CN113203494B - Temperature sensing circuit - Google Patents

A temperature sensing circuit, comprising: a current source circuit, a resistor, a band gap voltage generating circuit, a voltage equalizing circuit and a temperature judging circuit. The current source circuit has a first and a second current output terminals. The first end of the resistor is electrically coupled to the first current output end. The bandgap voltage generating circuit comprises a pair of bipolar junction transistors, wherein the first transistor is electrically coupled to the second end of the resistor, and the second transistor is electrically coupled to the second current output end. The voltage equalization circuit equalizes the voltages of the first current output terminal and the second current output terminal. The temperature judgment circuit includes: sampling capacitance and calculation circuit. The sampling capacitor samples a first voltage at a first end of the resistor. The calculating circuit receives the sampled first voltage and the second voltage of the second end of the resistor, and calculates the voltage difference to generate a temperature value.

温度感测电路Temperature Sensing Circuit

技术领域Technical Field

本发明涉及一种温度感测技术，且特别涉及一种温度感测电路。The present invention relates to a temperature sensing technology, and in particular to a temperature sensing circuit.

背景技术Background Art

在低电压的系统单芯片电路中，可采用根据时间变化或信号延迟随温度而具有差异的特性来感测芯片内部的温度。然而，常见的温度感测电路不论是利用延迟路径(delayline)产生具有时间差的信号进行温度的感测，或是利用电流镜间的电流差异来进行温度的感测，都容易受到电路中的金属氧化物半导体晶体管的工艺偏移或是通道长度改变的效应，而造成温度感测的不精确。In low-voltage system-on-a-chip circuits, the temperature inside the chip can be sensed based on the time variation or the signal delay characteristics that vary with temperature. However, common temperature sensing circuits, whether using a delay line to generate a signal with a time difference for temperature sensing or using the current difference between current mirrors for temperature sensing, are susceptible to the effects of process offsets of metal oxide semiconductor transistors in the circuit or changes in channel length, resulting in inaccurate temperature sensing.

因此，如何设计一个新的温度感测电路，以解决上述的缺失，乃为此一业界亟待解决的问题。Therefore, how to design a new temperature sensing circuit to solve the above-mentioned deficiencies is an urgent problem to be solved in the industry.

发明内容Summary of the invention

发明内容旨在提供本公开内容的简化摘要，以使阅读者对本公开内容具备基本的理解。此发明内容并非本公开内容的完整概述，且其用意并非在指出本发明实施例的重要/关键元件或界定本发明的范围。The invention summary is intended to provide a simplified summary of the present disclosure so that readers can have a basic understanding of the present disclosure. This invention summary is not a complete overview of the present disclosure, and it is not intended to point out the important/critical elements of the embodiments of the present invention or to define the scope of the present invention.

本发明内容的一目的是在于提供一种温度感测电路，借此改善现有技术的问题。An object of the present invention is to provide a temperature sensing circuit to improve the problems of the prior art.

为达上述目的，本发明内容的一技术实施方式涉及一种温度感测电路，包含：电流源电路、电阻、带隙电压产生电路、电压等化电路以及温度判断电路。电流源电路具有第一电流输出端以及第二电流输出端。电阻包含电性耦接于第一电流输出端的第一端以及第二端。带隙电压产生电路包含具有相电性耦接的一对基极的一对双极性接面型晶体管，这对双极性接面型晶体管的第一者电性耦接于电阻的第二端，第二者电性耦接于第二电流输出端。电压等化电路配置以电性耦接第一电流输出端以及第二电流输出端，并控制电流源电路，使第一电流输出端以及第二电流输出端等电压。温度判断电路包含：取样电容以及计算电路。取样电容配置以在第一操作时间中取样电阻的第一端的具有第一负温度系数的第一电压后与第一端相电性隔离。计算电路配置以在第一操作时间后的第二操作时间中接收取样电容取样的第一电压以及自电阻的第二端接收具有大于第一负温度系数的第二负温度系数的第二电压，并通过计算第一电压以及第二电压的电压差据以产生温度值。To achieve the above-mentioned purpose, a technical implementation of the content of the present invention relates to a temperature sensing circuit, comprising: a current source circuit, a resistor, a bandgap voltage generating circuit, a voltage equalization circuit and a temperature judgment circuit. The current source circuit has a first current output terminal and a second current output terminal. The resistor comprises a first terminal and a second terminal electrically coupled to the first current output terminal. The bandgap voltage generating circuit comprises a pair of bipolar junction transistors having a pair of bases electrically coupled to each other, wherein the first of the pair of bipolar junction transistors is electrically coupled to the second end of the resistor, and the second is electrically coupled to the second current output terminal. The voltage equalization circuit is configured to electrically couple the first current output terminal and the second current output terminal, and control the current source circuit to make the first current output terminal and the second current output terminal equal in voltage. The temperature judgment circuit comprises: a sampling capacitor and a calculation circuit. The sampling capacitor is configured to electrically isolate from the first end after sampling the first voltage having a first negative temperature coefficient at the first end of the resistor during the first operation time. The calculation circuit is configured to receive a first voltage sampled by the sampling capacitor and a second voltage having a second negative temperature coefficient greater than the first negative temperature coefficient from a second end of the resistor in a second operation time after the first operation time, and generate a temperature value by calculating a voltage difference between the first voltage and the second voltage.

