US20020057100A1 - Threshold invariant voltage detecting device - Google Patents
Threshold invariant voltage detecting device Download PDFInfo
- Publication number
- US20020057100A1 US20020057100A1 US09/526,746 US52674600A US2002057100A1 US 20020057100 A1 US20020057100 A1 US 20020057100A1 US 52674600 A US52674600 A US 52674600A US 2002057100 A1 US2002057100 A1 US 2002057100A1
- Authority
- US
- United States
- Prior art keywords
- voltage
- transistor
- terminal
- detecting circuit
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
- G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
- G01R19/16552—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies in I.C. power supplies
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
Definitions
- the present invention generally relates to voltage detecting circuits, and more particularly to a voltage detecting circuit which detects the voltage of a substrate of a semiconductor integrated circuit device.
- a voltage detecting circuit of a semiconductor integrated circuit device detects a negative substrate voltage VBB thereof, and generates a signal vbelz for adjusting a substrate voltage generating circuit on the basis of the substrate voltage VBB detected.
- the substrate voltage generating circuit generates the substrate voltage VBB based on the signal vbelz.
- FIG. 1 is a circuit diagram of a voltage detecting circuit.
- FIG. 2 shows an example of the operation of the voltage detecting circuit.
- FIG. 3 is a timing chart of an example of the operation of the voltage detecting circuit.
- a voltage detecting circuit 100 shown in FIG. 1 includes a load part 110 , a detection part 120 , and NOT circuits 130 - 1 and 130 - 2 .
- the voltage detecting circuit 100 When the voltage detecting circuit 100 is supplied with a power source voltage VDD generated outside of the semiconductor integrated circuit device or a power source voltage Vii generated inside the semiconductor integrated circuit device at time t 100 shown in part (A) of FIG. 3, a PMOS (P-channel Metal Oxide Semiconductor) transistor 111 of the load part 110 is turned ON, as shown in part (B) thereof. An NMOS (N-channel MOS) transistor 121 of the detection part 120 is turned OFF, as shown in part (C) of FIG. 3. Thus, the potential of a node N 1 rises and reaches a high level.
- the NOT circuit 130 - 2 is supplied with the low level from the NOT circuit 130 - 1 , and inverts the low level thus supplied, so that the high level is output from the NOT circuit 130 - 2 .
- the signal output from the NOT circuit 130 - 2 shown in part (H) of FIG. 3 is used as the signal vbelz for adjusting the substrate voltage generating circuit (not shown).
- the substrate voltage generating circuit starts to generate the substrate voltage VBB from the signal vbelz.
- the substrate voltage generating circuit generates the negative substrate voltage VBB in response to the signal vbelz which is at the high level. Then, as shown in part (I) of FIG. 3, the substrate voltage VBB gradually decreases, and reaches, at time t 120 , a value defined by equation (1) shown below:
- VBB V GND ⁇ Vth (1)
- V GND is the ground potential
- Vth is the threshold voltage of the NMOS transistor 121 .
- equation (1) When equation (1) stands (is in effect), the NMOS transistor 121 is turned ON, as shown in part (c) of FIG. 3. Thus, as shown in part (D) of FIG. 3, the node N 1 switches to the low level. Then, the gate potentials of the PMOS transistor 131 and the NMOS transistor 132 of the NOT circuit 130 - 1 change to the low level. Thus, as shown in parts (E) and (F), the PMOS transistor 131 is turned ON, and the NMOS transistor 132 is turned OFF. Then, as shown in part (G) of FIG. 3, the potential of the node N 3 changes to the high level.
- the NOT circuit 130 - 2 inverts the high level supplied from the NOT circuit 130 - 1 , and outputs the signal vbelz which is at the low level, as shown in part (H) of FIG. 3.
- the substrate voltage generating circuit stops generating the negative substrate voltage VBB.
- the substrate voltage VBB is adjusted so that equation (1) stands.
- the substrate voltage VBB is adjusted based on the potential of the node N 1 .
- FIG. 2 shows states of the transistors with respect to the substrate voltage VBB.
- “deeply biased” denotes that the substrate voltage VBB is greater in the negative-side direction than that defined by equation (1)
- “lightly biased” denotes that VBB is greater in the positive-side direction than that defined by equation (1).
- the threshold voltages Vth of the transistors of the voltage detecting circuit shown in FIG. 1 deviate from the target value due to variations in factors involved in the process of fabricating the semiconductor integrated circuit devices.
- the threshold voltage Vth of the PMOS transistor 111 has a variation different from that of the threshold voltage Vth of the NMOS transistor 121 , the variations cannot be mutually canceling at the node N 1 .
- the operation of detecting the substrate voltage VBB is affected by variation in the threshold voltage Vth of the PMOS transistor 111 , so that the substrate voltage VBB cannot be adjusted accurately.
- the NOT circuit 130 - 1 is set at an intermediate level when a level transition occurs at the node N 1 . At this time, the PMOS transistor 131 and the NMOS transistor 132 are both ON. Thus, a pass-through current flows through the NOT circuit 130 - 1 , and power is wastefully consumed.
- a more specific object of the present invention is to provide a voltage detecting circuit capable of accurately detecting the substrate voltage by reducing variations in the threshold voltages of transistors.
- Another object of the present invention is to provide a voltage detecting circuit consuming a reduced amount of power.
- a voltage detecting circuit including a constant-voltage source, a load part including a first transistor coupled to the constant-voltage source, and a detecting part which is connected to the load part and includes a second transistor of the same type as that of the first transistor.
- the detecting part detects a given voltage applied thereto.
- FIG. 1 is a circuit diagram of a conventional voltage detecting circuit
- FIG. 2 shows an operation of the voltage detecting circuit shown in FIG. 1;
- FIG. 3 is a waveform diagram of an example of the operation of the voltage detecting circuit shown in FIG. 1;
- FIG. 4 is a circuit diagram of a voltage detecting circuit according to a first embodiment of the present invention.
- FIG. 5 is a diagram showing an operation of the voltage detecting circuit shown in FIG. 4;
- FIG. 6 is a timing chart of an operation of the voltage detecting circuit shown in FIG. 4;
- FIG. 7 is a circuit diagram of a constant-voltage source used in a voltage detecting part according to a second embodiment of the present invention.
