Temperature sensor comprising a diode and a capacitor

Abstract

A temperature sensor configured to generate an output signal corresponding to a sensed and / or measured temperature, comprising: a diode comprising a cathode coupled to a ground node; a first capacitor comprising a first end coupled to the ground node; a switch circuit configured to connect a second end of the first capacitor to a positive voltage node or an anode of the diode according to a control signal; a switch control circuitry configured to generate the control signal based on a reference voltage and a voltage of the anode; and an output signal generator configured to generate the output signal corresponding to the sensed temperature based on a frequency of the control signal.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2019-0108940, filed on September 3, 2019, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Various exemplary embodiments of the present invention relate to temperature sensors, and more specifically, to temperature sensors and / or temperature sensing methods including diodes and capacitors. Background Technology

[0004] Temperature sensors can be used to measure and / or acquire temperature in a variety of applications. For example, devices included in integrated circuits may be temperature-dependent, and temperature sensors can be used to compensate for device performance when temperatures change. Furthermore, multiple temperature sensors can be arranged in an integrated circuit to control heat generation within the circuit. Therefore, temperature sensors with desired performance characteristics, such as high accuracy, high resolution, wide measurement range, low power consumption, and small area, are desirable. Summary of the Invention

[0005] Various exemplary embodiments of the present invention provide a temperature sensor that offers high accuracy and has a simple structure.

[0006] According to at least one exemplary embodiment of the present invention, a temperature sensor is provided, configured to generate an output signal corresponding to a sensed temperature, the temperature sensor comprising: a diode including a cathode coupled to a ground node; a first capacitor including a first end coupled to the ground node; a switching circuit configured to connect a second end of the first capacitor to a positive voltage node or the anode of the diode based on a control signal; a switching control circuit system configured to generate the control signal based on a reference voltage and the voltage of the anode of the diode; and an output signal generator configured to generate the output signal based on the frequency of the control signal.

[0007] According to an aspect of at least one example embodiment of the inventive concept, there is provided a temperature sensor configured to generate an output signal corresponding to a sensed temperature by switching between a first phase and a second phase, the temperature sensor comprising: a first capacitor and a diode; a first switch circuit configured to charge the first capacitor with a positive voltage in the first phase and to discharge the first capacitor through the diode in the second phase; a reference voltage generator configured to generate a reference voltage independently of the discharge of the first capacitor; a switch control circuitry configured to control the first switch circuit and to terminate the second phase based on a discharge voltage of the first capacitor and the reference voltage; and an output signal generator configured to generate the output signal corresponding to the sensed temperature based on a duration of the second phase.

[0008] According to an aspect of at least one example embodiment of the inventive concept, there is provided a temperature sensor configured to generate an output signal corresponding to a sensed temperature by switching between a first phase and a second phase, the temperature sensor comprising: a plurality of switches and a diode; a first capacitor configured to be charged with a positive voltage during the first phase through at least one of the plurality of switches and to be discharged through the diode during the second phase; a second capacitor configured to be discharged through the diode during the first phase through at least one of the plurality of switches and to be charged with the positive voltage during the second phase; a switch control circuitry configured to maintain a duration of the first phase and to terminate the second phase based on a reference voltage and a voltage of the first capacitor; and an output signal generator configured to generate the output signal corresponding to the sensed temperature based on a duration of the second phase. BRIEF DESCRIPTION OF DRAWINGS

[0009] Example embodiments of the inventive concept will become more fully understood from the detailed description given herein below, taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a block diagram of a temperature sensor according to at least one example embodiment;

[0011] Figure 2A and Figure 2B is a graph illustrating a capacitor-diode discharge characteristic according to at least one example embodiment;

[0012] Figure 3 is a block diagram of a switch control circuitry according to at least one example embodiment;

[0013] Figure 4 is a circuit diagram of a temperature sensor according to at least one example embodiment;

[0014] Figure 5is a timing chart illustrating an example of the operation of the temperature sensor according to at least one example embodiment. Figure 4

[0015] Figure 6 is a circuit diagram of the temperature sensor according to at least one example embodiment.

[0016] Figure 7 is a timing chart illustrating an example of the operation of the temperature sensor according to at least one example embodiment. Figure 6

[0017] Figure 8 is a circuit diagram of the temperature sensor according to at least one example embodiment.

[0018] Figure 9 is a timing chart illustrating an example of the operation of the temperature sensor according to at least one example embodiment. Figure 8

[0019] is a graph illustrating an example of a reference voltage according to at least one example embodiment. Figures 10A-10C

[0020] Figure 11 is a circuit diagram of the reference voltage generator according to at least one example embodiment.

[0021] Figure 12 is a circuit diagram of the temperature sensor according to at least one example embodiment.

[0022] Figure 13 is a circuit diagram and layout diagram of a diode included in the temperature sensor according to at least one example embodiment.

[0023] Figure 14 is a block diagram of the output signal generator according to at least one example embodiment.

[0024] Figure 15 is a timing chart illustrating an example of the operation of the output signal generator according to at least one example embodiment.

[0025] Figure 16 is a flowchart illustrating a method of sensing a temperature according to at least one example embodiment; and

[0026] Figure 17 is a block diagram of a system including a temperature sensor according to at least one example embodiment. DETAILED DESCRIPTION

[0027] Figure 1 is a block diagram of a temperature sensor 10 according to at least one example embodiment. The temperature sensor 10 can sense an ambient temperature and generate an output signal OUT corresponding to the sensed temperature. As shown in FIG. 1, the temperature sensor 10 includes a diode D1, a reference voltage generator 20, and an output signal generator 30.​​​Figure 1 As illustrated in FIG. 10, the temperature sensor 10 can include a first capacitor C1, a diode D, a first switching circuit 11, a switching control circuit system 13, a reference voltage generator 15, and / or an output signal generator 17, but is not limited thereto, and can include more or less constituent components. In some example embodiments, at least one of the components of the temperature sensor 10 can be manufactured through a semiconductor process. Also, in some example embodiments, the temperature sensor 10 can further be included in an integrated circuit manufactured by a semiconductor process.

[0028] The first capacitor C1 can have a first end coupled to a ground node to which a ground potential is applied and a second end coupled to the first switching circuit 11. The diode D can have a cathode coupled to the ground node and an anode coupled to the first switching circuit 11. The first switching circuit 11 can be coupled to the first capacitor C1, the diode D, and a positive voltage node to which a positive power supply voltage VDD is applied, but is not limited thereto. Here, the connection with the positive voltage node to which the positive power supply voltage VDD is applied can be simply referred to as the connection with the positive power supply voltage VDD, and the connection with the ground node to which the ground potential is applied can be simply referred to as the ground potential.

