CN111969987A - Power-on reset circuit - Google Patents
Power-on reset circuit Download PDFInfo
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- CN111969987A CN111969987A CN202010825186.XA CN202010825186A CN111969987A CN 111969987 A CN111969987 A CN 111969987A CN 202010825186 A CN202010825186 A CN 202010825186A CN 111969987 A CN111969987 A CN 111969987A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/22—Modifications for ensuring a predetermined initial state when the supply voltage has been applied
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/22—Modifications for ensuring a predetermined initial state when the supply voltage has been applied
- H03K2017/226—Modifications for ensuring a predetermined initial state when the supply voltage has been applied in bipolar transistor switches
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Abstract
The invention provides a power-on reset circuit, which comprises a band-gap reference branch circuit and a comparator, wherein the band-gap reference branch circuit comprises a first triode and a second triode which are interconnected by two bases, a first resistor and a second resistor, the output ends of the first triode and the second triode are grounded, the input end of the first triode is connected with a power supply voltage through the first resistor, and the input end of the second triode is connected with the power supply voltage through the second resistor; the positive input end of the comparator is connected to one end, far away from the power supply voltage, of the second resistor, and the negative input end of the comparator is connected to one end, far away from the power supply voltage, of the first resistor; the output end of the comparator outputs a reset signal.
Description
Technical Field
The invention relates to the field of integrated circuits, in particular to a power-on reset circuit.
Background
In the field of integrated circuits, many chips include a power-on reset circuit, which is used to generate a reset signal when a system is powered on and off, and is used for digital reset, various IP circuit start-up, and the like, so that analog and digital circuits are initialized to a known state. With the continuous progress of the process, the size of the chip is continuously reduced, the power supply voltage of the chip is continuously reduced, so that the threshold voltage of the power-on reset circuit is also continuously reduced, and the threshold voltage of the power-on reset circuit is closer to the lowest working voltage of various IP circuits such as EEPROM, Flash and the like, so that the requirement on the accuracy of the threshold voltage of the power-on reset circuit is also continuously improved. In addition, in order to reduce the cost of the chip, a standard CMOS process is often selected, and an additional device is rarely added.
In the prior art, a traditional power-on reset circuit generally adopts a circuit structure of delaying and adding an inverter, in the power-on process of a chip power supply voltage, after a certain delay, the voltage of an input end of the inverter also rises along with the power supply voltage, and when the voltage exceeds the overturning threshold voltage of the inverter, the inverter overturns and drives the subsequent inverter to overturn continuously, and finally a power-on reset signal is output. However, in this scheme, the threshold voltage of the power-on reset is determined by the flip threshold, and the flip of the inverter varies with the process, and the operating temperature varies greatly, so that the fluctuation range of the threshold voltage of the power-on reset is large, and the requirement of low power supply voltage application cannot be met.
Therefore, it is necessary to design a power-on reset circuit in which the influence of temperature on the threshold voltage is small.
Disclosure of Invention
In order to solve one of the above problems, the present invention provides a power-on reset circuit, which includes a bandgap reference branch and a comparator, where the bandgap reference branch includes a first triode and a second triode with interconnected bases, a first resistor and a second resistor, the output ends of the first triode and the second triode are both grounded, the input end of the first triode is connected to a power supply voltage through the first resistor, and the input end of the second triode is connected to the power supply voltage through the second resistor;
the positive input end of the comparator is connected to one end, far away from the power supply voltage, of the second resistor, and the negative input end of the comparator is connected to one end, far away from the power supply voltage, of the first resistor; the output end of the comparator outputs a reset signal.
As a further improvement of the present invention, the first resistor and the second resistor have the same resistance; the area of the second triode is N times of that of the first triode.
As a further improvement of the present invention, the power-on reset circuit further includes a voltage dividing branch connected between the power voltage and ground, the voltage dividing branch includes a third resistor and a fourth resistor connected in series, one end of the third resistor is connected to the power voltage, and a base of the first triode is connected to the other end of the third resistor.
