US 5,608,595 AGranted

Semiconductor power module and power conversion device

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsMajumdar Gourab, Takahiro Hiramoto, Takeshi Tanaka

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Abstract

A semiconductor power module which provides reliable overvoltage protection including an overvoltage protection device which functions so that when an overcurrent flows to an IGBT (1), a sink transistor (10) turns on and the IGBT (1) turns off accordingly. As the IGBT (1) turns off to cut off the overcurrent, a high surge voltage is applied to the IGBT (1). At this time, however, a clamp current flows trough a clamping circuit including a Zener diode (6), a diode (7) and a resistance (8) and part of it is divided to a transistor (Q11), so that a transistor (Q12) turns on and the sink transistor (10) turns off as the result. Accordingly, the clamp current increases a gate voltage of the IGBT (1). Hence, large part of the load current flows in the IGBT (1), and only a little flows to the clamping circuit. Accordingly, overheat of and damage by burning to the clamping circuit will not be caused even if both the overcurrent and overvoltage are applied.

Claims22

Dependent claims

A semiconductor power module, comprising:

(a) a switching semiconductor element having first and second main electrodes which are a pair of main electrodes, and a control electrode, for controlling a main current flowing between the pair of main electrodes in response to a control signal applied to the control electrode, and
wherein said first main electrode of said switching semiconductor element has a large electrode through which main part of said main current flows and a small electrode through which a small current in proportion to said main current flows;
(b) control means responsive to an input signal for outputting said control signal;
(c) overcurrent protection means for realizing a conducting state between said first main electrode and said control electrode when said main current exceeds a predetermined reference value to cut off said main current between said pair of main electrodes, and said overcurrent protection means further comprises,
switch means having its one end connected to said control electrode and the other end connected to said large electrode and which becomes conductive in response to an overcurrent detection signal;
(d) clamp means connected between said second main electrode and said control electrode and which becomes conductive when a voltage exceeding a predetermined reference voltage is applied;
and
(e) cancelling means for cancelling operation of said overcurrent protection means when said clamp means becomes conductive and for cancelling conduction of said switch means which becomes conductive in response to said overcurrent detection signal, when said clamp means becomes conductive.

5 more elements

A power conversion device, comprising:

(a) switching means interposed between a high potential side direct current bus and a low potential side direct current bus, wherein the switching means comprises,
(a-1) a plurality of semiconductor power modules connected in series, each of said plurality of semiconductor power modules comprising,
(a-1-1) a switching semiconductor element having first and second main electrodes which are a pair of main electrodes, and a control electrode, for controlling a main current flowing between the pair of main electrodes in response to a control signal applied to the control electrode, and
wherein said first main electrode of said switching semiconductor element has a large electrode through which main part of said main current flows and a small electrode through which a small current in proportion to said main current flows;
(a-1-2) control means responsive to an input signal for outputting said control signal,
(a-1-3) overcurrent protection means for realizing a conducting state between said first main electrode and said control electrode when said main current exceeds a predetermine reference value to cut off said main current between said pair of main electrodes, and said overcurrent protection means further comprises,
switch means having its one end connected to said control electrode and the other end connected to said large electrode and which becomes conductive in response to an overcurrent detection signal;
(a-1-4) clamp means having its one end connected to said second main electrode and the other end connected to said control electrode and which becomes conductive when a voltage exceeding a predetermined reference voltage is applied, and
(a-1-5) cancelling means for cancelling operation of said overcurrent protection means by cancelling conduction of said switch means which becomes conductive in response to said overcurrent detection signal, when said clamp means becomes conductive and for outputting a predetermined error signal, and
said power conversion device further comprises,
(b) gate control means for sending said input signal to each of said plurality of semiconductor power modules, and
(c) cutting off means for cutting off all of said plurality of semiconductor power modules when at least one of said plurality of semiconductor power modules sends said predetermined error signal.

9 more elements

Dependencies are inferred from the claim text.