- FIG. 8 is a circuit diagram of a constant-voltage source used in a voltage detecting part according to a third embodiment of the present invention.
- FIG. 9 is a circuit diagram of a load part and a detecting part used in a voltage detecting circuit according to a fourth embodiment of the present invention.
- FIG. 10 is a circuit diagram of a load part and a detecting part used in a voltage detecting circuit according to a fifth embodiment of the present invention.
- FIG. 4 is a circuit diagram of a voltage detecting circuit 1 according to a first embodiment of the present invention.
- the voltage detecting circuit 1 includes a constant-voltage source 10 , a voltage correcting part 20 , a load part 30 , a detecting part 40 , and NOT circuits (inverters) 50 - 1 and 50 - 2 .
- the constant-voltage source 10 is made up of resistors 11 and 12 , and the voltage correcting part 20 formed of a PMOS transistor 21 (PT 11 ).
- the source of the PMOS transistor 21 is coupled to a power source voltage VDD via the resistor 11 , and the gate (control terminal) thereof is grounded.
- the drain of the PMOS transistor 21 is coupled to the drain of an NMOS transistor 31 (NT 12 ) via a node N 0 .
- the resistors 11 and 12 are used as necessary, and have resistance values depending on the relationship between the power source voltage VDD generated outside of the semiconductor integrated device and a voltage required in the voltage detecting circuit 1 .
- the load part 30 includes the NMOS transistor 31 .
- the drain of the NMOS transistor 31 is connected to the node N 0 and gate thereof, and the source thereof is connected via a node N 1 to the drain of an NMOS transistor 41 (NT 11 ) and the gates of a PMOS transistor 52 (PT 21 ) and an NMOS transistor 53 (NT 21 ).
- the detecting part 40 includes the NMOS transistor 41 , the gate of which is grounded.
- the source of the NMOS transistor 41 is supplied with the substrate voltage VBB, which is to be detected by the voltage detecting circuit 1 .
- the drain of the NMOS transistor 41 is connected to the node N 1 .
- the NOT circuit 50 - 1 includes PMOS transistor 51 (PT 22 ), the PMOS transistor 52 (PT 21 ), and the NMOS transistor 53 (NT 21 ).
- the source of the PMOS transistor 51 is connected to the power source voltage VDD, and the gate thereof is grounded.
- the drain of the PMOS transistor 51 is coupled to the source of the PMOS transistor 52 via a node N 2 .
- the gate of the PMOS transistor 52 is connected to the node N 1 , and the drain thereof is coupled to the drain of the NMOS transistor 53 and the NOT circuit 50 - 2 via a node N 3 .
- the gate of the NMOS transistor 53 is connected to the node N 1 , and the drain thereof is connected to the node N 3 , while the source thereof is grounded.
- the NOT circuit 50 - 2 has the same construction as that of the NOT circuit 50 - 1 .
- the constructions of the NOT circuits 50 - 1 and 50 - 2 may be modified based on the driving voltage generated by a substrate voltage generating circuit (not shown) located on the output side of the NOT circuit part 50 - 2 .
- a substrate voltage generating circuit not shown located on the output side of the NOT circuit part 50 - 2 .
- the driving voltage of the substrate voltage generating circuit is large, a modification will be made such that an increased number of NOT circuit parts is provided so as to follow the node N 1 .
- the PMOS transistors 21 and 51 are turned ON, as shown in part (B) of FIG. 6.
- the PMOS transistor 21 is provided so as to correspond to the PMOS transistor 51 , and functions to cancel a deviation of the threshold voltage Vth of the PMOS transistor 51 introduced during the fabricating process.
- the node N 0 becomes a high level defined by dividing the power source voltage VDD by the resistors 11 and 12 , as shown in part (c) of FIG. 6.
- the above high level is supplied to the drain and gate of the NMOS transistor 31 (NT 12 ), so that the NMOS transistor 31 is turned ON, as shown in part (E) of FIG. 6. Further, as shown in part (D) of FIG. 6, the NMOS transistor 41 (NT 11 ) is turned OFF.
- the potential of the node N 1 increases to the high level, as shown in part (F) of FIG. 6.
- the voltage detecting circuit 1 is constructed so that the load part 30 and the detecting part 40 are formed of the NMOS transistors 31 and 41 , respectively. Since the load part 30 and the detecting part 40 are formed of transistors of the same type (N-channel type), a deviation of the threshold voltage Vth of the NMOS transistor 41 of the detecting part 40 can be canceled by a deviation of the threshold voltage Vth of the NMOS transistor 31 of the load part 30 . This utilizes the fact that the transistors of the same type within the semiconductor device have almost the same deviations.
- the NOT circuit part 50 - 2 receives the low level from the NOT circuit part 50 - 1 , and outputs the high level by inverting the received low level.
- the signal output from the NOT circuit part 50 - 2 shown in part (J) of FIG. 6 is the signal vbelz which adjusts the substrate voltage generating circuit (not shown).
- the substrate voltage generating circuit starts, from time t 20 , to generate the substrate voltage VBB based on the signal vbelz.
- the substrate voltage generating circuit When the substrate voltage generating circuit is supplied with the signal vbelz which is at the high level, it generates the negative substrate voltage VBB. Then, as shown in part (K) of FIG. 6, the substrate voltage VBB gradually decreases, and reaches the level defined by equation (2) shown below:
- VBB V GND ⁇ Vth 4 (2)
- Vth4 is the threshold voltage of the NMOS transistor 41 .
- the PMOS transistor 52 is turned ON, and the NMOS transistor 53 is turned OFF, so that the potential of the node N 3 switches to the high level, as shown in part (I) of FIG. 6.
- the NOT circuit part 50 - 2 inverts the high level supplied from the NOT circuit part 50 - 1 and thus outputs the signal vbelz which is at the low level, as shown in part (J) of FIG. 6.
- the substrate voltage generating circuit stops generating the negative substrate voltage VBB, so that the voltage VBB is thus adjusted so as to have the level defined by equation (2), as shown in part (K) of FIG. 6.
- the PMOS transistor 51 may cause a reduction of the level of the signal vbelz and a situation in which the potential of the node N 2 in the NOT circuit part 50 - 1 varies in a way different from that in which the potential of the node N 0 in the constant-voltage source 10 varies due to variations in some factors involved in the fabricating process.
