JPH03194474A - Threshold value detecting circuit - Google Patents

Abstract

PURPOSE: To obtain an output voltage from a threshold detecting circuit in response to an input exceeding a preset threshold inputted to an output node by providing an input node and a current sink and resistance element connected to the input node. CONSTITUTION: A nose 12 receives an input voltage and supplies the voltage to current mirrors through a resistor 32. A first current mirror 16 incorporates an npn transistor Q18 and another transistor Q20 which is N times as large as the transistor Q18, receives a reference current IPTAT, and sucks a current NIPTAT which is N times as large as the reference current IPTAT after mirroring. A second current mirror 22 incorporates an npn transistor Q24 and another transistor Q26 which is M time as large as the transistor Q24, is connected to the first current mirror 16, and mirrors the current NIPTAT. The collector current of the transistor Q26 becomes (M×N)IPTAT. Since a current sink 28 incorporates an npn transistor Q29 and has the maximum sucking current IPTAT, an excessive current (M×N)IPTAT-IPTAT becomes the base current of a pnp transistor Q30 and, when the sucking current of the sink 28 is exceeded, supplies an output voltage level to a node 14. When a threshold detecting circuit is constituted in such a way, the circuit can detect a threshold level exceeding the power supply voltage without relying upon the ambient temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates generally to integrated electronic devices, and in particular to:
The present invention relates to circuits and methods for detecting threshold voltages.

[Prior Art] Many threshold detection devices are commercially available today. As usual, the threshold detection function is implemented through the use of differential comparator circuits.

Such threshold detection circuits have limitations in their application, thus limiting their use.

One of the desirable features of the threshold detection circuit is that the voltage threshold level is independent of ambient temperature. Many integrated electronic devices are designed to operate within well-defined operating temperature ranges.

To meet the requirement of temperature independence, more complex circuitry would have to be added in addition to the differential comparator circuit. Adding circuitry to achieve the above requirements makes the threshold detection circuit unnecessarily complex and cumbersome.

Another desirable feature of the threshold detection circuit is the ability to detect threshold voltages that are substantially higher than the operating supply voltage.

For J5 applications where the desired threshold voltage is inherently higher than the supply voltage, auxiliary circuitry, such as a resistor network, is typically required to step down the input voltage to a level below the supply voltage. It is said that This additional circuit increases the size of the threshold detection circuit.

Therefore, a threshold sensing circuit having a relatively small number of components can maintain an essentially constant voltage threshold over a wide temperature range and can sense threshold voltages higher than the supply voltage. A demand has arisen for threshold detection circuits.

In accordance with the present invention, a threshold detection circuit is provided that essentially eliminates or reduces the drawbacks and problems associated with conventional threshold detection circuits.

One feature of the invention is to provide a threshold detection circuit that includes an input node for receiving an input voltage and a current sink connected to the input node. Furthermore, a resistive element is connected to the input node which determines the threshold value to be detected. An output voltage is available at the output node responsive to an input voltage exceeding a predetermined threshold.

In other features of the invention, the circuit receives a reference current and reproduces a first current having a magnitude that is a constant multiple of the magnitude of the reference current; Contains a current mirror. A second current mirror is provided to reproduce and supply a second current having a magnitude that is a constant multiple of the magnitude of the first current. A first transistor having a conductor, collector, and emitter is connected to a second F6i-style mirror. A second transistor having a base, collector, and emitter is coupled to the first transistor to receive a portion of the second current in excess of what can be sunk by the first transistor.

In yet another aspect of the invention, a method is provided for detecting a voltage threshold. The method includes the steps of providing an input voltage to an input node, connecting a resistor to the input node, receiving a reference current, and producing a first current that exceeds the reference current by a first predetermined amount. including. Additionally, the method includes sinking a predetermined portion of the first current. The switching element is driven with a first current in excess of the sinkable portion, and an output voltage is generated at the output node responsive to the input voltage exceeding the threshold.

In other features of the invention, a method for constructing a threshold detection circuit is provided. The method includes forming an input node, forming a current sink leading to the input node, forming an output node responsive to an input voltage exceeding a predetermined threshold, and forming a resistive element leading to the input node. It includes a step of forming.

