Chip and voltage detection circuit thereof

Abstract

The invention discloses a chip and a voltage detection circuit thereof, and the voltage detection circuit comprises a detection current generation unit which is used for obtaining a detection current according to a voltage difference between a to-be-detected voltage and a first reference voltage; the mirroring unit is used for mirroring the detection current to obtain a pull-up current of an output node; the temperature compensation unit is used for obtaining a temperature compensation current according to a second reference voltage and obtaining a pull-down current of the output node according to the temperature compensation current, the output voltage of the output node depends on a comparison result of the pull-up current and the pull-down current, the first reference voltage has a negative temperature coefficient, and the second reference voltage has a negative temperature coefficient. The second reference voltage has a positive temperature coefficient such that a threshold voltage of the voltage detection circuit has a zero temperature coefficient and may be less than 1.2 V.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a chip and a voltage detection circuit thereof. Background Art

[0002] In modern electronic devices and systems, the stability of the power supply voltage is a key factor in ensuring the normal operation of the circuit and the integrity of the data. With the continuous development of electronic technology, the requirements of various electronic devices on the power supply voltage are becoming increasingly stringent. When the supply voltage is lower than a certain threshold, the circuit may not work properly and may even cause a series of serious problems, including but not limited to data loss, hardware failure, and permanent damage. In addition, low-voltage operation may also cause a significant decrease in system efficiency, increase energy consumption, and may cause safety hazards such as thermal runaway.

[0003] In order to ensure the stability and reliability of the circuit, a voltage detection circuit needs to be set to disable the power supply output when the supply voltage is lower than a certain threshold. The threshold voltage of the existing voltage detection circuit often changes significantly with the change of the manufacturing process angle (process angle) and the fluctuation of the ambient temperature. This instability greatly limits the application of the voltage detection circuit in situations where high-precision voltage monitoring is required.

[0004] Therefore, a new voltage detection circuit is needed to solve the above problems. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide a chip and a voltage detection circuit thereof, so that the threshold voltage of the voltage detection circuit has a zero temperature coefficient.

[0006] According to one aspect of the present invention, there is provided a voltage detection circuit, comprising a detection current generating unit, for obtaining a detection current according to a voltage difference between a voltage to be measured and a first reference voltage; a mirror unit, for mirroring the detection current to obtain a pull-up current of an output node; a temperature compensation unit, for obtaining a temperature compensation current according to a second reference voltage, and obtaining a pull-down current of the output node according to the temperature compensation current, wherein the output voltage of the output node depends on a comparison result of the pull-up current and the pull-down current, wherein the first reference voltage has a negative temperature coefficient, and the second reference voltage has a positive temperature coefficient.

[0007] Optionally, the detection current generating unit includes a first resistor and a first bipolar transistor, which are connected in sequence between the voltage to be measured and the ground voltage, the control end of the first bipolar transistor is connected to the first resistor and the intermediate node of the first bipolar transistor, and the detection current flows through the first resistor, wherein the first reference voltage is the voltage difference between the control end and the second pole of the first bipolar transistor.

[0008] Optionally, the mirror unit includes a first transistor and a second bipolar transistor, which are connected in sequence between the voltage to be measured and the ground voltage, the control end of the first transistor is connected to the intermediate node between the first transistor and the second bipolar transistor, and the control end of the second bipolar transistor is connected to the control end of the first bipolar transistor; a second transistor is connected between the voltage to be measured and the output node, and the control end is connected to the control end of the first transistor.

[0009] Optionally, the temperature compensation unit includes a temperature compensation current generating unit, used to obtain the temperature compensation current according to the second reference voltage; a shunt unit, used to mirror the temperature compensation current and shunt the mirrored temperature compensation current to obtain a first shunt current and a second shunt current; and a pull-down current generating unit, used to obtain the pull-down current according to the first shunt current.

