Semiconductor device provided with overheat protection circuit and electronic circuit using the same
View Patent ↗A overheat protection circuit is formed on the same semiconductor substrate as a power MOS FET is formed on. As the configuration, a first resistor is connected between an input terminal and a gate of the power MOS FET, a second resistor, a temperature sensing element, and a third resistor are connected in this order between the input terminal and a ground point, an FET for clamp is connected in parallel to a series circuit of the temperature sensing element and the third resistor, a series circuit of an FET for current adjustment and a fourth resistor is connected in parallel to the MOS FET for clamp, a series circuit of a fifth and sixth resistors is connected between the input terminal and the ground point, a node of the fifth and sixth resistors is connected to a gate of the FET for current adjustment, an FET for switching is connected between the gate of the power MOS FET and the ground point, and a node of the temperature sensing element and the third resistor is connected to a gate of the FET for switching.
1. A semiconductor device, comprising:
a power semiconductor element, which has a control terminal and is disposed on a semiconductor substrate; and
an overheat protection circuit, which is arranged between the control terminal of said power semiconductor element and a ground terminal, and is disposed on said semiconductor substrate, wherein:
said overheat protection circuit comprises:
a driving signal input terminal, to which a driving signal for driving said power semiconductor element is supplied;
a first resistor connected between said driving signal input terminal and the control terminal of said power semiconductor element;
a second resistor, one end of which is connected to said driving signal input terminal;
a semiconductor element for temperature sensing, which has a high potential side terminal connected to the other end of said second resistor, and has a low potential side terminal, and changes a voltage across the high potential side terminal and the low potential terminal according to a temperature change of said semiconductor substrate;
a third resistor connected between the low potential side terminal of said semiconductor element for temperature sensing and said ground terminal;
a semiconductor element for switching, which has a control terminal connected to the low potential side terminal of said semiconductor element for temperature sensing, and has two main terminals connected to the control terminal of said power semiconductor element and said ground terminal, respectively;
a semiconductor element for clamp, which has a high potential side terminal connected to the other end of said second resistor, and has a low potential side terminal connected to said ground terminal, and keeps a voltage between the high potential side terminal of said semiconductor element for temperature sensing and said ground terminal at an almost constant voltage; and
a current stabilizing circuit, which keeps a current flow amount into the high potential side terminal of said semiconductor element for clamp at an almost constant level, and
said current stabilizing circuit comprises:
a transistor for current bypass, the drain of which is connected to the high potential side terminal of said semiconductor element for clamp;
a fourth resistor connected between a source of said transistor for current bypass and said ground terminal;
a fifth resistor connected between said driving signal input terminal and a gate of said transistor for current bypass; and
a sixth resistor connected between the gate of said transistor for current bypass and said ground terminal.
2. A semiconductor device, comprising:
a power semiconductor element, which has a control terminal and is disposed on a semiconductor substrate; and
an overheat protection circuit, which is arranged between the control terminal of said power semiconductor element and a ground terminal, and is disposed on said semiconductor substrate, wherein:
said overheat protection circuit comprises:
a driving signal input terminal, to which a driving signal for driving said power semiconductor element is supplied;
a first resistor connected between said driving signal input terminal and the control terminal of said power semiconductor element;
a second resistor, one end of which is connected to said driving signal input terminal;
a semiconductor element for temperature sensing, which has a high potential side terminal connected to the other end of said second resistor, and has a low potential side terminal, and changes a voltage across the high potential side terminal and the low potential terminal according to a temperature change of said semiconductor substrate;
a third resistor connected between the low potential side terminal of said semiconductor element for temperature sensing and said ground terminal;
a semiconductor element for switching, which has a control terminal connected to the low potential side terminal of said semiconductor element for temperature sensing, and has two main terminals connected to the control terminal of said power semiconductor element and said ground terminal, respectively;
a semiconductor element for clamp, which has a high potential side terminal connected to the other end of said second resistor, and has a low potential side terminal connected to said ground terminal, and keeps a voltage between the high potential side terminal of said semiconductor element for temperature sensing and said ground terminal at an almost constant voltage; and
a current stabilizing circuit, which keeps a current flow amount into the high potential side terminal of said semiconductor element for clamp at an almost constant level, and
said current stabilizing circuit comprises:
a transistor for current bypass, the drain of which is connected to the high potential side terminal of said semiconductor element for clamp, and the source of which is connected to said ground terminal, and which functions as an output side element of a current mirror;
a fourth resistor, one end of which is connected to said driving signal input terminal; and
a transistor for bypass current adjustment, the drain and the gate of which are connected to the other end of said fourth resistor and a gate of said transistor for current bypass, and the source of which is connected to said ground terminal, and which functions as an input side element of said current mirror.
