Power detection circuit, system and method

Abstract

A power detection circuit, system, and method are provided. The power detection circuit includes a comparison circuit configured to generate an output signal in response to an input signal. The output signal is configured to change from a first value to a second value in response to the input signal reaching a first threshold. The output signal is configured to change from the second value to the first value in response to the input signal subsequently reaching a second threshold. A current limiting circuit is connected to the comparison circuit and is operable to limit the leakage current of the comparison circuit.

Description

Technical Field

[0001] Embodiments of the present invention relate to a power detection circuit, system, and method. Background Art

[0002] It is generally desirable to detect the power flow of a circuit such as a power supply on a chip to reduce or prevent interface leakage in a dual - power system. For example, a power detector can be configured to detect the voltage level of the input power. When the voltage level is higher than a certain threshold, the power detector outputs a specific logic state to indicate that the power supply is turned on. When the voltage is lower than a certain threshold, the power detector outputs another logic state to indicate that the power supply is turned off. Summary of the Invention

[0003] According to one aspect of an embodiment of the present invention, a power detection circuit is provided, including: a comparison circuit for generating an output signal in response to an input signal, wherein the output signal is configured to change from a first value to a second value in response to the input signal reaching a first threshold, and wherein the output signal is configured to change from the second value to the first value in response to the input signal subsequently reaching a second threshold; and a current - limiting circuit connected to the comparison circuit and for limiting the leakage current of the comparison circuit.

[0004] According to another aspect of an embodiment of the present invention, a power detection device is provided, including a power detection circuit, wherein the power detection circuit includes: a comparison circuit for generating an output signal in response to an input signal, wherein the comparison circuit for generating the output signal is configured to: provide an output signal including a first logic value in response to the input signal reaching a first threshold, and provide an output signal including a second logic value when the input signal subsequently reaches a second threshold, the second logic value being different from the first logic value; a current - limiting circuit connected to the comparison circuit and for limiting the leakage current of the comparison circuit; and a feedback circuit connected to the comparison circuit and for controlling the first predetermined threshold and the second predetermined threshold.

[0005] According to another aspect of an embodiment of the present invention, a method for detecting power in a circuit is provided. The method includes: receiving an input signal at a comparison circuit; comparing the input signal with a first threshold by the comparison circuit; based on comparing the input signal with the first threshold, providing an output signal by the comparison circuit, wherein providing the output signal based on comparing the input signal with the first threshold includes providing an output signal including a first logic value in response to the input signal reaching the first threshold; comparing the input signal with a second threshold after reaching the first threshold by the comparison circuit; in response to the input signal reaching the second threshold after reaching the first threshold, providing an output signal including a second value by the comparison circuit; controlling the first threshold and the second threshold by a feedback circuit, wherein the feedback circuit is connected to the comparison circuit; and limiting the leakage current of the comparison circuit by a current limiting circuit, wherein the current limiting circuit is connected in parallel with the feedback circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] When read in conjunction with the Figure 1 following detailed description, the embodiments of the present invention can be best understood. It should be noted that, in accordance with standard practice in the industry, the various components are not drawn to scale. In fact, for the sake of clear discussion, the dimensions of the various components can be arbitrarily increased or decreased.

[0007] Figure 1 is a schematic diagram of a power detection circuit according to some embodiments.

[0008] Figure 2 is a diagram showing signals of a power detection circuit according to some embodiments.

[0009] Figure 3 is a partial block diagram and partial circuit diagram of a power detection circuit according to some embodiments.

[0010] Figure 4 is an exemplary circuit diagram of a power detection circuit according to some embodiments.

[0011] Figure 5A and Figure 5B show power-on detection according to some embodiments.

[0012] Figure 6A and Figure 6B show power-off detection according to some embodiments.

[0013] Figure 7 is a diagram showing the leakage current of a power detection circuit in some embodiments of the present invention.

[0014] Figure 8 is a partial block diagram and partial circuit diagram of a first alternative power detection circuit according to some embodiments.

[0015] Figure 9 is a partial block diagram and a partial circuit diagram of a second alternative power detection circuit according to some embodiments.

[0016] Figure 10 is a flowchart showing a method for detecting input power in a circuit according to some embodiments. Detailed Description

[0017] The following disclosure provides many different embodiments or examples for implementing the different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present invention. Of course, these are merely examples and are not intended to limit the present invention. For example, in the following description, forming a first component above or on a second component may include embodiments where the first component and the second component are in direct contact, and may also include embodiments where additional components may be formed between the first component and the second component such that the first component and the second component may not be in direct contact. Additionally, the present invention may repeat reference numerals and / or characters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0018] It will be understood that although terms such as "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another. Thus, without departing from the spirit and scope of the present invention, the first element, first component, first region, first layer, or first section described below may be referred to as a second element, second component, second region, second layer, or second section.

[0019] It will be understood that when an element or layer is referred to as being "on", "connected to", or "coupled to" another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or there may be one or more intervening elements or intervening layers. Additionally, it will also be understood that when an element or layer is referred to as being "between" two elements or two layers, it can be the only element or layer between the two elements or two layers, or there may also be one or more intervening elements or intervening layers.

