Digital circuit system and power supply method

Abstract

The embodiment of the present application discloses a digital circuit system and a power supply method, wherein the digital circuit system includes a reference voltage generator, a rail-to-rail low voltage dropout regulator, and a logic circuit. The reference voltage generator generates a plurality of reference voltages. The rail-to-rail low voltage dropout regulator generates a plurality of control signals according to the reference voltages, and generates a plurality of driving voltages according to the control signals, wherein the driving voltages have the same variation trend. The logic circuit operates in a voltage interval between the driving voltages.

Description

Technical Field

[0001] The present application relates to a digital circuit system, and in particular to a digital circuit system with low power consumption and a power supply method thereof. Background Art

[0002] Due to process advancement, the size of transistors is getting smaller and smaller, making it easy for transistors to leak current in low-voltage operating environments, resulting in unnecessary power consumption. In some prior arts, an additional bias is provided to the base of the transistor to adjust the critical voltage of the transistor, thereby reducing the leakage current of the transistor. However, in these technologies, special processes or additional masks are required to achieve the base bias, resulting in additional cost expenditure. In other prior arts, the leakage current is reduced by increasing the length of the transistor. However, the above approach cannot completely reduce the leakage current generated when the transistor operates in the subcritical region, and it will also cause additional cost expenditure. Summary of the invention

[0003] The embodiments of the present application provide a digital circuit system and a power supply method with low power consumption to improve the deficiencies of the prior art.

[0004] The embodiment of the present application provides a digital circuit system, including a reference voltage generator, a rail-to-rail low-dropout voltage regulator, and a logic circuit. The reference voltage generator generates a plurality of reference voltages. The rail-to-rail low-dropout voltage regulator generates a plurality of control signals according to the reference voltages, and generates a plurality of driving voltages according to the control signals, wherein the driving voltages have the same variation trend. The logic circuit operates in a voltage interval between the driving voltages.

[0005] An embodiment of the present application also provides a power supply method, comprising the following steps: generating multiple reference voltages; generating multiple control signals based on the reference voltages; and generating multiple driving voltages based on the control signals to power a logic circuit, wherein the driving voltages have the same change trend.

[0006] The features, implementation and effects of the present application are described in detail below with reference to the drawings as preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0008] Figure 1 A schematic diagram of a digital circuit system provided in an embodiment of the present application;

[0009] Figure 2 Provided in the embodiments of this application Figure 1 Schematic diagram of a rail-to-rail low dropout regulator in; and

[0010] Figure 3 A flowchart of a power supply method provided in an embodiment of the present application.

[0011]

Explanation of symbols

[0012] 100: Digital Circuit System

[0013] 110: Reference voltage generator

[0014] 120: Rail-to-Rail Low Dropout Regulator

[0015] 130:Logic Circuit

[0016] 221,222:Amplifier

[0017] 300: Power supply method

[0018] C: Capacitor

[0019] MN,MP:Transistor

[0020] R: Resistance

[0021] S310, S320, S330: Operation

[0022] VC1, VC2: control signal

[0023] VD,VS: driving voltage

[0024] VP: Power supply voltage

[0025] VREF1, VREF2: reference voltage DETAILED DESCRIPTION

[0026] All words used herein have their usual meanings. The definitions of the above words in commonly used dictionaries, including any use examples of the words discussed herein in the content of this application are only examples and should not limit the scope and meaning of this application. Similarly, this application is not limited to the various embodiments shown in this specification.

[0027] As used herein, "coupled" or "connected" may refer to two or more elements making direct physical or electrical contact with each other, or making indirect physical or electrical contact with each other, or may refer to two or more elements operating or acting on each other. As used herein, the term "circuit system" may be a single system formed by one or more circuits, and the term "circuit" may be a device composed of at least one transistor and / or at least one active and passive element connected in a certain manner to process signals.

[0028] Figure 1 The digital circuit system 100 provided in accordance with an embodiment of the present application is a schematic diagram of the digital circuit system 100 . The digital circuit system 100 includes a reference voltage generator 110 , a rail-to-rail low dropout voltage regulator 120 , and a logic circuit 130 .