As a further improvement of the present invention, the first triode and the second triode are PNP transistors, and the bandgap reference branch further includes a fifth resistor, and the second resistor and the fifth resistor are connected in series and are connected to an emitter of the second triode.
As a further improvement of the invention, when the positive input end and the negative input end of the comparator are equal in voltage, the current I flowing through the first triodeQ1And the current I of the second triodeQ2And is also equal to the above-mentioned general formula,
IQ1＝IQ2＝VBE2-VBE1/R5；
at this time, the voltage V across the third resistorR3Comprises the following steps:
VR3＝(VBE2-VBE1)*R1/R5+VBE1；
wherein, VBE2Is the voltage between the base and emitter of the second triode, VBE1Is the voltage between the base and emitter of the first triode.
As a further improvement of the present invention, the power supply voltage after adjusting the magnitude of the power supply voltage and making the voltages of the positive input end and the negative input end of the comparator equal is the threshold voltage of the power-on reset circuit.
As a further improvement of the invention, the voltage at two ends of the third resistor is equal to the band-gap reference voltage of the band-gap reference branch circuit after the resistance relation of the first resistor and the fifth resistor is adjusted.
As a further improvement of the present invention, the first triode and the second triode are NPN transistors, the first resistor is directly connected in series between the power supply voltage and the collector of the first triode, and the second resistor is directly connected in series between the power supply voltage and the collector of the second triode;
the band-gap reference resistor further comprises a first resistor branch and a second resistor branch, an emitting electrode of the first triode is grounded through the first resistor branch, an emitting electrode of the second triode is grounded through the second resistor branch, and the resistance value of the second resistor branch is larger than that of the first resistor branch.
As a further improvement of the present invention, the second resistive branch includes a fifth resistor and a sixth resistor connected in series with each other, and the first resistive branch includes a fifth resistor.
As a further improvement of the invention, when the positive input end and the negative input end of the comparator are equal in voltage, the current I flowing through the first triode and the second triodeQ1And IQ2And is also equal to the above-mentioned general formula,
IQ1＝IQ2＝VBE1-VBE2/R6；
at this time, the voltage Vb at the base of the first triode is:
Vb＝(VBE1-VBE2)*R5/R6+VBE1；
wherein, VBE2Is the voltage between the base and emitter of the second triode, VBE1Is the voltage between the base and emitter of the first triode.
As a further improvement of the present invention, the power supply voltage after adjusting the magnitude of the power supply voltage and making the voltages of the positive input end and the negative input end of the comparator equal is the threshold voltage of the power-on reset circuit.
As a further improvement of the invention, the voltage at two ends of the third resistor is equal to the band-gap reference voltage of the band-gap reference branch circuit after the resistance relation of the fifth resistor and the sixth resistor is adjusted.
As a further improvement of the present invention, the power-on reset circuit further includes a hysteresis branch, where the hysteresis branch includes a hysteresis resistor and a transistor, the hysteresis resistor is connected in series in the voltage dividing branch, and one end of the hysteresis resistor is connected to the fourth resistor, and the other end is grounded; the input end and the output end of the transistor are connected in parallel to two sides of the hysteresis resistor, and the grid of the transistor is connected to the output end of the comparator.
Compared with the prior art, in the invention, as the power supply voltage rises, the voltage of the output end of the comparator can be switched between a high level and a low level, so that the power supply voltage when the voltages of the positive input end and the negative input end of the comparator are equal is the threshold voltage, and therefore, the threshold voltage is related to the band-gap reference voltage of the band-gap reference branch. According to the prior art, the size of the band-gap reference voltage of the band-gap reference branch is irrelevant to the temperature, the band-gap reference voltage is relevant to the forbidden band width of the process, the influence of the fluctuation of the process and the working temperature change of a chip on the band-gap reference voltage is small, and therefore the influence on the threshold voltage is small.
