JP2005142205A - Semiconductor device - Google Patents

Abstract

To reduce power consumption of a semiconductor device.
A semiconductor device includes first and second circuits formed on the same semiconductor substrate and each having a predetermined function. When it is necessary to operate the second circuit, the power supply voltage and the ground voltage are respectively supplied to the first and second terminals for receiving the supply of power by the second circuit, and the second circuit is When it is not necessary to operate, supply of voltage to the first and second terminals is stopped, or the first terminal and the second terminal are set to the same potential.
[Selection] Figure 3

Description

  The present invention relates to a semiconductor device having a plurality of circuits.

  In recent years, there has been a remarkable spread of portable electronic devices such as mobile phones and notebook computers. As for these devices, as well as higher performance and higher functionality, further progress is expected in terms of weight reduction in consideration of portability and enabling driving with a battery for a long time. In particular, in order to lengthen the time that can be driven by a battery, reduction of power consumption of a semiconductor device mounted on these electronic devices is one of important issues.

  Semiconductor device manufacturing process rules are becoming finer year by year. As a result, effects such as higher speed and smaller area can be obtained. In recent semiconductor device development, there is a tendency to increase functionality by incorporating more circuits and to increase added value by adopting a form of SOC (system-on-a-chip).

  However, on the other hand, the channel leakage current in the circuit stop state tends to increase due to the short channel effect of the transistor accompanying the miniaturization. Since the leakage current of a single transistor increases and the number of transistors increases as the semiconductor device becomes larger, the leakage current of the entire semiconductor device, that is, the power supply current that flows even when the semiconductor device is in a stopped state is It will increase more and more. For this reason, the power consumption is reduced by reducing the power supply voltage or by devising the circuit.

  As a method for reducing power consumption by devising a circuit, there are methods such as reducing the peak current by making the circuit asynchronous, or stopping the operation of unnecessary flip-flops by using a gated clock.

Further, as a state-of-the-art manufacturing process technique, a method of reducing power consumption in a circuit stop state by using SOI (silicon on insulator) or the like is known (for example, see Patent Document 1). There is also known a semiconductor device in which a resistance element is inserted in a path of a power supply current to the internal circuit to suppress a leakage current flowing through the internal circuit (for example, see Patent Document 2).
US Pat. No. 5,930,643 Japanese Patent Laid-Open No. 11-231024

  However, according to the above-described method for reducing power consumption by devising the circuit, there is almost no effect in reducing power consumption when the circuit is stopped, that is, reducing leakage current. In addition, these methods have problems such as it becomes very difficult to automatically design a circuit, test patterns cannot be automatically generated, or become extremely difficult.

  Further, when SOI is used, there is a big problem in terms of manufacturing cost. This is because SOI wafers are considerably more expensive than bulk wafers. Further, according to the semiconductor device in which the resistance element is inserted in the path of the power supply current to the internal circuit, there is a problem that the leakage current cannot be sufficiently suppressed.

  An object of the present invention is to reduce the power consumption of a semiconductor device by suppressing the channel leakage current of a transistor.

  The present invention prevents both a power supply voltage and a ground voltage from being applied to a circuit that does not need to be operated, prevents a leakage current from being generated inside the circuit, and reduces the power consumption of the semiconductor device. Is.

  Specifically, in order to solve the above-mentioned problem, the means taken by the invention of claim 1 is the first and second circuits formed on the same semiconductor substrate as a semiconductor device, each having a predetermined function. And when the second circuit needs to be operated, the power supply voltage and the ground voltage are respectively supplied to the first and second terminals for receiving the power supply of the second circuit, When it is not necessary to operate the second circuit, supply of voltage to the first and second terminals is stopped, or the first terminal and the second terminal are set to the same potential. It is comprised as follows.

  According to the first aspect of the present invention, the operation of a circuit that does not need to be operated can be stopped and the leakage current in the circuit can be reduced, so that the power consumption of the entire semiconductor device can be reduced.

  According to a second aspect of the present invention, in the semiconductor device according to the first aspect, the second circuit is a test circuit used when testing the first circuit.