An important technical feature of the present invention is that it provides a circuit and method for detecting a threshold voltage level that exceeds a supply voltage level. Other technical features of the present invention are:
Threshold! The voltage level does not depend on ambient temperature changes.

[Example] For a better understanding of the present invention, description will be given below with reference to the drawings.

Referring to the drawings, FIG. 1 depicts a threshold detection circuit constructed in accordance with the present invention, designated by the reference numeral 1o. Circuit 10 includes an input node 12 and an output node 14. Input node 12 is adapted to receive an input voltage whose voltage level circuit 10 monitors.

The threshold Wi voltage detection circuit 10 further constitutes a first current mirror including a first transistor 18 and a second transistor 20. The collector of the first transistor 18 is coupled to its base, which in turn is coupled to the base of the second transistor 20. 1st and 2nd
The emitters of transistors 18 and 20 are connected together.

The first and second transistors are made such that they exhibit essentially the same transfer characteristics, with N being a predetermined factor.
The difference is that the size of the first transistor 18 is N times larger than that of the first transistor 18.

This size can be achieved, for example, by forming the emitter of the second +- transistor 20 to be N times larger than the emitter of the first transistor 18. The first and second transistors 18,20 are shown as bipolar junction transistors of the NPN type, however, as is well known to those skilled in the art, the invention also operates with transistors of the PNP type.

The first current mirror 16 receives the base t\ lightning current (PPT
It takes A■, mirrors a current of magnitude N1, and draws it in. ■ is the first transition PT^
1 flows into the collector of the transistor 20 of the second TAT.

The NIPTAT factor N is due to the difference in size between the first and second transistors.

a second current mirror 22 is coupled to the first current mirror;
Once again, the current Nl is mirrored. The second current mirror 22 includes a third transistor 24 and a fourth transistor 26 whose bases are connected together. The collector of the third transistor 24 is further coupled to its base.

The emitters of the third transistor 24 and the fourth transistor 26 are connected to each other. The third and fourth transistors also have essentially the same transfer characteristics, except that the fourth transistor 26 has an emitter that is M times larger than the emitter of the third transistor 24. .

The current flowing out of the collector of the third transistor 24 and into the collector of the second transistor 20 is N'P
TA, so since the fourth transistor 26 is M times the third transistor 24, the current flowing out of the collector of the fourth transistor 260 is (MxN)1
It is.

The TAT current sink 28 is adapted to receive a portion PT^ of the current (MXN)I flowing out of the collector of the fourth transistor 26. Current sink 28 includes a transistor 29 having its collector coupled to the collector of fourth transistor 26 . The base of transistor 29 is coupled to the bases of first and second transistors 18.20. The maximum lightning current that can be sunk by the current sink 28 is made to be l.

The excess current of magnitude (MTAT
This becomes the base drive current to the PT8 register 30. The fifth transistor 30 driven by the base current is connected to the output node 1
The output voltage level is supplied to 4.

In order for fifth transistor 30 to switch its state, the base current of fifth transistor 30 must be large enough to drive fifth transistor 30 into the active region. Then, when the current that current sink 28 can sink exceeds, the collector current flowing out of fourth transistor 26 must provide base drive current. In order for the base of the fifth transistor 30 to begin receiving current, the input node 12
The current IIN flowing into the current sink 28 is sufficient to supply the sum of the current I flowing into the current sink 28 and the current Nl flowing into the first current mirror 16.
T must. The threshold voltage level for the circuit 10 to change state has the base-emitter voltage VBE of the fifth transistor 30, the saturation voltage 8A1 of the fourth transistor 26, and the value R1, as shown in the following equation. equal to the sum of the voltage drops across resistor 32.

VTH=VBE+VSAT+(ITH” R1
) (1) where 'TH is the input current at the threshold, R1 is the resistance value of the resistor 32 connected between the input node 12 and the second current mirror 22. As is clear from the above equation (1), the threshold voltage ■■H can be adjusted by changing the resistance value R1 of the resistor 32 without changing the threshold current 'Tl+.