- the PMOS transistor 21 is provided in the voltage correcting part 20 of the constant-voltage source 10 .
- the PMOS transistor 21 makes it possible to cause the potentials of the nodes N 0 and N 2 to vary in the same way due to similarity in variations in some factors involved in the transistor manufacturing process.
- FIG. 5 shows the states of the transistors with respect to the substrate voltage VBB.
- “deeply biased” denotes that the substrate voltage VBB is greater in the negative-side direction than that defined by equation (1)
- “lightly biased” denotes that VBB is greater in the positive-side direction than that defined by equation (1).
- FIG. 7 is a circuit diagram of an essential part of a voltage detecting circuit according to a second embodiment of the present invention.
- the constant-voltage source 10 shown in FIG. 7 differs from that shown in FIG. 4 in the positions of the PMOS transistor 21 and the resistor 11 . It is possible to interchange the positions of the resistor 11 and the PMOS transistor 21 forming the voltage correcting part 20 as long as the resistor 11 and the PMOS transistor 21 are interposed between the power source voltage VDD and the node N 0 .
- the voltage detecting circuit has the same construction as that of the voltage detecting circuit shown in FIG. 4.
- FIG. 8 shows a construction of the constant-voltage source 10 used in a voltage detecting circuit according to a third embodiment of the present invention.
- the circuit shown in FIG. 8 utilizes, instead of the power source voltage VDD externally supplied, a power source voltage Vii generated within the semiconductor integrated circuit device.
- the internal power source voltage Vii is not greatly affected by noise. Further, the voltage Vii is regulated and is thus stable.
- the voltage Vii is applied to the source of the PMOS transistor 21 , and the drain thereof is connected to the node N 0 .
- the other parts of the voltage detecting circuit according to the third embodiment of the present invention are the same as those corresponding to the first embodiment thereof.
- FIG. 9 is a circuit diagram of a construction of the detecting part 40 used in a voltage detecting circuit according to a fourth embodiment of the present invention.
- the detecting part 40 shown in FIG. 9 differs from that shown in FIG. 4 in that the detecting part 40 is made up of two NMOS transistors 42 (NT 31 ) and 43 (NT 32 ).
- the drain of the NMOS transistor 42 is connected to the source of the NMOS transistor 31 via the node N 1 , and the gate of the NMOS transistor 42 is grounded.
- the source of the NMOS transistor 42 is connected to the drain and gate of the NMOS transistor 43 .
- the source of the NMOS transistor 43 receives the substrate voltage VBB.
- the NOT circuit part 50 - 1 When the node N 1 switches to the high level, the NOT circuit part 50 - 1 outputs the low-level signal.
- the NOT circuit part 50 - 2 inverts the low-level signal from the NOT circuit part 50 - 1 into the high-level signal.
- the high-level signal from the NOT circuit part 50 - 2 is the signal vbelz used to adjust the substrate voltage generating circuit.
- VBB V GND ⁇ Vth (3)
- Vth is the threshold voltage of the NMOS transistor 43 .
- the NMOS transistor 43 is turned ON.
- the substrate voltage VBB decreases and reached the level defined by the following expression:
- VBB V GND ⁇ 2 Vth (4)
- the potential of the node N 1 switches to the low level when the substrate voltage VBB reaches the level defined by equation (4). Then, the output signal of the NOT circuit 50 - 1 is switched to the high level, which is received by the NOT circuit part 50 - 2 . Then, the low level signal is output by the NOT circuit part 50 - 2 as the signal vbelz. In response to the low-level substrate voltage VBB, the substrate voltage generating circuit stops generating the declining substrate voltage VBB, which is thus adjusted so that equation (4) stands.
- the fourth embodiment of the present invention is capable of further increasing the substrate voltage VBB to be detected in the negative-side direction and thus adjusting the substrate voltage VBB more deeply in the negative-side direction.
- FIG. 10 is a circuit diagram of the load part 30 and the detecting part 40 used in a fifth embodiment of the present invention.
- the detecting part 40 shown in FIG. 10 differs from that shown in FIG. 4 in that the circuit shown in FIG. 10 is made up of two NMOS transistors 44 (NT 33 ) and 45 (NT 34 ).
- the drain of the NMOS transistor 44 is connected to the source of the NMOS transistor 31 via the node N 1 , and the gate thereof is grounded.
- the source of the NMOS transistor 44 is connected to the drain of the NMOS transistor 45 .
- the gate of the NMOS transistor 45 is grounded, and the source thereof is connected to the substrate voltage VBB.
- the NOT circuit part 50 - 1 When the node N 1 switches to the high level, the NOT circuit part 50 - 1 outputs the low-level signal, which is inverted by the NOT circuit 50 - 2 .
- the high-level signal output from the NOT circuit part 50 - 2 is used as the signal vbelz for adjusting the substrate voltage generating circuit (not shown).
- the substrate voltage generating circuit generates the substrate voltage VBB based on the signal vbelz.
- the substrate voltage generating circuit When the signal vbelz is at the high level, the substrate voltage generating circuit generates the negative substrate voltage VBB, which gradually decreases and reaches the level defined by equation (3) described before. At that time, the NMOS transistor 45 is turned ON. The substrate voltage VBB further decreases and reaches the level defined by equation (4) described before. Then, the NMOS transistor 44 is turned ON.
- the potential of the node N 1 switches to the low level when the substrate voltage VBB becomes the level defined by equation (4).
- the NOT circuit part 50 - 1 outputs the high-level signal, which is inverted by the NOT circuit part 50 - 2 .
- the low-level signal from the NOT circuit part 50 - 2 is the low-level signal vbelz.
- the substrate voltage generating circuit stops generating the negative substrate voltage VBB, so that the voltage VBB is adjusted so as to satisfy equation (4).
- the fifth embodiment of the present invention is capable of further increasing the substrate voltage VBB to be detected in the negative-side direction and thus adjusting the substrate voltage VBB more deeply in the negative-side direction.
- the load part (which corresponds to the load part 30 ) and the detecting part (which corresponds to the detecting part 40 ) are of transistors of the same type.
- the voltage detecting circuit of the present invention can accurately detect the given voltage (the substrate voltage).
