, the second inverting unit M2, and the fourth inverting unit M1 may be configured as a Darlington transistor array.

The second inverting unit M2 of the microcomputer congestion monitoring unit provided in the IPM protection circuit of the present invention is provided with a power input terminal for receiving a predetermined voltage from the outside.

The third inverting unit includes a smoothing capacitor C6 that smoothes the signal output from the microcomputer and an inverting device M3 that inverts the signal smoothed by the smoothing capacitor C6. In this case, the inversion apparatus may be configured as a darlington transistor array similar to the first inversion unit M4, the second inversion unit M2, and the fourth inversion unit M1.

Hereinafter, the operation principle of the IPM protection circuit of the present invention is as follows. The overheat monitoring unit 200, the overcurrent monitoring unit 300, and the micom congestion monitoring unit 100 have almost the same operation as those installed in the conventional IPM protection circuit, and thus description thereof will be omitted. The operation of the unit 100 and the error signal generator 400 will be described.

The microcomputer that operates normally, that is, the microcomputer in the uncongested state, outputs a pulse as shown in FIG. 5A. This pulse is detected at point A in FIG. The pulse output from the microcomputer is inverted into a pulse as shown in FIG. 6A while passing through the first inverting unit M4.

At this time, the pulse output from the microcomputer is converted into a low signal by the smoothing capacitor C6 of the third inverting unit while passing through the third inverting unit, and is high by the Darlington transistor array M3 of the third inverting unit. high) signal.

The voltage Vcc of a predetermined level applied from the power input terminal is converted into a low signal by the smoothing capacitor C5, and the signal is converted into a high signal while passing through the second inverting unit M2. Is reversed.

The signal inverted high by the second inverting unit M2 is inverted back to a low signal while passing through the fourth inverting unit M1. That is, when the microcomputer outputs a normal pulse signal, a high signal is always input to the input terminal of the fourth inverting unit M1. Therefore, when the micom operates normally, the micom congestion monitoring unit 100 always outputs a low signal, so that the error signal generating unit 400 does not output the error signal.

However, when the microcomputer is congested, the microcomputer does not output a normal pulse signal, but outputs an abnormal DC component signal as shown in FIG. 5B. The signal of this DC component is detected at point A of FIG. Therefore, the signal of the DC component is inverted by the first inverting unit M4 and converted into a signal as shown in FIG. 6B and applied to the input terminal of the second inverting unit M2.

If the congested microcomputer continuously outputs a high signal, it is charged in the smoothing capacitor C6 of the third inverting unit so that the Darlington transistor array M3 of the third inverting unit inputs a low signal. Will receive. As a result, the third inverting unit outputs a high signal, and the fourth inverting unit M1 outputs a low signal.

However, the high signal continuously output from the microcomputer is inverted into a low signal by the first inverting unit M4 and is coupled to the input terminal of the second inverting unit M2 together with the voltage Vcc of the power input terminal. Since it is applied, the second inverting unit M2 outputs a low signal. Since the low signal output from the second inverting unit M2 is inverted to a high signal by the fourth inverting unit M1, the micom congestion monitoring unit 100 eventually outputs a high signal. Done.

Therefore, when the microcomputer is congested and outputs a high level signal, the microcomputer congestion monitoring unit 100 outputs a high signal so that the error signal generator 400 outputs an error signal.

Further, when the microcomputer congests and continuously outputs a low level signal, the voltage charged in the smoothing capacitor C6 of the third inverting unit is applied to the Darlington transistor array M3 of the third inverting unit. Then, the Darlington transistor array M3 of the third inverter outputs a low signal, and the fourth inverter M1 outputs a high signal. That is, when the microcomputer is congested and outputs a low level signal, the microcomputer congestion monitoring unit 100 is output by the signal output from the third inversion unit regardless of the signal output from the second inversion unit M2. The high signal is output. As a result, the error signal generator 400 generates an error signal.

After all, if the microcomputer operates normally, the fourth inverting unit M1 of the microcomputer congestion monitoring unit 100 always outputs a low signal, but if the microcomputer falls into the congestion state, the fourth half of the microcomputer congestion monitoring unit 100 The whole M1 always outputs a high signal by the signal output from the second inverting unit M2 or the third inverting unit.

Therefore, the IPM protection circuit of the present invention may generate an error signal regardless of whether the microcomputer is operating even if the microcomputer is congested.

Unlike the conventional IPM protection circuit, the IPM protection circuit of the present invention can automatically detect a congested state of the microcomputer. Therefore, even if the micom congestion of the IPM circuit can be quickly stopped the operation of the system, there is an effect that can improve the operation reliability of the IPM circuit and extend the life of the IPM circuit.

Claims (6)

Overheat monitoring unit for outputting an overheat signal by detecting the overheat of the IPM circuit, An overcurrent monitoring unit which detects whether the current flowing in the IPM circuit is excessive and outputs an overcurrent signal; A micom congestion monitoring unit for detecting the congestion of the micom installed in the IPM circuit and outputting a congestion signal, and And an error signal generator for generating an error signal to stop the IPM circuit when at least one of the overheat signal, the overcurrent signal, and the congestion signal is output. According to claim 1, wherein the micom congestion monitoring unit A first inverting unit for inverting a signal applied from the microcomputer, A second inversion unit inverting the signal output from the first inversion unit, A third inverting unit smoothing and inverting the signal applied from the microcomputer, and And a fourth inversion unit for inverting a signal applied from the second inversion unit and the third inversion unit. 3. The IPM protection circuit of claim 2, wherein at least one of the first inverting unit, the second inverting unit, and the fourth inverting unit is configured of a Darlington transistor array. The IPM protection circuit according to claim 2, wherein a power input terminal for applying a predetermined voltage from the outside is additionally installed at an input terminal of the second inverting unit. The method of claim 2, wherein the third inverting portion Smoothing capacitor to smooth the signal output from the micom, And an inverting device for inverting the signal smoothed in the smoothing capacitor. 6. The IPM protection circuit of claim 5, wherein the inverter is configured of a Darlington transistor array.