本发明的温度感测电路避免金属氧化物半导体晶体管的工艺或通道长度改变的影响，进而通过高精确度的时钟信号计算时间长度，并据以取得温度值，大幅提升温度测量的精确度。The temperature sensing circuit of the present invention avoids the influence of the process or channel length change of the metal oxide semiconductor transistor, and further calculates the time length through a high-precision clock signal to obtain the temperature value, thereby greatly improving the accuracy of temperature measurement.

附图说明BRIEF DESCRIPTION OF THE DRAWINGS

为让本发明的上述和其他目的、特征、优点与实施例能更明显易懂，附图的说明如下：In order to make the above and other objects, features, advantages and embodiments of the present invention more clearly understood, the following are the descriptions of the accompanying drawings:

图1为本发明一实施例中，一种温度感测电路的电路图；FIG1 is a circuit diagram of a temperature sensing circuit in one embodiment of the present invention;

图2为本发明一实施例中，第一电压以及第二电压随温度变化的示意图；以及FIG2 is a schematic diagram showing how the first voltage and the second voltage vary with temperature in one embodiment of the present invention; and

图3为本发明一实施例中，取样电容取样后的第一电压、第二电压、比较结果、时钟信号以及时间长度的波形图。3 is a waveform diagram of a first voltage, a second voltage, a comparison result, a clock signal and a time length after sampling by a sampling capacitor in one embodiment of the present invention.

符号说明Explanation of symbols

100：温度感测电路 110：电流源电路100: Temperature sensing circuit 110: Current source circuit

120：带隙电压产生电路 130：电压等化电路120: Bandgap voltage generation circuit 130: Voltage equalization circuit

140：温度判断电路 150：计算电路140: Temperature judgment circuit 150: Calculation circuit

160：比较器 170：计数器160: Comparator 170: Counter

175：与门(AND gate，及闸) 180：判断电路175: AND gate 180: Decision circuit

B1、B2：基极 C1、C2：集极B1, B2: Base C1, C2: Collector

CLK：时脉信号 CR：比较结果CLK: Clock signal CR: Comparison result

CS：取样电容 CS1：第一控制信号CS: sampling capacitor CS1: first control signal

CS2：第二控制信号 D1、D2：漏极CS2: Second control signal D1, D2: Drain

E1、E2：射极 G1、G2：栅极E1, E2: Emitter G1, G2: Gate

GND：接地端 I1、I2：电流GND: ground terminal I1, I2: current

P1、P2：P型金属氧化物半导体晶体管 Q1、Q2：双极性接面型晶体管P1, P2: P-type metal oxide semiconductor transistors Q1, Q2: bipolar junction transistors

RG：电阻RG: resistance

RD：放电电阻 SW1：第一开关RD: discharge resistor SW1: first switch

S1、S2：源极 T1：第一端S1, S2: source T1: first end

SW2：第二开关 TL：时间长度SW2: Second switch TL: Time length

T2：第二端 TO2：第二操作时间T2: Second end TO2: Second operation time

TO1：第一操作时间 TS：时间点TO1: First operation time TS: Time point

TP：温度值 V2：第二电压TP: Temperature value V2: Second voltage

V1：第一电压V1: first voltage

VDD：电压源VDD: voltage source

具体实施方式DETAILED DESCRIPTION

请参照图1。图1为本发明一实施例中，一种温度感测电路100的电路图。温度感测电路100包含：电流源电路110、电阻RG、带隙电压产生电路120、电压等化电路130以及温度判断电路140。Please refer to FIG. 1 . FIG. 1 is a circuit diagram of a temperature sensing circuit 100 according to an embodiment of the present invention. The temperature sensing circuit 100 includes a current source circuit 110 , a resistor RG, a bandgap voltage generating circuit 120 , a voltage equalizing circuit 130 and a temperature determining circuit 140 .

