Overheat protection circuit, and semiconductor integrated circuit device and vehicle therewith

Patent metadata

Field	Value
Publication number	US-10366977-B2
Application number	US-201615147135-A
Country	US
Kind code	B2
Filing date	May 5, 2016
Priority date	May 11, 2015
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

An overheat protection circuit has an NPN transistor, a power terminal to which a supply voltage is applied, a transmission path by which the supply voltage is transmitted from the power terminal to the collector of the NPN transistor without passing through a current source, and an output voltage generator that generates an output voltage commensurate with the base-emitter voltage of the NPN transistor.

First claim

What is claimed is:

1. An overheat protection circuit, comprising:
a NPN transistor;
a power terminal to which a supply voltage is applied;
a transmission path by which the supply voltage is transmitted from the power terminal to a collector of the NPN transistor without passing through a current source;
a voltage divider operable to divide a reference voltage in a voltage division ratio to generate a division voltage, the voltage divider including a switch operable to change the voltage division ratio; and
a comparator operable to compare an emitter voltage of the NPN transistor with the division voltage to switch an output voltage from a normal state to an overheated state, and vice versa, wherein
the switch is operable to be turned on/off in response to the switching of the output voltage between the normal state and the overheated state to change the division voltage.

2. The overheat protection circuit of claim 1 , further comprising:
the current source that is connected to the emitter of the NPN transistor.

3. The overheat protection circuit of claim 1 ,
wherein
the reference voltage is applied to a base of the NPN transistor.

4. A semiconductor integrated circuit device, comprising:
a power device; and
the overheat protection circuit of claim 1 .

5. The semiconductor integrated circuit device of claim 4 , wherein the NPN transistor and the power device are formed on a single semiconductor substrate.

6. The semiconductor integrated circuit device of claim 5 , wherein
the NPN transistor and the power device are arranged next to each other.

7. The semiconductor integrated circuit device of claim 6 , wherein
a guard ring region that surrounds the power device is formed on the semiconductor substrate.

8. A semiconductor integrated circuit device comprising:
a power device; and
an overheat protection circuit including:
a NPN transistor;
a power terminal to which a supply voltage is applied;
a transmission path by which the supply voltage is transmitted from the power terminal to a collector of the NPN transistor without passing through a current source; and
an output voltage generator operable to generate an output voltage commensurate with a base-emitter voltage of the NPN transistor, wherein

the power device is a MOS transistor,
the semiconductor integrated circuit device further comprises:
a controller operable to generate an ON/OFF control signal for the MOS transistor; and
a pre-driver operable to generate a gate voltage for the MOS transistor in response to the ON/OFF control signal, and

the overheat protection circuit is arranged between, at one end, the MOS transistor and, at another end, the controller and the pre-driver.

9. The semiconductor integrated circuit device of claim 4 , wherein
the supply voltage is supplied to the semiconductor integrated circuit device from outside the semiconductor integrated circuit device, and
the reference voltage is generated within the semiconductor integrated circuit device.

10. A vehicle comprising:
the semiconductor integrated circuit device of claim 4 .

11. A semiconductor integrated circuit device, comprising:
an overheat protection circuit including:
a NPN transistor;
a power terminal to which a supply voltage is applied;
a transmission path by which the supply voltage is transmitted from the power terminal to a collector of the NPN transistor without passing through a current source; and
an output voltage generator operable to generate an output voltage commensurate with a base-emitter voltage of the NPN transistor;

a power device;
a controller operable to generate an ON/OFF control signal for the power device; and
a pre-driver operable to generate a gate voltage for the power device in response to the ON/OFF control signal, wherein
the power device and the controller is arranged in a first direction, and
the overheat protection circuit is arranged between, at one end, the power device and, at another end, the controller and the pre-driver as viewed in a second direction perpendicular to the first direction.

Assignees

• Rohm Co Ltd

Inventors

• Yuki Hirofumi
• Takahashi Shuntaro

Classifications

• H02H5/044

  using a semiconductor device to sense the temperature · CPC title

• H01L27/0259 Primary

  Electricity · mapped topic

• H01L29/0619

  Electricity · mapped topic

• H02H7/00

  Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions · CPC title

• H01L29/735

  Electricity · mapped topic