[0020] There are known techniques for detecting the power flow to a circuit. However, these known techniques have disadvantages such as high leakage of power. The leakage results in low circuit efficiency and increased power consumption. Figure 1It is a block diagram of a power detection circuit according to some embodiments. The power detection circuit 100 can be associated with a device or a circuit and is used to determine the state of the input voltage or input power of the associated device or circuit. For example, the power detection circuit 100 is used to continuously compare the value of the input voltage or input power with a first threshold and a second threshold. Based on this comparison, the power detection circuit 100 is used to provide a predetermined value to the output signal, which indicates whether the input voltage or input power is higher or lower than the first threshold and the second threshold. For example, the power detection circuit 100 is used to provide an output signal with a first logic value in response to determining that the input voltage of the associated circuit or device is greater than (or has reached) the first threshold. In addition, the power detection circuit 100 is used to provide an output signal with a second logic value in response to determining that the input voltage of the associated circuit or device is lower than (or has reached) the second threshold after reaching the first threshold. That is, the power detection circuit 100 is used to change the value of the output signal from the first logic value to the second logic value in response to the input voltage dropping below the second threshold after reaching the first threshold.

[0021] As Figure 1 shown, the power detection circuit 100 includes a first input terminal 102 (also referred to as PWR_IN102). In addition, the power detection circuit 100 includes a second input terminal 104 (also referred to as PWR_REF 104). The first input terminal 102 (i.e., PWR_IN 102) is used to receive an input signal, and the second input terminal 104 (i.e., PWR_REF 104) is used to receive a reference signal. The input signal represents the input voltage or input power supplied to the associated device or circuit. The reference signal represents the power supply voltage (also referred to as the power supply or reference voltage) applied to the associated device or circuit. In some embodiments, the input signal is also referred to as the PWR_IN signal, and the output signal is referred to as the PWR_RDY signal. Although Figure 1 the power detection circuit 100 shown is depicted as including only one power supply voltage input (i.e., PWR_REF 104), it will be apparent to those of ordinary skill in the art that the power detection circuit 100 can include more than one power supply voltage input terminal.

[0022] Continuing Figure 1 , the power detection circuit 100 further includes a comparison circuit 108, a current limiting circuit 110, and a feedback circuit 112. The comparison circuit 108 is used to generate an output signal (i.e., the PWR_RDY signal) in response to the input signal (i.e., the PWR_IN signal). For example, the comparison circuit 108 is used to continuously compare the value of the input signal with a first threshold and a second threshold. In an exemplary embodiment, each of the first threshold and the second threshold can be based on the PWR_REF signal. For example, the first threshold can be 0.5 times the voltage of the PWR_REF signal, and the second threshold can be 0.3 times the voltage of the PWR_REF signal.

[0023] The comparison circuit 108 is also configured to generate an output signal having a first logic value (i.e., logic value 1 or logic value 0) based on a comparison in response to the input signal reaching a first threshold, and to provide an output signal having a second logic value (i.e., logic value 0 or logic value 1) when the input signal subsequently reaches a second threshold. The comparison circuit 108 includes one or more transistors. In an example embodiment, the transistors of the comparison circuit 108 may each include a metal-oxide-semiconductor field-effect transistor, an n-channel metal-oxide-semiconductor transistor, a p-channel metal-oxide-semiconductor transistor, or a complementary metal-oxide-semiconductor transistor. However, other types of transistors are also within the scope of the present invention.

[0024] The current-limiting circuit 110 is connected between the comparison circuit 108 and the power supply voltage. Additionally, the current-limiting circuit 110 may also be connected between the comparison circuit 108 and ground. The current-limiting circuit 110 is configured to limit the leakage current of the comparison circuit 108. For example, the current-limiting circuit 110 is configured to limit the leakage current of one or more transistors of the comparison circuit 108. The current-limiting circuit 110 includes one or more resistors or transistors. In an example embodiment, the transistors of the current-limiting circuit 110 may include metal-oxide-semiconductor field-effect transistors, n-channel metal-oxide-semiconductor transistors, p-channel metal-oxide-semiconductor transistors, and complementary metal-oxide-semiconductor transistors. Additionally, it will be apparent to those skilled in the art after reading the present invention that other types of transistors are also within the scope of the present invention.

[0025] The feedback circuit 112 is connected to the comparison circuit 108. In some instances, the feedback circuit is connected in parallel with the current-limiting circuit 110. The feedback circuit 112 is configured to control one or both of the first threshold and the second threshold associated with the comparison circuit 108. The feedback circuit 112 includes one or more transistors. In an exemplary embodiment, the transistors of the feedback circuit 112 may include metal-oxide-semiconductor field-effect transistors, n-channel metal-oxide-semiconductor transistors, p-channel metal-oxide-semiconductor transistors, and complementary metal-oxide-semiconductor transistors. However, other types of transistors are also within the scope of the present invention.

[0026] Figure 2 Chart 200 is a graph showing the input signal and the output signal of the power detection circuit 100 according to some embodiments. As Figure 2 shown, chart 200 includes a first graph 202 representing the input signal (i.e., the PWR_IN signal), a second graph 204 representing the reference signal (i.e., the PWR_REF signal), and a third graph 206 representing the input signal (i.e., the PWR_RDY signal).

[0027] As shown in the first graph 210 and the third graph 206 of the chart 200, when the value of the input signal (i.e., the PWR_IN signal) exceeds the first threshold (also referred to as vtripr 208), the value of the output signal (i.e., that is, the PWR_RDY signal) changes from the first logic value to the second logic value (i.e., from logic value 0 to logic value 1), and remains at the second logic as long as the value of the PWR_IN signal remains higher than the second threshold (also referred to as vtripf 210). However, when the value of the PWR_IN signal subsequently reaches (or drops below) the second threshold (i.e., vtripf 210), the value of the PWR_RDY signal changes from the second logic value to the first logic value (i.e., from logic value 1 to logic value 0).