于一实施例中，电流源电路110为一对P型金属氧化物半导体晶体管P1、P2。其中，P型金属氧化物半导体晶体管P1、P2的一对源极S1、S2电性耦接于电压源VDD。P型金属氧化物半导体晶体管P1的漏极D1作为第一电流输出端，以输出电流I1。P型金属氧化物半导体晶体管P2的漏极D2则作为第二电流输出端，以输出电流I2。In one embodiment, the current source circuit 110 is a pair of P-type metal oxide semiconductor transistors P1 and P2. A pair of sources S1 and S2 of the P-type metal oxide semiconductor transistors P1 and P2 are electrically coupled to a voltage source VDD. The drain D1 of the P-type metal oxide semiconductor transistor P1 serves as a first current output terminal to output a current I1. The drain D2 of the P-type metal oxide semiconductor transistor P2 serves as a second current output terminal to output a current I2.

电阻RG包含电性耦接于第一电流输出端的第一端T1以及第二端T2。The resistor RG includes a first terminal T1 electrically coupled to the first current output terminal and a second terminal T2 .

带隙电压产生电路120包含一对双极性接面型晶体管Q1、Q2。于一实施例中，双极性接面型晶体管Q1、Q2在运行导通时，具有不同的电流密度。于一实施例中，双极性接面型晶体管Q1、Q2的尺寸不相同，而造成运行导通时不同的电流密度。The bandgap voltage generating circuit 120 includes a pair of bipolar junction transistors Q1 and Q2. In one embodiment, the bipolar junction transistors Q1 and Q2 have different current densities when they are turned on. In one embodiment, the sizes of the bipolar junction transistors Q1 and Q2 are different, resulting in different current densities when they are turned on.

举例而言，双极性接面型晶体管Q1、Q2的通道尺寸比例可为N，亦即双极性接面型晶体管Q1的通道尺寸为双极性接面型晶体管Q2的通道尺寸的N倍。For example, the ratio of the channel sizes of the BJTs Q1 and Q2 may be N, that is, the channel size of the BJT Q1 is N times the channel size of the BJT Q2.

就连接关系而言，双极性接面型晶体管Q1、Q2的一对基极B1、B2相电性耦接，且这对基极B1、B2还电性耦接于接地端GND。双极性接面型晶体管Q1、Q2的一对集极C1、C2电性耦接于接地端GND。In terms of connection relationship, a pair of bases B1 and B2 of the bipolar junction transistors Q1 and Q2 are electrically coupled, and the pair of bases B1 and B2 are also electrically coupled to the ground terminal GND. A pair of collectors C1 and C2 of the bipolar junction transistors Q1 and Q2 are electrically coupled to the ground terminal GND.

并且，双极性接面型晶体管Q1的射极E1电性耦接于电阻RG的第二端T2。因此，双极性接面型晶体管Q1的射极E1与第一电流输出端之间，亦即与P型金属氧化物半导体晶体管P1的漏极D1之间，是通过电阻RG相电性耦接。而双极性接面型晶体管Q2的射极E2电性耦接于第二电流输出端，亦即P型金属氧化物半导体晶体管P2的漏极D2。Furthermore, the emitter E1 of the bipolar junction transistor Q1 is electrically coupled to the second end T2 of the resistor RG. Therefore, the emitter E1 of the bipolar junction transistor Q1 and the first current output end, that is, the drain D1 of the P-type metal oxide semiconductor transistor P1, are electrically coupled through the resistor RG. The emitter E2 of the bipolar junction transistor Q2 is electrically coupled to the second current output end, that is, the drain D2 of the P-type metal oxide semiconductor transistor P2.