Threshold 1n current 10. is defined as the input current at which the base of the fifth transistor 30 begins to receive current. Therefore, this threshold current is the sum of the current flowing through current sink 928 and the current flowing through one branch of first current mirror 16 .

I=l +NI (21THPTAT
P Ding ^ ■ Thunder style I is K (Kelvin degree)
It is proportional to the absolute temperature TAT expressed as This temperature-dependent current ■ is the PTA
T provides a current whose magnitude is proportional to the junction temperature of the device and can be generated by circuits well known to those skilled in the art. As described below, the temperature characteristics of (1) contribute to the constancy of the voltage threshold of the threshold detection circuit 10.

FIG. 2 shows an embodiment of the invention designated by the reference numeral 33. The illustrated circuit 33 can be divided into two functional circuit blocks for convenience of explanation.

The first and second current mirrors 34 and 36 and the current sink 38 are connected to the first and second current mirrors 16 described in FIG.
and 22, and of essentially the same structure as current sink 28.

Based on PTAT to generate a current 1 proportional to absolute temperature 11! A current generator circuit 40 is used. Current mirror 42 is used to supply current I PTAT to first current mirror 34 . IPTAT can be expressed as a function of absolute junction temperature as shown in the following equation.

Here, k is the Boltzmann constant, ■ is the absolute junction side Lq expressed in K, is the unit charge of an electron, N is the ratio of the transistor emitter size, and R2 is the resistance of the resistor 44 used in the reference current generator circuit 40. It is the resistance value.

As already shown in FIG. 1, the circuit 4o and @flow mirror 42
The current generated by TAT is received by the first current TAT mirror 34. In this example, the first
The emitter area ratio of current mirror transistors 68 and 70 is 2:1, so that a current of magnitude 2I flows from second current mirror 36 to first current mirror 34. Similarly, the emitter area ratio of the transistors in TAT 2 current mirror 36 is 0.67:1. Therefore, the second current mirror 36
The current generated at is 0.67 times PTAT of 2I, which is equal to 1.331.

PTAT A diode-connected transistor 46 has its base connected to its collector and is arranged to receive a current of 1.331 PTAT from the second current mirror 36. PTA absorbs current of magnitude 1(r)
■ A current sink 38 that can be connected to the emitter of a diode-connected transistor 46. Output stage 4
8 receives excess current from the second current mirror 36 and takes GJ;
It is designed to supply an output voltage that means threshold voltage detection. The detailed structure and function of this embodiment of the invention will be described below.

The reference current generator circuit 40 is coupled to the supply voltage via a first resistor 50. A first resistor 5° is connected to the collector of the first transistor 52. The collector and base of the @1 transistor 52 are tied together and connected to the base of the second transistor 54. 1st
The emitter of transistor 52 is also coupled to the collector of third transistor 56 and the base of fourth transistor 58. The base of the third transistor 56 is coupled to the collector of a fourth transistor 58, which in turn is coupled to the emitter of the second transistor 54. The emitter of the fourth transistor 58 is connected to a resistor 44 having a resistance value R2. fourth transistor 5
8 is the first, second, and third transistor 52, 54.5
It is made eight times the size of each of the six. The resistance value R2 of resistor 44 has an important role in determining the threshold voltage level detected by circuit 33.

A current having a magnitude 2 is generated by the reference current generator circuit TAT circuit 40 and mirrored by the current mirror 42. Current mirror 42 includes a fifth transistor 60 having its emitter connected to the supply voltage. The collector of the fifth transistor 60 is connected to the reference current generator circuit 40.
The collector of the second transistor 54 is connected to the collector of the second transistor 54 . The base of the sixth transistor 62 is coupled to the base of the fifth transistor 60 and further coupled via a resistor 64 to the supply voltage. Resistor 64 is further coupled to the emitter of a seventh transistor 66, which has its base coupled to the collector of fifth transistor 60 and its collector to ground. The current produced by the reference current generator circuit 40 is therefore sourced from the fifth 1-transistor zero of the current mirror 42. The collector of the sixth transistor 62 is coupled to the first current mirror 34 of the threshold detection circuit 33 to provide a reference current I.