[0028] In some embodiments, the first threshold (i.e., vtripr 208) and the second threshold (i.e., vtripf 210) are predetermined. For example, each of the first threshold (i.e., vtripr 208) and the second threshold (i.e., vtripf 210) is predetermined by the user or through the design of the power detection circuit 100. In addition, the first threshold (i.e., vtripr 208) may be different from the second threshold (i.e., vtripf 210). For example, the first threshold (i.e., vtripr 208) is higher than the second threshold (i.e., vtripf 210). In an exemplary embodiment, the first threshold may be the minimum voltage required to turn on a component of a device or circuit associated with the power detection circuit 100. In addition, the second threshold may be the minimum voltage required to keep a component of a device or circuit associated with the power detection circuit 100 turned on. In some embodiments, each of the first threshold (i.e., vtripr 208) and the second threshold (i.e., vtripf 210) is configured dynamically.

[0029] Figure 3 is a partial block diagram and a partial circuit diagram of a power detection circuit 100 according to some embodiments. As Figure 3 shown, the power detection circuit 100 includes a comparison circuit 108, a first current limiting circuit 110A, a second current limiting circuit 110B, and a feedback circuit 112. Although Figure 3 the power detection circuit 100 of is shown as including two current limiting circuits (i.e., the first current limiting circuit 110A and the second current limiting circuit 110B), it will be apparent to those skilled in the art after reading the present invention that the power detection circuit 100 may include only one current limiting circuit 110 or more than two current limiting circuits. In addition, the power detection circuit 100 includes a first input terminal 102 (i.e., PWR_IN 102) and a second input terminal 104 (i.e., PWR_REF 104).

[0030] Comparator circuit 108 is used to determine the value of the input signal and provides an output signal (i.e., the PWR_RDY signal) by comparing the determined value with a plurality of thresholds, such as a first threshold (i.e., vtripr 208) and a second threshold (i.e., vtripf 210). As Figure 3 shown, comparator circuit 108 includes a first transistor M1302, a second transistor M2304, and an inverter 306. The first transistor M1302 may be a pMOS transistor, and the second transistor M2304 may be an nMOS transistor. However, after reading this invention, it will be obvious to those of ordinary skill in the art that other types of transistors are also within the scope of this invention.

[0031] Inverter 306 is a NOT logic gate. However, after reading this invention, it will be obvious to those of ordinary skill in the art that other types of inverters are also within the scope of this invention. Feedback circuit 112 includes a third transistor M3308. The third transistor M3308 may be an nMOS transistor. However, after reading this invention, it will be obvious to those of ordinary skill in the art that other types of transistors are also within the scope of this invention.

[0032] The drain / source of the first transistor M1302 is connected to the source / drain of the second transistor M2304 at a first node 312. In addition, the input terminal of the inverter 306 is connected to the first node 312. The output terminal of the inverter 306 is connected to a second node 314. The output terminal of the inverter 306 is also the output terminal of the comparator circuit 108 and the power detection circuit 100. The output terminal of the comparator circuit 108 is set as the output signal at PWR_RDY 106.

[0033] Continue Figure 3 , the drain / source of the second transistor M2304 is connected to a third node 316. In addition, the source / drain of the third transistor M3308 is also connected to the third node 316. In addition, the first terminal of the second current limiting circuit 110B is connected to the third node 316. The second terminal of the second current limiting circuit 110B is grounded. In addition, the drain / source of the third transistor M3308 is also grounded. Therefore, the third transistor M3308 is connected in parallel with the second current limiting circuit 110B. Therefore, the second current limiting circuit 110B is connected in parallel with the feedback circuit 112.

[0034] Still continue Figure 3, the source / drain of the first transistor 302 is connected to the fourth node 318. In addition, the second terminal of the first current limiting circuit 110A is connected to the fourth node 318. In addition, the first terminal of the first current limiting circuit 110A is connected to the power supply voltage (i.e., PWR_REF 104). Thus, the first current limiting circuit 110A is connected between the power supply voltage and the comparison circuit 108. As will be discussed further below, the first current limiting circuit 110A is used to control or limit the leakage current of the comparison circuit 108 through PWR_REF 104.

[0035] The first terminal of the second current limiting circuit 110B is connected to the third node 316, and the second terminal of the second current limiting circuit 110B is grounded. Thus, the second current limiting circuit 110B is connected between the comparison circuit 108 and ground. Thus, the second current limiting circuit 110B is used to control or limit the leakage current of the comparison circuit 108 to ground.

[0036] Figure 4 is an exemplary circuit diagram of the power detection circuit 100 according to some embodiments. As Figure 4 shown, the first current limiting circuit 110A includes a fourth transistor M4402A, and the second current limiting circuit 110B includes a fifth transistor M5402B. Each of the fourth transistor M4402A of the first current limiting circuit 110A and the fifth transistor M5402B of the second current limiting circuit 110B is an nMOS transistor. However, after reading the present invention, it will be apparent to those of ordinary skill in the art that other types of transistors are also within the scope of the present invention.