Drawings
FIG. 1 is a circuit diagram of a first embodiment of a power-on-reset circuit of the present invention;
fig. 2 is a circuit diagram of a second embodiment of the power-on reset circuit of the present invention.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1 to 2, the present invention provides a power-on reset circuit, which includes a bandgap reference branch and a comparator COMP, where the bandgap reference branch includes a first triode Q1 and a second triode Q2 with interconnected bases, a first resistor R1 and a second resistor R2, output ends of the first triode Q1 and the second triode Q2 are both grounded, an input end of the first triode Q1 is connected to a power supply voltage VCC through the first resistor R1, and an input end of the second triode Q2 is connected to the power supply voltage VCC through the second resistor R2;
a positive input end vip of the comparator COMP is connected to one end, far away from the power supply voltage VCC, of the second resistor R2, and a negative input end vin is connected to one end, far away from the power supply voltage VCC, of the first resistor R1; an output terminal PORB of the comparator COMP outputs a reset signal.
In the invention, as the power supply voltage VCC rises, the voltage of the output terminal PORB of the comparator COMP is switched between a high level and a low level, so that the power supply voltage VCC when the voltages of the positive and negative input terminals of the comparator COMP are equal is the threshold voltage VTH, and therefore, the threshold voltage VTH is related to the bandgap reference voltage of the bandgap reference branch. According to the prior art, the size of the band-gap reference voltage of the band-gap reference branch circuit is irrelevant to the temperature, the band-gap reference voltage is relevant to the forbidden band width of the process, the influence of the fluctuation of the process and the working temperature change of a chip on the band-gap reference voltage is small, and therefore the influence on the threshold voltage VTH is small.
Further, the resistance values of the first resistor R1 and the second resistor R2 are the same; the area of the second transistor Q2 is N times that of the first transistor Q1.
Therefore, in the present invention, as the power supply voltage VCC rises, the base voltage between the power supply voltage VCC and the base of the first transistor Q1 or the second transistor Q2 also rises, and when the base voltage is small, the current flowing through the first transistor Q1 or the second transistor Q2 is small, and thus the voltage VBE between the base and the emitter of the first transistor Q1 or the second transistor Q2 occupies a major portion of the base voltage. Since the area of the second transistor Q2 is N times that of the first transistor Q1, the current flowing through the second transistor Q2 is also N times that of the first transistor Q1. Since the resistances of the first resistor R1 and the second resistor R2 are the same, the voltage drop across the second resistor R2 is also larger than the voltage drop across the first resistor R1, so that the voltage at the positive input end vip of the comparator COMP is smaller than the voltage at the negative input end vin, and the comparator COMP outputs a high level.
In fact, the power-on reset circuit further includes a voltage dividing branch connected between the power voltage VCC and the ground, the voltage dividing branch includes a third resistor R3 and a fourth resistor R4 connected in series, one end of the third resistor R3 is connected to the power voltage VCC, and the base of the first triode Q1 is connected to the other end of the third resistor R3.
Thus, since the bases of the first transistor Q1 and the second transistor Q2 are interconnected, the bases of the first transistor Q1 and the second transistor Q2 are both substantially connected to the other end of the third resistor R3. The voltage dividing branch circuit can directly and effectively divide the power supply voltage VCC, so that the basic voltage between the power supply voltage VCC and the base of the first triode Q1 or the base of the second triode Q2 is the divided voltage of the third resistor R3.
Furthermore, the triode comprises an NPN tube or a PNP tube, so that the invention has two specific embodiments.
In the first embodiment, as shown in fig. 1, the first transistor Q1 and the second transistor Q2 are PNP transistors, and the bandgap reference branch further includes a fifth resistor R5, and the second resistor R2 and the fifth resistor R5 are connected in series and to the emitter of the second transistor Q2. The collectors of the first transistor Q1 and the second transistor Q2 are both directly grounded.