PTAT The threshold detection circuit 33 shown in FIG. 2 corresponds to the circuit 10 shown in FIG. first current mirror 34
is composed of a first transistor 68 and a second transistor 70. The collector and base of the first transistor 68 are coupled together to the base of the second transistor 7o. first and second transistor 68.7
The emitter of 0 is tied together to ground. Second
The transistor 70 is made twice the size of the first transistor 68, so the current induced in the collector of the second transistor 70 is 2I. Thus, the second current mirror 36 coupled to the first current mirror TAT 34 provides a current TAT current of magnitude 21 to the first current mirror 34.

The second current mirror 36 includes first and second transistors 72, 74 whose bases are connected together. 1st
The base of transistor 72 is coupled to its collector. The second transistor 74 is made to have a size 0.67 times the size of the first transistor 72. As already mentioned, the size difference is produced by varying the size of the emitter region. The magnitude of the current drawn by the second transistor 74 is 2I of 0
．． 67 times, which is 1.33 TAT ■. First and second transistors 72, PTA
Both emitters of T 74 are connected to the input node 12 via a resistor 75 with a resistor 1iR1.

Transistor 46 is connected in series with the collector of second transistor 74 of second current mirror 36 . The base of transistor 46 is connected to its collector and is configured like a diode. The emitter of transistor 46 is coupled to current sink 38, which includes transistor 76.

Transistor 76 receives and sinks a current having a magnitude of 1 from second current mirror 36 and transistor 46.

The output stage 48 is coupled to the current sink 38 and is connected to the first
, second and third transistors 78, 79, and 80. The two collectors of the first transistor 78 as output stage 48 are connected to the collector of the second transistor 79 . The emitter of the second transistor 79 is connected to the supply voltage, while the emitter of the first transistor 78 is connected to ground. The collector of the first transistor 78 is further coupled to the base of a third transistor 80. The base of the second transistor 79 is connected to the pair of current mirrors 42 from 1 to 0.62
is connected to the base of The collector of the third transistor 80 is connected to the supply voltage via a resistor 81, while its emitter is connected to ground. The base of first transistor 78 is coupled to the collector input of current sink 38 to receive excess current from second current mirror 36 that current sink 36 cannot sink.

As is clear from Fig. 2 and equation (2), the input current 'I
The threshold is reached when N equals the sum of the collector current of current sink 38 and the collector current of second transistor 70 of first current mirror 34 . Therefore, I
is THPTAr P between l and 21
TAT sum, that is, 3I. PTA beyond 3I
Any input current T PTAT drives the base of first transistor 78 of output stage 48, thereby driving transistor 80.
is cut off, and the state of the output node 14 is changed.

In the present embodiment of the invention shown in FIG. 2, the threshold voltage level is the sum of the base-emitter voltages of both first transistor 78 and diode-connected transistor 46; This is explained as the sum of the saturation voltage of 74 and the voltage drop of resistor 75.

VTII-VBE1 +VBE2 +VSAT +(I
THoRl ) (4) The saturation voltage of the second transistor 74 of the second current mirror 36 has been ignored as it contributes only a small contribution to the sum. 'Substituting equation (3) for Tl+ and assuming v −■ BEI B[:
2 and the threshold voltage v111 are expressed by the following equation.

Here, the fourth transistor 5 of the current generator circuit 40
For an emitter size of 8, N=8.

It will be understood that the temperature characteristics of the threshold voltage depend on the temperature characteristics of each term on the right side of equation (5). The base-emitter temperature characteristics of transistors are well predictable and are typically -2 mV/°C. By solving the equation obtained by differentiating equation (5) with respect to temperature and setting it equal to zero, the temperature at which the temperature change in the threshold voltage takes the minimum value can be obtained.

The differentiated connecting beam is shown in equation (6).

T 2 q (6) By rearranging this equation, it is clear that temperature changes in the base-emitter voltage of the transistor 46.78 can be compensated for by adjusting the resistance values R and R2 of the resistor 75°44 in the circuit 33. Dew.