[0037] Continue Figure 4 , the source / drain of the fourth transistor M4402A of the first current limiting circuit 110A is connected to PWR_REF104 (i.e., the power supply voltage). In addition, the gate of the fourth transistor M4402A is also connected to PWR_REF 104 (i.e., the power supply voltage). In addition, the drain / source of the fourth transistor M4402A is connected to the fourth node 318. Thus, the fourth transistor M4402A is connected between the power supply voltage and the comparison circuit 108. In operation, the fourth transistor M4402A is used to control or limit the leakage current of the comparison circuit 108 through PWR_REF 104.

[0038] The source / drain of the fifth transistor M5402B is connected to the third node 316. In addition, the gate of the fifth transistor M5402B is also connected to the third node 316. In addition, the drain / source of the fifth transistor M5402B is grounded. Thus, the fifth transistor M5402B is connected between the comparison circuit 108 and ground. In operation, the fifth transistor M5402B is used to control or limit the leakage current of the comparison circuit 108 to ground.

[0039] Figure 5A and Figure 5B illustrates power-on detection according to some embodiments. In Figure 5A shows a power-on region 502 of an input signal. As Figure 5A shown, the power-on region 502 represents a region near a first threshold value (i.e., vtripr 208) of a first curve graph 202 representing an input signal (i.e., input voltage or input power). In an exemplary embodiment, the value of the input signal in the power-on region 502 (represented by the first curve graph 202) is less than the first threshold value (i.e., vtripr 208), but is sufficient to turn on a first transistor M1302 and a second transistor M2304 of the comparison circuit 108.

[0040] In an exemplary embodiment, since the value of the input signal (represented by the first curve graph 202) in the power-on region 502 is less than the first threshold value (i.e., vtripr 208), the value of the output signal of the power detection circuit 100 is at a logical value 0. Accordingly, a second node 314 of the power detection circuit 100 is at a logical value 0. Since the second node 314 is at a logical value 0, a first node 312 of the power detection circuit 100 is at a logical value 1. Further, in the power-on region 502, the value of the input signal is still not sufficient to turn on the second transistor M2304 of the comparison circuit 108. Accordingly, the second transistor M2304 of the comparison circuit 108 remains turned off. However, in the power-on region 502, the first transistor M1302 of the comparison circuit 108 is turned on. Further, since the second node 314 is at a logical value 0, a third transistor M3308 of a feedback circuit 112 of the power detection circuit 100 is disconnected from the power detection circuit 100 (this disconnection is represented by a dashed line).

[0041] Further, in the power-on region 502, since the second transistor M2304 of the comparison circuit 108 is turned off, a fifth transistor M5402B of a second current limiting circuit 110B is also turned off, thereby limiting leakage current from the comparison circuit 108 to ground. Further, although a fourth transistor M4402A of a first current limiting circuit 110A is turned on, a first terminal of the fourth transistor M4402A is connected to a power supply voltage higher than the input voltage, thereby limiting leakage current from the comparison circuit 108 to ground. Accordingly, the first threshold value is determined by one or more of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the fifth transistor 402B. For example, the first threshold value is determined by the width and type of the material or other inherent characteristics of one or more of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the fifth transistor M5402B.

[0042] For example, the current provided through the fourth transistor M4402A is:

[0043]

[0044] Similarly, the current supplied through the first transistor M1302 is:

[0045]

[0046] In addition, the current supplied through the second transistor M2304 is:

[0047]

[0048] In addition, the current supplied through the fifth transistor M5402B is:

[0049]

[0050] where V x is the voltage of the fourth node 318, V y is the voltage of the first node 312, and V0 is the voltage of the third node 316.

[0051] In Figure 5B I M4 is equal to I M1 , which is equal to I M2 , which is equal to I M5 . That is:

[0052] I M4 = I M1 = I M2 = I M5 …(5)

[0053] In addition, to simplify the calculation, if it is assumed that K, Vt, and are the same for each of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the fifth transistor M5402B. In addition, V0 is assumed to be equal to 0.5(V PWR_REF ). Therefore, according to equations (1), (2), (3), (4), and (5):

[0054] V x = 0.75(V PWR_REF )

[0055] V y = 0.25(V PWR_REF )

[0056] V tripr = 0.50(V PWR_REF )

[0057] Thus, in an exemplary embodiment, by changing the K, Vt, and of each of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the fifth transistor M5402B,

[0058] Figure 6A and Figure 6B shows power-off detection according to some embodiments. In Figure 6A the power-off region 602 of the input signal is shown. As Figure 6A shown, the power-off region 602 represents a region near the second threshold (i.e., vtripf210) of the first curve graph 202 representing the input signal (i.e., input voltage or input power). In an exemplary embodiment, the value of the input signal in the power-off region 602 (represented by the first curve graph 202) is greater than the second threshold (i.e., vtripf210) and less than the first threshold (i.e., vtripr 208), but is not sufficient to turn off the second transistor M2304 of the comparison circuit 108.