[0029] The first switching circuit 11 can include at least one switch and can connect the first capacitor C1 to one of the positive power supply voltage VDD and the diode D according to a control signal CTR provided from the switching control circuit system 13. For example, the first switching circuit 11 can connect the first capacitor C1 to the positive power supply voltage VDD in response to a first desired voltage level (e.g., a high-level voltage, etc.) of the control signal CTR, and can connect the first capacitor C1 to the diode D (i.e., the anode of the diode D) in response to a second desired voltage level (e.g., a low-level voltage) of the control signal CTR, or vice versa. Here, an "ON" state of the switch can refer to a state in which both ends of the switch are electrically connected to each other, and an "OFF" state of the switch can refer to a state in which both ends of the switch are electrically disconnected from each other. Also, two or more components electrically connected via an ON switch can be referred to as simply connected to each other, and two or more components always electrically connected to each other through a wire or the like can be referred to as simply coupled to each other.

[0030] In a period in which the first capacitor C1 is connected to the positive power supply voltage VDD (hereinafter, referred to as a charging period, a reset period, a first stage, etc.), the first capacitor C1 can be charged with the positive power supply voltage VDD. However, in a period in which the first capacitor C1 is connected to the diode D (hereinafter, referred to as a discharging period, a second stage, etc.), the first capacitor C1 can be discharged through the diode D. Accordingly, the voltage V C1The first capacitor voltage (hereinafter referred to as a diode voltage) can be maintained at the positive supply voltage VDD, and then gradually decreases by a discharge current passing through the diode D. As described below with reference to Figure 2A and Figure 2B When the first capacitor C1 is discharged through the diode D, the diode voltage V D (or the first capacitor voltage V C1 ) can decrease independently of the voltage at which the discharge is started (i.e., the positive supply voltage VDD), and can decrease differently and / or based on temperature as temperature varies.

[0031] The switch control circuitry 13 can generate the control signal CTR based on the diode voltage V D and the reference voltage V REF and / or by comparing the diode voltage V D and the reference voltage V REF . For example, when the diode voltage V D becomes lower than the reference voltage V REF , the switch control circuitry 13 can generate the control signal CTR such that the first switch circuit 11 connects the first capacitor C1 to the positive supply voltage VDD, can generate the control signal CTR such that the first switch circuit 11 connects the first capacitor C1 to the diode D after a desired and / or specific period of time has elapsed, but example embodiments are not limited thereto. Examples of the switch control circuitry 13 will be described later with reference to Figure 3 .

[0032] The reference voltage generator 15 can generate the reference voltage V REF (e.g., a threshold voltage) to be compared with the diode voltage V D by the switch control circuitry 13. The reference voltage generator 15 can generate, in some embodiments, a voltage of a desired and / or specific magnitude (i.e., a DC voltage of a desired voltage level) as the reference voltage V REF , can generate, in some example embodiments, a voltage that varies over time, and / or can generate, in some example embodiments, a voltage that varies over and / or based on temperature. Examples of the reference voltage generator 15 will be described later with reference to Figure 10A , Figure 10B , Figure 10C and Figure 11 .

[0033] Output signal generator 17 can receive a control signal CTR from the switch control circuit system 13 and generate an output signal OUT by and / or based on the control signal CTR. In some example embodiments, output signal generator 17 can measure the frequency of the control signal CTR and generate the output signal OUT based on the measured frequency, but is not limited thereto. In some example embodiments, the output signal OUT can be a digital signal having a value corresponding to the sensed temperature. Reference will follow. Figure 14 Here is an example to describe the output signal generator 17.

[0034] As described above, the temperature sensor 10 can have a simple structure, omitting complex circuitry such as analog-to-digital converters, successive application registers (SARs), capacitor arrays, charge pumps, etc. Furthermore, as referenced below... Figure 2A and Figure 2B As described, the temperature sensor 10 can provide a wide temperature measurement range and high resolution due to the capacitor-diode discharge characteristics, thereby providing accurate temperature readings.

[0035] Figure 2A and Figure 2B This is a graph showing the capacitor-diode discharge characteristics according to at least one example embodiment. More specifically, Figure 2A The graph shows Figure 1 The first capacitor voltage V C1 The variation of positive power supply voltage VDD with time under different values ​​and at different temperatures, Figure 2B The graph shows the voltage V of the first capacitor. C1 The variation at different temperatures on a logarithmic time axis. This will be discussed in the following text. Figure 1 describe Figure 2A and Figure 2B .

[0036] Reference Figure 2A The first switching circuit 11 can connect the first capacitor C1 to the positive power supply voltage VDD until time t0, and can connect the first capacitor C1 to the diode D after time t0. Therefore, the voltage of the first capacitor VDD is... C1 The voltage can be maintained at the positive power supply voltage VDD until time t0, and can gradually decrease after time t0. Here, the voltage VDD of the first capacitor is due to the discharge of the first capacitor C1 through the diode D. C1 The change can be referred to as the discharge curve of the first capacitor C1.

[0037] In some example embodiments, the first capacitor voltage V C1 It can discharge continuously regardless of the charging voltage. For example, such as Figure 2AAs shown, the first capacitor C1 can have the same discharge curve at the same temperature after time t0 even when charged with different magnitudes of voltages, such as the first voltage V1, the second voltage V2, the third voltage V3, etc. In other words, if the diode D and the first capacitor C1 are maintained at the first temperature, the first capacitor C1 has the same discharge curve independent of the starting voltage of the first capacitor C1. Thus, even when the positive power supply voltage VDD for charging the first capacitor C1 changes due to various reasons (e.g., the output voltage of the battery decreases due to battery aging, etc.), the first capacitor voltage V C1 can continuously decrease, whereby the characteristics of the temperature sensor 10 can be maintained.

[0038] The discharge curve of the first capacitor C1 can depend on the temperature of the diode D and the first capacitor C1. For example, as Figure 2A shown, the discharge curve of the first capacitor C1 at a relatively low first temperature T1 can correspond to a higher voltage, etc. than at a relatively high second temperature T2. Here, the first temperature T1 can refer to a temperature lower than the second temperature T2 (T1 < T2), but is not limited thereto. As described below with reference to Figure 12 and Figure 13 , the discharge curve of the first capacitor C1 can vary according to the size of the diode D and / or the number of diodes serially coupled at a constant temperature.