电压等化电路130为配置以电性耦接第一电流输出端以及第二电流输出端(P型金属氧化物半导体晶体管P1、P2的漏极D1、D2)，并控制电流源电路110，使第一电流输出端以及第二电流输出端的电压相等。The voltage equalization circuit 130 is configured to electrically couple the first current output terminal and the second current output terminal (the drains D1 and D2 of the P-type metal oxide semiconductor transistors P1 and P2), and control the current source circuit 110 to make the voltages of the first current output terminal and the second current output terminal equal.

更详细地说，于一实施例中，电压等化电路130为运算放大器，并包含在图1中分别以‘+’、‘-’以及‘o’记号标示的正输入端、负输入端以及输出端。More specifically, in one embodiment, the voltage equalization circuit 130 is an operational amplifier and includes a positive input terminal, a negative input terminal, and an output terminal, which are marked with ‘+’, ‘-’, and ‘o’ respectively in FIG. 1 .

其中，正输入端电性耦接于第一电流输出端(P型金属氧化物半导体晶体管P1的漏极D1)以及通过电阻RG电性耦接于双极性接面型晶体管Q1的射极E1。负输入端电性耦接于第二电流输出端(P型金属氧化物半导体晶体管P2的漏极D2)以及双极性接面型晶体管Q2的射极E2。The positive input terminal is electrically coupled to the first current output terminal (the drain D1 of the P-type metal oxide semiconductor transistor P1) and is electrically coupled to the emitter E1 of the bipolar junction transistor Q1 through the resistor RG. The negative input terminal is electrically coupled to the second current output terminal (the drain D2 of the P-type metal oxide semiconductor transistor P2) and the emitter E2 of the bipolar junction transistor Q2.

输出端电性耦接于P型金属氧化物半导体晶体管P1、P2的一对栅极G1、G2，并配置以控制P型金属氧化物半导体晶体管P1、P2，达到使第一电流输出端以及第二电流输出端的电压相等的技术效果。The output terminal is electrically coupled to a pair of gates G1 and G2 of the P-type metal oxide semiconductor transistors P1 and P2, and is configured to control the P-type metal oxide semiconductor transistors P1 and P2 to achieve the technical effect of making the voltages of the first current output terminal and the second current output terminal equal.

上述的电流源电路110、电阻RG、带隙电压产生电路120以及电压等化电路130可形成一个带隙电压产生电路，使电阻RG的第一端T1的第一电压V1以及第二端T2的第二电压V2分别具有负温度系数。更详细地说，当温度感测电路100所位于的环境温度愈高，第一电压V1以及第二电压V2的电压值将愈低。The above-mentioned current source circuit 110, resistor RG, bandgap voltage generating circuit 120 and voltage equalization circuit 130 can form a bandgap voltage generating circuit, so that the first voltage V1 of the first end T1 of the resistor RG and the second voltage V2 of the second end T2 respectively have negative temperature coefficients. In more detail, when the ambient temperature of the temperature sensing circuit 100 is higher, the voltage values of the first voltage V1 and the second voltage V2 will be lower.

请同时参照图2。图2为本发明一实施例中，第一电压V1以及第二电压V2随温度变化的示意图。Please refer to FIG2 at the same time. FIG2 is a schematic diagram showing how the first voltage V1 and the second voltage V2 vary with temperature in one embodiment of the present invention.

如图2所示，于一实施例中，第二电压V2具有的第二负温度系数大于第一电压V1具有的第一负温度系数。因此，当温度感测电路100所位于的环境温度愈高时，第二电压V2下降的幅度将大于第一电压V1下降的幅度。更进一步地说，当温度感测电路100所位于的环境温度愈高时，第一电压V1与第二电压V2之间的电压差愈大，当环境温度愈低时，第一电压V1与第二电压V2之间的电压差愈小。As shown in FIG. 2 , in one embodiment, the second negative temperature coefficient of the second voltage V2 is greater than the first negative temperature coefficient of the first voltage V1. Therefore, when the temperature sensing circuit 100 is located in an environment with a higher temperature, the second voltage V2 will decrease more than the first voltage V1. Specifically, when the temperature sensing circuit 100 is located in an environment with a higher temperature, the voltage difference between the first voltage V1 and the second voltage V2 will increase, and when the temperature sensing circuit 100 is located in an environment with a lower temperature, the voltage difference between the first voltage V1 and the second voltage V2 will decrease.