  According to the invention of claim 2, it is possible to stop the operation of the test circuit which becomes unnecessary during actual use.

  According to a third aspect of the present invention, in the semiconductor device according to the first aspect, the first power supply wiring and the first ground wiring for supplying a voltage for operating the first circuit to the first circuit; A second power supply line connected to the first terminal and supplying the power supply voltage to the second circuit; and connected to the second terminal and supplying the ground voltage to the second circuit. A second ground wiring, and when it is necessary to operate the second circuit, the power supply voltage and the ground voltage are supplied to the second power wiring and the second ground wiring, respectively. If it is not necessary to operate the second circuit, supply of voltage to the second power supply wiring and the second ground wiring is stopped, or the second power supply wiring and the second ground wiring are stopped. Are set to the same potential.

  According to the third aspect of the invention, the voltage supplied to the second circuit can be controlled by controlling the voltage supplied to the second power supply wiring and the second ground wiring. When there are a plurality of second circuits, the supply of electric power can be controlled collectively.

  According to a fourth aspect of the present invention, in the semiconductor device according to the first aspect, a power supply wiring for supplying the power supply voltage to the second circuit and a ground for supplying the ground voltage to the second circuit. And further comprising: a wiring; a first fuse connected between the power supply wiring and the first terminal; and a second fuse connected between the ground wiring and the second terminal. It is.

  According to the invention of claim 4, when the first and second fuses are cut when the semiconductor device is mounted on a product, it is possible to prevent the power supply voltage and the ground voltage from being applied to the second circuit. Since the second circuit is physically disconnected from the power supply wiring and the ground wiring, malfunctions are extremely reduced.

  According to a fifth aspect of the present invention, in the semiconductor device according to the first aspect, a power supply wiring for supplying the power supply voltage to the second circuit and a ground for supplying the ground voltage to the second circuit. A first switch that is connected between a wiring, the power supply wiring, and the first terminal, and that opens and closes according to a control signal indicating whether or not the second circuit needs to be operated; and the ground wiring And a second switch connected between the second terminal and opened / closed according to the control signal.

  According to the fifth aspect of the present invention, the power supply voltage and the ground voltage can be prevented from being applied to the second circuit by operating the first and second switches. Further, if necessary, the power supply voltage and the ground voltage can be reapplied to the second circuit.

  According to a sixth aspect of the present invention, in the semiconductor device according to the fifth aspect, the control signal is input from outside the semiconductor device.

  According to a seventh aspect of the present invention, in the semiconductor device according to the fifth aspect of the present invention, the semiconductor device further includes a storage unit that stores a set value, and a signal representing the set value output from the storage unit is used as the control signal. .

  According to an eighth aspect of the present invention, in the semiconductor device according to the fifth aspect, the first and second switches operate even when the first circuit is in operation.

  According to a ninth aspect of the present invention, in the semiconductor device according to the first aspect, the power supply wiring connected to the first terminal for supplying the power supply voltage to the second circuit, and the second circuit When it is necessary to operate the second circuit according to a ground wiring for supplying the ground voltage and a control signal indicating whether or not the second circuit needs to be operated, the second circuit A switch for connecting between the second terminal and the power supply wiring when the second circuit does not need to be operated. is there.

  According to the invention of claim 9, when it is not necessary to operate the second circuit, the ground voltage can be prevented from being applied. If necessary, the ground voltage can be reapplied to the second circuit. Since one switch is provided for one second circuit, the number of control signals for controlling the switch can be reduced.

  According to a tenth aspect of the present invention, in the semiconductor device according to the ninth aspect, the control signal is input from the outside of the semiconductor device.

  According to an eleventh aspect of the present invention, the semiconductor device according to the ninth aspect further includes a storage unit that stores a set value, and a signal that represents the set value output from the storage unit is used as the control signal. .

  According to a twelfth aspect of the present invention, in the semiconductor device according to the ninth aspect, the switch operates even when the first circuit is operating.