[0039] Referring to Figure 2B , the discharge curve of the first capacitor C1 can decline logarithmically. According to Edward H Hellen, “Verifying the diode - capacitor circuit voltage decay”, American Journal of Physics, August, 2003, which is incorporated herein by reference, the discharge curve of the diode voltage V D during the discharge period can be expressed as Equation 1 below as a function of time t.

[0040]

Equation 1

[0041]

[0042] In Equation 1, I S is the current passing through the diode D, V T is a value determined by the elementary charge q, the Boltzmann constant k, and the temperature T (e.g., kT / q = V T = 25 mV), C is the capacitance of the first capacitor C1, and m is a constant. Thus, the discharge curve can vary over a wide temperature range and can be evenly distributed within the temperature range, e.g., linearly with temperature change, asFigure 2B As a result, the temperature measurement range and resolution of the temperature sensor 10 can be improved.

[0043] Figure 3 is a block diagram of the switch control circuitry 30 according to at least one example embodiment. As described above with reference to Figure 1 , Figure 3 The switch control circuitry 30 of D and a reference voltage V REF , and can generate a control signal CTR. As shown in Figure 3 , the switch control circuitry 30 can include a comparator 32, a delay circuit 34, and / or an inverter 36, but is not limited thereto. In other example embodiments, the switch control circuitry 30 can include processing circuitry such as a hardware / software combination of at least one processor executing software, or a combination of hardware circuitry and at least one processor executing software. For example, the switch control circuitry 30 can more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a system on chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit (ASIC), etc. Hereinafter, the switch control circuitry 30 will be described with reference to Figure 1 . Figure 3 .

[0044] According to at least one example embodiment, the comparator 32 can receive the diode voltage V D and the reference voltage V REF , and can generate a comparison signal CMP based on the diode voltage V D and the reference voltage V REF and / or by comparing the diode voltage V D and the reference voltage V REF . The comparator 32 can have any structure, can provide offset correction in some example embodiments, and can include an amplifier with a chopper in some example embodiments, but is not limited thereto. Here, it is assumed that the comparison signal CMP has a low-level voltage when the diode voltage V D is greater than the reference voltage V REF , and has a high-level voltage when the diode voltage V D is lower than the reference voltage V REF . However, example embodiments are not limited thereto.

[0045] The delay circuit 34 can receive the comparison signal CMP from the comparator 32, and can generate a first control signal CTR1 by delaying the comparison signal CMP. The delay circuit 34 can have any structure, and can include a series of delay units such as inverters, etc. As described below with reference toFigure 5 The delay provided by the delay circuit 34 can be configured to correspond to the charging period of the first capacitor C1, i.e., the duration of the first phase. In other words, the delay circuit 34 can be configured and / or designed to delay the comparison signal CMP based on the charging period of the first capacitor C1.

[0046] The inverter 36 can generate the second control signal CTR2 by inverting the first control signal CTR1. To control the switches included in the first switch circuit 11, the control signals CTR can include the first control signal CTR1 and the second control signal CTR2 by generating and / or obtaining the first control signal CTR1 and the second control signal CTR2 by inverting the first control signal CTR1. In some example embodiments, the inverter 36 can be omitted, and the first control signal CTR1 generated by the delay circuit 34 can be generated as the control signals CTR alone.

[0047] Figure 4 is a circuit diagram of a temperature sensor 40 according to at least one example embodiment, Figure 5 is a timing diagram illustrating an example of an operation of the temperature sensor 40 according to at least one example embodiment. Figure 4 is a timing diagram illustrating an example of an operation of the temperature sensor 40 according to at least one example embodiment. Hereinafter, the description provided above with respect to Figure 1 will be omitted to avoid redundancy.

[0048] Referring to Figure 4 , similar to the temperature sensor 10 of Figure 1 , the temperature sensor 40 can include the first capacitor C1, the diode D, the first switch circuit 41, the switch control circuitry 43, the reference voltage generator 45, and / or the output signal generator 47, etc., but is not limited thereto. In addition, the temperature sensor 40 can further include a third switch SW3, and the first switch circuit 41 can include a first switch SW1 and a second switch SW2. Although not shown, the first switch SW1, the second switch SW2, and the third switch SW3 can receive the control signals CTR and can be turned on or off according to and / or based on the control signals CTR. The first switch SW1, the second switch SW2, and the third switch SW3 can have any structure and can include, for example, an n-channel field effect transistor (NFET) and / or a p-channel field effect transistor (PFET) having a gate for receiving the control signals CTR, etc.

[0049] The control signals CTR can have the first phase P1 and the second phase P2 alternately repeated. The first phase P1 can correspond to a period in which the first capacitor C1 is charged with the positive supply voltage VDD, but is not limited thereto. For example, in the first phase P1, the first switch SW1 can be turned on, and the second switch SW2 can be turned off. Figure 5In particular, a first phase P1 corresponding to the control signal CTR of the high level voltage can occur between the time t50 and the time t51, the first switch SW1 can be open in the first phase P1, but the second switch SW2 and the third switch SW3 can be closed. Thus, when the anode of the diode D can be connected to the reset node to which the reset voltage V RST is applied through the third switch SW3, the first capacitor C1 can be charged with the positive supply voltage VDD, and the diode voltage V D can be identical to the reset voltage V RST . The reset voltage V RST can be greater than the reference voltage V REF , in some example embodiments can be a voltage, i.e. a DC voltage, of a desired and / or specific size, and in some example embodiments can be a voltage that varies over time. For example, as shown in Figure 5 , in the first phase P1, the diode voltage V D can have the same voltage level as the reset voltage V RST , the reset voltage V RST can be greater than the reference voltage V REF , but example embodiments are not limited thereto, and other voltage levels can be used for the diode voltage V D , the reset voltage V RST and / or the reference voltage V REF .