[0059] In an exemplary embodiment, even though it is lower than the first threshold, the value of the input signal in the power-off region 602 (represented by the first curve graph 202) is still greater than the second threshold (i.e., vtripf210), and the value of the output signal of the power detection circuit 100 is still at the logical value 1. Therefore, the second node 314 of the power detection circuit 100 is still at the logical value 1. Since the second node 314 is at the logical value 1, the first node 312 of the power detection circuit 100 is at the logical value 0. In addition, although it is lower than the first threshold (vtripr 208), the value of the input signal in the cut-off region 602 is still not sufficient to turn off the second transistor M2304 of the comparison circuit 108. Therefore, in the power-off region 602, the first transistor M1302 of the comparison circuit 108 is turned off, and the second transistor M2304 of the comparison circuit 108 is turned on. In addition, the fourth transistor M4402A of the first current limiting circuit 110A is also turned off, thereby limiting the leakage current of the comparison circuit 108 through PWR_REF 104. For example, when the input signal (represented by the first curve graph 202) approaches the threshold of the power detection circuit 100, the first transistor M1302 and the second transistor M2304 can be turned on simultaneously, thereby generating a leakage path. By adding the current limiting circuit 110, due to the voltage drop generated by the current limiting circuit 110, the bias voltage (Vgs) of the first transistor M1302 and the bias voltage (Vgs) of the second transistor M2304 are reduced. Therefore, the leakage current is reduced according to the saturation current equation Id = 1 / 2K(Vgs - Vt)^2, where Vt is the threshold voltage of the first transistor M1302 and the second transistor M2304.

[0060] In addition, in the power-off area 602, since the second node 314 is at a logic value of 1, the third transistor M3308 of the feedback circuit 112 of the power detection circuit 100 is turned on. In addition, since the third transistor M3308 is turned on, the third node 316 is at a logic value of 0. Therefore, the fifth transistor M5402B of the second current-limiting circuit 110B is disconnected from the power detection circuit 100 (the disconnection is indicated by a dotted line). In addition, the second threshold (i.e., vtripf210) is determined by one or more of the first transistor M1302, the second transistor M2304, the third transistor M3308, and the fourth transistor M4402A. For example, the second threshold is determined by the width and type of the material or other inherent characteristics of one or more of the first transistor M1302, the second transistor M2304, the third transistor M3308, and the fourth transistor M4402A.

[0061] For example, the current supplied through the fourth transistor M4402A is:

[0062]

[0063] Similarly, the current supplied through the first transistor M1302 is:

[0064]

[0065] In addition, the current supplied through the second transistor M2304 is:

[0066]

[0067] In addition, it can be assumed that the current flowing through the third transistor M3308 operating in a linear mode is supplied as:

[0068] I M3 =K3(V PWR_REF -V t3 )V y …(9)

[0069] In Figure 6B I M4 is equal to I M1 which is equal to I M2 which is equal to I M5 . That is:

[0070] I M4 =I M1 =I M2 =I M3 …(10)

[0071] In addition, to simplify the calculation, if for each of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the third transistor M3308, K, Vt, and are the same. In addition, V0 is assumed to be equal to 0.5(V PWR_REF ), and V y is equal to 0. Therefore, according to equations (6), (7), (8), (9), and (10):

[0072] V x = 2 / 3(V PWR_REF )

[0073] V tripf = 1 / 3(V PWR_REF )

[0074] Therefore, in the exemplary embodiment, by changing K, Vt, and for each of the first transistor M1302, the second transistor M2304, the fourth transistor M4402A, and the third transistor M3308, the second threshold Vtripf is changed.

[0075] Figure 7 FIG. 700 is a graph showing the leakage current of the power detection circuit 100 in some embodiments of the present invention. As Figure 7 shown, the graph 700 includes a first curve 702 representing the input signal, a second curve 704 representing the reference signal, a third curve 706 representing the PWR_RDY signal (represented by a dashed line), a fourth curve 708 representing the leakage current (represented by a dashed line), a fifth curve 710 representing the PWR_RDY signal of the conventional power detection circuit (represented by a solid line), and a sixth curve 712 representing the leakage current in the conventional power detection circuit (represented by a solid line). As shown by the first curve 702 and the third curve 706 of the graph 700, when the input signal reaches the first threshold (denoted as vtripr 208), the PWR_RDY signal changes from the first logic value (e.g., logic value 0) to the second logic value (e.g., logic value 1). In addition, and as shown by the first curve 702 and the third curve 706 of the graph 700, after the second threshold (denoted as vtripf210) reaches the first threshold, when the input signal drops below the second threshold (denoted as vtripf210), the PWR_RDY signal changes from the second logic value (e.g., logic value 1) to the first logic value (e.g., logic value 0).

[0076] Continue Figure 7, compared with the sharp increase in the leakage current (represented by the sixth graph 712) of the conventional power detection circuit, the leakage current (represented by the fourth graph 708) remains constant and does not change with the change of the input voltage. In addition, as shown by the fourth curve 708, near the power-on region 502 and the power-off region 602, the increase in the leakage current is limited. However, compared with the sharp increase of the conventional power detection circuit, this increase is limited (as shown by the sixth graph 712).

[0077] Figure 8 is a partial block diagram and a partial circuit diagram of a first alternative power detection circuit 100' according to some embodiments. As Figure 8 shown, the first alternative power detection circuit 100' includes a first current limiting circuit 110A. In addition, the first alternative power detection circuit 100' includes a first transistor M1302, a second transistor M2304, a third transistor M3308, and an inverter 306. The first transistor M1302, the second transistor M2304, and the inverter 306 form a comparison circuit 108. The third transistor M3308 forms a feedback circuit 112 connected in parallel with the first current limiting circuit 110A. For example, the gate of the third transistor M3308 is connected to the second node 314, the source / drain of the third transistor M3308 is connected to PWR_REF 104, and the drain / source of the third transistor M3308 is connected to the fourth node 318. The first current limiting circuit 110A is connected between the fourth node 318 and PWR_REF 104, and is used to limit the leakage current of the comparison circuit 108 via PWR_REF 104.