- the present invention generates a detection signal based on the relationship between the given voltage to be detected and a reference voltage.
- the reference voltage is based on the threshold voltage of the transistor included in the detecting part.
- it is possible to arbitrarily adjust the voltage to be detected. For example, a plurality of transistors can be used if it is desired to increase the given voltage in the negative-side direction.
- the load part is connected to the drain of a transistor forming the detecting part, and the gate thereof grounded. Further, the source of the above transistor is connected to the given voltage to be detected. Thus, it is possible to produce the detection signal based on the relationship between the given voltage and the threshold voltage of the transistor.
- the present invention may include a level converting part (which corresponds to the PMOS transistor 52 and the NMOS transistor 53 ) which converts the level of the detection signal supplied from the detecting part, so that the level of the detection can arbitrarily be adjusted.
- a current adjusting part (which corresponds to the PMOS transistor 51 ) may be provided in the level converting part. The current adjusting part prevents an excessive current from flowing through the level converting part, so that wasteful power consumption can be avoided.
- the current adjusting part may be formed of a transistor having a long gate length.
- a constant-voltage generating part (which corresponds to the constant-voltage source 10 ) may include a voltage correcting part formed of a transistor of the same type of that of the transistor forming the current adjusting part. It is thus possible to cancel variations in the threshold values of the transistors due to variations in some factors involved in the fabricating process.
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Dram (AREA)
- Semiconductor Integrated Circuits (AREA)
- Logic Circuits (AREA)
- Measurement Of Current Or Voltage (AREA)
- Control Of Electrical Variables (AREA)
Abstract
Description
- 1. Field of the Invention
- The present invention generally relates to voltage detecting circuits, and more particularly to a voltage detecting circuit which detects the voltage of a substrate of a semiconductor integrated circuit device.
- 2. Description of the Related Art
- A voltage detecting circuit of a semiconductor integrated circuit device detects a negative substrate voltage VBB thereof, and generates a signal vbelz for adjusting a substrate voltage generating circuit on the basis of the substrate voltage VBB detected. The substrate voltage generating circuit generates the substrate voltage VBB based on the signal vbelz.
- FIG. 1 is a circuit diagram of a voltage detecting circuit. FIG. 2 shows an example of the operation of the voltage detecting circuit. FIG. 3 is a timing chart of an example of the operation of the voltage detecting circuit. A
voltage detecting circuit 100 shown in FIG. 1 includes aload part 110, adetection part 120, and NOT circuits 130-1 and 130-2. - When the
voltage detecting circuit 100 is supplied with a power source voltage VDD generated outside of the semiconductor integrated circuit device or a power source voltage Vii generated inside the semiconductor integrated circuit device at time t100 shown in part (A) of FIG. 3, a PMOS (P-channel Metal Oxide Semiconductor)transistor 111 of theload part 110 is turned ON, as shown in part (B) thereof. An NMOS (N-channel MOS)transistor 121 of thedetection part 120 is turned OFF, as shown in part (C) of FIG. 3. Thus, the potential of a node N1 rises and reaches a high level. - When the potential of the node N1 reaches the high level, the gate of a
PMOS transistor 131 of the NOT circuit 130-1 and the gate of anNMOS transistor 132 thereof are set to the high level. As shown in parts (E) and (F) of FIG. 3, thePMOS transistor 131 is turned OFF, and theNMOS transistor 132 is turned ON. Thus, as shown in part (G) of FIG. 3, the potential of a node N3 reaches a low level. - The NOT circuit130-2 is supplied with the low level from the NOT circuit 130-1, and inverts the low level thus supplied, so that the high level is output from the NOT circuit 130-2. The signal output from the NOT circuit 130-2 shown in part (H) of FIG. 3 is used as the signal vbelz for adjusting the substrate voltage generating circuit (not shown). At time t110, the substrate voltage generating circuit starts to generate the substrate voltage VBB from the signal vbelz.
- The substrate voltage generating circuit generates the negative substrate voltage VBB in response to the signal vbelz which is at the high level. Then, as shown in part (I) of FIG. 3, the substrate voltage VBB gradually decreases, and reaches, at time t120, a value defined by equation (1) shown below:
- VBB=V GND −Vth (1)
- where VGND is the ground potential, and Vth is the threshold voltage of the
NMOS transistor 121. - When equation (1) stands (is in effect), the
NMOS transistor 121 is turned ON, as shown in part (c) of FIG. 3. Thus, as shown in part (D) of FIG. 3, the node N1 switches to the low level. Then, the gate potentials of thePMOS transistor 131 and theNMOS transistor 132 of the NOT circuit 130-1 change to the low level. Thus, as shown in parts (E) and (F), thePMOS transistor 131 is turned ON, and theNMOS transistor 132 is turned OFF. Then, as shown in part (G) of FIG. 3, the potential of the node N3 changes to the high level. - The NOT circuit130-2 inverts the high level supplied from the NOT circuit 130-1, and outputs the signal vbelz which is at the low level, as shown in part (H) of FIG. 3. In response to the low-level signal Vbelz, the substrate voltage generating circuit stops generating the negative substrate voltage VBB. Thus, as shown in part (I) of FIG. 3, the substrate voltage VBB is adjusted so that equation (1) stands.
- As described above, the substrate voltage VBB is adjusted based on the potential of the node N1. FIG. 2 shows states of the transistors with respect to the substrate voltage VBB. In FIG. 2, “deeply biased” denotes that the substrate voltage VBB is greater in the negative-side direction than that defined by equation (1), and “lightly biased” denotes that VBB is greater in the positive-side direction than that defined by equation (1).
- However, there is a possibility that the threshold voltages Vth of the transistors of the voltage detecting circuit shown in FIG. 1 deviate from the target value due to variations in factors involved in the process of fabricating the semiconductor integrated circuit devices. For example, in case where the threshold voltage Vth of the
PMOS transistor 111 has a variation different from that of the threshold voltage Vth of theNMOS transistor 121, the variations cannot be mutually canceling at the node N1. - Thus, the operation of detecting the substrate voltage VBB is affected by variation in the threshold voltage Vth of the
PMOS transistor 111, so that the substrate voltage VBB cannot be adjusted accurately. Further, the NOT circuit 130-1 is set at an intermediate level when a level transition occurs at the node N1. At this time, thePMOS transistor 131 and theNMOS transistor 132 are both ON. Thus, a pass-through current flows through the NOT circuit 130-1, and power is wastefully consumed. - It is a general object of the present invention to provide a voltage detecting circuit in which the above drawbacks are eliminated.