[0050] As described above with reference to Figure 3 , the duration of the first phase P1 can be determined based on a delay provided by a delay circuit included in the switch control circuitry 43. For example, as shown in Figure 5 , the comparison signal CMP can have a rising edge before the time t50 due to the diode voltage V D and the reference voltage V REF . Due to the rising edge of the comparison signal CMP, the control signal CTR can have a rising edge at the time t50 due to the diode voltage V D and the reset voltage V RSThas the same voltage level, and thus a falling edge of the comparison signal CMP can be generated. Due to the falling edge of the comparison signal CMP, the control signal CTR can have a falling edge at time t51, and thus the first phase P1 can be terminated. Similarly, due to the rising edges of the comparison signal CMP generated at times t52 and t57, rising edges of the control signal CTR can be generated at times t53 and t58, respectively. In addition, due to the falling edges of the comparison signal CMP generated at times t53 and t58, falling edges of the control signal CTR can be generated at times t54 and t59, respectively. Thus, the first phase P1 can occur between times t53 and t54 and between times t55 and t56, respectively. As a result, the duration of the first phase P1 can correspond to the delay from the comparison signal CMP to the control signal CTR, and can remain constant. In Figure 5 In the example embodiment, the duration of the first phase P1 can be exaggerated for ease of illustration, and the example embodiment is not limited thereto.

[0051] The second phase P2 can correspond to a period in which the first capacitor C1 is discharged by the diode D. For example, in Figure 5 In the example embodiment, the second phase P2 corresponding to the control signal CTR of the low level voltage can occur between times t51 and t53, the first switch SW1 can be turned on in the second phase P2, but the second switch SW2 and the third switch SW3 can be turned off. Thus, the first capacitor C1 and the diode D can be connected in parallel, and the charge stored in the first capacitor C1 can be moved to the ground node (e.g., discharged) by the diode D. Thus, the diode voltage V D may decrease from the positive supply voltage VDD to the ground level. Similarly, the second phase P2 can occur between times t56 and t58.

[0052] As described above with reference to Figure 2A and Figure 2B The discharge curve at a relatively low temperature can have a relatively high voltage, and thus, as shown in Figure 5 the duration of the second phase P2 at the first temperature T1 (i.e., the length from time t51 to time t53) can be longer than the duration of the second phase P2 at the second temperature T2 (i.e., the length from time t56 to time t58). As described above, since the first phase P1 has a constant duration, the frequency of the control signal CTR can be higher at the second temperature T2 than at the first temperature T1. Thus, the output signal generator 47 can generate the output signal OUT (e.g., a temperature reading, etc.) by measuring the frequency of the control signal CTR.

[0053] Figure 6 is a circuit diagram of a temperature sensor 60 according to at least one example embodiment,Figure 7 This illustrates at least one example embodiment. Figure 6 A timing diagram illustrating an example of the operation of temperature sensor 60. The above information will be omitted in the following text. Figure 1 and Figure 5 The description provided is to avoid redundancy.

[0054] Reference Figure 6 ,and Figure 1 Similar to temperature sensor 10, temperature sensor 60 may include, but is not limited to, a first capacitor C1, a diode D, a first switching circuit 61, a switching control circuit system 63, a reference voltage generator 65, and / or an output signal generator 67. Additionally, temperature sensor 60 may also include a second capacitor C2 and a second switching circuit 62, which may include a third switch SW3 and a fourth switch SW4, but is not limited to these. Although not shown, the first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 can receive a control signal CTR and can be turned on or off according to (and / or based on) the control signal CTR. The first switch SW1, the second switch SW2, the third switch SW3, and the fourth switch SW4 can have any structure and may include, for example, an NFET and / or a PFET having a gate for receiving the control signal CTR, etc.

[0055] As described above Figure 5 Similarly, the control signal CTR can have an alternating first stage P1 and a second stage P2, but is not limited to this. Figure 4 Compared to temperature sensor 40, diode voltage V D During the first stage P1, the reset voltage V varies with time. RST They have the same voltage level. For example, such as Figure 6 As shown, in the first stage P1, the anode of diode D can be connected to the second capacitor C2 through the third switch SW3. In the second stage P2, the second capacitor C2 is charged with the positive power supply voltage VDD. Therefore, diode D can be connected to the second capacitor C2 in the first stage P1 and can be connected to the first capacitor C1 in the second stage P2.

[0056] Reference Figure 7 The first stage P1, corresponding to the high-level control signal CTR, can occur between time t70 and time t71. The first switch SW1 and the fourth switch SW4 can be open during the first stage P1, but the second switch SW2 and the third switch SW3 can be closed; however, this example embodiment is not limited to this. Therefore, when the anode of diode D can be connected to a reset voltage V applied to it via the third switch SW3... RSTthe reset node, the first capacitor C1 can be charged with the positive supply voltage VDD. Thus, the diode D and the second capacitor C2 can be connected in parallel when the second capacitor C2 is discharged, as Figure 7 the diode voltage V D may be gradually reduced.

[0057] the diode voltage V D at time t70 based on the positive supply voltage VDD, the comparison signal CMP can have a falling edge. Thus, the control signal CTR can have a falling edge at time t71, and the first phase PI can be terminated. Similarly, rising edges of the comparison signal CMP generated at times t72 and t77 can generate rising edges of the control signal CTR at times t73 and t78, respectively. In addition, falling edges of the comparison signal CMP generated at times t73 and t78 can generate falling edges of the control signal CTR at times t74 and t79, respectively. Thus, the first phase PI can occur between times t73 and t74 and between times t75 and t76, respectively. In Figure 7 for ease of illustration, the duration of the first phase PI can be exaggerated, and example embodiments are not limited thereto.

[0058] The second phase P2 corresponding to the low voltage level of the control signal CTR can occur between times t71 and t73, the first switch SW1 can be turned on in the second phase P2, and the second switch SW2 and the third switch SW3 can be turned off. Thus, when the first capacitor C1 and the diode D can be connected in parallel, and the charge stored in the first capacitor C1 can be moved to the ground node (e.g., discharged) through the diode D, the second capacitor C2 can be charged with the positive supply voltage VDD. Thus, the diode voltage V D may be reduced from the positive supply voltage VDD to the ground level. Similarly, the second phase P2 can occur between times t76 and t78.

[0059] As Figure 7 indicated in FIG. 6, the duration of the second phase P2 at the first temperature T1 (i.e., the length from time t71 to time t73) can be longer than the duration of the second phase P2 at the second temperature T2 (i.e., the length from time t76 to time t78). Since the first phase PI has a constant duration, the frequency of the control signal CTR can be higher at the second temperature T2 than at the first temperature T1.

[0060] Figure 8 is a circuit diagram of a temperature sensor 80 according to at least one example embodiment, Figure 9 is a graph illustrating a voltage of a control signal CTR according to at least one example embodiment, Figure 8of the temperature sensor 80. In the following, the above description regarding Figure 1 and Figure 5 provided descriptions will be omitted to avoid redundancy.