[0010] Optionally, the temperature compensation current generating unit includes a third transistor, a third bipolar transistor and a second resistor, which are connected in sequence between the voltage to be measured and the ground voltage, the control end of the third transistor is connected to the intermediate node of the third transistor and the third bipolar transistor, the control end of the third bipolar transistor is connected to the control end of the first bipolar transistor, and the temperature compensation current flows through the second resistor, wherein the second reference voltage = Vbe2-Vbe3, Vbe2 represents the voltage difference between the control end and the second pole of the first bipolar transistor, and Vbe3 represents the voltage difference between the control end and the second pole of the third bipolar transistor.

[0011] Optionally, the shunt unit includes a fourth transistor and a fourth bipolar transistor, which are connected between the voltage to be measured and the ground voltage in sequence, the control end of the fourth transistor is connected to the control end of the third transistor, the control end of the fourth bipolar transistor is connected to the intermediate node between the fourth transistor and the fourth bipolar transistor, and the first shunt current is the second pole current of the fourth bipolar transistor; a third resistor is connected between the control end of the fourth bipolar transistor and the ground voltage, and the second shunt current flows through the third resistor.

[0012] Optionally, the pull-down current generating unit includes a fifth bipolar transistor connected between the output node and the ground voltage, and a control end of the fifth bipolar transistor is connected to a control end of the fourth bipolar transistor.

[0013] Optionally, the threshold voltage of the voltage detection circuit is adjusted by adjusting the resistance values ​​of the first resistor, the second resistor and the third resistor.

[0014] Optionally, a size of the third bipolar transistor is greater than a size of the first bipolar transistor, and the first to fifth bipolar transistors are bipolar transistors of the same type produced under the same process.

[0015] According to another aspect of the present invention, a chip is provided, comprising a power supply terminal; and the voltage detection circuit as described above, wherein the power supply terminal provides the voltage to be measured.

[0016] The present invention provides a chip and a voltage detection circuit thereof, wherein a detection current generating unit obtains a detection current according to a voltage difference between a voltage to be measured and a first reference voltage having a negative temperature coefficient, a mirror unit mirrors the detection current to obtain a pull-up current of an output node, and a temperature compensation unit obtains a temperature compensation current according to a second reference voltage having a positive temperature coefficient, and obtains a pull-down current of the output node according to the temperature compensation current, wherein the output voltage of the output node depends on a comparison result of the pull-up current and the pull-down current, thereby making the threshold voltage of the voltage detection circuit have a zero temperature coefficient.

[0017] In a preferred embodiment, the first resistor and the second resistor can be adjusted to obtain a zero temperature coefficient threshold voltage of 1.2V, and any zero temperature coefficient threshold voltage less than 1.2V can be obtained by adding and adjusting the third resistor.

[0018] In a preferred embodiment, the first to fifth bipolar transistors are bipolar transistors of the same type produced under the same process, so that the threshold voltage of the voltage detection circuit does not vary with the process angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A circuit diagram of a voltage detection circuit according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0021] Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements or modules are represented by the same or similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0022] It should be understood that in the following description, a "circuit" may include a single or multiple combined hardware circuits, programmable circuits, state machine circuits, and / or elements capable of storing instructions executed by programmable circuits. When an element or circuit is said to be "connected to" another element or an element or circuit is said to be "connected between" two nodes, it may be directly coupled or connected to another element or there may be an intermediate element, and the connection between the elements may be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0023] At the same time, certain words are used in this patent specification and claims to refer to specific components. It should be understood by those skilled in the art that hardware manufacturers may use different nouns to refer to the same component. This patent specification and claims do not use the difference in name as a way to distinguish components, but use the difference in function of the components as the criterion for distinction. In addition, it should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0024] Figure 1 A circuit diagram of a voltage detection circuit according to an embodiment of the present invention is shown.

[0025] The voltage detection circuit 100 includes a detection current generating unit 110 , a mirror unit 120 and a temperature compensation unit 130 .

