A hysteretic comparator circuit and method supporting divide-by-logic

Abstract

A kind of hysteresis comparison circuit supporting voltage division logic, it is characterized in that: the circuit includes power supply voltage division unit and hysteresis comparison unit;Wherein, the power supply voltage division unit, with chip power supply voltage, the hysteresis comparison unit is connected respectively, for generating stable voltage division based on chip power supply voltage, and input into the hysteresis comparison unit;The hysteresis comparison unit, with the power supply voltage division unit is connected, for realizing hysteresis comparison function based on the stable voltage division of the power supply voltage division unit received, and output trigger signal.The present application scheme, can still guarantee the double threshold comparison logic of schmitt trigger when power supply voltage is in a wide range of floating, expand the application range of schmitt trigger, simple and easy to realize, circuit structure is simple, power consumption is small, chip area is less.

Description

Technical Field

[0001] This invention relates to integrated circuits, and more specifically, to a hysteresis comparator circuit and method supporting voltage divider logic. Background Technology

[0002] In existing technologies, Schmitt triggers, based on their dual-threshold hysteresis comparison characteristics, can shape analog signal waveforms into square wave waveforms that can be processed by digital circuits, and are therefore widely used in waveform shaping circuits. Their hysteresis characteristics can also be used for anti-interference and the implementation of multivibrators. Therefore, Schmitt triggers are currently widely used in various integrated circuits.

[0003] However, the output logic of existing Schmitt triggers is affected by the chip's power supply voltage, thus imposing strict requirements on the fluctuation range of the chip's power supply voltage. When the chip's power supply voltage is high, its fluctuation range is correspondingly large, causing the Schmitt trigger to fail to properly determine the dual threshold.

[0004] Therefore, there is an urgent need for a hysteresis comparison method that can support voltage divider logic and simultaneously implement Schmitt trigger judgment logic in chips with high voltage. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hysteresis comparator circuit that supports voltage divider logic. By connecting a power supply voltage divider unit with a hysteresis comparator unit, a hysteresis comparator trigger signal can be generated based on a stable voltage divider.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention relates to a hysteresis comparator circuit supporting voltage divider logic, wherein the circuit includes a power supply voltage divider unit and a hysteresis comparator unit; wherein the power supply voltage divider unit is connected to the chip power supply voltage and the hysteresis comparator unit respectively, and is used to generate a stable voltage divider based on the chip power supply voltage and input it to the hysteresis comparator unit; the hysteresis comparator unit is connected to the power supply voltage divider unit, and is used to implement the hysteresis comparator function based on the stable voltage divider received from the power supply voltage divider unit, and output a trigger signal.

[0008] Preferably, the output terminal of the power supply voltage divider unit is connected to the high voltage terminal of the hysteresis comparator unit to provide a stable power supply voltage for the hysteresis comparator unit.

[0009] Preferably, the power supply voltage divider unit is a secondary voltage regulator used to generate the secondary power supply voltage.

[0010] Preferably, the chip power supply voltage varies between 1.3V and 12V, and the secondary power supply voltage is stable at 1.2V.

[0011] Preferably, the hysteresis comparator is a Schmitt trigger.

[0012] Preferably, the lowest high-level threshold voltage of the Schmitt trigger is 0.78V, and the highest low-level threshold voltage is 0.42V.

[0013] Preferably, the power supply voltage divider unit includes an error amplifier EA, a PMOS transistor Mp, a current source, and a capacitor; wherein, the negative input terminal of the error amplifier is connected to the reference voltage Vref, the positive input terminal is connected to one end of the current source, the high voltage terminal is connected to the chip power supply voltage, and the output terminal is connected to the gate of the PMOS transistor Mp; the source of the PMOS transistor Mp is connected to the chip power supply voltage, and the drain is connected to the current source, the positive input terminal of the amplifier, and one end of the capacitor, respectively, to generate a voltage divider voltage Vreg for the high voltage terminal of the Schmitt trigger; the other end of the current source and the other end of the capacitor are both grounded.

[0014] A second aspect of the present invention relates to a hysteresis comparison method supporting voltage divider logic, wherein the method employs a hysteresis comparison circuit supporting voltage divider logic as described in the first aspect of the present invention.

