EP0483744A2
Expired / Lapsed
EP
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Current detection circuit of power semiconductor device and power converter using the circuit
Assignee: Hitachi Ltd
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Filing: 1991-10-29
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Granted: —
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Expires: 2011-10-29
Abstract
Abstract According to the invention different detection levels of a load current can be detected. Preferably, these detection levels are an overcurrent control level and/or a constant current control level. Said constant current control level can be a constant current value associated with chopper control or a value which judges an overload when a chopper control current exceeds a predetermined current level beyond a predetermined number of times. Said overcurrent control level can be a value corresponding to short-circuit-protection. Further, according to the invention a control circuit can control power semiconductor devices by decreasing a control voltage in a plurality of steps to zero in the case where an overcurrent detecting circuit outputs a detection signal corresponding to an overcurrent control level. According to a further aspect of the invention a power converter with a plurality of semiconductor devices is improved by control means and current detection circuits showing the above mentioned advantages of the invention. <IMAGE>
Inventors
- 👤 Hideki Miyazaki
- 👤 Kouzou Watanabe
- 👤 Kenichi Onda
- 👤 Tomoyuki Tanaka
- 👤 Naoki Sakurai
- 👤 Mutsuhiro Mori
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 15:29
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16566; G01R19/16571; G01R19/1659; G01R19/16595; G01R19/175; H; H02; H02H; H02H3/00; H02H3/08; H02H3/087; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/1563; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H02M7/53875; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0822; H03K17/0828; H02H1/00; H02H1/0007; H02M1/00; H02M1/0003; H02M1/0009; H03K2217/00; H03K2217/0027
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
299 words
A current detection circuit of a power semiconductor device for detecting a load current flowing through a power semiconductor device for controlling a load current, and for outputting at least one detection signal when said load current exceeds at least one detection level, said current detection circuit comprising: - a comparison circuit (M₂, Q₄; Q₉, Q₄) including at least one single pair of first (M₂ ; Q₉) and second transistors (Q₄; Q₄) connected in series with one another, for detecting the potential at a common junction (V s1 ) of said first and second transistors as a detection signal; - a reference current supply circuit (M₁, Q₇; Q₈) including a third transistor (M₁; Q₈) connected in a mirror connection with said first transistor (M₂; Q₉) of said comparison circuit, for supplying a predetermined reference current in accordance with said detection level to said comparison circuit; and - a detection current extraction circuit (Q₂, Q₃; M₅, Q₃) including a fourth transistor (Q₃, Q₃) connected in a current mirror connection with said second transistor(Q₄; Q₄) of said comparison circuit, for supplying a control current of a level associated with said load current circuit of said semiconductor device to a main current of said second transistor (Q₄; Q₄) wherein said main current is a current flowing through a transistor being not a current for switching the transistor ; characterized in that - said comparison circuit comprises at least a further pair (M₃ Q₅; Q₁₀ Q₅) of first and second transistors connected in series with one another, for detecting the potential at each common junction (V s1 , V s2 ) of said first and second transistors as a detection signal; and - each of said pairs is used in order to detect different detection levels of said load current (I L ).
Claim 2
Dependent Claim
106 words
A current detection circuit of a power semiconductor device according to claim 1, wherein the ratio (A₁ : A₂) of the current flowing areas relating to the main current of said plurality of first transistors (M₂ M₃; Q₉, Q₁₀) is set in match with the ratio of the value obtained by subtracting a current quantityces-necessary for turning on said fourth transistor (Q₃) from the detection level of said load current (I L ) associated with each of said first transistors (M₂, M₃; Q₉, Q₁₀) and wherein the current flowing areas relating to the main current of said second transistors (Q₄, Q₅) are set to the same.
Claim 3
Dependent Claim
100 words
A current detection circuit of a power semiconductor device according to claim 1, wherein the current flowing areas relating to the main current of said plurality of first transistors (M₂ M₃; Q₉, Q₁₀) are set to the same, and wherein the ratio(B₁ : B) of the current flowing areas relating to the main current of said second transistors(Q₄, Q₅) is set to an inverse number of the ratio obtained by subtracting an offset current necessary for turning ON said fourth transistor (Q₃) from the detection level of said load current(I L ) relating to each of said second transistors(Q₄, Q₅).
Claim 4
Dependent Claim
110 words
A current detection circuit of a power semiconductor device according to any of the preceding claims, wherein said detection current extraction circuit (Q₁ Q₃; Q₅, Q₃) connects the main circuit of said fourth transistor(Q₃) in parallel with said power semiconductor device through a main circuit of a detection semiconductor device(Q₂, M₅) having the same characteristics as those of said power semiconductor device (Q₁; M₄) connects the control electrode of said fourth transistor (Q₃) to a junction between said fourth transistor (Q₃) and said detection semiconductor device (Q₂, M₅)and connects the control electrode of said detection semiconductor device (Q₂, M₅) to the control electrode of said power semiconductor device (Q₁; M₄).