[0029] The reference voltage generator 110 generates a reference voltage VREF1 and a reference voltage VREF2. In some embodiments, the reference voltage generator 110 may be implemented by, but not limited to, a bandgap voltage reference circuit. The rail-to-rail low dropout regulator 120 generates a plurality of control signals (e.g., Figure 2 The control signals VC1 and VC2 in the logic circuit 130 are used to generate a driving voltage VD and a driving voltage VS according to the control signals. In some embodiments, the driving voltage VD and the driving voltage VS have the same change trend. For example, when the driving voltage VS increases, the driving voltage VD also increases. Alternatively, when the driving voltage VS decreases, the driving voltage VD also decreases. In this way, the voltage difference between the driving voltage VD and the driving voltage VS can be maintained within a preset range. In some embodiments, the driving voltage VD and the driving voltage VS can be used to power the logic circuit 130. In this way, the logic circuit 130 can operate in a voltage range between the driving voltage VD and the driving voltage VS.

[0030] In some embodiments, the logic circuit 130 may be a digital circuit with low power consumption requirements. In some embodiments, the logic circuit 130 may be a circuit or device that is primarily powered by a battery. For example, in some applications, the logic circuit 130 may be, but is not limited to, a real-time clock (RTC) generator that can be used to generate a reference clock for use by other circuits. Since the real-time clock generator needs to operate continuously, if its power consumption is too high, the battery power will be quickly exhausted. The above types of logic circuits 130 are used for example, and the present application is not limited thereto.

[0031] Generally speaking, in order to achieve low power consumption applications, the leakage current and dynamic power consumption of transistors in the circuit can be reduced. Ideally, when the transistor is turned off, the transistor should not generate leakage current. As the process progresses, the size of the transistor is getting smaller and smaller, so that the transistor may operate in the subthreshold region under a low voltage environment and cannot be completely turned off, thereby generating leakage current. Referring to relevant literature, it can be known that the critical voltage of the transistor is positively correlated with the voltage difference between the source and the base of the transistor, and the leakage current generated when the transistor operates in the subthreshold region is positively correlated with the voltage difference between the gate and the source of the transistor and / or the voltage difference between the drain and the source. Therefore, the critical voltage can be adjusted by adjusting the source voltage of the transistor to turn off the transistor as much as possible and reduce the leakage current generated by the transistor in the subthreshold region at the same time. For example, under the condition that the base voltage is 0V, if the source voltage is higher, the critical voltage of the transistor can be increased and the leakage current generated in the subthreshold region can be decreased. In some embodiments of the present application, the aforementioned driving voltage VS can be used to adjust the source voltage of the transistor in the logic circuit 130 to adjust the critical voltage of the transistor. In some embodiments, the driving voltage VD can be used as a high supply voltage (usually labeled as VDD) of the logic circuit 130, and the driving voltage VS can be used as a low supply voltage (usually labeled as VSS) of the logic circuit 130.

[0032] On the other hand, as mentioned above, the driving voltage VD and the driving voltage VS have the same variation trend. Thus, when the driving voltage VS changes, the driving voltage VD can have the same or similar variation to ensure that the voltage difference between the driving voltage VD and the driving voltage VS remains within a predetermined range, thereby ensuring that the logic circuit 130 can have a sufficient voltage operation range and a correct operation timing. Furthermore, by setting the voltage difference between the driving voltage VD and the driving voltage VS, the voltage operation range of the logic circuit 130 can be set, and the dynamic power consumption generated by the logic circuit 130 can be further adjusted.

[0033] In some embodiments, the logic circuit 130 may be implemented by one or more input / output (I / O) transistors. The input / output transistors generally have a higher withstand voltage characteristic and a lower gate leakage current. In this way, the leakage current can be further reduced without increasing the length of the transistor or the number of transistors, thereby saving more power consumption. In some embodiments, the voltage received by the base of the transistor in the logic circuit 130 may be 0V, but the present application is not limited thereto.