[0026] The detection current generating unit 110 is connected between the voltage to be measured Vin and the ground voltage VSS, and is used to obtain the detection current I2 according to the voltage difference between the voltage to be measured Vin and the first reference voltage Vbe2. The detection current generating unit 110 includes a resistor R1 and a bipolar transistor Q2 which are sequentially connected between the voltage to be measured Vin and the ground voltage VSS, and the control end of the bipolar transistor Q2 is connected to the middle node of the resistor R1 and the bipolar transistor Q2. The detection current I2 flows through the resistor R1 and the bipolar transistor Q2, and the detection current I2 can be expressed as:

[0027] I2=(Vin-Vbe2) / R1, where Vbe2 represents the voltage difference between the control terminal (base) and the second terminal (emitter) of the bipolar transistor Q2, and R1 represents the resistance value of the resistor R1. Vbe2 is the first reference voltage and has a negative temperature coefficient.

[0028] The mirror unit 120 is used to mirror the detection current I2 to obtain the pull-up current I5 of the output node. The mirror unit 120 includes a transistor Mp1 and a bipolar transistor Q1 which are sequentially connected between the voltage to be measured Vin and the ground voltage VSS. The control end of the transistor Mp1 is connected to the middle node of the transistor Mp1 and the bipolar transistor Q1, and the control end of the bipolar transistor Q1 is connected to the control end of the bipolar transistor Q2. The bipolar transistors Q1 and Q2 have the same size, and the voltage difference between their control end (base) and the second pole (emitter) is equal, that is, Vbe1=Vbe2. Therefore, the emitter currents of the bipolar transistors Q1 and Q2 are equal. When the base currents of the bipolar transistors Q1 and Q2 are ignored, the current I1 flowing through the bipolar transistor Q1 and the transistor Mp1 is equal to the detection current I2. The mirror unit 120 also includes a transistor Mp4 connected between the voltage to be measured Vin and the output node, the control end of the transistor Mp4 is connected to the control end of the transistor Mp1, wherein the transistor Mp4 and the transistor Mp1 have the same size so that the pull-up current I5, i.e., the current flowing through the transistor Mp4, is equal to the current I1 flowing through the transistor Mp1.

[0029] The temperature compensation unit 130 is used to obtain the temperature compensation current I3 according to the second reference voltage ΔVbe, and obtain the pull-down current I6 of the output node according to the temperature compensation current I3, wherein the output voltage Vout of the output node depends on the comparison result of the pull-up current I5 and the pull-down current I6. When the pull-up current I5 is greater than the pull-down current I6, the output voltage Vout of the output node is pulled up to the voltage to be measured Vin, and when the pull-up current I5 is less than the pull-down current I6, the output voltage Vout of the output node is pulled down to the ground voltage VSS.

[0030] The temperature compensation unit 130 includes a temperature compensation current generating unit 131, a shunt unit 132, and a pull-down current generating unit 133. The temperature compensation current generating unit 131 is used to obtain a temperature compensation current I3 according to a second reference voltage ΔVbe; the shunt unit 132 is used to mirror the temperature compensation current I3 and shunt the mirrored temperature compensation current I4 to obtain a shunt current Ie4 and a shunt current I7; the pull-down current generating unit is used to obtain a pull-down current I6 according to the shunt current Ie4.

[0031] The temperature compensation current generating unit 131 includes a transistor Mp2, a bipolar transistor Q3 and a resistor R2 which are sequentially connected between the voltage to be measured Vin and the ground voltage VSS. The control end of the transistor Mp2 is connected to the middle node of the transistor Mp2 and the bipolar transistor Q3. The control end of the bipolar transistor Q3 is connected to the control end of the bipolar transistor Q2. The size of the bipolar transistor Q3 is larger than that of the bipolar transistor Q2. The temperature compensation current I3 can be expressed as:

[0032] I3=ΔVbe / R2, where ΔVbe=Vbe2-Vbe3, R2 represents the resistance of resistor R2, and Vbe3 represents the voltage difference between the control terminal (base) and the second terminal (emitter) of bipolar transistor Q3. ΔVbe is the second reference voltage and has a positive temperature coefficient.