[0061] Referring to Figure 8 , like the temperature sensor 10 of Figure 1 , the temperature sensor 80 can include a first capacitor CI, a diode D, a first switch circuit 81 which can include a first switch SW1 and a second switch SW2, a switch control circuitry 83, a reference voltage generator 85, and / or an output signal generator 87, etc. Although not shown, the first switch SW1 and the second switch SW2 can receive a control signal CTR and can turn on or off according to the control signal CTR. The first switch SW1 and the second switch SW2 can have any structure and can include, for example, NFETs and / or PFETs having gates for receiving the control signal CTR, etc. As shown in Figure 8 , the switch control circuitry 83 can receive a discharge voltage of the first capacitor CI (i.e., a first capacitor voltage V C1 ), instead of a diode voltage V D , and can compare the first capacitor voltage V C1 with a reference voltage V REF .

[0062] Like the control signal CTR described above with reference to Figure 5 , the control signal CTR can have a first phase PI and a second phase P2 which are alternately repeated. In comparison with the temperature sensor 40 of Figure 4 , an anode of the diode D can be floated during the first phase PI. For example, as shown in Figure 8 , during the first phase PI, the anode of the diode D can be floated by the first switch SW1 which is in an off state.

[0063] Referring to Figure 9 , the first phase PI corresponding to the control signal CTR of the high level voltage can occur between a time t90 and a time t91, the first switch SW1 can be off in the first phase PI, but the second switch SW2 can be on, but example embodiments are not limited thereto. Thus, when the anode of the diode D can be floated by the first switch SW1, the first capacitor CI can be charged with the positive supply voltage VDD during the first phase PI. Thus, the first capacitor voltage V C1 can be maintained to be equal to the positive supply voltage VDD during the first phase PI.

[0064] Since the first capacitor voltage V C1The comparison signal CMP can have a falling edge based on the rising of the positive supply voltage VDD at time t90. Accordingly, the control signal CTR can have a falling edge at time t91, and the first phase P1 can be terminated. Similarly, rising edges of the control signal CTR can be generated at times t93 and t98 due to rising edges of the comparison signal CMP generated at times t92 and t97, respectively. In addition, falling edges of the control signal CTR can be generated at times t94 and t99 due to falling edges of the comparison signal CMP generated at times t93 and t98, respectively. Accordingly, the first phase P1 can occur between times t93 and t94 and between times t98 and t99. In Figure 9 In the following detailed description, the duration of the first phase P1 can be exaggerated for the sake of explanation, and example embodiments are not limited thereto.

[0065] The second phase P2 corresponding to the control signal CTR of the low voltage level can occur between times t91 and t93, the first switch SW1 can be turned on in the second phase P2, but the second switch SW2 can be turned off, but is not limited thereto. Accordingly, the first capacitor C1 and the diode D can be connected in parallel, and the charge stored in the first capacitor C1 can be moved to the ground node (e.g., discharged) through the diode D. Accordingly, the first capacitor voltage V C1 may be decreased from the positive supply voltage VDD during the second phase P2. Similarly, the second phase P2 can occur between times t96 and t98.

[0066] As shown in Figure 9 , the duration of the second phase P2 at the first temperature T1 (i.e., the length from time t91 to time t93) can be longer than the duration of the second phase P2 at the second temperature T2 (i.e., the length from time t96 to time t98). Since the first phase P1 has a constant duration, the frequency of the control signal CTR can be higher at the second temperature T2 than at the first temperature T1.

[0067] Figures 10A-10C is a graph showing examples of the reference voltage VREF according to at least one example embodiment. In more detail, Figures 10A-10C Each of the graphs of Figure 1 will be described below with reference to Figures 10A-10C .

[0068] Referring to Figure 10A , the reference voltage generator 15 can generate a reference voltage V REF with a desired and / or specific size. For example, as shown in Figure 10A , the reference voltage V REFIt can be a DC voltage, and can be compared with a discharge voltage that gradually decreases after time t0. For example... Figure 10A As shown, the discharge curve can vary with temperature, and from time t0 to the reference voltage V, the discharge curve correlates with the temperature. REF The length of the intersection time point can vary with (and / or based on) temperature. The reference voltage V can be determined based on the range in which the discharge curve varies with temperature. REF Size.

[0069] Reference Figure 10B The reference voltage generator 15 can generate a reference voltage V that varies with time. REF For example, such as Figure 10B As shown, the reference voltage generator 15 can generate a gradually increasing ramp voltage. In some example embodiments, the reference voltage generator 15 can generate a first reference voltage V that begins to rise before time t0. REF1 Furthermore, in some example embodiments, a second reference voltage V that increases from time t0 can be generated. REF2 .like Figure 10B As shown, from time t0 to the discharge curve and the first reference voltage V REF1 Or the second reference voltage V REF2 The length of the intersection point can vary with temperature.

[0070] Reference Figure 10C The reference voltage generator 15 can generate a reference voltage V that varies with temperature. REF For example, such as Figure 10C As shown in the top graph, the reference voltage generator 15 can generate a reference voltage V that decreases as the temperature increases. REF and with Figure 10C Reference voltage V REF Similarly, a voltage that decreases with increasing temperature can be referred to as a temperature-to-absolute complement (CTAT) voltage. In some example embodiments, the reference voltage generator 15 can generate a reference voltage V that decreases linearly with increasing temperature. REF Therefore, as by Figure 10C The reference voltage V is shown as the dashed line in the bottom curve graph. REF It can vary with (and / or be based on) temperature. The reference voltage V can be determined based on the range of variation in the temperature profile. REF Size and range of variation (i.e., representing) Figure 10C The reference voltage V in the top curve of the graph REF (The slope and offset of the line). In the following text, reference will be made to... Figure 11 Description of the method used to generate reference voltage V REF Example of a reference voltage generator 15 for CTAT voltage.

[0071] Figure 11 is a circuit diagram of the reference voltage generator 110 according to at least one example embodiment. In more detail, Figure 11 the circuit diagram of Figure 1 is an example of the reference voltage generator 15 of Figure 10C described above with reference to REF the reference voltage generator 110 of Figure 11 As shown in Figure 1 the reference voltage generator 15 of Figure 11 is not limited to what is shown in Figure 10C and can have any structure. In the following, the Figure 11 will be described with reference to

[0072] The diode DO can have a cathode coupled to a ground node and can have an anode coupled to an inverting input of the operational amplifier OA and a second transistor M2 of the current source circuit CS, but is not limited thereto. The reference voltage V REF may be generated at an anode of the diode DO. The resistor RO can have a first end coupled to the ground node and can have a second end coupled to a non-inverting input of the operational amplifier OA and a first transistor Ml of the current source circuit CS, but is not limited thereto. As shown in Figure 11 , a voltage at the second end of the resistor RO can be referred to as a resistance voltage V R .