  According to a thirteenth aspect of the present invention, in the semiconductor device according to the first aspect, the power supply wiring for supplying the power supply voltage to the second circuit and the second terminal are connected to the second circuit. When it is necessary to operate the second circuit according to a ground wiring for supplying the ground voltage and a control signal indicating whether or not the second circuit needs to be operated, the first circuit When there is no need to operate the second circuit by connecting between the first terminal and the power supply wiring, the terminal further includes a switch for connecting between the first terminal and the ground wiring. is there.

  According to the thirteenth aspect of the present invention, when it is not necessary to operate the second circuit, the power supply voltage can be prevented from being applied. If necessary, the power supply voltage can be reapplied to the second circuit. Since one switch is provided for one second circuit, the number of control signals for controlling the switch can be reduced.

  According to a fourteenth aspect of the present invention, in the semiconductor device according to the thirteenth aspect, the control signal is input from the outside of the semiconductor device.

  According to a fifteenth aspect of the present invention, in the semiconductor device according to the thirteenth aspect, a storage unit that stores a set value is further provided, and a signal that represents the set value output from the storage unit is used as the control signal. .

  According to a sixteenth aspect of the present invention, in the semiconductor device according to the thirteenth aspect, the switch operates even when the first circuit is in operation.

  As described above, according to the present invention, since the channel leakage current of a transistor in a circuit that does not always have to be operated can be suppressed, the power consumption of the entire semiconductor device can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention. The semiconductor device of FIG. 1 includes circuit blocks (first circuits) 12 and 14 having predetermined functions, test circuits (second circuits) 22 and 26, a first power supply wiring 42, and a first ground. A wiring 44, a second power supply wiring 46, and a second ground wiring 48 are provided. The above components are formed on the same semiconductor substrate. The test circuit 22 has first and second terminals 23 and 24 for receiving power supply. Similarly, the test circuit 26 has first and second terminals 27 and 28.

  1 includes a power supply circuit (not shown), and the power supply circuit outputs power supply voltages VDD1 and VDD2 and ground voltages GND1 and GND2. The circuit blocks 12 and 14 are supplied with the power supply voltage VDD1 through the first power supply wiring 42 and are supplied with the ground voltage GND1 through the first ground wiring 44. The test circuits 22 and 26 are supplied with the power supply voltage VDD2 through the second power supply wiring 46 and are supplied with the ground voltage GND2 through the second ground wiring 48.

  The test circuits 22, 26 are circuits for facilitating the test used when testing the circuit blocks 12, 14, etc., and are, for example, a BIST (built-in self test) circuit or a logic BIST circuit. . The test circuits 22 and 26 transmit and receive signals to and from the circuit blocks 12 and 14, and test these circuit blocks 12 and 14. When the power supply voltage VDD2 is supplied to the first terminal 23 and the ground voltage GND2 is supplied to the second terminal 24, the test circuit 22 operates. Similarly, when the power supply voltage VDD2 is supplied to the first terminal 27 and the ground voltage GND2 is supplied to the second terminal 28, the test circuit 26 operates.

  The test circuits 22 and 26 are circuits used when testing the semiconductor device of FIG. 1 before shipment, and are not necessary when the semiconductor device of FIG. 1 is actually used, that is, mounted in some product. It is a simple circuit.

  A transistor that constitutes a circuit such as a test circuit that does not necessarily operate is the same as a transistor that constitutes another circuit of the semiconductor device. For this reason, even when a circuit that is not necessarily operated is stopped, a channel leak current flows through the transistor. Since this leakage current increases power consumption, it becomes a factor that hinders battery driving for a long time in a portable electronic device.

  Here, the cause of the increase in the leakage current is due to the short channel effect of the transistor accompanying the miniaturization of the manufacturing process of the semiconductor device. If both are open, channel leakage current can be suppressed.

  Therefore, in the semiconductor device of FIG. 1, when it is necessary to operate the test circuit 22, the power supply voltage and the ground voltage are supplied to the first and second terminals 23 and 24, respectively, and the test circuit 22 is operated. When it is not necessary to supply the voltage, the supply of voltage to the terminals 23 and 24 is stopped or the terminals 23 and 24 are set to the same potential.