Therefore, as the power supply voltage VCC further rises, when the divided voltage of the third resistor R3 is larger, that is, the base voltage between the power supply voltage VCC and the base of the first transistor Q1 or the second transistor Q2 is also larger, the current flowing through the first transistor Q1 or the second transistor Q2 is also larger; due to the negative feedback effect of the first resistor R1, the second resistor R2 and the fifth resistor R5 on the current of the triode, the voltage division of the resistor with the emitter electrodes of the triode connected in series accounts for the main part of the basic voltage; since the emitter of the first transistor Q1 is only connected in series with the first resistor R1, the emitter of the second transistor Q2 is connected in series with the second resistor R2 and the fifth resistor R5, and the resistances of the first resistor R1 and the second resistor R2 are the same, the resistance of the emitter of the first transistor Q1 connected in series is smaller than the resistance of the emitter of the second transistor Q2 connected in series, so that the current flowing through the first transistor Q1 is larger than the current flowing through the second transistor Q2, the voltage drop across the first resistor R1 is also larger than the voltage drop across the second resistor R2, the voltage at the positive input terminal vip of the comparator COMP is larger than the voltage at the negative input terminal vin, and the comparator COMP outputs a low level.
When the voltages of the positive input terminal vip and the negative input terminal vin of the comparator COMP are equal, the current I flowing through the first transistor Q1Q1And a current I flowing through a second transistor Q2Q2Are also equal;
IQ1＝IQ2＝VBE2-VBE1/R5；
at this time, the voltage V across the third resistor R3R3Comprises the following steps:
VR3＝(VBE2-VBE1)*R1/R5+VBE1；
VBE2 is the voltage between the base and the emitter of the second transistor Q2, and VBE1 is the voltage between the base and the emitter of the first transistor Q1.
Therefore, according to the above formula, the power supply voltage VCC, which is obtained by adjusting the magnitude of the power supply voltage VCC and making the positive input end vip and the negative input end vin of the comparator COMP equal, is the threshold voltage VTH of the power-on reset circuit.
Furthermore, the voltage V at the two ends of the third resistor R3 after the resistance relation between the first resistor R1 and the fifth resistor R5 is adjusted is further adjustedR3The temperature drift of the threshold voltage VTH of the power-on reset circuit is smaller and the precision is higher when the band-gap reference voltage of the band-gap reference branch circuit is equal. Therefore, the proportional relationship between the resistances of the first resistor R1 and the fifth resistor R5 in the above formula can be adjusted, so that the voltage V across the third resistor R3 can be obtainedR3Equal to the bandgap reference voltage, which is about 1.2V. Therefore, the threshold voltage VTH of the power-on reset circuit realized in the invention is related to the resistance voltage division ratio, and the standard CMOS process can realize high-precision resistance matching, thereby further improving the precision of the threshold voltage VTH of the power-on reset circuit in the invention.
Alternatively, as shown in fig. 2, in the second embodiment of the present invention, the first transistor Q1 and the second transistor Q2 are NPN transistors, the first resistor R1 is directly connected in series between the power supply voltage VCC and the collector of the first transistor Q1, and the second resistor R2 is directly connected in series between the power supply voltage VCC and the collector of the second transistor Q2; the band gap reference resistor further comprises a first resistor branch and a second resistor branch, an emitting electrode of the first triode Q1 is grounded through the first resistor branch, an emitting electrode of the second triode Q2 is grounded through the second resistor branch, and the resistance value of the second resistor branch is larger than that of the first resistor branch.
Therefore, as the power supply voltage VCC further rises, when the base voltage Vb of the first transistor Q1 or the second transistor Q2 is also larger, the current flowing through the first transistor Q1 or the second transistor Q2 is also larger; due to the negative feedback effect of the resistors on the first resistor branch and the second resistor branch on the current of the triode, the voltage division of the resistor connected in series at the emitter of the triode accounts for the main part of the basic voltage; because the resistance value of the resistor on the second resistor branch of the emitter of the second triode Q2 connected in series is greater than that of the first resistor branch, the current flowing through the second triode Q2 is less than the current flowing through the first triode Q1, the voltage drop across the second resistor R2 is less than that across the first resistor R1, the voltage at the positive input end vip of the comparator COMP is greater than the voltage at the negative input end vin, and the comparator COMP outputs a low level.
Specifically, the second resistance branch comprises a fifth resistor R5 and a sixth resistor R6 which are connected in series with each other, and the first resistance branch comprises a fifth resistor R5. Therefore, the emitter of the second transistor Q2 is grounded through a fifth resistor R5 and a sixth resistor R6, one end of the fifth resistor R5 is grounded, and the emitter of the first transistor Q1 is connected between the fifth resistor R5 and the sixth resistor R6.