2 q Given the known resistance values R2 and N of the resistor 44, use the expression in equation (1) to find a resistor that minimizes or eliminates the temperature dependence of the threshold detection circuit 33. The optimum resistance value R1 for 75 can be determined.

As shown in equation (4), the threshold voltage level is the base-emitter voltage VB of the plurality of transistors 46.78.
It is determined by the sum of E, a slight saturation voltage, and the voltage drop across resistor 75. Accordingly, the threshold voltage level can be adjusted by varying the plurality of base-emitter voltages vBE between the second transistor 74 of the second current mirror 36 and the first transistor 78 of the output stage 48.

In the embodiment shown in FIG. 2, these transistors 7
There is only one vBF between 4.78 and 4.78. Furthermore, transistor 46 is used to change the threshold voltage level v011.
an integer number of diode-connected transistors, such as
Can be connected in series.

When a non-integer number of VBEs is required, a circuit as shown in FIG. 3, generally designated by the reference numeral 82, is used.

Referring to FIG. 3, circuit 82 includes a transistor 84 having a first resistor 86 between its collector and base and a second resistor 87 between its base and emitter. Node 88 connected to the collector of transistor 84 is connected to second current mirror 36, and node 89 connected to the emitter is connected to current sink 38. The first resistor 86 has a resistance value RA, and the second resistor 87 has a resistance value R. The multiplier f for VBE is equal to that expressed in equation (8).

B Thus, in order to realize a non-integer equivalent vBE,
The resistance values of the first and second resistors 86 and 87 can be selected as desired.

Referring now to FIG. 4, current generator circuit 40 of FIG.
Another example is shown. - The circuit designated by the reference numeral 90 inside the shell employs PNP type transistors and can be used in place of both the current generator circuit 40 and the current mirror 42 in FIG. can. Circuit 90 includes a first transistor 92 having its base coupled to the collector of a second transistor 94 and its collector coupled to the emitter of a third transistor 96. The collector of the second transistor 94 is further coupled to the emitter of a fourth transistor 98 and the base of the second transistor 94 is coupled to the collector of the first transistor 92. The collector of the third transistor 96 is coupled to a resistor 100. The emitter of the second transistor 94 is connected to the power supply bar via a resistor 102 having a resistance value R2. The emitter of the second transistor 94 is made eight times larger than the emitter of the fourth transistor 98. A current I proportional to the temperature change is generated by circuit 90 and flows out of the collector of transistor 98 through PT8.

Circuit 90 generally functions similar to current generator circuit 40. According to the characteristics of the PNPI transistor, the current mirror circuit 42 can be omitted and the current generator circuit 90 can be replaced by the first current mirror 16 of the threshold detection circuit 10 of FIG. 1 or the threshold detection circuit 33 of FIG. the first current mirror 34 of
connected directly to.

In summary, by examining equation (4) it is clear that the threshold voltage level is independent of the supply voltage value.

Therefore, a threshold detection circuit constructed in accordance with the present invention can also be used to detect voltages far above the supply voltage level. Further, by changing the plurality of diode-connected transistors connected between the second %il mirror 36 and the switching transistor 78, and further adjusting the resistance value R1 of the resistor 75, the threshold of this circuit can be adjusted. It is also clear that the value voltage level can be set to any desired level. Thus, the threshold characteristics of this circuit can be varied by adjusting a relatively small number of circuit components.

An additional feature of the circuit of the invention is that a high impedance state can be achieved at its input node 12. Note that no input current 11Ntfi flows into circuit 10 unless base current is provided to the transistors of second current mirror 22 or 36.

Therefore, Nl to the second current mirror 22 or 36
A high impedance state can be achieved by inhibiting current flow. For example, to disable TAT to disable Nl, or to disable R to ground, PTA
■ A high impedance state can be created by

Modifications may be made to the circuit shown herein without departing from the scope of the invention.

For example, the configuration of current mirrors, current sources, and current sinks can vary according to the circuit application. In addition to the history, there are many methods to create a current proportional to temperature. The suggestion of a specific embodiment, such as that shown in FIG. 2, is merely to illustrate important technical features of the invention and is not intended to limit or cover the scope of the invention.