  The semiconductor device of FIG. 1 includes dedicated power supply wiring 46 and ground wiring 48 for the test circuits 22 and 26. Therefore, when the test circuits 22 and 26 need to be operated, The power supply voltage VDD2 is applied to the power supply wiring 46, and the ground voltage GND2 is applied to the second ground wiring 48. When it is not necessary to operate the test circuits 22 and 26, the power supply circuit does not apply a voltage to the second power supply wiring 46 and the second ground wiring 48, or the same voltage is used. (For example, the power supply voltage VDD2 or the ground voltage GND2) is applied.

  Then, when it is not necessary to operate the test circuits 22 and 26 after being mounted on a product, the channel leakage current between the source and drain of the transistors constituting the test circuits 22 and 26 is reduced, and the test circuit 22 , 26 can be reduced.

  Note that in a semiconductor device having many functions, there are functions unnecessary for some users. A circuit for realizing such a function is a circuit that can select whether or not to use for each user, and for users who do not need the function, a test circuit when a semiconductor device is actually used Similarly, it is an unnecessary circuit. A circuit that operates only when a specific function is executed is an unnecessary circuit when the function is not used. These circuits are not necessarily required to operate.

  Therefore, instead of the test circuit, a circuit that can select the use / non-use for each user, a circuit that operates only when a specific function is executed, and the like are provided. You may make it connect to the ground wiring 48 of this. Then, when it is not necessary to operate these circuits, power can be prevented from being consumed by these circuits.

  Further, the power supply voltage VDD1 and the power supply voltage VDD2 may be the same voltage, and the ground voltage GND1 and the ground voltage GND2 may be the same voltage.

(First modification)
FIG. 2 is a block diagram of a semiconductor device according to a first modification of the embodiment of the present invention. The semiconductor device of FIG. 2 includes circuit blocks 12 and 14, test circuits 22 and 26, power supply wiring 42, ground wiring 44, first fuses 51 and 52, and second fuses 53 and 54. ing. The above components are formed on the same semiconductor substrate. A fuse 51 is connected between the power supply wiring 42 and the first terminal 23 of the test circuit 22, and a fuse 53 is connected between the ground wiring 44 and the second terminal 24 of the test circuit 22. A fuse 52 is connected between the power supply wiring 42 and the first terminal 27 of the test circuit 26, and a fuse 54 is connected between the ground wiring 44 and the second terminal 28 of the test circuit 26.

  The circuit blocks 12 and 14 and the test circuits 22 and 26 are supplied with the power supply voltage VDD from the power supply circuit via the power supply wiring 42 and the ground voltage GND via the ground wiring 44. When the power supply voltage VDD is supplied to the terminal 23 and the ground voltage GND is supplied to the terminal 24, the test circuit 22 operates. When the power supply voltage VDD is supplied to the terminal 27 and the ground voltage GND is supplied to the terminal 28, the test circuit 26 operates. These points are the same in the following drawings.

  First, when the fuses 51 to 54 are in a conductive state, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, the fuses 51 to 54 are cut. Then, no power is supplied, so that the test circuits 22 and 26 do not operate. In order to cut the fuses 51 to 54, a method such as applying a high voltage is used.

  In addition, it may replace with a test circuit and may be provided with the circuit etc. which can select the presence or absence of use for every user. Then, power can be prevented from being consumed when it is not necessary to operate these circuits.

(Second modification)
FIG. 3 is a block diagram of a semiconductor device according to a second modification of the embodiment of the present invention. The semiconductor device of FIG. 3 includes switches 61, 62, 63, and 64 on the same semiconductor substrate instead of the fuses 51 to 54 in the semiconductor device of FIG. The semiconductor device of FIG. 3 further includes external terminals 66 and 67.

  Control signals indicating whether the test circuits 22 and 26 need to be operated are input to the external terminals 66 and 67 from the outside of the semiconductor device of FIG. The switches 61 and 63 open and close according to the control signal input to the external terminal 66, and the switches 62 and 64 open and close according to the control signal input to the external terminal 67.

  First, a control signal indicating that the test circuits 22 and 26 need to be operated is given to the external terminals 66 and 67, respectively. Then, since the switches 61 to 64 are all turned on, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, a control signal indicating that it is not necessary to operate the test circuits 22 and 26 is applied to the external terminals 66 and 67, respectively. Then, the switches 61 to 64 are all turned off, and the test circuits 22 and 26 stop operating.