[0073] The first transistor Ml of the current source circuit CS can have a gate coupled to an output node of the operational amplifier OA and can control a size of a current provided from a positive supply voltage VDD to the resistor RO according to (and / or based on) an output voltage of the operational amplifier OA, but is not limited thereto. Similarly, the second transistor M2 of the current source circuit CS can have a gate coupled to the output node of the operational amplifier OA and can control a size of a current provided from the positive supply voltage VDD to the diode DO according to (and / or based on) the output voltage of the operational amplifier OA, but is not limited thereto. In some example embodiments, the operational amplifier OA can be an amplifier with a chopper or the like.

[0074] At the diode DO, when the current through the diode DO is constant, the voltage at the anode can decrease as the temperature increases, and when the voltage at the anode is constant, the current through the diode DO can decrease as the temperature increases. When the reference voltage V REFWhen the voltage V varies with temperature, the current supplied to resistor R0 and diode D0 can be controlled by operating amplifier OA, thus controlling the voltage across the resistor V. R Follow the reference voltage V REF (and / or with reference voltage V) REF (Corresponding). The magnitudes of the current supplied to resistor R0 and diode D0 can depend on (and / or be based on) the size ratio of the first transistor M1 to the second transistor M2 in the current source circuit CS, and can be based on... Figure 10C The reference voltage V in the top curve of the graph REF The offset of the straight line is used to determine the size ratio of the first transistor M1 to the second transistor M2. For example... Figure 11 As shown, the reference voltage generator 110 may generate only the CTAT voltage, but is not limited to this. Therefore, in order to generate both the CTAT voltage and the temperature-to-absolute-temperature (PTAT) voltage, the dynamic element matching (DEM) desired and / or required to accurately achieve the current ratio provided by the current source circuit CS can be omitted. As a result, the reference voltage generator 110 can have a small physical area and low power consumption, etc.

[0075] Figure 12 This is a block diagram of a temperature sensor 120 according to at least one example embodiment. More specifically, Figure 12 A temperature sensor 120 comprising two or more diodes coupled in series is shown. Figure 6 Similar to temperature sensor 60, temperature sensor 120 may include a first capacitor C1, a second capacitor C2, a diode D, a first switching circuit 121, a second switching circuit 122, a switch control circuit system 123, a reference voltage generator 125, and / or an output signal generator 127, but is not limited thereto. Additionally, the first switching circuit 121 may include a first switch SW1 and a second switch SW2, and the second switching circuit 122 may include a third switch SW3 and a fourth switch SW4, but the example embodiment is not limited thereto. In the following text, the above information regarding... Figure 6 The description provided is to avoid redundancy.

[0076] Diode D may include two or more diode devices connected in series. For example, such as Figure 12 As shown, diode D may include a first diode device D1 and a second diode device D2, etc., connected in series. In some example embodiments, the first diode device D1 and the second diode device D2 may have the same structure, but are not limited thereto. The number of series-coupled diode devices included in diode D can be determined based on the range of discharge curves as a function of temperature. For example, as the number of series-coupled diode devices increases, the number of series-coupled diode devices increases with temperature. Figure 2AThe position of the discharge curve corresponding to the first temperature T1 in the curve graph can rise upwards, and Figure 2A The intervals of the discharge curves shown can be wider. Therefore, in order to adjust the diode voltage V... D The range of variation is related to the reference voltage V. REF Correspondingly, the temperature sensor 120 may include two or more diode devices coupled in series, so the switch control circuit system 123 can more easily convert the diode voltage V D With reference voltage V REF Compare them.

[0077] Figure 13 This is a circuit diagram and layout diagram of a diode included in a temperature sensor according to at least one example embodiment. More specifically, in Figure 13 The top shows the circuit diagram of diode 130, and... Figure 13 The bottom shows the layout of diode 130.

[0078] In some example embodiments, diode 130 can be implemented using a dynamic threshold voltage MOSFET (DTMOS). For example, as... Figure 13 As shown, the body, drain, and gate of the P-type DTMOS, which are commonly connected to the ground node, can be used as the cathode of diode 130, while the source of the P-type DTMOS can be used as the anode of diode 130. Therefore, diode 130 can be easily implemented in a complementary metal-oxide-semiconductor (CMOS) process, and diode 130 can contribute to the high accuracy of the temperature sensor due to its low sensitivity to threshold voltage changes. Additionally, in some example embodiments, the size of the DTMOS can be determined based on the slope of the discharge curve. For example, as the size of the DTMOS increases, Figure 2A The discharge curve in the graph can drop more sharply after time t0. In some example embodiments, Figure 11 The diode D0 can also include DTMOS.

[0079] Figure 14 This is a block diagram of an output signal generator according to at least one example embodiment. Figure 15 This is a timing diagram illustrating an example of the operation of an output signal generator according to at least one example embodiment. (Refer to the above...) Figure 1 As described, the output signal generator 140 can generate an output signal OUT with a value corresponding to the temperature sensed and / or measured by the temperature sensor 10, based on the control signal CTR. Referring below... Figure 1 describe Figure 14 and Figure 15 .

[0080] Reference Figure 14The output signal generator 140 can include a clock generator 142 and / or a frequency counter 144, but is not limited thereto. As described above with reference to the drawings, the frequency of the control signal CTR can vary as the duration of the second phase P2 varies with temperature. Accordingly, the output signal generator 140 can measure the frequency of the control signal CTR, and generate an output signal OUT corresponding to the sensed and / or measured temperature, the output signal OUT having the measured frequency or a value obtained by processing the measured frequency.