Although the invention has been described in detail herein, without departing from the spirit and scope of the invention as set forth in the claims below.
It is understood that various changes, substitutions, and modifications may be made.

Regarding the above explanation, the following IQ will be further disclosed.

(1) A threshold detection circuit comprising an input node for receiving an input voltage, a circuit that receives a reference current and operates to generate a first current proportional to the reference current, and the input node a resistive element coupled between the current receiving and generating circuit and a current sink arranged to sink a portion of the first current; and a resistive element coupled to the current sink and configured to sink a portion of the first current. an output node that generates an output voltage in response to said input terminal exceeding a value.

(2) In the threshold detection circuit of paragraph (1), the current receiving and generating circuit includes: a first current mirror arranged to receive the reference current; and a first current mirror arranged to receive the reference current. a second current mirror coupled between the resistive element and the current sink, the second current mirror being induced by the first current mirror to supply the first current; a flow mirror; and a threshold detection circuit.

(3) The threshold value detection circuit according to paragraph (1),
and a threshold detection circuit including a switching circuit coupled between the current receiving and generating circuit and the current source, the switching circuit being responsive to a portion of the first current.

(4) The threshold value detection circuit of item (3), wherein y
a switching circuit connected to the output node;
Can the switching circuit sink by the current sink? A threshold detection circuit responsive to the 1c current that is larger than the JS current.

(5) The threshold detection circuit according to item (3), wherein the switching circuit includes a first transistor having a base, a collector, and an emitter, and the base of the first transistor is connected to the current sink. a threshold detection circuit arranged to receive a portion of the first current;

(6) In the (5) mound threshold detection circuit, the switching circuit further includes a second transistor having a base, a collector, and an emitter, and the collector of the second transistor is connected to the output node. and a base of the second transistor is coupled to a collector of the first transistor, the second transistor receiving the first current in response to the first transistor and outputting the first current to the output node. A threshold detection circuit that generates voltage.

(7) The threshold detection circuit of paragraph (1), wherein the current receiving and generating circuit includes a current source configured to supply a first current in response to the reference current; A threshold detection circuit, wherein the current sink is coupled to the current source and is capable of sinking a portion of the first current.

(8) The threshold detection circuit according to paragraph (7), further comprising a switching circuit connected between the current source and the current sink, and responsive to a portion of the first current. Threshold detection circuit including switching circuit.

(9) The threshold detection circuit of paragraph (8), wherein the switching circuit is coupled to the output node so that the switching circuit receives the first current that exceeds the current that can be sunk by the current sink. Threshold detection circuit that responds.

(10) The threshold detection circuit according to item (2), further comprising at least one transistor having a base, a collector, and an emitter, connected between the second current mirror and the current sink. Threshold detection circuit that includes a transistor.

(11) The threshold value detection circuit according to item (10), wherein the base of the transistor is connected to the collector of the transistor.

(12) The threshold detection circuit according to item (10), further comprising: a first resistor connected between the base and collector of the transistor; and a first resistor connected between the base and emitter of the transistor. a threshold detection circuit comprising: a second resistor coupled thereto;

(13) The threshold value detection circuit according to item (1), wherein the reference current is proportional to absolute temperature.

(14) The threshold value detection circuit according to item (1), wherein the predetermined threshold value is proportional to its resistance value.

(15) The threshold detection circuit of paragraph (1), wherein the input node has a high input impedance characteristic in response to the current received by the receiving and generating circuit being less than a predetermined activation value. A threshold detection circuit shown in FIG.

(16) t, a threshold detection circuit, comprising: an input node; a first current receiving a reference N current and generating a first current having a magnitude of a first predetermined constant multiple of the reference current; a second current mirror that generates a second current having a magnitude that is a second predetermined constant multiple of the first current; a current sink arranged to sink a predetermined amount of a second current; a resistor coupled between the input node and the second current mirror; and the second current mirror and the current sink. a switching circuit coupled between the switching circuit and the switching circuit responsive to the human powered node having at least a predetermined threshold voltage level; and a threshold detection circuit.

