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JP-2026075969-A - Semiconductor equipment

JP2026075969AJP 2026075969 AJP2026075969 AJP 2026075969AJP-2026075969-A

Abstract

[Problem] To provide a semiconductor device that can generate a correct over-temperature detection signal for the output transistor even when a reverse current is generated from the load towards the output transistor. [Solution] The temperature sensing diode 13 is formed on the semiconductor substrate adjacent to the power transistor 7 and generates a forward voltage Vf with a magnitude that reflects the temperature of the power transistor 7. The over-temperature detection circuit 62 detects over-temperature of the power transistor 7 by comparing the magnitude of the forward voltage Vf with a reference voltage VREF, and asserts an over-temperature detection signal OT1 in that case. The reverse current detection circuit 65 detects the occurrence of a reverse current Iinv in the power transistor 7 and asserts a reverse current detection signal INVD during the period in which it occurs. The semiconductor device 101 then uses the reverse current detection signal INVD to perform, for example, mask processing of the over-temperature detection signal OT1. [Selection Diagram] Figure 1

Inventors

  • 中原 明宏
  • 太田 智明

Assignees

  • ルネサスエレクトロニクス株式会社

Dates

Publication Date
20260511
Application Date
20241023

Claims (14)

  1. An output transistor formed on a semiconductor substrate, connected between a power supply terminal and a power output terminal, and which supplies power to a load connected to the power output terminal when controlled to be ON, A temperature sensing diode is formed on the semiconductor substrate adjacent to the output transistor and generates a forward voltage of a magnitude that reflects the temperature of the output transistor, A bias circuit that supplies bias current to the temperature sensing diode, An over-temperature detection circuit that detects over-temperature of the output transistor by comparing the magnitude of the forward voltage with a threshold voltage, and asserts a first over-temperature detection signal when over-temperature is detected, A reverse current detection circuit that detects the occurrence of a reverse current from the power output terminal toward the power supply terminal and asserts a reverse current detection signal during the period in which the reverse current is occurring, A mask circuit that receives the reverse current detection signal and the first over-temperature detection signal and generates a second over-temperature detection signal fixed to the negate level during the assertion period of the reverse current detection signal, Equipped with, Semiconductor equipment.
  2. In the semiconductor device described in claim 1, Furthermore, it includes a control switch that controls the output transistor to turn off during the assertion period of the second over-temperature detection signal. Semiconductor equipment.
  3. In the semiconductor device described in claim 1, The output transistor is composed of a plurality of unit output transistors. The temperature sensing diode is formed in a rectangular region, Two or more sides constituting the rectangular region are adjacent to one or more unit output transistors among the plurality of unit output transistors. Semiconductor equipment.
  4. In the semiconductor device described in claim 3, The output transistor is composed of a vertical n-channel MOSFET with the back surface of the semiconductor substrate as the drain. The source and drain of the output transistor are connected to the power output terminal and the power supply terminal, respectively. Between the output transistor and the temperature sensing diode, a PNP-type parasitic bipolar transistor is formed, with the back gate of the output transistor as the emitter and the drain as the base, and which is turned on by the reverse current. Semiconductor equipment.
  5. In the semiconductor device described in claim 1, The aforementioned load is either a capacitive load or an inductive load. Semiconductor equipment.
  6. An output transistor formed on a semiconductor substrate, connected between a power supply terminal and a power output terminal, and which supplies power to a load connected to the power output terminal when controlled to be ON, A temperature sensing diode is formed on the semiconductor substrate adjacent to the output transistor and generates a forward voltage of a magnitude that reflects the temperature of the output transistor, A bias circuit that supplies bias current to the temperature sensing diode, A reverse current detection circuit that detects the occurrence of a reverse current from the power output terminal toward the power supply terminal and asserts a reverse current detection signal during the period in which the reverse current is occurring, A compensation circuit that generates a compensation current and compensates the magnitude of the diode current flowing through the temperature sensing diode using the compensation current during the assertion period of the reverse current detection signal, An over-temperature detection circuit that detects over-temperature of the output transistor by comparing the magnitude of the forward voltage with a threshold voltage, and asserts an over-temperature detection signal when over-temperature is detected, Equipped with, Semiconductor equipment.
  7. In the semiconductor device described in claim 6, Furthermore, it includes a control switch that controls the output transistor to turn off during the assertion period of the over-temperature detection signal. Semiconductor equipment.
  8. In the semiconductor device described in claim 6, The output transistor is composed of a plurality of unit output transistors. The temperature sensing diode is formed in a first rectangular region, Two or more sides constituting the first rectangular region are adjacent to one or more unit output transistors among the plurality of unit output transistors. Semiconductor equipment.
  9. In the semiconductor device described in claim 8, The output transistor is composed of a vertical n-channel MOSFET with the back surface of the semiconductor substrate as the drain. The source and drain of the output transistor are connected to the power output terminal and the power supply terminal, respectively. Between the output transistor and the cathode of the temperature sensing diode, a first parasitic bipolar transistor of type PNP is formed, with the back gate of the output transistor as the emitter and the drain as the base, and which is turned on by the reverse current. The magnitude of the compensation current is determined by reflecting the magnitude of the first parasitic current flowing through the first parasitic bipolar transistor. Semiconductor equipment.
  10. In the semiconductor device described in claim 9, The compensation circuit increases the diode current, which has been reduced by the first parasitic current, by the compensation current. Semiconductor equipment.
  11. In the semiconductor device described in claim 9, The compensation circuit includes a variable current source capable of adjusting the magnitude of the compensation current. The magnitude of the compensation current is determined during testing of the semiconductor device. Semiconductor equipment.
  12. In the semiconductor device described in claim 9, The compensation circuit includes a dummy temperature sensing diode formed on the semiconductor substrate adjacent to the output transistor. A second parasitic bipolar transistor of type PNP, which is turned on by the reverse current, is formed between the output transistor and the cathode of the dummy temperature sensing diode. The compensation circuit is configured to set the second parasitic current flowing through the second parasitic bipolar transistor as the compensation current. Semiconductor equipment.
  13. In the semiconductor device according to claim 12, The dummy temperature sensing diode is formed in a second rectangular region, One or more sides constituting the second rectangular region are adjacent to one or more unit output transistors among the plurality of unit output transistors. Semiconductor equipment.
  14. In the semiconductor device described in claim 6, The aforementioned load is either a capacitive load or an inductive load. Semiconductor equipment.

