阅读说明：本技术 电压检测电路及控制器和电子设备 (Voltage detection circuit, controller and electronic equipment ) 是由 樊磊 张晋芳 刘计平 丁春楠 于 2020-06-05 设计创作，主要内容包括：本发明提供一种电压检测电路,其包括：分压电阻单元,具有多个分压点以提供电源电压的多个分压；数字模拟转换电路,包括电压选择并组合单元以根据第一调整信号的控制对所述多个分压进行选择并组合以产生占所述电源电压第一预定比例的检测电压；参考电压产生电路,用以根据第二调整信号产生第二预定比例,以及根据带隙参考电压与所述第二预定比例的倒数的乘积产生参考电压；以及比较器,包括正输入端、负输入端及输出端,所述正输入端与所述检测电压耦接,所述负输入端与所述参考电压耦接,且所述输出端用以提供输出电压。(The present invention provides a voltage detection circuit, comprising: a voltage dividing resistance unit having a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage; the digital-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to the control of a first adjusting signal so as to generate a detection voltage occupying a first preset proportion of the power supply voltage; the reference voltage generating circuit is used for generating a second preset proportion according to a second adjusting signal and generating a reference voltage according to the product of the bandgap reference voltage and the reciprocal of the second preset proportion; and a comparator including a positive input terminal coupled to the detection voltage, a negative input terminal coupled to the reference voltage, and an output terminal for providing an output voltage.)

1. A voltage detection circuit, comprising:

a voltage dividing resistance unit including a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage;

the digital-to-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to a first adjustment signal so as to generate a detection voltage occupying a first preset proportion of the power supply voltage;

a reference voltage generating circuit for generating a second predetermined ratio according to a second adjustment signal and generating a reference voltage according to a product of the bandgap reference voltage and a reciprocal of the second predetermined ratio; and

the comparator has a positive input terminal coupled to the detection voltage, a negative input terminal coupled to the reference voltage, and an output terminal for providing an output voltage.

2. The detection circuit of claim 1, wherein the reference voltage generation circuit comprises:

the voltage dividing resistance circuit comprises a first end, a control end, a second end and a voltage dividing output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with a second adjusting signal, the second end is coupled with a reference ground, and the voltage dividing resistance circuit enables the resistance value between the voltage dividing output end and the reference ground to occupy the second preset proportion of the total resistance value under the control of the second adjusting signal.

3. The detection circuit of claim 2, wherein the reference voltage generation circuit comprises:

the operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end is coupled with the band gap reference voltage, the negative input end is coupled with the voltage division output end, and the output end is coupled with the first end to generate the reference voltage.

4. A controller, comprising a voltage detection circuit and a cpu, wherein the voltage detection circuit is configured to generate an indication signal by using an output voltage to notify the cpu when an under-voltage condition of a power supply voltage is monitored, and the voltage detection circuit comprises:

a voltage dividing resistance unit including a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage;

the digital-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to the control of a first adjusting signal so as to generate a detection voltage accounting for a first preset proportion of the power supply voltage;

the reference voltage generating circuit is used for generating a second preset proportion according to a second adjusting signal and generating a reference voltage according to the product of the bandgap reference voltage and the reciprocal of the second preset proportion; and

the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled to the detection voltage, the negative input terminal is coupled to the reference voltage, and the output terminal is used for providing an output voltage.

5. The controller according to claim 4, wherein the reference voltage generating circuit comprises:

and the divider resistance circuit comprises a first end, a control end, a second end and a divider output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with the second adjusting signal, the second end is coupled with the reference ground, and the divider resistance circuit is controlled by the second adjusting signal to enable the resistance value between the divider output end and the reference ground to occupy the second preset proportion of the total resistance value.

6. The controller of claim 5, wherein the reference voltage generation circuit further comprises:

the operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end is coupled with the band gap reference voltage, the negative input end is coupled with the voltage division output end, and the output end is coupled with the first end to generate the reference voltage.

7. The controller of claim 4, comprising a chip selected from the group consisting of a touch chip, a display driver chip, and a TDDI chip.