Claim 5
Dependent Claim
34 words
A current detection circuit of a power semiconductor device according to any of the preceding claims, wherein said current detection circuit is formed on the same semiconductor substrate as said power semiconductor device(Q₁; M₄).
Claim 6
Dependent Claim
78 words
A current detection circuit of a power semiconductor device according to any of the preceding claims, where in another transistor(Q₁₁) is connected in parallel with at least one of said plurality of second transistors(Q₄, Q₅) or first transistors(M₂, M₃) through a switch(8), and there is provided an overheat detection circuit(10) which detects a temperature corresponding to the temperature of said power semiconductor device and turns on respective off said switch(8) when the temperature is above a reference temperature.
Claim 7
Dependent Claim
43 words
A current detection circuit of a power semiconductor device according to any of the preceding claims, comprising a temperature compensation circuit (R, D₁...D n , Q₆; R, D₁...D n ) for controlling the current (Ir) flowing through said reference current supply circuit(M₁, Q₇).
Claim 8
Dependent Claim
94 words
A current detection circuit of a power semiconductor device according to clairn 7, wherein said temperature compensation circuit (R, D₁...D n , Q₆; R, D₁...D n ) includes a fifth transistor inserted into and connected to the main circuit of said third transistor(Q₈) or a fifth transistor(Q₆) connected to a sixth transistor (Q₄) of said reference current supply circuit in a current mirror connection, and the main circuit of said sixth transistor is connected to a constant voltage source through said temperature compensation circuit whose resistance value changes in accordance with an ambient temperature.
Claim 9
Dependent Claim
32 words
A current detection circuit of a power semiconductor device according to any of the preceding claims, where in said detection levels are an overcurrent control level and/or a constant current control level.
Claim 10
Dependent Claim
57 words
A current detection circuit according to claim 9, wherein said overcurrent control level is a value corresponding to short-circuit-protection and said constant current control level is a constant current value associated with chopper control or a value which judges an overload when a chopper control current exceeds a predetermined current level beyond a predetermined number of times.
Claim 11
Dependent Claim
85 words
A control circuit for controlling power semiconductor devices, capable of controlling the turning off of said power semiconductor devices, said control circuit comprising an overcurrent detecting circuit (34) for detecting an overcurrent and a voltage decreasing means(35, 36, 37, 38a, 38b) for decreasing the control voltage of said power semiconductor devices, characterized in, that said control voltage is decreased in a plurality of steps to zero in the case where said overcurrent detecting circuit (34) outputs said detection signal corresponding to an overcurrent control level.
Claim 12
Dependent Claim
43 words
A control circuit according to claim 11, wherein said control circuit is a part of a current detection circuit as claimed in any of the claims 1 to 10, wherein said overcurrent detecting circuit(34) comprises said comparison circuit and said detection extraction circuit.
Claim 13
Dependent Claim
21 words
A control circuit according to claim 11 or 12, wherein said power semiconductor device comprises a IGBT (Insulated Gate Bipolar Transistor).
Claim 14
Dependent Claim
120 words
A control circuit according to any of the claims 11 to 13, wherein said voltage decreasing means (35, 36, 37, 38a, 38b) includes a plurality of gate signal generating circuits (35, 36) and a plurality of switching elements (37, 38a, 38b) connected between the gate of the power semiconductor device (31) and the ground and controlled by said gate signal generating circuit (35, 36), wherein the gate voltage of the power semiconductor device (31) is sequentially lowered in a plurality of steps to zero by generating gate signals sequentially and is controlling the corresponding switching elements by the signals when an overcurrent flowing through the power semiconductor device (31) is detected continuously for a time longer than a predetermined period.
Claim 15
Dependent Claim
32 words
A control circuit according to claim 14, wherein said switching elements are configured with MOSFETs (315, 316a, 316b) or with bipolar transistors or with circuits having MOSFETs and resistors arranged in series.
Claim 16
Dependent Claim
73 words
A power converter comprising - a plurality of power semiconductor devices (QU, QV, QW, Q 1x , Q 1y , Q 1z ) connected to one another in a bridge connection; - current detection circuits (21A, 21B, 21C, 25A, 25B, 25C) as claimed in any of the claims 1 to 10; and - control means (3U, 3V, 3W, 3X, 3Y, 3Z, 6) for controlling said power semiconductor devices based on said detection signals.
Claim 17
Dependent Claim
50 words
A power converter according to claim 16, wherein said detection current extraction circuit and said comparison circuit (21A, 21B, 21C, 25A, 25B, 25C) are disposed in such a manner as to correspond to each of said power semiconductor devices on the cathode side arm of a power conversion main circuit.
Claim 18
Dependent Claim
24 words
A power converter according to claim 16 or 17, where in said control means comprises a voltage decreasing means as defined in claim 14.
References Cited (Backward Citations)
No citation records indexed.
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