(17) Threshold 1 of item (16) ``1 detection circuit, wherein the first current error is a first transistor having a base, a collector, and an emitter, and the base and the collector are connected to each other. a first transistor connected to each other, and a second transistor having a base, collector, and emitter, the base of which is connected to the base of the first transistor; The threshold detection circuit is constructed such that the emitter area of the second transistor is a first predetermined constant times the emitter area of the first transistor.

(18) In the threshold detection circuit according to item (17), the second current mirror is a third transistor having a base, a collector, and an emitter, and the base and collector are connected to each other. a third transistor, the collector of which is connected to the collector of the second transistor; and a fourth transistor having a base, a collector, and an emitter, the base of which is connected to the base of the third transistor. a fourth transistor connected together, and a threshold configured such that the emitter area of the fourth transistor is a second predetermined constant times the emitter area of the third transistor. detection circuit.

(19) The threshold detection circuit according to item (17), wherein the current sink includes a third transistor having a base, a collector, and an emitter, and the base of the third transistor is connected to the first and second transistors. A threshold detection circuit is connected to both bases of transistor No.2.

(20) The threshold detection circuit according to item (16), further comprising at least one transistor having a base, a collector, and an emitter, connected between the second current mirror and the current sink. Threshold detection circuit that includes a transistor.

(21) The threshold value detection circuit according to item (20), wherein the base of the transistor is connected to the collector of the transistor.

(22) The threshold detection circuit according to item (20), further comprising: a first resistor connected between the base and collector of the transistor; and a first resistor connected between the base and emitter of the transistor. a threshold detection circuit comprising: a second resistor coupled thereto;

(23) The threshold value detection circuit according to item (16), wherein the switching circuit includes a first transistor having a base, a collector, and an emitter, and the base of the first transistor is connected to the current sink. a threshold detection circuit arranged to receive a portion of the second current;

(24) The threshold value detection circuit according to item (23), further including a second transistor having a base, a collector, and an emitter, wherein the collector of the second transistor is connected to the first i~ transistor. a threshold detection circuit coupled to the collector of the second transistor and the emitter of the second transistor coupled to the supply voltage.

(25) The threshold detection circuit according to item (24), further including a third transistor having a base, a collector, and an emitter, the base of the third transistor being the collector of the first transistor. a threshold detection circuit, the output node being coupled to the collector of the third transistor;

(26) The threshold value detection circuit according to item (16), wherein the Sonoki reference current is proportional to absolute temperature.

(27) The threshold value detection circuit according to item (16), wherein the threshold voltage level is adjustable by changing the value of the resistor.

(28) The threshold detection circuit according to item (16), which is capable of detecting a threshold voltage level that exceeds the supply voltage level of the circuit.

(29) The threshold detection circuit according to item (16), wherein the input node is at high impedance in response to the reference current supply means being inactive.

(30) An L threshold detection circuit comprising: an input node; a first resistor connected in series with the input node; 1, which is arranged to regenerate and sink the current of
a second current mirror connected to the resistor and arranged to reproduce and supply a second current having a magnitude that is a constant multiple of the magnitude of the first current; a first transistor having a base, a collector, and an emitter, the collector coupled to the second current mirror;
a first transistor arranged to draw in a predetermined amount of 1HFE of 1HFE; and a second transistor having a base, collector, and emitter, the base being connected to the collector of the first transistor; a second transistor arranged to receive a portion of the second current in excess of the current that can be sunk by the first transistor; a second resistor; and a third transistor having a base, a collector, and an emitter. and the base is of the second transistor]
a third transistor coupled to the collector; an output node coupled to the collector of the third transistor, the output node being responsive to the input voltage exceeding a predetermined threshold; Contains threshold detection circuit.

(31) A method for detecting a threshold, comprising supplying an input voltage to an input node having a resistance value, receiving a reference current, and supplying a first current that is a predetermined constant multiple of the reference current. generating and sinking a predetermined portion of said first current, driving a switching circuit with a portion of said first current exceeding said sinking portion; generating an output voltage to an output node responsive to said input voltage exceeding said threshold value.