Thus, when the voltages of the positive input terminal vip and the negative input terminal vin of the comparator COMP are equal, the current I flowing through the first transistor Q1Q1And a current I flowing through a second transistor Q2Q2Are also equal;
IQ1＝IQ2＝VBE1-VBE2/R6；
at this time, the voltage Vb at the base of the first triode Q1 is:
Vb＝(VBE1-VBE2)*R5/R6+VBE1；
wherein, VBE2Is the voltage between the base and emitter of the second transistor Q2, VBE1Is the voltage between the base and emitter of the first transistor Q1.
Therefore, according to the above formula, the power supply voltage VCC, which is obtained by adjusting the magnitude of the power supply voltage VCC and making the positive input end vip and the negative input end vin of the comparator COMP equal, is the threshold circuit of the power-on reset circuit.
Similarly, the voltage V across the third resistor R3 after adjusting the resistance relationship between the fifth resistor R5 and the sixth resistor R6 is adjustedR3The temperature drift of the threshold voltage VTH of the power-on reset circuit is smaller and the precision is higher when the band-gap reference voltage of the band-gap reference branch circuit is equal. Therefore, the proportional relationship between the resistances of the fifth resistor R5 and the sixth resistor R6 in the above formula can be adjusted, so that the voltage V across the third resistor R3 can be obtainedR3Equal to the bandgap reference voltage, which is about 1.2V. Therefore, the threshold voltage VTH of the power-on reset circuit realized in the invention is related to the resistance voltage division ratio, and the standard CMOS process can realize high-precision resistance matching, thereby further improving the precision of the threshold voltage VTH of the power-on reset circuit in the invention.
In addition, the power-on reset circuit further comprises a hysteresis branch, the hysteresis branch comprises a hysteresis resistor Rd and a transistor M1, the hysteresis resistor Rd is connected in series in the voltage division branch, one end of the hysteresis resistor Rd is connected with the fourth resistor R4, and the other end of the hysteresis resistor Rd is grounded; the input end and the output end of the transistor M1 are connected in parallel to two sides of the hysteresis resistor Rd, and the gate of the transistor M1 is connected to the output end PORB of the comparator COMP.
In this embodiment, the transistor M1 is an NMOS transistor, and thus its source is grounded and its drain is connected between the hysteresis resistor Rd and the fourth resistor R4. Therefore, a certain hysteresis exists between the upper threshold voltage VTH and the lower threshold voltage VTH of the power-on reset circuit, and the power-on reset circuit can be effectively prevented from being overturned for many times due to the noise of the power supply voltage VCC in the power-on and power-off processes.
In summary, in the present invention, as the power supply voltage VCC rises, the output terminal PORB of the comparator COMP switches between a high level and a low level, so that the power supply voltage VCC when the voltages of the positive and negative input terminals of the comparator COMP are equal is the threshold voltage VTH, and thus the threshold voltage VTH is related to the bandgap reference voltage of the bandgap reference branch. According to the prior art, the size of the band-gap reference voltage of the band-gap reference branch circuit is irrelevant to the temperature, the band-gap reference voltage is relevant to the forbidden band width of the process, the influence of the fluctuation of the process and the working temperature change of a chip on the band-gap reference voltage is small, and therefore the influence on the threshold voltage VTH is small.
Furthermore, the threshold voltage VTH of the power-on reset circuit is related to the bandgap reference voltage and the resistor voltage division ratio, the bandgap reference voltage is related to the forbidden bandwidth of the process, and the influence of the process fluctuation on the reference voltage is small; in addition, the resistor matching with high precision can be realized in the standard CMOS process, so that the threshold voltage VTH of the power-on reset circuit realized by the invention has high precision.
In addition, the invention also adopts a hysteresis branch, the source of the transistor M1 in the hysteresis branch is grounded, and the drain is connected between the hysteresis resistor Rd and the fourth resistor R4. Therefore, a certain hysteresis exists between the upper threshold voltage and the lower threshold voltage of the power-on reset circuit, and the power-on reset circuit can be effectively prevented from being overturned for many times due to the noise of the power supply voltage VCC in the power-on and power-off processes.