8. An electronic device comprising a controller and peripheral circuits, wherein the controller is configured to execute a corresponding program to control the peripheral circuits when an under-voltage condition of a power supply voltage is monitored, the controller comprises a voltage detection circuit and a central processing unit, wherein the voltage detection circuit is configured to generate an indication signal according to an output voltage to notify the central processing unit to execute the corresponding program when the under-voltage condition is monitored, and the voltage detection circuit comprises:

a voltage dividing resistor unit including a plurality of voltage dividing points for providing a plurality of divided voltages of the power voltage;

the digital-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to the control of a first adjusting signal so as to generate a detection voltage accounting for a first preset proportion of the power supply voltage;

the reference voltage generating circuit is used for generating a second preset proportion according to a second adjusting signal and generating a reference voltage according to the product of the bandgap reference voltage and the reciprocal of the second preset proportion; and

the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled to the detection voltage, the negative input terminal is coupled to the reference voltage, and the output terminal is used for providing an output voltage.

9. The electronic device of claim 7, wherein the reference voltage generation circuit comprises:

the voltage dividing resistance circuit comprises a first end, a control end, a second end and a voltage dividing output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with the second adjusting signal, the second end is coupled with the reference ground, and the voltage dividing resistance circuit enables the resistance value between the voltage dividing output end and the reference ground to account for the second preset proportion of the total resistance value under the control of the second adjusting signal.

10. The electronic device of claim 8, wherein the reference voltage generation circuit further comprises:

the operational amplifier comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled with the band gap reference voltage, the negative input terminal is coupled with the voltage division output terminal, and the output terminal is coupled with the first terminal to generate the reference voltage.

11. An electronic device according to any of claims 7-9, wherein the electronic device is selected from the group consisting of an LCD display, an LED display, an OLED display, an information processing device, and an electric power system of an electric vehicle, and the information processing device is selected from a smartphone, a tablet computer, a laptop computer, a fingerprint card reader, and a door access device.

Technical Field

The invention relates to the field of integrated circuit design, in particular to a voltage detection circuit, a controller and electronic equipment.

Background

Fig. 1 shows a schematic diagram of a low voltage detection circuit in the prior art. As shown in FIG. 1, the circuit includes a voltage divider 10 and a detection circuit 20 for monitoring a power supply voltage V_PPWhether or not an under-voltage condition is generated and is at V_PPGenerating the output voltage V in the over-low voltage state_OUTA low potential is present.

The voltage divider circuit 10 includes a resistor unit 11 and a plurality of switches (12a, 12b, 12c), wherein the resistor unit 11 is coupled to a power voltage V_PPAnd a reference ground, wherein a plurality of nodes (A, B, C, D, E, F, G) are provided, and the node A is used for providing a detection voltage V_XThe contact B, C is connected to both ends of the channel of the switch 12a, the contact D, E is connected to both ends of the channel of the switch 12b, the contact F, G is connected to both ends of the channel of the switch 12c, and V is determined by the on/off combination of the switches (12a, 12b, 12c)_XAnd V_PPThe proportional relationship between them.

The detection circuit 20 comprises a PMOS transistor 20a, a resistor 20b and an inverter 20c, wherein the PMOS transistor 20a has a source, a gate and a drain, the source is connected to the DC voltage V_DDCoupled to the gate and a detection voltage V_XCoupling; a resistor 20b coupled between the drain and the ground reference for generating a primary output voltage V at the drain_Y(ii) a And an inverter 20c having an input terminal and an output terminal, the input terminal and the primary output voltage V_YCoupled to the output terminal for providing an output voltage V_OUT。

During actual operation, when the power supply voltage V is applied_PPFalling below a predetermined level causes the PMOS transistor 20a to generate a current I_DWhen the critical value is exceeded, the current I_DThe primary output voltage V established at the resistor 20b_YThe level of the voltage level is raised to drive the output voltage VOUT of the inverter 20c to reverse from high to low to indicate the power voltage V_PPA low voltage state occurs in which the current I_DAnd K_P(V_DD-V_X-V_TH)²In positive correlation, wherein, K_PIs a physical structural parameter of the PMOS transistor 20a, which is proportional to (W/L), W being of the channelWidth, L being the length of the channel, and V_THIs the turn-on threshold voltage of the PMOS transistor 20 a.

However, due to K of PMOS transistor 20a_PAnd V_THAnd the resistance of the resistor 20b is highly sensitive to the variation of the process, and the absolute value thereof varies by about 20% -40%, so that the conventional low voltage detection circuit is liable to have a false indication of the power supply voltage V after mass production_PPA low voltage condition occurs. Fig. 2 shows a monitoring voltage variation phenomenon generated by the low voltage detection circuit of fig. 1 after mass production. As shown in fig. 2, the monitoring voltage of the low voltage detection circuit of fig. 1 varies by about 1.4V.

Therefore, there is a need in the art for a low voltage detection circuit that provides accurate voltage detection.