(32) The method of item (31), wherein the step of providing the resistance value includes selecting a resistance value such that the predetermined threshold value is proportional to the resistance value.

(33) A method for manufacturing an L threshold detection circuit, the method comprising: forming an input node for receiving an input voltage; receiving a reference current; and generating a first current proportional to the magnitude of the reference current. forming a circuit of: forming a current sink arranged to sink a portion of said first current; forming an output node responsive to said input voltage exceeding a predetermined threshold; A method comprising forming a resistive element coupled between a node and the circuit.

(34) A threshold detection circuit 10 including an input node 12 and an output node 14 is obtained. Input node 12 is coupled to current mirror 22 via resistor 32.

Current mirror 22 is coupled to a further current mirror 16, which is arranged to receive a reference current proportional to absolute temperature. This reference current is mirrored and multiplied by a constant before being received by current sink 28. When the voltage at input node 12 exceeds a predetermined threshold level, the excess current that can be sunk by current sink 28 is directed to the base of switching transistor 30 leading to output node 14, and 14 to generate an output voltage level indicating that the threshold voltage level has been reached or the threshold I voltage level has been exceeded at input node 12. The predetermined threshold fIi voltage may exceed the supply voltage level of the circuit and is independent of the operating temperature of the atmosphere.

[Brief explanation of drawings]

FIG. 1 is a schematic circuit diagram of a horizontally constructed threshold detection circuit according to the present invention. FIG. 2 is a circuit diagram of one embodiment of the present invention. FIG. 3 is a circuit diagram of a portion of another embodiment of the invention. Is Figure 4 a standard? FIG. 3 is a schematic circuit diagram of a first flow supply circuit. [Reference number-1 10・ ・ 12 ・ ・ 14 ・ ・ 16 ・ 18 ・ ・ 20 ・ ・ 22 ・ ・ 24 ・ ・ 26 ・ ・ 28 ・ ・ 29 ・ ・ 30 ・ ・ 32 ・ ・ 33 ・ ・ 34 ・ ・36 ・ ・ 38 ・ ・ 40 ・ ・ 42 ・ ・ 44 ・ ・ Threshold detection circuit・Input node・Output node・First current mirror・First transistor・Second transistor・Second current mirror・Third transistor, fourth transistor, current sink, transistor, fifth transistor, resistor, threshold detection circuit, first current mirror, second current mirror, current sink, reference current generator circuit, current Mirror resistor 46...Diode-connected transistor 48...Output stage 50...First resistor 52...First transistor 54...Second i~ transistor 56...Third transistor 58... Fourth transistor 60... Fifth transistor 62... Sixth transistor 64... Resistor 66... Seventh transistor 68... First transistor 70... 2 transistors 72...first transistor 74...second transistor 75...resistor 76...transistor 78...first transistor 79...second transistor 80...th No. 3 transistor 81...Resistor 82...Circuit 84...Transistor 86...First resistor 87...Second resistor 88...Node 89...Node 90...Reference current Generator circuit 92...first transistor 94...second transistor 96...third transistor 98...fourth transistor 100...resistance 102...resistance

Claims (2)

[Claims] (1) A threshold detection circuit comprising: an input node for receiving an input voltage; a circuit operable to receive a reference current and generate a first current proportional to the reference current; and the input node. a resistive element connected between the current sink and the current receiving and generating circuit, a current sink arranged to sink a portion of the first current, and a predetermined current sink connected to the current sink; a threshold detection circuit comprising: an output node that generates an output voltage in response to the input voltage exceeding the threshold; (2) A method for detecting a threshold, the method comprising supplying an input voltage to an input node having a resistance value, receiving a reference current, and supplying a first current that is a predetermined constant multiple of the reference current. generating and sinking a predetermined portion of said first current, driving a switching circuit with a portion of said first current that exceeds said sinking portion, and applying said voltage to an output node coupled to said switching circuit; A method for detecting a threshold comprising: generating an output voltage responsive to said input voltage exceeding a threshold.