[0015] The beneficial effects of this invention are that, compared with the prior art, the hysteresis comparator circuit supporting voltage divider logic in this invention can still implement the dual threshold comparator logic of Schmitt trigger in chips with high voltage and large voltage fluctuation range, thereby expanding the application range of Schmitt trigger, reducing the requirements of power supply voltage fluctuation range during application of Schmitt trigger, and without modifying the internal structure of Schmitt trigger, the implementation method is simple, the entire circuit structure is simple, the power consumption is low, and the chip area occupied is small.

[0016] The beneficial effects of the present invention also include:

[0017] 1. In the power supply voltage divider unit, the error amplifier can turn on the PMOS transistor Mp based on the reference voltage Vref generated by the power supply voltage divider unit and stably generate the divided voltage Vreg. This circuit has a simple structure, low power consumption, and the output divided voltage is automatically adjusted based on the feedback of the error amplifier, so the output is very stable.

[0018] 2. In one embodiment of the present invention, it can be ensured that the Schmitt trigger can achieve the accuracy of output logic at lower voltages, such as 1.2V, regardless of any variation in the power supply voltage between 1.8V and 5.5V, effectively expanding the application range of the Schmitt trigger. Furthermore, the circuit of the present invention is applicable to a wider range of power supply voltages. For example, the power supply voltage divider unit of the present invention can receive power supply voltages from 1.3V to 40V and output a reference voltage stable at approximately 1.2V. Therefore, when the power supply voltage varies between 1.3V and 40V, the normal operation of the Schmitt trigger with 1.2V output logic can be ensured. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the connection relationship of a hysteresis comparator circuit in the prior art of this invention;

[0020] Figure 2 This is a schematic diagram of the circuit structure of a hysteresis comparator circuit in the prior art of this invention;

[0021] Figure 3 This is a logic block diagram of a hysteresis comparator circuit supporting voltage divider logic according to the present invention.

[0022] Figure 4 This is a circuit connection diagram of a hysteresis comparator circuit supporting voltage divider logic according to the present invention.

[0023] Figure 5 This is a schematic diagram of the circuit connection of the power supply voltage divider unit in a hysteresis comparator circuit that supports voltage divider logic according to the present invention. Detailed Implementation

[0024] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present application.

[0025] Figure 1 This is a schematic diagram of the connection relationship of a hysteresis comparator circuit in the prior art of this invention. Figure 2 This is a schematic diagram of the circuit structure of a hysteresis comparator circuit in the prior art of this invention. For example... Figure 1 and Figure 2 As shown, the hysteresis comparator circuit in this invention can employ a Schmitt trigger, commonly used in the prior art. Specifically, as shown in the figure, the input voltage of the Schmitt trigger is Vin, and the output voltage is Vout. Its MOSFETs are interconnected, and the high-voltage terminal is typically directly connected to the power supply voltage Vdd, while the low-voltage terminal is grounded (GND). When the chip's power supply voltage is high, the parameters of each MOSFET in the Schmitt trigger can be adjusted accordingly, thereby enabling it to achieve a minimum high-level threshold voltage Vout. IHand the highest threshold voltage V at low level IL It can be proportional to the power supply voltage.

[0026] However, when the power supply voltage is unstable, its fluctuation range can be significantly affected by the conditions of the connected load. For example, when the power supply voltage is around 5.5V, the actual supply voltage can fluctuate between 1.8V and 5.5V depending on changes in the load conditions or other factors. Following the design logic of a Schmitt trigger, such as designing the chip's minimum high-level threshold voltage V... IH The voltage is 65% of the supply voltage, and the highest low-level threshold voltage V. IL This is 35% of the power supply voltage. It should be noted that when the actual supply voltage is 1.8V, there is V... IH =1.17V, V IL = 0.63V. When the actual supply voltage of the power supply is 5.5V, V IH =3.575V, has V IL =1.925V.

[0027] This situation can be considered: when the power supply voltage is 5.5V, in order to ensure that the output meets the 1.2V logic, V... IH <1.2V * 65% = 0.78V ≈ 5.5V * 14%, that is, V at this time IH It should be less than 14% of the supply voltage. Therefore, a suitable MOSFET should be selected for the Schmitt trigger with a high-level parameter of 14%. When the supply voltage is 1.8V, in order to ensure a 1.2V logic, V should be... IL >1.2V * 35% = 0.42V ≈ 1.8V * 23%. In this case, a suitable MOSFET should be selected from the Schmitt trigger with 23% as the low-level parameter. This creates a contradiction between the high and low level parameters, demonstrating that when the power supply voltage fluctuates between 1.8V and 5.5V, even modifying a conventional Schmitt trigger will not achieve the correct output logic.