[0034] Figure 2 Provided in the embodiments of this application Figure 1Schematic diagram of the rail-to-rail low voltage dropout regulator 120 in FIG. The rail-to-rail low voltage dropout regulator 120 includes an amplifier 221, an amplifier 222, a resistor R, a transistor MP, and a transistor MN. The amplifier 221 and the amplifier 222 can generate a control signal VC1 and a control signal VC2 according to the reference voltage VREF1 and the reference voltage VREF2, respectively. In detail, the negative input terminal of the amplifier 221 receives the reference voltage VREF1, the positive input terminal of the amplifier 221 receives the driving voltage VD, and the output terminal of the amplifier 221 outputs the control signal VC1. In this way, the amplifier 221 can generate a control signal VC1 according to the reference voltage VREF1 and the driving voltage VD. Similarly, the negative input terminal of the amplifier 222 receives the reference voltage VREF2, the positive input terminal of the amplifier 222 receives the driving voltage VS, and the output terminal of the amplifier 222 outputs the control signal VC2. In this way, the amplifier 222 can generate a control signal VC2 according to the reference voltage VREF2 and the driving voltage VS.

[0035] In this example, the transistor MP is a P-type transistor, and the transistor MN is an N-type transistor. The first end (e.g., source) of the transistor MP receives the power supply voltage VP, the second end (e.g., drain) of the transistor MP generates the driving voltage VD, and the control end (e.g., gate) of the transistor MP receives the control signal VC1. In this way, the transistor MP can be controlled by the control signal VC1 to generate the driving voltage VD. Similarly, the first end (e.g., drain) of the transistor MN is coupled to the second end of the transistor MP via the resistor R and generates the driving voltage VS, the second end (e.g., source) of the transistor MN is coupled to the ground, and the control end (e.g., gate) of the transistor MN receives the control signal VC2. In this way, the transistor MN can be controlled by the control signal VC2 to generate the driving voltage VS.

[0036] In some embodiments, the amplifier 221 and the transistor MP can be operated as a current sourcing type low voltage dropout regulator, which can provide current to the resistor R and the logic circuit 130. Similarly, in some embodiments, the amplifier 222 and the transistor MN can be operated as a current draining type low voltage dropout regulator, which can draw current from the resistor R and the logic circuit 130. By using the resistor R to couple the outputs of the above two low voltage dropout regulators (i.e., the driving voltage VD and the driving voltage VS) in series, the driving voltage VD and the driving voltage VS can have the same change trend, so that the voltage range between the driving voltage VD and the driving voltage VS (equivalent to the voltage difference between the driving voltage VD and the driving voltage VS) has a more linear change trend. For example, if the level of the driving voltage VD is reduced due to factors such as process variation, voltage variation and / or temperature variation, the level of the driving voltage VS will also be reduced based on the series coupling relationship formed by the resistor R. Alternatively, if the level of the driving voltage VD increases due to the above factors, the level of the driving voltage VS will also increase based on the series coupling relationship formed by the resistor R. On the other hand, if the current used by the logic circuit 130 changes, the negative feedback mechanism formed by the two low-dropout regulators can adjust the control signal VC1 and the control signal VC2 accordingly, so that the driving voltage VD and the driving voltage VS are restored to a stable level. In this way, in addition to adjusting the driving voltage VS to reduce the leakage current of the logic circuit 130, it can also ensure that the logic circuit 130 has a sufficient operable voltage range.

[0037] In some embodiments, the size of the transistor MP, the size of the transistor MN and / or the resistance value of the resistor R can be adjusted according to the specification parameters such as the current required by the logic circuit 130. Figure 2 As shown, the rail-to-rail low dropout regulator 120 may further include a capacitor C. The capacitor C is coupled in parallel with the resistor R to stabilize the driving voltage VD and the driving voltage VS.

[0038] In some embodiments, the voltage interval between the driving voltage VS and the driving voltage VS may be approximately 0.8V, and the operation speed (or the signal frequency generated) of the logic circuit 130 may be approximately 200 kHz. The above values ​​are only for example, and the present application is not limited thereto.