  FIG. 4 is a block diagram showing another example of the semiconductor device of FIG. The semiconductor device shown in FIG. 4 is different from the semiconductor device shown in FIG. 3 in that registers 68 and 69 serving as storage units are provided in place of the external terminals 66 and 67.

  The register 68 stores the set value and outputs a signal representing the stored set value to the switches 61 and 63 as a control signal indicating whether or not the test circuit 22 needs to be operated. The register 69 stores the set value and outputs a signal representing the stored set value to the switches 62 and 64 as a control signal indicating whether or not the test circuit 26 needs to be operated.

  First, when setting values that turn on the switches 61 to 64 are stored in the registers 68 and 69, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, a set value that turns off the switches 61 to 64 is stored in the registers 68 and 69, and the test circuits 22 and 26 are stopped.

(Third Modification)
FIG. 5 is a block diagram of a semiconductor device according to a third modification of the embodiment of the present invention. The semiconductor device shown in FIG. 5 is the same as the semiconductor device shown in FIG. is there.

  The power supply wiring 42 is connected to the first terminal 23 of the test circuit 22 through the resistor 73, and is connected to the first terminal 27 of the test circuit 26 through the resistor 74. The resistors 73 and 74 have low resistance values, and it is desirable that the resistance values are approximately equal to the respective resistance values of the switches 71 and 72 when they are turned on.

  Control signals indicating whether or not the test circuits 22 and 26 need to be operated are input to the external terminals 66 and 67 from the outside of the semiconductor device of FIG. The switch 71 selects which of the power supply wiring 42 and the ground wiring 44 is connected to the second terminal 24 of the test circuit 22 according to the control signal input to the external terminal 66. Similarly, the switch 72 selects which of the power supply wiring 42 and the ground wiring 44 is connected to the second terminal 28 of the test circuit 26 according to the control signal input to the external terminal 67.

  First, a control signal indicating that the test circuits 22 and 26 need to be operated is given to the external terminals 66 and 67, respectively. Then, since the switches 71 and 72 both select the ground wiring 44, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, a control signal indicating that it is not necessary to operate the test circuits 22 and 26 is applied to the external terminals 66 and 67, respectively. Then, the switches 71 and 72 both select the power supply wiring 42, and the test circuits 22 and 26 stop operating.

  FIG. 6 is a block diagram illustrating another example of the semiconductor device of FIG. The semiconductor device in FIG. 6 includes the registers 68 and 69 as storage units instead of the external terminals 66 and 67 in the semiconductor device in FIG.

  The register 68 stores the set value and outputs a signal representing the stored set value to the switch 71 as a control signal indicating whether or not the test circuit 22 needs to be operated. The register 69 stores the set value and outputs a signal representing the stored set value to the switch 72 as a control signal indicating whether or not the test circuit 26 needs to be operated.

  First, when setting values for selecting the ground wiring 44 by the switches 71 and 72 are stored in the registers 68 and 69, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, the setting values for the switches 71 and 72 to select the power supply wiring 42 are stored in the registers 68 and 69, and the test circuits 22 and 26 are stopped.

(Fourth modification)
FIG. 7 is a block diagram of a semiconductor device according to a fourth modification of the embodiment of the present invention. The semiconductor device in FIG. 7 is the same as the semiconductor device in FIG. 5 except that the positions of the switch 71 and the resistor 73 are interchanged and the positions of the switch 72 and the resistor 74 are interchanged.

  The ground wiring 44 is connected to the second terminal 24 of the test circuit 22 through the resistor 73, and is connected to the second terminal 28 of the test circuit 26 through the resistor 74.

  Control signals are input to the external terminals 66 and 67 from the outside of the semiconductor device of FIG. 7, as in the semiconductor device of FIG. The switch 71 selects which of the power supply wiring 42 and the ground wiring 44 is connected to the first terminal 23 of the test circuit 22 according to the control signal input to the external terminal 66. Similarly, the switch 72 selects which of the power supply wiring 42 and the ground wiring 44 is connected to the first terminal 27 of the test circuit 26 according to the control signal input to the external terminal 67.