Disclosure of Invention

The present invention provides a voltage detection circuit, which can generate a detection voltage proportional to a power voltage by a voltage dividing resistor unit and a DAC (digital-to-analog converter) circuit, and generate a comparison voltage according to a bandgap reference voltage to compare with the detection voltage, so as to generate an indication signal when the power voltage is in an undervoltage state.

To achieve the above object, the present invention provides a voltage detection circuit, which includes:

a voltage dividing resistance unit including a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage;

the digital-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation and combination unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to the control of a first adjusting signal so as to generate a detection voltage which occupies a first preset proportion of the power supply voltage;

a reference voltage generating circuit for generating a second predetermined ratio according to a second adjustment signal and generating a reference voltage according to a product of the bandgap reference voltage and a reciprocal of the second predetermined ratio; and

the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled to the detection voltage, the negative input terminal is coupled to the reference voltage, and the output terminal is used for providing an output voltage.

In one embodiment, the reference voltage generating circuit includes:

and the divider resistance circuit comprises a first end, a control end, a second end and a divider output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with the second adjusting signal, the second end is coupled with the reference ground, and the divider resistance circuit enables the resistance value between the divider output end and the reference ground to occupy the second preset proportion of the total resistance value through the control of the second adjusting signal.

In one embodiment, the reference voltage generating circuit further includes:

an operational amplifier having a positive input terminal coupled to the bandgap reference voltage, a negative input terminal coupled to the voltage-dividing output terminal, and an output terminal coupled to the first terminal to generate the reference voltage.

To achieve the above object, the present invention further provides a controller having a voltage detection circuit and a cpu, wherein the voltage detection circuit is configured to generate an indication signal by using an output voltage to notify the cpu when an under-voltage condition of a power voltage is detected, and the low voltage detection circuit includes:

a voltage dividing resistance unit including a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage;

the digital-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to the control of a first adjusting signal so as to generate a detection voltage occupying a first preset proportion of the power supply voltage;

the reference voltage generating circuit is used for generating a second preset proportion according to a second adjusting signal and generating a reference voltage according to the product of the bandgap reference voltage and the reciprocal of the second preset proportion; and

the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled to the detection voltage, the negative input terminal is coupled to the reference voltage, and the output terminal is used for providing an output voltage.

In one embodiment, the reference voltage generating circuit includes:

the divider resistance circuit comprises a first end, a control end, a second end and a divider output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with the second adjusting signal, the second end is coupled with the reference ground, and the divider resistance circuit enables the resistance value between the divider output end and the reference ground to occupy the second preset proportion of the total resistance value under the control of the second adjusting signal.

In an embodiment, the reference voltage generation circuit further comprises:

the operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end is coupled with the band gap reference voltage, the negative input end is coupled with the voltage division output end, and the output end is coupled with the first end to generate the reference voltage.

In a possible embodiment, the controller may be a touch chip, a display driving chip, or a TDDI chip.

To achieve the above object, the present invention further provides an electronic device, which includes a controller and a peripheral circuit, wherein the controller is configured to execute a corresponding program to control the peripheral circuit when an under-voltage condition of a power supply voltage is monitored, the controller includes a voltage detection circuit and a central processing unit, wherein the voltage detection circuit is configured to generate an indication signal by using an output voltage to notify the central processing unit to execute the corresponding program when the under-voltage condition is monitored, and the voltage detection circuit includes:

a voltage dividing resistance unit including a plurality of voltage dividing points to provide a plurality of divided voltages of the power supply voltage;

the digital-to-analog conversion circuit comprises a voltage selection and combination unit, a voltage detection unit and a voltage regulation unit, wherein the voltage selection and combination unit is used for selecting and combining the plurality of divided voltages according to a first adjusting signal to generate a detection voltage accounting for a first preset proportion of the power supply voltage;

the reference voltage generating circuit is used for generating a second preset proportion according to a second adjusting signal and generating a reference voltage according to the product of the bandgap reference voltage and the reciprocal of the second preset proportion; and

the comparator comprises a positive input terminal, a negative input terminal and an output terminal, wherein the positive input terminal is coupled to the detection voltage, the negative input terminal is coupled to the reference voltage, and the output terminal is used for providing the output voltage.

In one embodiment, the reference voltage generating circuit includes:

and the voltage dividing resistance circuit comprises a first end, a control end, a second end and a voltage dividing output end, wherein a total resistance value is arranged between the first end and the second end, the control end is coupled with the second trimming signal, the second end is coupled with a reference ground, and the voltage dividing resistance circuit enables the resistance value between the voltage dividing output end and the reference ground to account for the second preset proportion of the total resistance value under the control of the second adjusting signal.