[0028] In order to continue using the hysteresis comparator circuit with voltage divider logic in chips with high power supply voltages, a power supply voltage divider unit method can be considered to achieve a stable voltage at the high voltage end of the Schmitt trigger.

[0029] Figure 3 This is a logic block diagram of a hysteresis comparator circuit that supports voltage divider logic according to the present invention. Figure 4 This is a circuit connection diagram of a hysteresis comparator circuit supporting voltage divider logic according to the present invention. Figure 3 , Figure 4As shown, a hysteresis comparator circuit 100 supporting voltage divider logic is disclosed. The circuit includes a power supply voltage divider unit 101 and a hysteresis comparator unit 102. The power supply voltage divider unit 101 is connected to the chip power supply voltage and the hysteresis comparator unit 102, respectively, and is used to generate a stable voltage divider based on the chip power supply voltage and input it into the hysteresis comparator unit 102. The hysteresis comparator unit 102 is connected to the power supply voltage divider unit 101 and is used to implement the hysteresis comparison function based on the stable voltage divider received from the power supply voltage divider unit 101, and output a trigger signal.

[0030] Preferably, the output terminal of the power supply voltage divider unit is connected to the high-voltage terminal of the hysteresis comparator unit to provide a stable voltage for the hysteresis comparator unit. In this invention, a low-dropout linear regulator (LDO) with a 1.2V output voltage, commonly used in the prior art, can be used as the power supply voltage divider unit. Alternatively, various methods in the prior art can be used to implement the hysteresis comparator unit in this invention. Preferably, the power supply voltage divider unit is a secondary regulator for generating the secondary power supply voltage. This regulator can generate a stable secondary regulated voltage during large fluctuations in the power supply voltage. Appropriate parameters can be selected to set this secondary regulated voltage to the device voltage required by the Schmitt trigger, for example, from 1.3V to 40V.

[0031] Specifically, various low-dropout linear regulators exist in the prior art. For example, patent publication CN111414035A discloses a low-dropout linear regulator with a wide input voltage range, capable of supporting input voltages from 5V to 42V while maintaining an output voltage approximately four times the reference voltage. In this invention, the model of the low-dropout linear regulator can be determined based on the logic of a Schmitt trigger. All low-dropout linear regulators capable of stabilizing the output voltage at approximately 1.2V can be applied to the technical solution of this invention.

[0032] Preferably, the chip power supply voltage varies between 1.3V and 40V, and the secondary regulated voltage is stabilized at 1.2V. Generally, to fully realize the function of the Schmitt trigger while ensuring low power consumption, the logic of the Schmitt trigger can be set to 1.2V, thus stabilizing the output of the secondary regulator at 1.2V. Similar to the logic of the chip power supply voltage varying between 1.8V and 5.5V described in the previous embodiment, based on the pre-implemented voltage division of the power supply voltage divider unit, even when the power supply voltage is very high or very low, the widely used low-dropout linear regulator with a wide input voltage range can still ensure that the output voltage fluctuates within a very small range around 1.2V, thus stabilizing the output at 1.2V.

[0033] Preferably, the hysteresis comparator is a Schmitt trigger. In this invention, in addition to using a Schmitt trigger, other hysteresis comparator circuits can be selected according to the actual function of the circuit.

[0034] Preferably, the high-level threshold of the Schmitt trigger is 0.78V, and the low-level threshold is 0.42V. In this invention, to achieve 1.2V circuit logic, the ratio of the lowest high-level threshold voltage and the highest low-level threshold voltage to the power supply voltage can be set to 65% and 35%, respectively. Based on this, the lowest high-level threshold voltage of the Schmitt trigger can be designed to be 0.78V, and the highest low-level threshold voltage to be 0.42V.

[0035] Figure 5 This is a schematic diagram of the circuit connection of the power supply voltage divider unit 101 in a hysteresis comparator circuit supporting voltage divider logic according to the present invention. Figure 5 As shown, preferably, the power supply voltage divider unit includes an error amplifier EA, a PMOS transistor Mp, a current source, and a capacitor; wherein, the negative input terminal of the error amplifier is connected to the reference voltage Vref, the positive input terminal is connected to one end of the current source, the high voltage terminal is connected to the chip power supply voltage, and the output terminal is connected to the gate of the PMOS transistor Mp; the source of the PMOS transistor Mp is connected to the chip power supply voltage, and the drain is connected to the current source, the positive input terminal of the amplifier, and one end of the capacitor, respectively, to generate a voltage divider voltage Vreg for the high voltage terminal of the Schmitt trigger; the other end of the current source and the other end of the capacitor are both grounded.