于一实施例中，由于双极性接面型晶体管Q1、Q2的基极B1、B2电性耦接于接地端GND，且第一电压V1相当于双极性接面型晶体管Q2的射极E2的电压，因此第一电压V1相当于双极性接面型晶体管Q2的射基极电压V_BE2(未标示于图中)，第二电压V2相当于双极性接面型晶体管Q1的射基极电压V_BE1(未标示于图中)。第一电压V1与第二电压V2之间的电压差ΔV_BE可由下式表示：In one embodiment, since the bases B1 and B2 of the bipolar junction transistors Q1 and Q2 are electrically coupled to the ground terminal GND, and the first voltage V1 is equivalent to the voltage of the emitter E2 of the bipolar junction transistor Q2, the first voltage V1 is equivalent to the emitter-base voltage V _BE2 (not shown in the figure) of the bipolar junction transistor Q2, and the second voltage V2 is equivalent to the emitter-base voltage V _BE1 (not shown in the figure) of the bipolar junction transistor Q1. The voltage difference ΔV _BE between the first voltage V1 and the second voltage V2 can be expressed by the following formula:

ΔV_BE＝(kT/q)×ln(N) (式1)ΔV _BE =(kT/q)×ln(N) (Formula 1)

其中，k为波兹曼常数，q为库伦常数，T为绝对温度，N为双极性接面型晶体管Q1、Q2之间的尺寸比例或电流密度比例。Wherein, k is the Boltzmann constant, q is the Coulomb constant, T is the absolute temperature, and N is the size ratio or current density ratio between the bipolar junction transistors Q1 and Q2.

温度判断电路140配置以根据第一电压V1与第二电压V2判断环境温度。于一实施例中，温度判断电路140包含：取样电容CS、计算电路150、第一开关SW1以及第二开关SW2。The temperature determination circuit 140 is configured to determine the ambient temperature according to the first voltage V1 and the second voltage V2. In one embodiment, the temperature determination circuit 140 includes: a sampling capacitor CS, a calculation circuit 150, a first switch SW1, and a second switch SW2.

取样电容CS配置以在第一开关SW1导通时，对电阻RG的第一端T1的第一电压V1进行取样。其中，第一开关SW1是根据第一控制信号CS1所控制。The sampling capacitor CS is configured to sample a first voltage V1 of a first terminal T1 of the resistor RG when the first switch SW1 is turned on. The first switch SW1 is controlled according to a first control signal CS1.

计算电路150则在第二开关SW2导通时，根据取样电容CS取样后的第一电压V1，以及电阻RG的第二端T2的第二电压V2进行计算，以判断温度。其中，第二开关SW2是根据第二控制信号CS2所控制。When the second switch SW2 is turned on, the calculation circuit 150 performs calculation based on the first voltage V1 sampled by the sampling capacitor CS and the second voltage V2 at the second end T2 of the resistor RG to determine the temperature. The second switch SW2 is controlled by the second control signal CS2.

于一实施例中，计算电路150包含放电电阻RD、比较器160、计数器170以及判断电路180。In one embodiment, the calculation circuit 150 includes a discharge resistor RD, a comparator 160 , a counter 170 and a determination circuit 180 .

其中，放电电阻RD在第二开关SW2导通时对取样电容CS进行放电。比较器160电性耦接于放电电阻RD以及电阻RG的第二端T2，以对取样电容CS所取样且经由放电电阻RD放电的第一电压V1的值以及第二电压V2的值进行比较，输出比较结果CR。The discharge resistor RD discharges the sampling capacitor CS when the second switch SW2 is turned on. The comparator 160 is electrically coupled to the discharge resistor RD and the second end T2 of the resistor RG to compare the value of the first voltage V1 sampled by the sampling capacitor CS and discharged through the discharge resistor RD with the value of the second voltage V2, and output a comparison result CR.

计数器170进一步根据时钟信号CLK对比较结果CR进行计数，以判断由取样电容CS取样的第一电压V1的值放电至第二电压V2的值所需的时间长度TL。判断电路180再依据时间长度TL判断温度值TP。The counter 170 further counts the comparison result CR according to the clock signal CLK to determine the time length TL required for the first voltage V1 sampled by the sampling capacitor CS to discharge to the second voltage V2. The determination circuit 180 then determines the temperature value TP according to the time length TL.