In one embodiment, the reference voltage generating circuit further includes:

the operational amplifier comprises a positive input end, a negative input end and an output end, wherein the positive input end is coupled with the band gap reference voltage, the negative input end is coupled with the voltage division output end, and the output end is coupled with the first end to generate the reference voltage.

In possible embodiments, the electronic device may be an LCD display, an LED display, an OLED display, an information processing device or an electric power system of an electric vehicle, and the information processing device may be a smart phone, a tablet computer, a notebook computer, a fingerprint card reader or an entrance guard.

Drawings

Fig. 1 is a circuit diagram of a known low voltage detection circuit.

FIG. 2 is a diagram illustrating a monitoring voltage variation phenomenon generated by the low voltage detection circuit of FIG. 1.

FIG. 3 is a circuit diagram of an embodiment of a voltage detection circuit of the present invention.

FIG. 4 is a diagram illustrating a comparison between the variation of the monitor voltage generated by the voltage detection circuit of FIG. 3 and the variation of the monitor voltage generated by the conventional low voltage detection circuit.

FIG. 5 is a diagram of a controller according to an embodiment of the present invention.

FIG. 6 is a diagram of an embodiment of an electronic device employing a controller of the present invention.

Notation, 10-voltage divider circuit; 11-a resistance unit; 12 a-a switch; 12 b-a switch; 12 c-a switch; 20-a detection circuit; 20a-PMOS transistor; 20 b-resistance; 20 c-inverter; 100-voltage detection circuit; 110-voltage dividing resistance unit; 120-digital-to-analog conversion circuit; 121-voltage select and combine unit; 130-reference voltage generating circuit; 131-a voltage dividing resistance circuit; 132-an operational amplifier; 140-a comparator; 200-a controller; 210-a voltage detection circuit; 220-a central processing unit; 300-an electronic device; 310-a controller; 320-peripheral circuits.

Detailed Description

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present disclosure.

The principle of the voltage detection circuit of the present invention is that:

1. providing a plurality of partial voltages of a power supply voltage to a DAC (digital-to-analog conversion) circuit by a plurality of partial voltage points of a partial voltage resistance unit, and driving the DAC circuit by a first adjusting (trimming) signal to select and combine the plurality of partial voltages so as to enable the DAC circuit to generate a detection voltage accounting for a first preset proportion of the power supply voltage;

2. driving a reference voltage generating circuit by a second adjusting signal so as to enable a voltage dividing resistance circuit in the reference voltage generating circuit to generate a second preset proportion and generate a preset reference voltage according to the band gap reference voltage; and

3. and comparing the detection voltage with the preset reference voltage to generate an indication signal when the power supply voltage has an undervoltage state so that the detection voltage is lower than the preset reference voltage.

Fig. 3 is a circuit diagram of an embodiment of the voltage detection circuit of the present invention. As shown in fig. 3, the voltage detection circuit 100 includes a voltage dividing resistance unit 110, a digital-to-analog conversion circuit 120, a reference voltage generation circuit 130 and a comparator 140, wherein the digital-to-analog conversion circuit 120 includes a voltage selection and combination unit 121; the reference voltage generating circuit 130 includes a voltage dividing resistor circuit 131 and an operational amplifier 132.

The voltage dividing resistor unit 110 has a plurality of voltage dividing points for providing the power voltage V_PPTo the digital-to-analog conversion circuit 120.

The voltage selecting and combining unit 121 of the digital-to-analog converting circuit 120 selects and combines the plurality of divided voltages according to the control of the first adjustment signal a so that the digital-to-analog converting circuit 120 generates the occupied supply voltage V_PPA first predetermined ratio of the detected voltage V_DETThe first predetermined ratio is a real number between 0 and 1, such as (but not limited to) 0.4.

The voltage dividing resistor circuit 131 of the reference voltage generating circuit 130 includes a first terminal, a control terminal, a second terminal and a voltage dividing output terminal, wherein a total resistance value is provided between the first terminal and the second terminal, the control terminal is coupled to a second adjusting signal B, the second terminal is coupled to a reference ground, and the voltage dividing resistor circuit 131 is controlled by the second adjusting signal B such that a resistance value between the voltage dividing output terminal and the reference ground occupies a second predetermined ratio of the total resistance value, the second predetermined ratio is a real number between 0 and 1, such as (but not limited to) 0.5, and the second predetermined ratio and the first predetermined ratio are values independent of each other.

