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DE-102020131358-B4 - Semiconductor device

DE102020131358B4DE 102020131358 B4DE102020131358 B4DE 102020131358B4DE-102020131358-B4

Abstract

comprising a semiconductor device: • a detection circuit (110) which is connected between a positive electrode and a negative electrode of a semiconductor switching element (10a), wherein • the detection circuit has a current source (120) and a first resistance element (121) which are connected in series between the positive electrode and the negative electrode via a first node (N1), wherein the first resistance element has a first electrical resistance value (R1), • the current source (120) operates such that an output current (1a) of the current source (120) increases to a saturated constant value (I1) when a voltage of the positive electrode becomes higher relative to a voltage of the negative electrode, • the semiconductor device furthermore comprises a voltage comparator (130) which outputs a comparison result between a DC voltage (Vt) applied to a second node and a voltage of the first node, • the DC voltage and the first electrical resistance value are set such that if an intermediate electrode voltage (Vce) between the positive electrode and the negative electrode becomes higher than a predefined setpoint voltage (Vth), the voltage of the first node is higher than the DC voltage, and • the detection circuit and the voltage comparator are mounted on the same integrated circuit.

Inventors

  • Yo Habu
  • Akihisa Yamamoto

Assignees

  • MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date
20260513
Application Date
20201126
Priority Date
20191212

Claims (7)

  1. Semiconductor device comprising: • a detection circuit (110) connected between a positive electrode and a negative electrode of a semiconductor switching element (10a), wherein • the detection circuit comprises a current source (120) and a first resistive element (121) connected in series between the positive electrode and the negative electrode via a first node (N1), the first resistive element having a first electrical resistance value (R1), • the current source (120) operates such that an output current (1a) of the current source (120) increases to a saturated constant value (I1) when a voltage of the positive electrode increases relative to a voltage of the negative electrode, • the semiconductor device further comprises a voltage comparator (130) which outputs a comparison result between a DC voltage (Vt) applied to a second node and a voltage of the first node, • the DC voltage and the first electrical resistance value are set such that when an intermediate electrode voltage (Vce) between the positive electrode and the negative electrode becomes higher than a predefined reference voltage (Vth), the voltage of the first node is higher than the DC voltage, and • the detection circuit and the voltage comparator are mounted on the same integrated circuit.
  2. Semiconductor device according to Claim 1 , wherein • the detection circuit (110) further comprises a second resistive element (122) which is connected in series with the current source (120) between the positive electrode and the first node (N1), • the second resistive element has a second electrical resistance value (R2), • the first electrical resistance values (R1), the second electrical resistance value (R2) and the DC voltage (Vt) are set in such a way that when the intermediate electrode voltage (Vce) becomes higher than the detection voltage (Vth), the voltage of the first node is higher than the DC voltage.
  3. Semiconductor device according to Claim 1 or 2 , wherein the power source (120) comprises a diode-connected field-effect transistor.
  4. Semiconductor device according to Claim 1 or 2 , wherein the current source (120) has a plurality of field-effect transistors (T1 to T6) which form a current mirror circuit (125, 126).
  5. Semiconductor device according to one of the Claims 1 until 4 further comprising a driver circuit (150) which controls a control electrode of the semiconductor switching element (10a), • wherein the driver circuit is mounted on the same integrated circuit as the detection circuit (110) and the voltage comparator (130).
  6. Semiconductor device according to Claim 5 further comprising a protection circuit (180) which receives a first control signal (SIN) for controlling the switching on and off of the semiconductor switching element (10a) and an output signal (Sab) from the voltage comparator (130) and outputs a second control signal (S3) to the driver circuit, • wherein the second control signal is generated to to instruct the driver circuit (150) to turn off the semiconductor switching element when the intermediate electrode voltage (Vce) does not become less than the set voltage (Vth), even if the first control signal changes from a first level (L) indicating the turning off of the semiconductor switching element to a second level (H) indicating the turning on of the semiconductor switching element.
  7. Semiconductor device according to Claim 6 , wherein the protection circuit (180) is mounted on the same integrated circuit as the driver circuit (150).