请同时参照图3。图3为本发明一实施例中，取样电容CS取样后的第一电压V1、第二电压V2、比较结果CR、时钟信号CLK以及时间长度TL的波形图。以下将搭配图1与图3，对于温度判断电路140的运行进行更详细的说明。Please refer to FIG3 at the same time. FIG3 is a waveform diagram of the first voltage V1, the second voltage V2, the comparison result CR, the clock signal CLK and the time length TL after sampling by the sampling capacitor CS in one embodiment of the present invention. The operation of the temperature determination circuit 140 will be described in more detail below in conjunction with FIG1 and FIG3.

在第一操作时间TO1中，第一开关SW1导通，且第二开关SW2断开。取样电容CS与电阻RG的第一端T1将通过第一开关SW1电性耦接。电阻RG的第一端T1将对取样电容CS充电，以达到使取样电容CS对第一电压V1进行取样的目的。In the first operation time TO1, the first switch SW1 is turned on and the second switch SW2 is turned off. The sampling capacitor CS and the first end T1 of the resistor RG are electrically coupled through the first switch SW1. The first end T1 of the resistor RG charges the sampling capacitor CS to enable the sampling capacitor CS to sample the first voltage V1.

在第一操作时间TO1后的第二操作时间TO2中，第一开关SW1断开，且第二开关SW2导通。取样电容CS与电阻RG的第一端T1将电性隔离，且取样电容CS与放电电阻RD将通过第二开关SW2电性耦接。放电电阻RD通过第二开关SW2对取样电容CS进行放电。In the second operation time TO2 after the first operation time TO1, the first switch SW1 is turned off and the second switch SW2 is turned on. The sampling capacitor CS is electrically isolated from the first end T1 of the resistor RG, and the sampling capacitor CS is electrically coupled to the discharge resistor RD through the second switch SW2. The discharge resistor RD discharges the sampling capacitor CS through the second switch SW2.

同时，电性耦接于放电电阻RD以及电阻RG的第二端T2的比较器170，配置以在第二操作时间TO2中进行电压比较，以输出比较结果CR。Meanwhile, the comparator 170 electrically coupled to the discharge resistor RD and the second end T2 of the resistor RG is configured to perform voltage comparison in the second operation time TO2 to output a comparison result CR.

如图3所示，由于放电电阻RD通过第二开关SW2持续对取样电容CS所取样到的第一电压V1进行放电，第一电压V1的值将愈来愈小。在时间点TS前，第一电压V1的值尚大于第二电压V2的值，以使比较器170输出的比较结果CR为高态。在时间点TS时，第一电压V1的值达到与第二电压V2相同的准位，以使比较结果CR转态。在时间点TS后，第一电压V1的值小于第二电压V2的值，以使比较结果CR为低态。As shown in FIG3 , since the discharge resistor RD continuously discharges the first voltage V1 sampled by the sampling capacitor CS through the second switch SW2, the value of the first voltage V1 will become smaller and smaller. Before the time point TS, the value of the first voltage V1 is still greater than the value of the second voltage V2, so that the comparison result CR output by the comparator 170 is high. At the time point TS, the value of the first voltage V1 reaches the same level as the second voltage V2, so that the comparison result CR changes state. After the time point TS, the value of the first voltage V1 is less than the value of the second voltage V2, so that the comparison result CR is low.

计数器170配置以在第二操作时间TO2中根据时钟信号CLK对比较结果CR进行计数，以判断由取样电容CS取样的第一电压V1的值放电至第二电压V2的值所需的时间长度TL。于一实施例中，计算电路150还包含与门175，且与门175同时接收第二控制信号CS2以及时钟信号CLK，以根据第二控制信号CS2的控制，仅在第二操作时间TO2将时钟信号CLK馈入至计数器170进行计数。The counter 170 is configured to count the comparison result CR according to the clock signal CLK in the second operation time TO2 to determine the time length TL required for the value of the first voltage V1 sampled by the sampling capacitor CS to discharge to the value of the second voltage V2. In one embodiment, the calculation circuit 150 further includes an AND gate 175, and the AND gate 175 simultaneously receives the second control signal CS2 and the clock signal CLK, so as to feed the clock signal CLK to the counter 170 for counting only in the second operation time TO2 according to the control of the second control signal CS2.