[0081] The clock generator 142 can generate a clock signal CLK in response to the control signal CTR. For example, as shown in FIG. 2B, the clock generator 142 can generate a clock signal CLK that transitions (or toggles, toggles back and forth) in response to rising edges of the control signal CTR. The rising edges of the control signal CTR can be generated more frequently at the second temperature T2 higher than the first temperature T1, and thus the clock signal CLK can have a higher frequency at the second temperature T2 than at the first temperature T1. In some example embodiments, the clock generator 142 can include a toggle flip-flop that receives the control signal CTR, but is not limited thereto. Figure 15

[0082] The frequency counter 144 can receive the clock signal CLK from the clock generator 142, and generate the output signal OUT by measuring the frequency of the clock signal CLK. For example, the frequency counter 144 can count the rising edges and / or falling edges of the clock signal CLK for a desired and / or predefined time, and can generate the output signal OUT having a count value. For example, as shown in FIG. 2C, the output signal OUT can have a digital value f1 representing a relatively low frequency of the clock signal CLK at the first temperature T1 as a multi-bit signal, while having a digital value f2 representing a relatively high frequency of the clock signal CLK at the second temperature T2, but is not limited thereto. Figure 15

[0083] Figure 16 is a flowchart illustrating a method of sensing a temperature according to at least one example embodiment. In some example embodiments, the method of Figure 1 may be performed by the temperature sensor 10 of Figure 16 , and Figure 16 may be referred to as an operation method of the temperature sensor 10. As shown in Figure 16 , the method of sensing a temperature can include a plurality of operations S11, S12, S13, S14, S15, and S16, and can perform the operation S11 and the operation S12 in the first phase P1, and can perform the operation S13, the operation S14, and the operation S15 in the second phase P2. In the description of Figure 16 , it is assumed that the switch control circuitry 13 of Figure 1 includes​​Figure 3 The components of the switch control circuitry 30 will be described with reference to Figure 1 and Figure 3 but example embodiments are not limited thereto, and the switch control circuitry 13 can have alternative structures.

[0084] In operation Sll, an operation of charging the capacitor with a positive voltage can be performed. For example, the first switch circuit 11 can connect the first capacitor Cl to the positive power supply voltage VDD according to the control signal CTR, and thus the first capacitor Cl can be charged with the positive power supply voltage VDD. Also, in some example embodiments, a reset voltage V RST may be provided to the diode D.

[0085] In operation S12, it can be determined whether a transition of the delayed comparison signal has occurred. In the second phase P2 before the first phase Pl, the comparator 32 included in the switch control circuitry 13 can generate a comparison signal CMP based on and / or by comparing the diode voltage V D with the reference voltage V REF , and the delay circuit 34 can delay the comparison signal CMP for a desired period of time. The delayed comparison signal CMP can correspond to the control signal CTR, and when a transition of the control signal CTR occurs (i.e., when a desired and / or specific time elapses after the first phase Pl starts), the first phase Pl can be terminated. Thereafter, operation S13 can be performed as shown in Figure 16 .

[0086] In operation S13, an operation of discharging the capacitor through the diode D can be performed. For example, the first switch circuit 11 can connect the first capacitor Cl to the diode D according to the control signal CTR, and thus the charge stored in the first capacitor Cl can be moved to the ground node (e.g., discharged) through the diode D. As described above with reference to Figure 2A and Figure 2B , the diode voltage V D (or the discharge voltage of the first capacitor Cl) can decrease independently of the voltage charged in the first capacitor Cl in the first phase Pl, and can decrease differently based on temperature. Also, the diode voltage V D may decrease logarithmically.

[0087] In operation S14, an operation of comparing the diode voltage V D with the reference voltage V REF may be performed. For example, the comparator 32 included in the switch control circuitry 13 can compare the diode voltage V D with the reference voltage V REFcomparison is made. When the diode voltage V D is reduced to the reference voltage V REF , the operation S15 can be subsequently performed, as shown in Figure 16 In some example embodiments, the comparator 32 can generate the comparison signal CMP having a low voltage level (e.g., a first voltage level) when the diode voltage V D is greater than the reference voltage V REF , and generate a high voltage level (e.g., a second voltage level) when the diode voltage V D is lower than the reference voltage V ref , but example embodiments are not limited thereto, e.g., the comparison signal CMP can have a high voltage level when the diode voltage V D is greater than the reference voltage V REF , etc. In some example embodiments, as described above with reference to Figure 8 , the discharge voltage of the first capacitor C1 (i.e., the first capacitor voltage V C1 ) can be compared with the reference voltage V REF .

[0088] In the operation S15, an operation of transitioning the comparison signal CMP can be performed. For example, the comparator 32 can transition the comparison signal CMP when the diode voltage V D becomes lower than the reference voltage V REF , but is not limited thereto. In some example embodiments, the comparator 32 can generate the comparison signal CMP having a rising edge when the diode voltage V D becomes lower than the reference voltage V REF , but example embodiments are not limited thereto. Thus, the second phase P2 can be terminated, and as shown in Figure 17 , the first phase P1 can be repeated.

[0089] In the operation S16, an operation of measuring a frequency of the comparison signal CMP can be performed. For example, the control signal CTR generated by the delay circuit 34 of the switch control circuit system 13 delaying the comparison signal CMP can have the same frequency as the comparison signal CMP. The output signal generator 17 can generate the output signal OUT by measuring the frequency of the control signal CTR.

[0090] Figure 17 is a block diagram of a system 170 including a temperature sensor according to at least one example embodiment. In some example embodiments, the system 170 can be a system-on-a-chip as an integrated circuit manufactured by a semiconductor process, but is not limited thereto. As shown in ​As illustrated in FIG. 17, the system 170 can include at least one processing circuitry 171, a memory 172, a hardware accelerator 173, an interface 174, and / or a bus 175, etc. The at least one processing circuitry 171, the memory 172, the hardware accelerator 173, and the interface 174 can communicate with each other via the bus 175.

[0091] The at least one processing circuitry 171 can include a processing circuitry such as hardware including a logic circuit, a hardware / software combination such as at least one processor core executing software and / or executing any instruction set, or a combination thereof. For example, the processing circuitry can more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor (DSP), a graphics processing unit (GPU), a communication process (CP), a microcomputer, a field programmable gate array (FPGA), a system on chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit (ASIC), etc. The at least one processing circuitry 171 can access the memory 172 by the bus 175, and execute computer-readable instructions stored in the memory 172.

[0092] The memory 172 can be a non-transitory computer readable medium, and can include a volatile memory such as a static random access memory (SRAM), a dynamic random access memory (DRAM), etc., and can include a non-volatile memory such as a flash memory, a phase change random access memory (PRAM), etc. The memory 172 can store instructions executed by the at least one processing circuitry 171, can store data generated by the at least one processing circuitry 171 or the hardware accelerator 173, or can store data received from the outside via the interface 174.

[0093] The hardware accelerator 173 can refer to a hardware block designed to perform a specific function, and can be referred to as a hardware intellectual property (IP) or an IP block. The at least one processing circuitry 171 can allow the hardware accelerator 173 to perform a specific task, the hardware accelerator 173 can generate output data by processing input data stored in the memory 172, and store the output data in the memory 172.