- A more specific object of the present invention is to provide a voltage detecting circuit capable of accurately detecting the substrate voltage by reducing variations in the threshold voltages of transistors.
- Another object of the present invention is to provide a voltage detecting circuit consuming a reduced amount of power.
- The above objects of the present invention are achieved by a voltage detecting circuit including a constant-voltage source, a load part including a first transistor coupled to the constant-voltage source, and a detecting part which is connected to the load part and includes a second transistor of the same type as that of the first transistor. The detecting part detects a given voltage applied thereto.
- Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
- FIG. 1 is a circuit diagram of a conventional voltage detecting circuit;
- FIG. 2 shows an operation of the voltage detecting circuit shown in FIG. 1;
- FIG. 3 is a waveform diagram of an example of the operation of the voltage detecting circuit shown in FIG. 1;
- FIG. 4 is a circuit diagram of a voltage detecting circuit according to a first embodiment of the present invention;
- FIG. 5 is a diagram showing an operation of the voltage detecting circuit shown in FIG. 4;
- FIG. 6 is a timing chart of an operation of the voltage detecting circuit shown in FIG. 4;
- FIG. 7 is a circuit diagram of a constant-voltage source used in a voltage detecting part according to a second embodiment of the present invention;
- FIG. 8 is a circuit diagram of a constant-voltage source used in a voltage detecting part according to a third embodiment of the present invention;
- FIG. 9 is a circuit diagram of a load part and a detecting part used in a voltage detecting circuit according to a fourth embodiment of the present invention; and
- FIG. 10 is a circuit diagram of a load part and a detecting part used in a voltage detecting circuit according to a fifth embodiment of the present invention.
- FIG. 4 is a circuit diagram of a
voltage detecting circuit 1 according to a first embodiment of the present invention. Thevoltage detecting circuit 1 includes a constant-voltage source 10, avoltage correcting part 20, aload part 30, a detectingpart 40, and NOT circuits (inverters) 50-1 and 50-2. - The constant-
voltage source 10 is made up ofresistors voltage correcting part 20 formed of a PMOS transistor 21 (PT11). The source of thePMOS transistor 21 is coupled to a power source voltage VDD via theresistor 11, and the gate (control terminal) thereof is grounded. The drain of thePMOS transistor 21 is coupled to the drain of an NMOS transistor 31 (NT12) via a node N0. Theresistors voltage detecting circuit 1. - The
load part 30 includes theNMOS transistor 31. The drain of theNMOS transistor 31 is connected to the node N0 and gate thereof, and the source thereof is connected via a node N1 to the drain of an NMOS transistor 41 (NT11) and the gates of a PMOS transistor 52 (PT21) and an NMOS transistor 53 (NT21). - The detecting
part 40 includes theNMOS transistor 41, the gate of which is grounded. The source of theNMOS transistor 41 is supplied with the substrate voltage VBB, which is to be detected by thevoltage detecting circuit 1. The drain of theNMOS transistor 41 is connected to the node N1. - The NOT circuit50-1 includes PMOS transistor 51 (PT22), the PMOS transistor 52 (PT21), and the NMOS transistor 53 (NT21). The source of the
PMOS transistor 51 is connected to the power source voltage VDD, and the gate thereof is grounded. The drain of thePMOS transistor 51 is coupled to the source of thePMOS transistor 52 via a node N2. - The gate of the
PMOS transistor 52 is connected to the node N1, and the drain thereof is coupled to the drain of theNMOS transistor 53 and the NOT circuit 50-2 via a node N3. The gate of theNMOS transistor 53 is connected to the node N1, and the drain thereof is connected to the node N3, while the source thereof is grounded. The NOT circuit 50-2 has the same construction as that of the NOT circuit 50-1. - The constructions of the NOT circuits50-1 and 50-2 may be modified based on the driving voltage generated by a substrate voltage generating circuit (not shown) located on the output side of the NOT circuit part 50-2. For example, if the driving voltage of the substrate voltage generating circuit is large, a modification will be made such that an increased number of NOT circuit parts is provided so as to follow the node N1.
- A description will be given, with reference to FIGS. 5 and 6, of an operation of the voltage detecting circuit shown in FIG. 4.
- When the power source voltage VDD generated outside of the semiconductor device is supplied at time t10 shown in part (A) of FIG. 6, the
PMOS transistors PMOS transistor 21 is provided so as to correspond to thePMOS transistor 51, and functions to cancel a deviation of the threshold voltage Vth of thePMOS transistor 51 introduced during the fabricating process. - Since the
PMOS transistor 21 is in the ON state, the node N0 becomes a high level defined by dividing the power source voltage VDD by theresistors NMOS transistor 31 is turned ON, as shown in part (E) of FIG. 6. Further, as shown in part (D) of FIG. 6, the NMOS transistor 41 (NT11) is turned OFF. Thus, the potential of the node N1 increases to the high level, as shown in part (F) of FIG. 6. - It is to be noted that the
voltage detecting circuit 1 is constructed so that theload part 30 and the detectingpart 40 are formed of theNMOS transistors load part 30 and the detectingpart 40 are formed of transistors of the same type (N-channel type), a deviation of the threshold voltage Vth of theNMOS transistor 41 of the detectingpart 40 can be canceled by a deviation of the threshold voltage Vth of theNMOS transistor 31 of theload part 30. This utilizes the fact that the transistors of the same type within the semiconductor device have almost the same deviations. - Turning back to FIGS. 4 through 6, when the node N1 reaches the high level, the high level is applied to the gates of the
PMOS transistor 52 and theNMOS transistor 53 of the NOT circuit part 50-1. Then, as shown in parts (G) and (H) of FIG. 6, thePMOS transistor 52 is turned OFF, and theNMOS transistor 53 is turned ON. Thus, the potential of the node N3 is switched to the low level, as shown in part (I) of FIG. 6. - The NOT circuit part50-2 receives the low level from the NOT circuit part 50-1, and outputs the high level by inverting the received low level. The signal output from the NOT circuit part 50-2 shown in part (J) of FIG. 6 is the signal vbelz which adjusts the substrate voltage generating circuit (not shown). The substrate voltage generating circuit starts, from time t20, to generate the substrate voltage VBB based on the signal vbelz.