于一实施例中，时间长度TL是以时钟信号CLK在第二操作时间TO2中所取样到的高态次数表示，例如但不限于图3中的4次。实际上，时间长度TL可由所取样到的高态次数乘以时钟信号CLK的每单位周期时间长度所得。因此，当时钟信号CLK的频率愈高，将可使时间长度TL的测量愈精确。In one embodiment, the time length TL is represented by the number of high states sampled by the clock signal CLK in the second operation time TO2, for example but not limited to 4 times in FIG. 3. In fact, the time length TL can be obtained by multiplying the number of high states sampled by the time length per unit cycle of the clock signal CLK. Therefore, when the frequency of the clock signal CLK is higher, the time length TL can be measured more accurately.

判断电路180配置以根据时间长度TL判断电压差，进而产生温度值TP。当时间长度TL愈长，表示取样电容CS取样到的第一电压V1与第二电压V2之间的电压差愈大，同时也表示温度愈高。相对的，时间长度TL愈短，表示取样电容CS取样到的第一电压V1与第二电压V2之间的电压差愈小，同时也表示温度愈小。因此，判断电路180可例如，但不限于根据时间长度TL先计算出电压差后，通过例如，但不限于查询温度与电压差之间的对照表或是关系曲线计算出温度值TP。The determination circuit 180 is configured to determine the voltage difference according to the time length TL, and then generate the temperature value TP. When the time length TL is longer, it means that the voltage difference between the first voltage V1 and the second voltage V2 sampled by the sampling capacitor CS is larger, and it also means that the temperature is higher. Conversely, the shorter the time length TL is, the smaller the voltage difference between the first voltage V1 and the second voltage V2 sampled by the sampling capacitor CS is, and it also means that the temperature is lower. Therefore, the determination circuit 180 can, for example, but not limited to, calculate the voltage difference according to the time length TL, and then calculate the temperature value TP by, for example, but not limited to, looking up a comparison table or a relationship curve between temperature and voltage difference.

在部分技术中，所采用的电路包含以金属氧化物半导体晶体管形成的延迟路径(delay line)或是电流镜，而容易受金属氧化物半导体晶体管的工艺精确度或是通道长度改变(channel length modulation)的影响，使温度测量的精确度下降。In some technologies, the circuits used include a delay line or a current mirror formed by metal oxide semiconductor transistors, which are easily affected by the process accuracy or channel length modulation of the metal oxide semiconductor transistors, thereby reducing the accuracy of temperature measurement.

本发明的温度感测电路100不需要使用延迟路径或是电流镜，且取样电容CS在取样到第一电压V1后即与电阻RG以及电流源电路110电性隔离，可避免金属氧化物半导体晶体管的工艺或通道长度改变的影响，进而通过高精确度的时钟信号CLK计算时间长度TL，并据以取得温度值TP。因此，本发明的温度感测电路100可大幅提升温度测量的精确度。The temperature sensing circuit 100 of the present invention does not need to use a delay path or a current mirror, and the sampling capacitor CS is electrically isolated from the resistor RG and the current source circuit 110 after sampling the first voltage V1, which can avoid the influence of the process or channel length change of the metal oxide semiconductor transistor, and then calculate the time length TL through the high-precision clock signal CLK, and obtain the temperature value TP accordingly. Therefore, the temperature sensing circuit 100 of the present invention can greatly improve the accuracy of temperature measurement.

需注意的是，图1所示出的温度感测电路100的电路结构仅为一范例。在其他实施例中，温度感测电路100可在不影响上述的电路运行下，增加其他的电路元件。本发明并不为其所限。It should be noted that the circuit structure of the temperature sensing circuit 100 shown in FIG1 is only an example. In other embodiments, the temperature sensing circuit 100 may be added with other circuit elements without affecting the operation of the above circuit. The present invention is not limited thereto.

虽然上文实施方式中公开了本发明的具体实施例，然其并非用以限定本发明，本发明所属技术领域中技术人员，在不悖离本发明的原理与构思的情形下，当可对其进行各种变动与修饰，因此本发明的保护范围当以附随权利要求所界定者为准。Although specific embodiments of the present invention are disclosed in the above implementation modes, they are not intended to limit the present invention. Technicians in the technical field to which the present invention belongs can make various changes and modifications without departing from the principles and concepts of the present invention. Therefore, the scope of protection of the present invention shall be based on that defined in the appended claims.