[0078] During operation, when the value of the input signal is less than the first threshold (i.e., vtripr208), the value of the output signal of the comparison circuit 108 is at the logical value 0. In addition, when the value of the input signal is less than the first threshold (i.e., vtripr208), the third transistor M3308 is turned on and the first current limiting circuit 110A is bypassed. However, when the value of the input signal is greater than the second threshold (i.e., vtripf210), the third transistor M3308 is cut off, and the leakage current is limited by the first current limiting circuit 110A. Therefore, according to an exemplary embodiment, when the value of the input signal is greater than the second threshold (i.e., vtripf210), the reference Figure 8 described first alternative power detection circuit 100' is used to limit the leakage current..

[0079] Figure 9 is a partial block diagram and a partial circuit diagram of a second alternative power detection circuit 100" according to some embodiments. As Figure 9As shown, the second alternative power detection circuit 100” includes a second current limiting circuit 110B. In addition, the first alternative power detection circuit 100' includes a first transistor M1302, a second transistor M2304, a third transistor M3308, and an inverter 306. The first transistor M1302, the second transistor M2304, and the inverter 306 form a comparison circuit 108. The third transistor M3308 forms a feedback circuit 112, and the feedback circuit 112 is connected in parallel with the second current limiting circuit 110B. For example, the gate of the third transistor M3308 is connected to the second node 314, the source / drain of the third transistor M3308 is connected to the third node 316, and the drain / source of the third transistor M3308 is connected to ground. The second current limiting circuit 110B is connected between the third node 316 and ground and is used to limit the leakage current of the comparison circuit 108 via ground.

[0080] During operation, when the value of the input signal is less than the first threshold (i.e., vtripr208), the value of the output signal of the comparison circuit 108 is at the logical value 0. In addition, when the value of the input signal is less than the first threshold (i.e., vtripr208), the third transistor M3308 is cut off. Therefore, the leakage current is limited by the second current limiting circuit 110B. However, when the value of the input signal is greater than the second threshold (i.e., vtripf210), the third transistor M3308 is turned on, and the second current limiting circuit 110B is bypassed. Therefore, according to the exemplary embodiment, when the value of the input signal is less than the first threshold (i.e., vtripr208), the second alternative power detection circuit 100” described with reference to Figure 9 is used to limit the leakage current.).

[0081] Figure 10 is a flowchart showing a method 1000 for detecting input power in a detection circuit according to some embodiments. For example, the method 100 can be implemented in the power detection circuits 100, 100', and 100” described with reference to Figure 1 , Figure 3 , Figure 4 , Figure 5B , Figure 6B , Figure 8 and Figure 9 . The method 1000 can be executed by a processor. In addition, the method 1000 can be stored as instructions on a storage device, and when executed by the processor, the instructions can cause the processor to execute the method 1000.

[0082] At block 1010 of method 1000, an output signal is provided in response to an input signal via a comparison circuit. For example, the PWR_IN signal is received at comparator 108 of power detection circuit 100 and compared with a first threshold (i.e., vtripr 208). In response to comparing the PWR_IN signal with the first threshold (i.e., vtripr 208), the PWR_RDY signal is provided by comparison circuit 108. For example, providing an output signal in response to an input signal includes providing a PWR_RDY signal having a first logic value (i.e., logic value 1) in response to the PWR_IN signal reaching the first threshold (i.e., vtripr 208), and providing a PWR_RDY signal including a second logic value (i.e., logic value 0) when the PWR_IN signal reaches a second threshold (i.e., vtripf 210) after reaching the first threshold (i.e., vtripr 208). The second logic value is different from the first logic value.

[0083] At block 1020 of method 1000, the first threshold (i.e., vtripr 208) and the second threshold (i.e., vtripf 210) are controlled. For example, each of the first threshold (i.e., vtripr 208) and the second threshold (i.e., vtripf 210) is controlled by controlling the width and type of a material or an inherent characteristic of one or more of the first transistor, or first transistor M1302, second transistor M2304, third transistor M3308, fourth transistor M4402A, and fifth transistor M5402B.

[0084] At block 1030 of method 1000, the leakage current of the comparison circuit is restricted via a current limiting circuit. For example, the leakage current of comparison circuit 108 is restricted by current limiting circuit 110 (i.e., one or both of first current limiting circuit 110A and second current limiting circuit 110B). Current limiting circuit 110 is connected to comparator 108 and is also connected in parallel with feedback circuit 112.

[0085] In an exemplary embodiment, the power detection circuit 100 described herein can be used to manage power in associated devices or circuits. Additionally, the power detection circuit 100 prevents or restricts power leakage from associated devices or circuits. For example, when the input voltage is close to the transition points (i.e., the first threshold and the second threshold), the power detection circuit 100 can restrict or reduce standby power leakage. Additionally, feedback circuit 112 of power detection circuit 100 provides transition point control, i.e., control of the first threshold and the second threshold. Thus, the power detection circuit 100 provides different thresholds for power on and power off detection. Additionally, each of the first threshold and the second threshold can be changed by changing feedback circuit 112. For example, the first threshold and the second threshold can be changed by changing the characteristics of third transistor M3306.

[0086] According to an exemplary embodiment, a power detection circuit includes: a comparison circuit configured to generate an output signal in response to an input signal, wherein the output signal is configured to change from a first value to a second value in response to the input signal reaching a first threshold, and wherein the output signal is configured to change from the second value to the first value in response to the input signal subsequently reaching a second threshold; and a current limiting circuit configured to limit a leakage current of the comparison circuit.