  First, a control signal indicating that the test circuits 22 and 26 need to be operated is given to the external terminals 66 and 67, respectively. Then, since both switches 71 and 72 select the power supply wiring 42, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, a control signal indicating that it is not necessary to operate the test circuits 22 and 26 is applied to the external terminals 66 and 67, respectively. Then, the switches 71 and 72 both select the ground wiring 44, and the test circuits 22 and 26 stop operating.

  FIG. 8 is a block diagram showing another example of the semiconductor device of FIG. The semiconductor device in FIG. 8 includes the registers 68 and 69 as storage units in place of the external terminals 66 and 67 in the semiconductor device in FIG.

  The register 68 stores the set value and outputs a signal representing the stored set value to the switch 71 as a control signal indicating whether or not the test circuit 22 needs to be operated. The register 69 stores the set value and outputs a signal representing the stored set value to the switch 72 as a control signal indicating whether or not the test circuit 26 needs to be operated.

  First, when setting values such that the switches 71 and 72 select the power supply wiring 42 are stored in the registers 68 and 69, the test circuits 22 and 26 operate to test the semiconductor device of FIG. After the test is completed, the setting values that cause the switches 71 and 72 to select the ground wiring 44 are stored in the registers 68 and 69, and the test circuits 22 and 26 are stopped.

  As described above, according to the semiconductor device of FIGS. 1 to 8, when it is not necessary to operate the test circuits 22 and 26 after being mounted on a product, the source of the transistors constituting the test circuits 22 and 26 The channel leakage current between the drains can be reduced, and the power consumption in the test circuits 22 and 26 can be suppressed.

  3 to 8, in place of the test circuit, a circuit that has a predetermined function and can be used or not used for each user, or a circuit that operates only when a specific function is executed. Etc. may be provided. Then, power can be prevented from being consumed when it is not necessary to operate these circuits.

  Further, an output of a processor or the like connected to the semiconductor device of FIG. 3, FIG. 5, or FIG. 7 may be given to the external terminals 66, 67, or the semiconductor device of FIG. 4, FIG. 6, or FIG. Further, a processor or the like that executes a program may be further provided, and the processor or the like may store values in the registers 68 and 69. Then, even when the circuit blocks 12 and 14 are operating, the switches 61 to 64, 71 and 72 operate, and the power supply voltage VDD and the ground voltage VSS are applied to a circuit which operates only when executing a specific function. Can be provided only when executing a specific function and not during other normal operations. As a result, further reduction in power consumption can be achieved.

  Further, although the case where the semiconductor device of FIG. 4, FIG. 6, or FIG. 8 includes the registers 68 and 69 as the storage unit has been described, a memory may be provided instead of the registers 68 and 69.

  In the semiconductor devices of FIGS. 1 to 3, by controlling the switches, the test circuits 22 and 26 and the circuit that can be selected for each user can be operated again instead. Can be easily done. For this reason, it is possible to perform failure analysis and detailed evaluation after shipment using the test circuits 22 and 26, and to add functions using a circuit that can select whether to use each user.

  As described above, the semiconductor device according to the present invention is useful as a semiconductor device having a plurality of circuits because leakage current in a circuit that does not always need to be operated can be suppressed and power consumption can be reduced. It is.

1 is a block diagram of a semiconductor device according to an embodiment of the present invention. It is a block diagram of a semiconductor device concerning the 1st modification of an embodiment of the present invention. It is a block diagram of a semiconductor device concerning the 2nd modification of an embodiment of the present invention. FIG. 4 is a block diagram illustrating another example of the semiconductor device in FIG. 3. It is a block diagram of the semiconductor device which concerns on the 3rd modification of embodiment of this invention. FIG. 6 is a block diagram illustrating another example of the semiconductor device in FIG. 5. It is a block diagram of a semiconductor device concerning the 4th modification of an embodiment of the present invention. FIG. 8 is a block diagram illustrating another example of the semiconductor device in FIG. 7.