- When the substrate voltage generating circuit is supplied with the signal vbelz which is at the high level, it generates the negative substrate voltage VBB. Then, as shown in part (K) of FIG. 6, the substrate voltage VBB gradually decreases, and reaches the level defined by equation (2) shown below:
- VBB=V GND −Vth4 (2)
- where Vth4 is the threshold voltage of the
NMOS transistor 41. - When the substrate voltage VBB reaches the level defined by equation (2) at time t30, the
NMOS transistor 41 is turned ON, as shown in part (D) of FIG. 6. Thus, the potential of the node N1 switches to the low level, as shown in part (F) of FIG. 6. Thus, the low level is applied to the gates of thePMOS transistor 52 and theNMOS transistor 53 of the NOT circuit part 50-1. - Thus, as shown in parts (G) and (H), the
PMOS transistor 52 is turned ON, and theNMOS transistor 53 is turned OFF, so that the potential of the node N3 switches to the high level, as shown in part (I) of FIG. 6. - The NOT circuit part50-2 inverts the high level supplied from the NOT circuit part 50-1 and thus outputs the signal vbelz which is at the low level, as shown in part (J) of FIG. 6. In response to the low-level signal vbelz, the substrate voltage generating circuit stops generating the negative substrate voltage VBB, so that the voltage VBB is thus adjusted so as to have the level defined by equation (2), as shown in part (K) of FIG. 6.
- A description will now be given of the reason why the
PMOS transistors voltage source 10 and the NOT circuit part 50-1, respectively. - There is a case where the
PMOS transistor 52 and theNMOS transistor 53 simultaneously turn ON during a period of potential transition at the node N1. In such a case, a pass-through current flows through the NOT circuit part 50-1. It is possible to reduce the pass-through current by providing thePMOS transistor 51 having a long gate length between the power source voltage VDD and thePMOS transistor 52. Thus, wasteful power consumption can be avoided. - However, the
PMOS transistor 51 may cause a reduction of the level of the signal vbelz and a situation in which the potential of the node N2 in the NOT circuit part 50-1 varies in a way different from that in which the potential of the node N0 in the constant-voltage source 10 varies due to variations in some factors involved in the fabricating process. - With the above in mind, an increased number of stages of NOT circuits following the node N3 can be provided. With this structure, it is possible to ensure a sufficient level of the signal vbelz. Further, in order to cancel variations in the threshold voltage Vth of the
PMOS transistor 51 caused by variations in some factors involved in the fabricating process, thePMOS transistor 21 is provided in thevoltage correcting part 20 of the constant-voltage source 10. ThePMOS transistor 21 makes it possible to cause the potentials of the nodes N0 and N2 to vary in the same way due to similarity in variations in some factors involved in the transistor manufacturing process. - As described above, the detection of the substrate voltage VBB is adjusted based on the potential of the node N1. FIG. 5 shows the states of the transistors with respect to the substrate voltage VBB. In FIG. 5, “deeply biased” denotes that the substrate voltage VBB is greater in the negative-side direction than that defined by equation (1), and “lightly biased” denotes that VBB is greater in the positive-side direction than that defined by equation (1).
- A description will be given of voltage detecting circuits according to other embodiments of the present invention.
- FIG. 7 is a circuit diagram of an essential part of a voltage detecting circuit according to a second embodiment of the present invention. In FIG. 7, parts that are the same as those shown in FIG. 4 are given the same reference numbers as previously. The constant-
voltage source 10 shown in FIG. 7 differs from that shown in FIG. 4 in the positions of thePMOS transistor 21 and theresistor 11. It is possible to interchange the positions of theresistor 11 and thePMOS transistor 21 forming thevoltage correcting part 20 as long as theresistor 11 and thePMOS transistor 21 are interposed between the power source voltage VDD and the node N0. Except for the construction of the constant-voltage source 10, the voltage detecting circuit has the same construction as that of the voltage detecting circuit shown in FIG. 4. - FIG. 8 shows a construction of the constant-
voltage source 10 used in a voltage detecting circuit according to a third embodiment of the present invention. In FIG. 8, parts that are the same as those shown in the previously described figures are given the same reference numbers as previously. The circuit shown in FIG. 8 utilizes, instead of the power source voltage VDD externally supplied, a power source voltage Vii generated within the semiconductor integrated circuit device. The internal power source voltage Vii is not greatly affected by noise. Further, the voltage Vii is regulated and is thus stable. The voltage Vii is applied to the source of thePMOS transistor 21, and the drain thereof is connected to the node N0. The other parts of the voltage detecting circuit according to the third embodiment of the present invention are the same as those corresponding to the first embodiment thereof. - FIG. 9 is a circuit diagram of a construction of the detecting
part 40 used in a voltage detecting circuit according to a fourth embodiment of the present invention. In FIG. 9, parts that are the same as those shown in the previously described figures are given the same reference numbers as previously. The detectingpart 40 shown in FIG. 9 differs from that shown in FIG. 4 in that the detectingpart 40 is made up of two NMOS transistors 42 (NT31) and 43 (NT32). - The drain of the
NMOS transistor 42 is connected to the source of theNMOS transistor 31 via the node N1, and the gate of theNMOS transistor 42 is grounded. The source of theNMOS transistor 42 is connected to the drain and gate of theNMOS transistor 43. The source of theNMOS transistor 43 receives the substrate voltage VBB. - When the node N1 switches to the high level, the NOT circuit part 50-1 outputs the low-level signal. The NOT circuit part 50-2 inverts the low-level signal from the NOT circuit part 50-1 into the high-level signal. The high-level signal from the NOT circuit part 50-2 is the signal vbelz used to adjust the substrate voltage generating circuit. When the negative substrate voltage VBB is generated by the substrate voltage generating circuit, the substrate voltage VBB gradually decreases and reaches the level defined by the following expression:
- VBB=V GND −Vth (3)
- where Vth is the threshold voltage of the
NMOS transistor 43. At that time, theNMOS transistor 43 is turned ON. Further, the substrate voltage VBB decreases and reached the level defined by the following expression: - VBB=V GND−2Vth (4)
- When the above equation stands, the
NMOS transistor 42 is turned ON. - Thus, the potential of the node N1 switches to the low level when the substrate voltage VBB reaches the level defined by equation (4). Then, the output signal of the NOT circuit 50-1 is switched to the high level, which is received by the NOT circuit part 50-2. Then, the low level signal is output by the NOT circuit part 50-2 as the signal vbelz. In response to the low-level substrate voltage VBB, the substrate voltage generating circuit stops generating the declining substrate voltage VBB, which is thus adjusted so that equation (4) stands.