[0087] In the above power detection circuit, a feedback circuit is further included, the feedback circuit is connected to the comparison circuit, and is configured to control the first threshold and the second threshold.

[0088] In the above power detection circuit, the comparison circuit includes a first transistor, a second transistor, and an inverter, wherein the gates of each of the first transistor and the second transistor are connected to the input signal, wherein the source / drain of the first transistor is connected to the source / drain of the second transistor at a first node, wherein the input terminal of the inverter is connected to the first node, and wherein the output terminal of the inverter is configured to provide an output signal at a second node.

[0089] In the above power detection circuit, the first transistor is an n-channel metal oxide semiconductor transistor, and wherein the second transistor is a p-channel metal oxide semiconductor transistor.

[0090] In the above power detection circuit, the feedback circuit is connected to the second node.

[0091] In the above power detection circuit, the feedback circuit includes a third transistor, wherein the gate of the third transistor is connected to the second node, wherein the source / drain of the third transistor is connected to a third node, and wherein the drain / source of the third transistor is connected to ground.

[0092] In the above power detection circuit, the current limiting circuit includes a fourth transistor, wherein the gate of the fourth transistor is connected to the third node, wherein the source / drain of the fourth transistor is connected to the third node, and wherein the drain / source of the fourth transistor is connected to ground.

[0093] In the above power detection circuit, the current limiting circuit further includes a fifth transistor, wherein the gate of the fifth transistor is connected to a power supply voltage, wherein the source / drain of the fifth transistor is connected to the power supply voltage; and wherein the drain / source of the fifth transistor is connected to a fourth node.

[0094] In the above power detection circuit, the source / drain of the first transistor is connected to the fourth node.

[0095] In the above power detection circuit, the drain / source of the second transistor is connected to the third node.

[0096] In an exemplary embodiment, the device includes a power detection circuit, wherein the power detection circuit includes: a comparison circuit operable to generate an output signal in response to an input signal, wherein the comparison circuit for generating the output signal includes the comparison circuit being operable to: provide an output signal including a first logic value in response to the input signal reaching a first threshold, and provide an output signal including a second logic value different from the first logic value when the input signal subsequently reaches a second threshold; a current limiting circuit for limiting the leakage current of the comparison circuit; and a feedback circuit for controlling the first predetermined threshold and the second predetermined threshold.

[0097] In the above device, the second threshold is different from the first threshold.

[0098] In the above device, the second threshold is lower than the first threshold.

[0099] In the above device, the current limiting circuit includes a first current limiting circuit and a second current limiting circuit, the first current limiting circuit is connected in parallel with the feedback circuit, and the second current limiting circuit is connected between the reference voltage and the comparison circuit.

[0100] In the above device, the comparison circuit includes a first transistor and a second transistor, wherein the feedback circuit includes a third transistor, and wherein the current limiting circuit includes a fourth transistor and a fifth transistor.

[0101] In the above device, when the input signal is less than the first threshold, the third transistor is turned off, and wherein the first threshold is determined based on the first transistor, the second transistor, the fourth transistor, and the fifth transistor.

[0102] In the above device, when the input signal is greater than the second threshold, the fourth transistor is turned off, and wherein the second threshold is determined based on the first transistor, the second transistor, the third transistor, and the fifth transistor.

[0103] In the above device, the current limiting circuit is connected in parallel with the feedback circuit.

[0104] In the above device, the current limiting circuit includes at least one of the following: a resistor and a transistor, and wherein the transistor includes at least one of the following: a metal oxide semiconductor field effect transistor, an n-channel metal oxide semiconductor transistor, a p-channel metal oxide semiconductor transistor, and a complementary metal oxide semiconductor transistor.

[0105] According to an exemplary embodiment, a method of detecting power in a detection circuit includes: receiving an input signal at a comparison circuit; the comparison circuit comparing the input signal with a first threshold; the comparison circuit providing an output signal based on comparing the input signal with the first threshold, wherein providing the output signal based on comparing the input signal with the first threshold includes providing an output signal including a first logic value in response to the input signal reaching the first threshold; after the input signal reaches the first threshold, the comparison circuit comparing the input signal with a second threshold; in response to the input signal reaching the second threshold after reaching the first threshold, the comparison circuit providing an output signal including a second value; controlling the first threshold and the second threshold by a feedback circuit, wherein the feedback circuit is connected to the comparison circuit; and limiting a leakage current of the comparison circuit by a current limiting circuit, wherein the current limiting circuit is connected in parallel with the feedback circuit.

[0106] The foregoing outlines the features of several embodiments such that those skilled in the art may better understand the embodiments of the present invention. Those skilled in the art should understand that they can readily use the present invention as a basis to design or modify other processes and structures for implementing the same purposes and / or achieving the same advantages as the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructs do not depart from the spirit and scope of the present invention, and that various changes, substitutions, and alterations can be made therein without departing from the spirit and scope of the present invention.

Claims

1. A power detection circuit, comprising: A comparison circuit for generating an output signal in response to an input signal, wherein the output signal is configured to change from a first value to a second value in response to the input signal reaching a first threshold, and wherein the output signal is configured to change from the second value to the first value in response to the input signal subsequently reaching a second threshold, wherein the first value is different from the second value; A feedback circuit connected to the comparison circuit and configured to control the first threshold and the second threshold; and A current limiting circuit connected to the comparison circuit and configured to limit the leakage current of the comparison circuit, wherein the setting of the first threshold and the second threshold is independent of the magnitude of the input signal, wherein the first threshold is greater than the second threshold, and before the input signal increases to the first threshold, the output signal always maintains the first value, wherein the current limiting circuit includes a first current limiting circuit and a second current limiting circuit, the first current limiting circuit is connected in parallel with the feedback circuit, and the second current limiting circuit is only connected between the reference voltage and the comparison circuit.