3. The semiconductor device according to claim 2 , wherein said current stabilizing circuit comprises a transistor for voltage adjustment inserted and connected between said fourth resistor and said transistor for current bypass, the drain and the gate of said transistor for voltage adjustment are connected to the other end of said fourth resistor, and the source of said transistor for voltage adjustment is connected to the gate of said transistor for current bypass.
4. The semiconductor device according to claim 2 , wherein said current stabilizing circuit further comprises:
a transistor for voltage adjustment inserted between said fourth resistor and said transistor for current bypass, the drain of which is connected to the other end of said fourth resistor, and the source of which is connected to the gate of said transistor for current bypass;
a fifth resistor connected between said driving signal input terminal and a gate of said transistor for voltage adjustment; and
a sixth resistor connected between the gate of said transistor for voltage adjustment and said ground terminal.
5. The semiconductor device according to claim 1 , further comprising:
a power supply for supplying a power to a load through said power semiconductor element; and
a drive circuit for driving said power semiconductor element, wherein
a driving signal for driving said power semiconductor element is supplied from said drive circuit to said driving signal input terminal of said overheat protection circuit.
6. The semiconductor device according to claim 2 , further comprising:
a power supply for supplying a power to a load through said power semiconductor element; and
a drive circuit for driving said power semiconductor element, wherein:
a driving signal for driving said power semiconductor element is supplied from said drive circuit to said driving signal input terminal of said overheat protection circuit.
7. The semiconductor device according to claim 3 , further comprising:
a power supply for supplying a power to a load through said power semiconductor element; and
a drive circuit for driving said power semiconductor element, wherein:
a driving signal for driving said power semiconductor element is supplied from said drive circuit to said driving signal input terminal of said overheat protection circuit.
8. The semiconductor device according to claim 4 , further comprising:
a power supply for supplying a power to a load through said power semiconductor element; and
a drive circuit for driving said power semiconductor element, wherein:
a driving signal for driving said power semiconductor element is supplied from said drive circuit to said driving signal input terminal of said overheat protection circuit.
9. The semiconductor device according to claim 5 , wherein said drive circuit comprises a microcomputer or an LSI.
10. The semiconductor device according to claim 6 , wherein said drive circuit comprises a microcomputer or an LSI.
11. The semiconductor device according to claim 7 , wherein said drive circuit comprises a microcomputer or an LSI.
12. The semiconductor device according to claim 8 , wherein said drive circuit comprises a microcomputer or an LSI.
13. The semiconductor device according to claim 1 , wherein when said semiconductor element for switching turns on, a potential of the control terminal of said power semiconductor element is lowered, and operation of said power semiconductor element is stopped.
14. The semiconductor device according to claim 5 , wherein when said semiconductor element for switching turns on, a potential of the control terminal of said power semiconductor element is lowered, and operation of said power semiconductor element is stopped.
15. The semiconductor device according to claim 6 , wherein when said semiconductor element for switching turns on, a potential of the control terminal of said power semiconductor element is lowered, and operation of said power semiconductor element is stopped.
16. The semiconductor device according to claim 7 , wherein when said semiconductor element for switching turns on, a potential of the control terminal of said power semiconductor element is lowered, and operation of said power semiconductor element is stopped.
17. The semiconductor device according to claim 8 , wherein when said semiconductor element for switching turns on, a potential of the control terminal of said power semiconductor element is lowered, and operation of said power semiconductor element is stopped.
18. The semiconductor device according to claim 1 , wherein said semiconductor element for clamp is a transistor, the drain and the gate of which are commonly connected.
19. The semiconductor device according to claim 5 , wherein said semiconductor element for clamp is a transistor, the drain and the gate of which are commonly connected.
20. The semiconductor device according to claim 6 , wherein said semiconductor element for clamp is a transistor, the drain and the gate of which are commonly connected.
21. The semiconductor device according to claim 7 , wherein said semiconductor element for clamp is a transistor, the drain and the gate of which are commonly connected.
22. The semiconductor device according to claim 8 , wherein said semiconductor element for clamp is a transistor, the drain and the gate of which are commonly connected.