[0094] The interface 174 can form a communication channel with the outside of the system 170. For example, the interface 174 can transmit data stored in the memory 172 to the outside through the communication channel, or store data received from the outside in the memory 172 through the communication channel.

[0095] The temperature sensor according to at least one of the example embodiments can be provided in at least one of components included in the system 170. The components included in the system 170 can provide different performances depending on (and / or based on) temperature. And can have high temperature during operation due to heat generated by the components of the system 170. As described above with reference to the drawings, by having a temperature sensor with high accuracy, high resolution, wide measurement range, low power consumption, and / or small physical area, etc., temperature can be sensed in different parts of the system 170. As a result, performance and efficiency of the system 170 can be improved.

[0096] While various example embodiments of the inventive concept have been particularly shown and described with reference to example embodiments of the inventive concept, it will be understood that various changes in form and details can be made to the example embodiments of the inventive concept without departing from the spirit and scope of the appended claims.

Claims

1. A temperature sensor configured to generate an output signal corresponding to a sensed temperature, the temperature sensor comprising: a diode including a cathode coupled to a ground node; a first capacitor including a first end coupled to the ground node; a switching circuit configured to connect a second end of the first capacitor to a positive voltage node to charge the first capacitor with a positive voltage provided by the positive voltage node or to connect the second end of the first capacitor to an anode of the diode to discharge the first capacitor through the diode based on a control signal; a switching control circuitry configured to generate the control signal based on a reference voltage and a voltage of the anode of the diode; and an output signal generator configured to generate the output signal based on a frequency of the control signal, wherein the switching circuit comprises: a first switch coupled between the second end of the first capacitor and the positive voltage node; and a second switch coupled between the second end of the first capacitor and the anode of the diode.

2. The temperature sensor of claim 1, further comprising: a third switch configured to connect the anode of the diode to a reset node while the second end of the first capacitor is connected to the positive voltage node based on the control signal.

3. The temperature sensor of claim 2, further comprising: a second capacitor including a first end and a second end, the first end of the second capacitor coupled to the ground node and the second end of the second capacitor coupled to the reset node; and a fourth switch configured to connect the reset node to the positive voltage node while the second end of the first capacitor is connected to the anode of the diode based on the control signal.

4. The temperature sensor of claim 2, wherein the reset node is configured to receive a voltage greater than the reference voltage.

5. The temperature sensor of claim 1, further comprising: a reference voltage generator configured to generate a complementary voltage to absolute temperature that decreases as the sensed temperature increases as the reference voltage. the reference voltage generator includes: a second diode including a cathode and an anode, the cathode of the second diode coupled to the ground node and the anode of the second diode configured to generate the reference voltage; 6. The temperature sensor of claim 5, wherein, a resistor including a first end coupled to the ground node; an operational amplifier configured to amplify a voltage of a second end of the resistor and the voltage of the anode of the second diode; and a biasing circuit configured to supply a current to the resistor and the second diode based on an output of the operational amplifier.

7. The temperature sensor of claim 1, further comprising: a reference voltage generator configured to generate a DC voltage or a ramp voltage as the reference voltage, the ramp voltage increasing over time in response to the control signal. the switching control circuitry includes: a comparator configured to compare the reference voltage to the voltage of the anode of the diode; and 8. The temperature sensor of claim 1, wherein, a ramp generator configured to generate the ramp voltage based on the control signal. ​ a delay circuit configured to generate the control signal by delaying an output signal of the comparator.

9. The temperature sensor of claim 8, wherein, the switch control circuitry further comprises an inverter configured to generate an inverted control signal from the control signal.

10. The temperature sensor of claim 1, wherein, the output signal generator comprises: a clock signal generator configured to generate a clock signal based on an edge of the control signal; and a frequency counter configured to measure a frequency of the clock signal.

11. The temperature sensor of claim 1, wherein, the diode comprises a plurality of diode devices coupled in series.

12. The temperature sensor of claim 1, wherein, the diode comprises a P-type dynamic threshold voltage MOSFET comprising a body connected to a cathode of the diode, a drain, and a gate.

13. A temperature sensor configured to generate an output signal corresponding to a sensed temperature by switching between a first phase and a second phase, the temperature sensor comprising: a first capacitor and a diode; a first switch circuit configured to charge the first capacitor to a positive voltage in the first phase and to discharge the first capacitor through the diode in the second phase; a reference voltage generator configured to generate a reference voltage independently of the discharge of the first capacitor; switch control circuitry configured to control the first switch circuit and to terminate the second phase based on a discharge voltage of the first capacitor and the reference voltage; an output signal generator configured to generate an output signal corresponding to a sensed temperature based on a duration of the second phase; and a second switch circuit controlled by the switch control circuitry, the second switch circuit configured to apply a reset voltage to the diode during the first phase.

14. The temperature sensor of claim 13, wherein, the switch control circuitry is configured to keep a duration of the first phase constant; and the output signal generator is configured to generate an output signal corresponding to a sensed temperature based on a frequency of a control signal representing the first phase and the second phase.

15. A temperature sensor configured to generate an output signal corresponding to a sensed temperature by switching between a first phase and a second phase, the temperature sensor comprising: a plurality of switches and a diode; a first capacitor configured to be charged with a positive voltage during the first phase through at least one of the plurality of switches and to be discharged through the diode during the second phase; a second capacitor configured to be discharged through the diode during the first phase through at least one of the plurality of switches and to be charged with the positive voltage during the second phase; switch control circuitry configured to maintain a duration of the first phase and to terminate the second phase based on a reference voltage and a voltage of the first capacitor; and an output signal generator configured to generate an output signal corresponding to a sensed temperature based on a duration of the second phase. ​ an output signal generator configured to generate an output signal corresponding to the sensed temperature based on a duration of the second phase, wherein a reset voltage is applied to the diode through at least one of the plurality of switches.

16. The temperature sensor of claim 15, wherein the diode and the second capacitor are connected in parallel during the first phase and the diode and the first capacitor are connected in parallel during the second phase through the plurality of switches.

17. The temperature sensor of claim 15, further comprising: a reference voltage generator configured to generate a complementary voltage to absolute temperature that decreases as the sensed temperature increases as the reference voltage.

18. The temperature sensor of claim 15, further comprising: a reference voltage generator configured to generate a DC voltage or a ramp voltage as the reference voltage, the ramp voltage increasing over time in the second phase.

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