- The other parts of the fourth embodiment of the present invention are the same as corresponding those of the first embodiment of the present invention.
- As described above, the fourth embodiment of the present invention is capable of further increasing the substrate voltage VBB to be detected in the negative-side direction and thus adjusting the substrate voltage VBB more deeply in the negative-side direction.
- FIG. 10 is a circuit diagram of the
load part 30 and the detectingpart 40 used in a fifth embodiment of the present invention. In FIG. 10, parts that are the same as those shown in the previously described figures are given the same reference numbers as previously. The detectingpart 40 shown in FIG. 10 differs from that shown in FIG. 4 in that the circuit shown in FIG. 10 is made up of two NMOS transistors 44 (NT33) and 45 (NT34). - The drain of the NMOS transistor44 is connected to the source of the
NMOS transistor 31 via the node N1, and the gate thereof is grounded. The source of the NMOS transistor 44 is connected to the drain of theNMOS transistor 45. The gate of theNMOS transistor 45 is grounded, and the source thereof is connected to the substrate voltage VBB. - When the node N1 switches to the high level, the NOT circuit part 50-1 outputs the low-level signal, which is inverted by the NOT circuit 50-2. The high-level signal output from the NOT circuit part 50-2 is used as the signal vbelz for adjusting the substrate voltage generating circuit (not shown). The substrate voltage generating circuit generates the substrate voltage VBB based on the signal vbelz.
- When the signal vbelz is at the high level, the substrate voltage generating circuit generates the negative substrate voltage VBB, which gradually decreases and reaches the level defined by equation (3) described before. At that time, the
NMOS transistor 45 is turned ON. The substrate voltage VBB further decreases and reaches the level defined by equation (4) described before. Then, the NMOS transistor 44 is turned ON. - Thus, the potential of the node N1 switches to the low level when the substrate voltage VBB becomes the level defined by equation (4). Then, the NOT circuit part 50-1 outputs the high-level signal, which is inverted by the NOT circuit part 50-2. The low-level signal from the NOT circuit part 50-2 is the low-level signal vbelz. In response to the low-level signal vbelz, the substrate voltage generating circuit stops generating the negative substrate voltage VBB, so that the voltage VBB is adjusted so as to satisfy equation (4).
- The other parts of the fifth embodiment of the present invention are the same as corresponding those of the first embodiment of the present invention.
- As described above, the fifth embodiment of the present invention is capable of further increasing the substrate voltage VBB to be detected in the negative-side direction and thus adjusting the substrate voltage VBB more deeply in the negative-side direction.
- According to the present invention, the following advantages can be obtained.
- The load part (which corresponds to the load part30) and the detecting part (which corresponds to the detecting part 40) are of transistors of the same type. Thus, it is possible to cancel variations in the threshold voltages of the transistors due to variations in some factors involved in the fabricating process. This utilizes the fact that the transistors of the same type have almost the same variations. Thus, the voltage detecting circuit of the present invention can accurately detect the given voltage (the substrate voltage).
- The present invention generates a detection signal based on the relationship between the given voltage to be detected and a reference voltage. The reference voltage is based on the threshold voltage of the transistor included in the detecting part. Thus, it is possible to arbitrarily adjust the voltage to be detected. For example, a plurality of transistors can be used if it is desired to increase the given voltage in the negative-side direction.
- The load part is connected to the drain of a transistor forming the detecting part, and the gate thereof grounded. Further, the source of the above transistor is connected to the given voltage to be detected. Thus, it is possible to produce the detection signal based on the relationship between the given voltage and the threshold voltage of the transistor.
- The present invention may include a level converting part (which corresponds to the
PMOS transistor 52 and the NMOS transistor 53) which converts the level of the detection signal supplied from the detecting part, so that the level of the detection can arbitrarily be adjusted. A current adjusting part (which corresponds to the PMOS transistor 51) may be provided in the level converting part. The current adjusting part prevents an excessive current from flowing through the level converting part, so that wasteful power consumption can be avoided. The current adjusting part may be formed of a transistor having a long gate length. - A constant-voltage generating part (which corresponds to the constant-voltage source10) may include a voltage correcting part formed of a transistor of the same type of that of the transistor forming the current adjusting part. It is thus possible to cancel variations in the threshold values of the transistors due to variations in some factors involved in the fabricating process.
- The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.