[0033] The shunt unit 132 includes a transistor Mp3 and a bipolar transistor Q4 connected in sequence between the voltage to be measured Vin and the ground voltage VSS, and a resistor R3 connected between the control end of the bipolar transistor Q4 and the ground voltage VSS. The control end of the transistor Mp3 is connected to the control end of the transistor Mp2, and the control end of the bipolar transistor Q4 is connected to the middle node of the transistor Mp3 and the bipolar transistor Q4. Among them, the size of the transistor Mp3 is the same as the size of the transistor Mp2, and the voltages of its control end (gate) and the first end (source) are the same. Therefore, the current I4 flowing through the transistor Mp3 is equal to the temperature compensation current I3 flowing through the transistor Mp2, that is, I3=I4. Among them, the current I4 is shunted into a shunt current Ie4 and a shunt current I7 through the bipolar transistor Q4 and the resistor R3. The shunt current Ie4 represents the second pole (emitter) current of the bipolar transistor Q4, and the shunt current I7 flows through the resistor R3. The shunt current I7 can be expressed as:

[0034] I7=Vbe4 / R3, where R3 represents the resistance value of the resistor R3.

[0035] The shunt current Ie4 can be expressed as:

[0036] Ie4=I4-I7=I4-(Vbe4 / R3).

[0037] By providing the resistor R3 in the shunt unit 132 , the threshold voltage Vin1 of the voltage detection circuit 100 can be less than 1.2V.

[0038] The pull-down current generating unit 133 includes a bipolar transistor Q5 connected between the output node and the ground voltage VSS, and the control terminal of the bipolar transistor Q5 is connected to the control terminal of the bipolar transistor Q4. The bipolar transistor Q5 has the same size as the bipolar transistor Q4, so that the pull-down current I6, i.e., the second pole (emitter) current of the bipolar transistor Q5, is equal to the shunt current Ie4. The intermediate node between the transistor Mp4 and the bipolar transistor Q5 provides the output voltage Vout as the output node of the voltage detection circuit 100.

[0039] When the pull-down current I6 is equal to the pull-up current I5, the output voltage Vout generates a flip point of logic flip. Since I6=I5, I5=I1=I2 and I6=Ie4, that is, Ie4=I2, and since the size of the bipolar transistor Q4 is equal to the size of the bipolar transistor Q2, the voltage difference Vbe4 between the control terminal (base) and the second terminal (emitter) of the bipolar transistor Q4 is Vbe2. At this time, the voltage to be measured Vin is the threshold voltage Vin1 of the voltage detection circuit 100, and the threshold voltage Vin1 can be expressed as:

[0040] Among them, Vbe=Vbe4=Vbe2.

[0041] It can be seen from the above formula that the threshold voltage Vin1 includes a voltage ΔVbe with a positive temperature coefficient and a voltage Vbe with a negative temperature coefficient, and therefore has a zero temperature coefficient. In addition, by adjusting the resistance values ​​of resistors R1, R2 and R3, the voltage value of the threshold voltage Vin1 can be adjusted to any value less than 1.2V.

[0042] Optionally, the bipolar transistors Q1-Q5 are formed by the same process and are all NPN bipolar transistors (bipolar junction transistor, BJT), so the threshold voltage Vin1 does not change with the change of the process angle. The first electrode of the NPN bipolar transistor is the collector, the second electrode is the emitter, and the control terminal is the base.

[0043] Optionally, the transistors Mp1-Mp4 are P-type metal-oxide-semiconductor (PMOS) transistors of the same size. The first end of the PMOS transistor is a source end, the second end is a drain end, and the control end is a gate end.

[0044] Furthermore, the present invention also provides a chip, which includes a power supply end and the voltage detection circuit 100 described above, the power supply end provides a voltage to be measured Vin, the voltage detection circuit 100 is used to detect the voltage to be measured Vin, and judge the size relationship between the voltage to be measured Vin and the threshold voltage based on the output voltage Vout.

[0045] The present invention provides a chip and a voltage detection circuit thereof, wherein a detection current generating unit obtains a detection current according to a voltage difference between a voltage to be measured and a first reference voltage having a negative temperature coefficient, a mirror unit mirrors the detection current to obtain a pull-up current of an output node, and a temperature compensation unit obtains a temperature compensation current according to a second reference voltage having a positive temperature coefficient, and obtains a pull-down current of the output node according to the temperature compensation current, wherein the output voltage of the output node depends on a comparison result of the pull-up current and the pull-down current, thereby making the threshold voltage of the voltage detection circuit have a zero temperature coefficient.