The operational amplifier 132 comprises a positive input terminal, a negative input terminal and an output terminal, the positive input terminal and the bandgap reference voltage V_ROThe negative input terminal is coupled to the voltage-dividing output terminal, and the output terminal is coupled to the first terminal such that the reference voltage generation circuit 130 generates the reference voltage according to the bandgap reference voltage V_ROAnd the inverse of the second predetermined ratio generates the predetermined reference voltage V_REFFor example, assume a bandgap reference voltage V_RO1.25V, and 0.5, the reference voltage V_REF2.5V. The comparator 140 includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal and the detection voltage V_DETCoupled to the negative input terminal with a reference voltage V_REFCoupled to the output terminal for providing an output voltage V_OUT。

Since the first predetermined ratio and the second predetermined ratio are relative ratio values between the resistances rather than absolute values, they have high accuracy, and the bandgap reference voltage V is added_ROAnd has an accurate level that does not vary with the supply voltage, so that the present invention can be applied to a power supply voltage V_PPThe under-voltage state occurs to make the detection voltage VDET lower than the predetermined reference voltage V_REFTime-lapse output voltage V_OUTAn indication signal is generated for switching from a high potential to a low potential. For example, assume a bandgap reference voltage V_RO1.25V, the first predetermined ratio is 0.5, the second predetermined ratio is 0.5, and the reference voltage V is then set to the reference voltage V_REFWould equal 2.5V. Accordingly, when the power supply voltage V is applied_PPDetecting the voltage V when a low voltage state lower than 5V occurs_DETWill be lower than 2.5V (═ 5V × 0.5), i.e. lower than the reference voltage V_REF(-2.5V) to thereby output a voltage V_OUTAn indication signal is generated to switch from a high voltage level to a low voltage level. As shown in fig. 4, fig. 4 is a diagram comparing the monitored voltage variation of the voltage detection circuit of fig. 3 with the monitored voltage variation of the known low voltage detection circuit. As shown in FIG. 4, the voltage detection circuit of the present invention monitors the voltage variation range (about)0.05V) is much smaller than the monitored voltage variation range (about 1.4V) of the known low voltage detection circuit.

In accordance with the above description, the present invention further provides a controller. Fig. 5 is a schematic diagram of a controller according to an embodiment of the invention. As shown in fig. 5, the controller 200 (for example, but not limited to, a touch chip, a display driver chip or a TDDI (touch display driver integration) chip) includes a voltage detection circuit 210 and a central processing unit 220, wherein the voltage detection circuit 210 is implemented by the voltage detection circuit 100 shown in fig. 3 for detecting the power voltage V when the power voltage V is detected_PPUsing output voltage V when under-voltage conditions occur_OUTGenerates an indication signal to notify the cpu 220, and the cpu 220 executes a corresponding program after receiving the indication signal. The controller 200 may be applied to an electronic device sensitive to a power supply state. FIG. 6 is a diagram of an electronic device employing a controller according to an embodiment of the present invention. As shown in fig. 6, the electronic device 300 includes a controller 310 and peripheral circuits 320, wherein the controller 310 is implemented by the controller 200 shown in fig. 5 for monitoring the power supply voltage V_PPWhen an under-voltage condition occurs, a corresponding program is executed to control peripheral circuitry 320 (e.g., disable peripheral circuitry 320). The electronic device 300 may be an LCD display, an LED display, an OLED display, an information processing device, or an electric power system of an electric vehicle, and the information processing device may be a smart phone, a tablet computer, a notebook computer, a fingerprint card reader, or an entrance guard.

Thus, the technical solutions of the present invention have been fully and clearly described above; moreover, the present invention has the following advantages as follows:

1. the voltage detection circuit of the invention adjusts the relative proportion value (rather than the absolute value) among the resistances of the voltage division resistance units by the adjusting (trimming) signal to provide accurate detection voltage, and can effectively solve the problem that the known absolute resistance value generates the detection voltage and is influenced by the manufacturing error of the resistance.

2. The voltage detection circuit of the invention provides accurate reference voltage by the characteristic that the band gap reference voltage does not change along with the supply voltage.

3. The voltage detection circuit of the invention can enable the output voltage to generate the indication signal when the detection voltage is lower than the reference voltage due to the undervoltage state of the power supply voltage by comparing the detection voltage with the reference voltage.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.