Description

This invention relates to a semiconductor device, and more particularly to a semiconductor device that supplies power to an externally connected load. Patent Document 1 describes a load drive circuit capable of detecting overcurrent and overtemperature and performing appropriate protection actions. This load drive circuit comprises an output transistor, an overcurrent detection circuit and an overtemperature detection circuit for detecting overcurrent and overtemperature in the output transistor, respectively, a cutoff circuit for controlling the output transistor to turn off in response to the detection of overcurrent or overtemperature, and a holding circuit. The holding circuit holds the overcurrent detection signal and then releases the holding of the overcurrent detection signal in response to an external signal. The overtemperature detection circuit detects overtemperature when the detected temperature is greater than the judgment temperature and then releases the overtemperature detection state when the temperature becomes less than the judgment temperature. Japanese Patent Publication No. 2014-60581 Figure 1 is a circuit diagram showing an example of the configuration of the main parts of a semiconductor device according to the first embodiment.Figure 2 is a schematic diagram showing an example of the layout configuration of the semiconductor device in Figure 1.Figure 3 is a cross-sectional view showing an example of the configuration between A and A' in Figure 2.Figure 4 is a cross-sectional view showing an example of the configuration between C and C' in Figure 2.Figure 5A is a timing chart showing an example of operation in the semiconductor device shown in Figure 1 when it is not over-temperature and no reverse current is flowing.Figure 5B is a timing chart showing an example of operation in the semiconductor device shown in Figure 1 when it is not over-temperature and a reverse current is flowing.Figure 6 is a circuit block diagram showing an example configuration of an electronic control unit (ECU) using the semiconductor device shown in Figure 1.Figure 7 is a schematic diagram showing an example of the configuration of a vehicle equipped with the electronic control unit (ECU) shown in Figure 6.Figure 8 is a circuit diagram showing an example of the configuration of the main part of a semiconductor device according to the second embodiment.Figure 9 is a timing chart showing an example of operation in the semiconductor device shown in Figure 8 when it is not over-temperature and a reverse current is flowing.Figure 10 is a circuit diagram showing an example of the configuration of the main part of a semiconductor device in a second embodiment, with the configuration of Figure 8 modified.Figure 11 is a circuit diagram showing an example of the configuration of the main part of a semiconductor device according to the third embodiment.Figure 12 is a timing chart showing an example of operation in the semiconductor device shown in Figure 11 when it is not over-temperature and a reverse current is flowing.Figure 13A is a schematic diagram showing an example of the layout configuration of the semiconductor device in Figure 11.Figure 13B is a schematic diagram showing a different layout configuration example from Figure 13A.Figure 13C is a schematic diagram showing a different layout configuration example from Figure 13A.Figure 13D is a schematic diagram showing a different layout configuration example from Figure 13A.Figure 14 is a cross-sectional view showing an example of the configuration between B and B' in Figure 13A.Figure 15 is a circuit diagram showing an example configuration of a semiconductor device as a comparative example.Figure 16 is a timing chart showing an example of operation in the semiconductor device shown in Figure 15 when it is not over-temperature and a reverse current is flowing. In the following embodiments, the description will be divided into multiple sections or embodiments where necessary for convenience. Unless otherwise specified, these are not unrelated; one may be a modification, detail, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including quantity, numerical value, amount, range, etc.), unless otherwise specified or clearly limited to a specific number in principle, the number is not limited to that specific number; it may be greater than or less than that number. Furthermore, in the following embodiments, it goes without saying that the constituent elements (including element steps, etc.) are not necessarily essential, except where specifically stated or where they are clearly essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc., of constituent elements, it shall include those substantially similar to or resembling them, except where specifically stated or where it is clearly not the case in princi