[0046] According to the embodiments of the present invention, as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention and their equivalents.

Claims

1. A voltage detection circuit, comprising: A detection current generating unit, used for obtaining a detection current according to a voltage difference between a voltage to be measured and a first reference voltage; A mirror unit, used for mirroring the detection current to obtain a pull-up current of an output node; a temperature compensation unit, configured to obtain a temperature compensation current according to a second reference voltage, and obtain a pull-down current of the output node according to the temperature compensation current, wherein the output voltage of the output node depends on a comparison result of the pull-up current and the pull-down current, The first reference voltage has a negative temperature coefficient, and the second reference voltage has a positive temperature coefficient.

2. The voltage detection circuit according to claim 1, wherein: The detection current generating unit comprises: A first resistor and a first bipolar transistor are connected in sequence between the voltage to be measured and the ground voltage, a control end of the first bipolar transistor is connected to an intermediate node between the first resistor and the first bipolar transistor, and the detection current flows through the first resistor. The first reference voltage is a voltage difference between a control terminal and a second terminal of the first bipolar transistor.

3. The voltage detection circuit according to claim 2, wherein: The mirror unit comprises: A first transistor and a second bipolar transistor are sequentially connected between the voltage to be measured and the ground voltage, the control end of the first transistor is connected to an intermediate node between the first transistor and the second bipolar transistor, and the control end of the second bipolar transistor is connected to the control end of the first bipolar transistor; The second transistor is connected between the voltage to be measured and the output node, and a control end thereof is connected to the control end of the first transistor.

4. The voltage detection circuit according to claim 3, wherein: The temperature compensation unit comprises: a temperature compensation current generating unit, configured to obtain the temperature compensation current according to the second reference voltage; A shunt unit, used for mirroring the temperature compensation current, and shunting the mirrored temperature compensation current to obtain a first shunt current and a second shunt current; A pull-down current generating unit is used to obtain the pull-down current according to the first shunt current.

5. The voltage detection circuit according to claim 4, wherein: The temperature compensation current generating unit comprises: A third transistor, a third bipolar transistor and a second resistor are connected in sequence between the voltage to be measured and the ground voltage, the control end of the third transistor is connected to the middle node of the third transistor and the third bipolar transistor, the control end of the third bipolar transistor is connected to the control end of the first bipolar transistor, and the temperature compensation current flows through the second resistor. The second reference voltage ΔVbe=Vbe2-Vbe3, Vbe2 represents the voltage difference between the control terminal and the second electrode of the first bipolar transistor, and Vbe3 represents the voltage difference between the control terminal and the second electrode of the third bipolar transistor.

6. The voltage detection circuit according to claim 5, wherein: The diversion unit comprises: A fourth transistor and a fourth bipolar transistor are sequentially connected between the voltage to be measured and the ground voltage, the control end of the fourth transistor is connected to the control end of the third transistor, the control end of the fourth bipolar transistor is connected to the middle node between the fourth transistor and the fourth bipolar transistor, and the first shunt current is the second pole current of the fourth bipolar transistor; The third resistor is connected between the control terminal of the fourth bipolar transistor and the ground voltage, and the second shunt current flows through the third resistor.

7. The voltage detection circuit according to claim 6, wherein: The pull-down current generating unit comprises: A fifth bipolar transistor is connected between the output node and the ground voltage, and a control end of the fifth bipolar transistor is connected to the control end of the fourth bipolar transistor.

8. The voltage detection circuit according to claim 7, wherein: The threshold voltage of the voltage detection circuit is adjusted by adjusting the resistance values ​​of the first resistor, the second resistor and the third resistor.

9. The voltage detection circuit according to claim 7, wherein: The size of the third bipolar transistor is greater than that of the first bipolar transistor, and the first to fifth bipolar transistors are bipolar transistors of the same type under the same process.

10. A chip, comprising: Power supply end; And the voltage detection circuit as described in any one of claims 1 to 9, wherein the power supply end provides the voltage to be measured.

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