[0036] It is understood that, in one embodiment of the present invention, the following can be employed: Figure 5 The structure described herein implements a power supply voltage divider unit. This unit generates a stable voltage, which serves as the reference voltage Vref for the Schmitt trigger. This voltage is used for error comparison and, through the negative feedback loop of the amplifier, generates a stable divided voltage Vreg. This voltage Vreg typically has driving capability and can be used as the device power supply for components such as hysteresis comparators. Therefore, this circuit structure is used in this invention to achieve a stable device voltage at the high-voltage end of the Schmitt trigger.

[0037] In the power supply voltage divider unit, the error amplifier can use the stable voltage generated by the power supply voltage divider unit as the reference voltage Vref of the Schmitt trigger to turn on the PMOS transistor Mp and stably generate the divided voltage Vreg. This circuit has a simple structure and low power consumption. The output divided voltage is automatically adjusted in real time based on the feedback of the error amplifier, so the output is very stable, which can bring good working conditions to the Schmitt trigger in this invention.

[0038] A second aspect of the present invention relates to a hysteresis comparison method supporting voltage divider logic, which can employ a hysteresis comparison circuit supporting voltage divider logic as described in the first aspect of the present invention.

[0039] The beneficial effects of this invention are that, compared with the prior art, the hysteresis comparator circuit supporting voltage divider logic in this invention can still implement the dual threshold comparator logic of Schmitt trigger in chips with high voltage and large voltage fluctuation range, thereby expanding the application range of Schmitt trigger, reducing the requirements of power supply voltage fluctuation range during application of Schmitt trigger, and without modifying the internal structure of Schmitt trigger, the implementation method is simple, the entire circuit structure is simple, the power consumption is low, and the chip area occupied is small.

[0040] The applicant of this invention has provided a detailed description of the embodiments of the invention in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the invention. The detailed description is only intended to help readers better understand the spirit of the invention and is not intended to limit the scope of protection of the invention. On the contrary, any improvements or modifications made based on the inventive spirit of the invention should fall within the scope of protection of the invention.

Claims

1. A hysteresis comparator circuit supporting voltage divider logic, characterized in that: The circuit includes a power supply voltage divider unit (101) and a hysteresis comparator unit (102); wherein, The power supply voltage divider unit (101) is connected to the chip power supply voltage and the hysteresis comparator unit respectively, and is used to generate a stable voltage divider based on the chip power supply voltage and input it to the hysteresis comparator unit; the hysteresis comparator unit is a Schmitt trigger. The power supply voltage divider unit is a secondary voltage regulator used to generate the secondary power supply voltage; the secondary power supply voltage is stabilized at 1.2V; The power supply voltage divider unit includes an error amplifier EA, a PMOS transistor Mp, a current source, and a capacitor; wherein... The negative input terminal of the error amplifier is connected to the reference voltage Vref, the positive input terminal is connected to one end of the current source, the high voltage terminal is connected to the chip power supply voltage, and the output terminal is connected to the gate of the PMOS transistor Mp. The source of the PMOS transistor Mp is connected to the chip power supply voltage, and the drain is connected to the current source, the positive input terminal of the amplifier, and one end of the capacitor, respectively, to generate a voltage divider Vreg for the high voltage terminal of the Schmitt trigger. The other end of the current source and the other end of the capacitor are both grounded; the hysteresis comparison unit (102) is connected to the power supply voltage divider unit and is used to realize the hysteresis comparison function based on the stable voltage division received from the power supply voltage divider unit, and output a trigger signal.

2. The hysteresis comparator circuit supporting voltage divider logic as described in claim 1, characterized in that: The output terminal of the power supply voltage divider unit (101) is connected to the high voltage terminal of the hysteresis comparator unit (102) to provide a stable power supply voltage divider for the hysteresis comparator unit (102).

3. A hysteresis comparator circuit supporting voltage divider logic as described in claim 2, characterized in that: The chip's power supply voltage varies between 1.3V and 40V.

4. A hysteresis comparator circuit supporting voltage divider logic as described in claim 3, characterized in that: The Schmitt trigger has a minimum high-level threshold voltage of 0.78V and a maximum low-level threshold voltage of 0.42V.

5. A hysteresis comparison method supporting voltage divider logic, characterized in that: A hysteresis comparator circuit supporting voltage divider logic is used as described in any one of claims 1-4.

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