Finally, compared with the prior art, the device used by the power-on reset circuit only adds the triode, and the triode can be realized by a parasitic triode in a standard CMOS process no matter what the type of the triode is, so that the manufacturing cost of a chip cannot be increased, and the development of chip miniaturization is promoted.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the embodiments may be appropriately combined to form other embodiments understood by those skilled in the art.
The above-listed detailed description is only a specific description of a possible embodiment of the present invention and is not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention are included in the scope of the present invention.
Claims (13)
1. A power-on reset circuit is characterized by comprising a band-gap reference branch circuit and a comparator, wherein the band-gap reference branch circuit comprises a first triode and a second triode with interconnected bases, a first resistor and a second resistor, the output ends of the first triode and the second triode are grounded, the input end of the first triode is connected with a power supply voltage through the first resistor, and the input end of the second triode is connected with the power supply voltage through the second resistor;
the positive input end of the comparator is connected to one end, far away from the power supply voltage, of the second resistor, and the negative input end of the comparator is connected to one end, far away from the power supply voltage, of the first resistor; the output end of the comparator outputs a reset signal.
2. The power-on reset circuit according to claim 1, wherein the first resistor and the second resistor have the same resistance; the area of the second triode is N times of that of the first triode.
3. The power-on reset circuit according to claim 2, further comprising a voltage dividing branch connected between the power voltage and ground, wherein the voltage dividing branch comprises a third resistor and a fourth resistor connected in series, one end of the third resistor is connected to the power voltage, and the base of the first transistor is connected to the other end of the third resistor.
4. The power-on reset circuit according to claim 3, wherein the first transistor and the second transistor are PNP transistors, and the bandgap reference branch further comprises a fifth resistor, and the second resistor and the fifth resistor are connected in series and to an emitter of the second transistor.
5. The power-on reset circuit of claim 4, wherein the current I flowing through the first transistor is equal to the voltage of the positive input terminal and the negative input terminal of the comparatorQ1And the current I of the second triodeQ2And is also equal to the above-mentioned general formula,
IQ1＝IQ2＝VBE2-VBE1/R5；
at this time, the voltage V across the third resistorR3Comprises the following steps:
VR3＝(VBE2-VBE1)*R1/R5+VBE1；
wherein, VBE2Is the voltage between the base and emitter of the second triode, VBE1Is the voltage between the base and emitter of the first triode.
6. The power-on reset circuit according to claim 5, wherein the power supply voltage obtained by adjusting the magnitude of the power supply voltage and making the voltages of the positive input terminal and the negative input terminal of the comparator equal is the threshold voltage of the power-on reset circuit.
7. The power-on reset circuit according to claim 6, wherein the voltage across the third resistor after adjusting the resistance relationship between the first resistor and the fifth resistor is equal to the bandgap reference voltage of the bandgap reference branch.
8. A power-on reset circuit according to claim 3, wherein the first transistor and the second transistor are NPN transistors, the first resistor is directly connected in series between the supply voltage and the collector of the first transistor, and the second resistor is directly connected in series between the supply voltage and the collector of the second transistor;
the band-gap reference resistor further comprises a first resistor branch and a second resistor branch, an emitting electrode of the first triode is grounded through the first resistor branch, an emitting electrode of the second triode is grounded through the second resistor branch, and the resistance value of the second resistor branch is larger than that of the first resistor branch.
9. The power-on-reset circuit of claim 8, wherein the second resistive branch comprises a fifth resistor and a sixth resistor connected in series with each other, and wherein the first resistive branch comprises the fifth resistor.
10. The power-on-reset circuit of claim 9, wherein the current I flowing through the first transistor and the second transistor is when the positive input terminal and the negative input terminal of the comparator are equal in voltageQ1And IQ2And is also equal to the above-mentioned general formula,
IQ1＝IQ2＝VBE1-VBE2/R6；
at this time, the voltage Vb at the base of the first triode is:
Vb＝(VBE1-VBE2)*R5/R6+VBE1；
wherein, VBE2Is the voltage between the base and emitter of the second triode, VBE1Is the voltage between the base and emitter of the first triode.