Explanation of symbols

12, 14 circuit block (first circuit)
22, 26 Test circuit (second circuit)
42 First power wiring 44 First ground wiring 46 Second power wiring 48 Second ground wiring 23, 27 First terminals 24, 28 Second terminals 51, 52 First fuses 53, 54 Second Fuses 61-64, 71, 72 switches 66, 67 external terminals 68, 69 registers (storage unit)

Claims (16)

First and second circuits formed on the same semiconductor substrate, each having a predetermined function,
When it is necessary to operate the second circuit,
A power supply voltage and a ground voltage are respectively supplied to first and second terminals for receiving power from the second circuit;
If it is not necessary to operate the second circuit,
A semiconductor device configured to stop supplying a voltage to the first and second terminals or to make the first terminal and the second terminal have the same potential. The semiconductor device according to claim 1,
The second circuit includes:
A semiconductor device comprising a test circuit used when testing the first circuit. The semiconductor device according to claim 1,
A first power supply wiring and a first ground wiring for supplying a voltage for operating the circuit to the first circuit;
A second power supply line connected to the first terminal for supplying the power supply voltage to the second circuit;
A second ground wiring connected to the second terminal for supplying the ground voltage to the second circuit;
When it is necessary to operate the second circuit,
Supplying the power supply voltage and the ground voltage to the second power supply wiring and the second ground wiring, respectively;
If it is not necessary to operate the second circuit,
Stopping supply of voltage to the second power supply wiring and the second ground wiring, or setting the second power supply wiring and the second ground wiring to the same potential . The semiconductor device according to claim 1,
Power supply wiring for supplying the power supply voltage to the second circuit;
A ground wiring for supplying the ground voltage to the second circuit;
A first fuse connected between the power supply wiring and the first terminal;
A semiconductor device, further comprising a second fuse connected between the ground wiring and the second terminal. The semiconductor device according to claim 1,
Power supply wiring for supplying the power supply voltage to the second circuit;
A ground wiring for supplying the ground voltage to the second circuit;
A first switch connected between the power supply wiring and the first terminal and opened / closed according to a control signal indicating whether or not the second circuit needs to be operated;
A semiconductor device further comprising: a second switch connected between the ground wiring and the second terminal and opened and closed in accordance with the control signal. The semiconductor device according to claim 5,
The control signal is
A semiconductor device which is input from the outside of the semiconductor device. The semiconductor device according to claim 5,
A storage unit for storing the setting value;
A signal representing the set value output from the storage unit is used as the control signal. The semiconductor device according to claim 5,
The first and second switches are:
A semiconductor device which operates even when the first circuit is operating. The semiconductor device according to claim 1,
Power supply wiring connected to the first terminal for supplying the power supply voltage to the second circuit;
A ground wiring for supplying the ground voltage to the second circuit;
When the second circuit needs to be operated in accordance with a control signal indicating whether or not the second circuit needs to be operated, a connection is made between the second terminal and the ground wiring. When there is no need to operate the second circuit, the semiconductor device further comprises a switch for connecting the second terminal and the power supply wiring. The semiconductor device according to claim 9.
The control signal is
A semiconductor device which is input from the outside of the semiconductor device. The semiconductor device according to claim 9.
A storage unit for storing the setting value;
A signal representing the set value output from the storage unit is used as the control signal. The semiconductor device according to claim 9.
The switch is
A semiconductor device which operates even when the first circuit is operating. The semiconductor device according to claim 1,
Power supply wiring for supplying the power supply voltage to the second circuit;
A ground wiring connected to the second terminal for supplying the ground voltage to the second circuit;
When the second circuit needs to be operated in accordance with a control signal indicating whether or not the second circuit needs to be operated, a connection is made between the first terminal and the power supply wiring. When there is no need to operate the second circuit, the semiconductor device further comprises a switch for connecting the first terminal and the ground wiring. The semiconductor device according to claim 13,
The control signal is
A semiconductor device which is input from the outside of the semiconductor device. The semiconductor device according to claim 13,
A storage unit for storing the setting value;
A signal representing the set value output from the storage unit is used as the control signal. The semiconductor device according to claim 13,
The switch is
A semiconductor device which operates even when the first circuit is operating.

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