Claims (17)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11-078110 | 1999-03-23 | ||
JP07811099A JP3457209B2 (en) | 1999-03-23 | 1999-03-23 | Voltage detection circuit |
Publications (2)
Publication Number | Publication Date |
---|---|
US20020057100A1 true US20020057100A1 (en) | 2002-05-16 |
US6404221B1 US6404221B1 (en) | 2002-06-11 |
Family
ID=13652758
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/526,746 Expired - Lifetime US6404221B1 (en) | 1999-03-23 | 2000-03-16 | Threshold invariant voltage detecting device |
Country Status (4)
Country | Link |
---|---|
US (1) | US6404221B1 (en) |
JP (1) | JP3457209B2 (en) |
KR (1) | KR100589467B1 (en) |
TW (1) | TW444254B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110025287A1 (en) * | 2009-07-28 | 2011-02-03 | Semiconductor Energy Laboratory Co., Ltd. | Regulator circuit |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4794782B2 (en) * | 2001-09-18 | 2011-10-19 | セイコーインスツル株式会社 | Voltage detection circuit and electronic device |
US7443710B2 (en) * | 2004-09-28 | 2008-10-28 | Spansion, Llc | Control of memory devices possessing variable resistance characteristics |
JP2006112906A (en) * | 2004-10-14 | 2006-04-27 | Sanyo Electric Co Ltd | Voltage detection circuit |
KR100733407B1 (en) * | 2005-06-30 | 2007-06-29 | 주식회사 하이닉스반도체 | Bulk bias voltage level detector in semiconductor memory device |
US9704581B2 (en) * | 2014-12-27 | 2017-07-11 | Intel Corporation | Voltage ramping detection |
JP6319668B2 (en) * | 2015-09-10 | 2018-05-09 | 日本電信電話株式会社 | Voltage detection circuit |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55149871A (en) * | 1978-07-31 | 1980-11-21 | Fujitsu Ltd | Line voltage detector |
JPH0740050B2 (en) * | 1987-05-20 | 1995-05-01 | 松下電器産業株式会社 | Voltage detection circuit |
JPH01182757A (en) * | 1988-01-13 | 1989-07-20 | Mitsubishi Electric Corp | Power source-voltage detecting circuit |
JPH0821849B2 (en) * | 1988-10-25 | 1996-03-04 | 富士通株式会社 | Semiconductor memory device |
DE69212889T2 (en) * | 1991-05-17 | 1997-02-20 | Rohm Co Ltd | Constant voltage circuit |
JP2824706B2 (en) * | 1991-09-27 | 1998-11-18 | 三菱電機株式会社 | Current source circuit and operation method thereof |
JPH07175535A (en) * | 1993-12-16 | 1995-07-14 | Nec Corp | Power circuit for fet amplifier |
JP3154906B2 (en) * | 1994-12-22 | 2001-04-09 | 松下電器産業株式会社 | Voltage detection circuit |
JP2830799B2 (en) * | 1995-10-25 | 1998-12-02 | 日本電気株式会社 | Semiconductor integrated circuit device |
JPH09330590A (en) * | 1996-06-07 | 1997-12-22 | Mitsubishi Electric Corp | Internal voltage detector and substrate voltage detector |
JPH10160768A (en) * | 1996-12-04 | 1998-06-19 | Fujitsu Ltd | Voltage-level detecting apparatus |
ITMI981525A1 (en) * | 1997-07-03 | 2000-01-02 | Denso Corp | LOAD CONTROL CIRCUIT WITH VOLTAGE RISE TIMING CONTROL |
JP3173727B2 (en) * | 1998-03-10 | 2001-06-04 | 日本電気株式会社 | Voltage detection circuit |
-
1999
- 1999-03-23 JP JP07811099A patent/JP3457209B2/en not_active Expired - Fee Related
-
2000
- 2000-03-14 TW TW089104615A patent/TW444254B/en not_active IP Right Cessation
- 2000-03-16 US US09/526,746 patent/US6404221B1/en not_active Expired - Lifetime
- 2000-03-22 KR KR1020000014505A patent/KR100589467B1/en not_active IP Right Cessation
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110025287A1 (en) * | 2009-07-28 | 2011-02-03 | Semiconductor Energy Laboratory Co., Ltd. | Regulator circuit |
Also Published As
Publication number | Publication date |
---|---|
JP2000275283A (en) | 2000-10-06 |
KR100589467B1 (en) | 2006-06-14 |
TW444254B (en) | 2001-07-01 |
KR20000076929A (en) | 2000-12-26 |
US6404221B1 (en) | 2002-06-11 |
JP3457209B2 (en) | 2003-10-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7358946B2 (en) | Offset cancel circuit of voltage follower equipped with operational amplifier | |
US7474143B2 (en) | Voltage generator circuit and method for controlling thereof | |
US7592862B2 (en) | Digital temperature sensing device using temperature depending characteristic of contact resistance | |
US20120044021A1 (en) | Differential amplifier circuit | |
US20190312575A1 (en) | Biasing cascode transistors of an output buffer circuit for operation over a wide range of supply voltages | |
US20080106309A1 (en) | Reset device | |
US9136827B2 (en) | Power-on reset circuit | |
US6750696B2 (en) | Level conversion circuit converting logic level of signal | |
US7482847B2 (en) | Power-on reset circuit | |
US20090230998A1 (en) | Driver circuit | |
US6411554B1 (en) | High voltage switch circuit having transistors and semiconductor memory device provided with the same | |
US20080157832A1 (en) | Power-On-Reset Circuit | |
US7750723B2 (en) | Voltage generation circuit provided in a semiconductor integrated device | |
US6404221B1 (en) | Threshold invariant voltage detecting device | |
US4999567A (en) | Constant current circuit | |
US7545128B2 (en) | Regulator circuit | |
US5955891A (en) | Semiconductor integrated circuit device with output circuit | |
US6191624B1 (en) | Voltage comparator | |
JPH05114291A (en) | Generating circuit of reference voltage | |
US20060066353A1 (en) | Output circuit with reduced gate voltage swings | |
US6771115B2 (en) | Internal voltage generating circuit with variable reference voltage | |
US20080238517A1 (en) | Oscillator Circuit and Semiconductor Device | |
JP2926921B2 (en) | Power-on reset circuit | |
US7652530B2 (en) | Amplifier circuit and method of generating bias voltage in amplifier circuit | |
JP2000115987A (en) | Short circuit protective circuit |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FUJITSU LIMITED, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KAWAKUBO, TOMOHIRO;TOMITA, HIROYOSHI;REEL/FRAME:010634/0013 Effective date: 20000307 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
AS | Assignment |
Owner name: FUJITSU MICROELECTRONICS LIMITED, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJITSU LIMITED;REEL/FRAME:021998/0645 Effective date: 20081104 Owner name: FUJITSU MICROELECTRONICS LIMITED,JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJITSU LIMITED;REEL/FRAME:021998/0645 Effective date: 20081104 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
AS | Assignment |
Owner name: FUJITSU SEMICONDUCTOR LIMITED, JAPAN Free format text: CHANGE OF NAME;ASSIGNOR:FUJITSU MICROELECTRONICS LIMITED;REEL/FRAME:024982/0245 Effective date: 20100401 |
|
FPAY | Fee payment |
Year of fee payment: 12 |
|
AS | Assignment |
Owner name: SOCIONEXT INC., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUJITSU SEMICONDUCTOR LIMITED;REEL/FRAME:035508/0637 Effective date: 20150302 |