11. The power-on reset circuit according to claim 10, wherein the power supply voltage obtained by adjusting the magnitude of the power supply voltage and making the voltages of the positive input terminal and the negative input terminal of the comparator equal is the threshold voltage of the power-on reset circuit.
12. The power-on reset circuit according to claim 11, wherein the voltage across the third resistor obtained by adjusting the resistance relationship between the fifth resistor and the sixth resistor is equal to the bandgap reference voltage of the bandgap reference branch.
13. The power-on reset circuit according to claim 3, further comprising a hysteresis branch, wherein the hysteresis branch comprises a hysteresis resistor and a transistor, the hysteresis resistor is connected in series in the voltage dividing branch, and one end of the hysteresis resistor is connected to the fourth resistor, and the other end is grounded; the input end and the output end of the transistor are connected in parallel to two sides of the hysteresis resistor, and the grid of the transistor is connected to the output end of the comparator.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101958640A (en) * | 2010-10-15 | 2011-01-26 | 苏州大学 | Undervoltage latch circuit with band gap reference structure |
| CN202133922U (en) * | 2010-12-29 | 2012-02-01 | 无锡华润矽科微电子有限公司 | Reference voltage circuit |
| CN102594312A (en) * | 2012-03-04 | 2012-07-18 | 北京工业大学 | Novel power-on reset circuit |
| CN202550986U (en) * | 2012-03-04 | 2012-11-21 | 北京工业大学 | Novel power-on reset circuit |
| CN102907002A (en) * | 2010-03-26 | 2013-01-30 | 桑迪士克科技股份有限公司 | Apparatus and method for host power-on reset control |
| CN105824349A (en) * | 2016-05-26 | 2016-08-03 | 上海巨微集成电路有限公司 | Self-calibration band-gap reference circuit and band-gap reference voltage self-calibration system and method |
| CN107809223A (en) * | 2016-09-08 | 2018-03-16 | 恩智浦美国有限公司 | Low-temperature coefficient clock-signal generator |
| US10404054B2 (en) * | 2017-02-09 | 2019-09-03 | Nuvoton Technology Corporation | Under voltage lockout circuit and device integrating with the same and reference voltage generating circuit |
| CN211183396U (en) * | 2019-11-29 | 2020-08-04 | 北京时代民芯科技有限公司 | Undervoltage protection circuit |
-
2020
- 2020-08-17 CN CN202010825186.XA patent/CN111969987A/en not_active Withdrawn
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102907002A (en) * | 2010-03-26 | 2013-01-30 | 桑迪士克科技股份有限公司 | Apparatus and method for host power-on reset control |
| CN101958640A (en) * | 2010-10-15 | 2011-01-26 | 苏州大学 | Undervoltage latch circuit with band gap reference structure |
| CN202133922U (en) * | 2010-12-29 | 2012-02-01 | 无锡华润矽科微电子有限公司 | Reference voltage circuit |
| CN102594312A (en) * | 2012-03-04 | 2012-07-18 | 北京工业大学 | Novel power-on reset circuit |
| CN202550986U (en) * | 2012-03-04 | 2012-11-21 | 北京工业大学 | Novel power-on reset circuit |
| CN105824349A (en) * | 2016-05-26 | 2016-08-03 | 上海巨微集成电路有限公司 | Self-calibration band-gap reference circuit and band-gap reference voltage self-calibration system and method |
| CN107809223A (en) * | 2016-09-08 | 2018-03-16 | 恩智浦美国有限公司 | Low-temperature coefficient clock-signal generator |
| US10404054B2 (en) * | 2017-02-09 | 2019-09-03 | Nuvoton Technology Corporation | Under voltage lockout circuit and device integrating with the same and reference voltage generating circuit |
| CN211183396U (en) * | 2019-11-29 | 2020-08-04 | 北京时代民芯科技有限公司 | Undervoltage protection circuit |
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