2. The power detection circuit according to claim 1, wherein, The first threshold is 0.5 times the reference voltage, and the second threshold is 0.3 times the reference voltage.

3. The power detection circuit according to claim 2, wherein, The comparison circuit includes a first transistor, a second transistor and an inverter, wherein the gates of each of the first transistor and the second transistor are connected to the input signal, wherein the source / drain of the first transistor is connected to the source / drain of the second transistor at a first node, wherein the input terminal of the inverter is connected to the first node, and wherein the output terminal of the inverter is configured to provide the output signal at a second node.

4. The power detection circuit according to claim 3, wherein, The first transistor is an n-channel metal oxide semiconductor transistor, and wherein the second transistor is a p-channel metal oxide semiconductor transistor.

5. The power detection circuit according to claim 3, wherein, The feedback circuit is connected to the second node.

6. The power detection circuit according to claim 3, wherein, The feedback circuit includes a third transistor, wherein the gate of the third transistor is connected to the second node, wherein the source / drain of the third transistor is connected to a third node, and wherein the drain / source of the third transistor is connected to ground.

7. The power detection circuit according to claim 6, wherein, The first current limiting circuit includes a fourth transistor, wherein the gate of the fourth transistor is connected to the third node, wherein the source / drain of the fourth transistor is connected to the third node, and wherein the drain / source of the fourth transistor is connected to ground.

8. The power detection circuit according to claim 7, wherein, The second current limiting circuit further includes a fifth transistor, wherein the gate of the fifth transistor is connected to the power supply voltage, wherein the source / drain of the fifth transistor is connected to the power supply voltage; and wherein the drain / source of the fifth transistor is only connected to a fourth node.

9. The power detection circuit according to claim 8, wherein The source / drain of the first transistor is connected to the fourth node.

10. The power detection circuit according to claim 7, wherein, The drain / source of the second transistor is connected to the third node.

11. A power detection device, including a power detection circuit, wherein, The power detection circuit includes: A comparison circuit for generating an output signal in response to an input signal, wherein the comparison circuit for generating the output signal is configured to: In response to the input signal reaching a first threshold, providing the output signal including a first logic value, and when the input signal subsequently reaches a second threshold, providing the output signal including a second logic value different from the first logic value; a current limiting circuit connected to the comparison circuit and configured to limit the leakage current of the comparison circuit; and a feedback circuit connected to the comparison circuit and configured to control the first threshold and the second threshold, wherein the setting of the first threshold and the second threshold is independent of the magnitude of the input signal, and before the input signal increases to the first threshold, the output signal always maintains the first logic value.

12. The power detection device according to claim 11, wherein, The second threshold is different from the first threshold.

13. The power detection device according to claim 11, wherein, The second threshold is lower than the first threshold.

14. The power detection device according to claim 11, wherein, The current limiting circuit includes a first current limiting circuit and a second current limiting circuit, the first current limiting circuit is connected in parallel with the feedback circuit, and the second current limiting circuit is connected between the reference voltage and the comparison circuit.

15. The power detection device according to claim 11, wherein, The comparison circuit includes a first transistor and a second transistor, wherein the feedback circuit includes a third transistor, and wherein the current limiting circuit includes a fourth transistor and a fifth transistor.

16. The power detection device according to claim 15, wherein, When the input signal is less than the first threshold, turning off the third transistor, and wherein the first threshold is determined based on the first transistor, the second transistor, the fourth transistor, and the fifth transistor.

17. The power detection device according to claim 15, wherein, When the input signal is greater than the second threshold, turning off the fourth transistor, and wherein the second threshold is determined based on the first transistor, the second transistor, the third transistor, and the fifth transistor.

18. The power detection device according to claim 11, wherein, The current limiting circuit is connected in parallel with the feedback circuit.

19. The power detection device according to claim 11, wherein, The current limiting circuit includes at least one of the following: a resistor and a transistor, and wherein the transistor includes at least one of the following: a metal oxide semiconductor field effect transistor, an n-channel metal oxide semiconductor transistor, a p-channel metal oxide semiconductor transistor, and a complementary metal oxide semiconductor transistor.

20. A method for detecting power in a circuit, the method comprising: receiving an input signal at a comparison circuit; comparing the input signal with a first threshold by the comparison circuit; providing an output signal by the comparison circuit based on comparing the input signal with the first threshold, wherein providing the output signal based on comparing the input signal with the first threshold includes providing the output signal including a first logic value in response to the input signal reaching the first threshold; comparing the input signal with a second threshold after reaching the first threshold by the comparison circuit; providing the output signal including a second value by the comparison circuit in response to the input signal reaching the second threshold after reaching the first threshold; controlling the first threshold and the second threshold by a feedback circuit, wherein the feedback circuit is connected to the comparison circuit; and, The leakage current of the comparison circuit is limited by a current limiting circuit, wherein the current limiting circuit is connected in parallel with the feedback circuit. Wherein, the setting of the first threshold and the second threshold is independent of the magnitude of the input signal. Before the input signal increases to the first threshold, the output signal always maintains the first logic value.

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