Description

Background of the invention Field of invention The present invention relates to a semiconductor device. Description of the state of the art Generally, an inverter or similar device uses a so-called arm configuration, in which two semiconductor switching elements (hereinafter simply referred to as "switching elements") are connected between a high-potential node and a low-potential node via an intermediate potential node. In the arm configuration, the switching element connected to the high-potential side is referred to as the high-side switching element, and the other switching element connected to the low-potential side is referred to as the low-side switching element. The Japanese patent disclosure number JP 2019 - 4 535 A Disclosing a semiconductor device that includes a sensing circuit configured to detect the state of the high-side switching element in the arm configuration. As stated in Japanese Patent Publication No. JP 2019 - 4 535 A As disclosed, the state of the high-side switching element is monitored by a sensing circuit and a signal transmission circuit, each comprising switching elements provided outside the semiconductor chip (IC: integrated circuit), which is mounted with a driver circuit for controlling the high-side switching element and the low-side switching element, each formed by an IGBT (insulated gate bipolar transistor). As stated in Japanese Patent Disclosure No. JP 2019 - 4 535 A As disclosed, the sensing circuit outputs a voltage in response to the state of the high-side switching element, and the signal transmission circuit comprises a signal switching element mounted on the semiconductor chip and configured to turn on and off in response to the voltage output of the sensing circuit, and a diode located outside the semiconductor chip and connected in series with the signal switching element. This allows monitoring of the voltage output by the sensing circuit, while the necessary isolation between the high-side and low-side switching elements is ensured by the diode. DE 690 05 755 T2 Disclosing a current sensing circuit with a FET, the current sensing circuit is used as an overcurrent sensing circuit in a power circuit. Summary of the invention According to the Japanese patent disclosure no. JP 2019 4 535 A However, in the disclosed configuration, since the required isolation between the high-side switching element and the low-side switching element is ensured by a diode connected to the IC from the outside, the state of the switching element is monitored by the elements mounted on the IC and by the element provided outside the IC, thereby increasing the number of components and the size of the circuit. On the other hand, it is known that when an overcurrent flows through a switching element, the switching element is placed in an unsaturated state, causing a voltage anomaly. This means that the voltage between the positive and negative electrodes can become abnormally high even when the switching element is in the ON state. Therefore, it is important to detect the voltage anomaly to prevent a continuous overcurrent from flowing through the switching element. In this case, however, it is desirable to detect the voltage anomaly using a simple circuit configuration to avoid the complex circuit configuration described in Japanese Patent Publication No. JP 2019 4 535 A has been revealed, to replace. It is an object of the present invention to provide a semiconductor device capable of detecting a voltage anomaly between a positive electrode and a negative electrode when a switching element is turned on, while ensuring isolation by means of a simple configuration. This problem is solved by the features of independent claim 1. The dependent claims contain advantageous embodiments of the invention. According to one aspect of the present invention, a semiconductor device comprises a sensing circuit connected between a positive electrode and a negative electrode of a semiconductor switching element and a voltage comparator. The sensing circuit comprises a current source and a first resistive element with a first electrical resistance value. The current source operates such that an output current of the current source leads to a saturated current. The voltage increases to a constant value when the voltage at the positive electrode becomes higher relative to the voltage at the negative electrode. The current source and the first resistive element are connected in series via a first node between the positive and negative electrodes. The voltage comparator outputs a comparison result between a DC voltage applied to a second node and the voltage at the first node. The DC voltage and the first resistive element are set such that when the voltage between the positive and negative electrodes exceeds a predefined reference voltage, the voltage at the first node is higher than the DC voltage. The sensing circuit and the voltage comparator are mounted on the same integrated circuit. The foregoing and