[0039] Figure 3 Flow chart of the power supply method 300 provided in the embodiment of the present application. In step S310, a plurality of reference voltages (for example Figure 1 or Figure 2 In step S320, a plurality of control signals (for example, Figure 2 In step S330, a plurality of driving voltages (for example, Figure 1 or Figure 2 The driving voltage VD and the driving voltage VS) are used to power a logic circuit, wherein the driving voltages have the same variation trend.

[0040] The above-mentioned multiple operations can be understood with reference to the above-mentioned embodiments, so they will not be repeated. The multiple operations of the above-mentioned power supply method 300 are only examples and are not limited to being performed in the order in this example. Without violating the operation mode and scope of the embodiments of the present application, the various operations under the power supply method 300 can be appropriately increased, replaced, omitted or performed in a different order (for example, they can be performed simultaneously or partially simultaneously).

[0041] It should be noted that, in the embodiments of the present application, “plurality” refers to “two” and “more than two”.

[0042] In summary, the digital circuit system and power supply method in some embodiments of the present application can use a rail-to-rail low voltage dropout regulator to power a logic circuit with low power consumption requirements. In this way, the threshold voltage of the transistor in the logic circuit can be adjusted and the leakage current can be reduced, and the operable voltage range of the logic circuit can be set to set the dynamic power consumption of the logic circuit, thereby meeting the low power consumption requirements.

[0043] The digital circuit system and power supply method provided by the embodiment of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A digital circuit system, characterized in that: include: a reference voltage generator, generating a plurality of reference voltages; a rail-to-rail low voltage dropout regulator, generating a plurality of control signals according to the plurality of reference voltages, and generating a plurality of driving voltages according to the plurality of control signals, wherein the plurality of driving voltages have the same variation trend; as well as a logic circuit operating in a voltage range between the plurality of driving voltages; A driving voltage among the plurality of driving voltages is used to adjust a threshold voltage of a transistor in the logic circuit.

2. The digital circuit system according to claim 1, wherein: The rail-to-rail low voltage dropout regulator comprises: A plurality of amplifiers, generating a first control signal and a second control signal among the plurality of control signals according to the plurality of reference voltages; a first transistor, controlled by the first control signal and generating a first driving voltage among the plurality of driving voltages; a second transistor, controlled by the second control signal and generating a second driving voltage among the plurality of driving voltages; and A resistor is coupled between the first transistor and the second transistor.

3. The digital circuit system according to claim 2, characterized in that: The plurality of amplifiers include: a first amplifier, generating the first control signal according to a first reference voltage among the plurality of reference voltages and the first driving voltage; and A second amplifier generates the second control signal according to a second reference voltage among the plurality of reference voltages and the second driving voltage.

4. The digital circuit system according to claim 2, characterized in that: The rail-to-rail low voltage dropout regulator further includes: A capacitor is coupled in parallel with the resistor.

5. The digital circuit system according to claim 1, wherein: The logic circuit is implemented by at least one input / output transistor.

6. The digital circuit system according to claim 1, wherein: The logic circuit is a real-time clock generator.

7. A power supply method, applied to a digital circuit system, characterized in that: include: Generate multiple reference voltages; generating a plurality of control signals according to the plurality of reference voltages; as well as generating a plurality of driving voltages according to the plurality of control signals to power a logic circuit in the digital circuit system, wherein the plurality of driving voltages have the same variation trend; One of the plurality of driving voltages is used to adjust a threshold voltage of a transistor in the logic circuit.

8. The power supply method according to claim 7, characterized in that: Generating a plurality of control signals according to the plurality of reference voltages comprises: generating a first control signal among the plurality of control signals according to a first reference voltage among the plurality of reference voltages and a first driving voltage among the plurality of driving voltages through a first amplifier; and A second control signal among the plurality of control signals is generated by a second amplifier according to a second reference voltage among the plurality of reference voltages and a second driving voltage among the plurality of driving voltages.

9. The power supply method according to claim 7, characterized in that: Generating a plurality of driving voltages according to the plurality of control signals comprises: generating a first driving voltage among the plurality of driving voltages according to a first control signal among the plurality of control signals by a first transistor; and A second driving voltage among the plurality of driving voltages is generated by a second transistor according to a second control signal among the plurality of control signals, wherein the first transistor is coupled to the second transistor via a resistor.

Images