Logarithmic circuit structure with temperature compensation and exponential circuit structure with temperature compensation

Abstract

The invention discloses a logarithmic circuit structure with temperature compensation and an exponential circuit structure with temperature compensation, and the logarithmic circuit structure with temperature compensation comprises a first logarithmic circuit which is a logarithmic circuit without temperature compensation; the temperature compensation circuit comprises a single-end-to-differential conversion circuit, the output end of the first logarithmic circuit is connected with the input end of the single-end-to-differential conversion circuit, and the output end of the single-end-to-differential conversion circuit outputs a first differential signal Vlg / 2 and a second differential signal-Vlg / 2; a first index circuit; a second index circuit; and a differential-to-single-ended conversion circuit. Therefore, the logarithmic circuit structure with temperature compensation eliminates the PN junction thermoelectric potential contained in the output voltage of the first logarithmic circuit, and can effectively eliminate the influence of temperature on the output of the logarithmic circuit. The device does not need to depend on the device characteristics of a temperature compensation element, is good in compensation linearity, is adjustable in gain, supports large signal input, and can achieve stable compensation in a full temperature range.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a logarithmic circuit structure with temperature compensation and an exponential circuit structure with temperature compensation. Background Technology

[0002] Logarithmic and exponential circuits are fundamental circuits for neural network activation functions, and their implementation relies on the exponential relationship between PN junction current and voltage. However, the reverse saturation current I of the PN junction... s and thermoelectric potential V T Both are temperature-dependent, which makes the output voltage of logarithmic and exponential circuits susceptible to temperature effects, severely impacting circuit performance.

[0003] In the prior art, to compensate for temperature, the logarithmic circuit outputs V lg The influence of temperature sensitivity is typically mitigated by cascading a negative temperature coefficient resistor (thermistor) after the circuit. However, the resistance-temperature characteristic curve of a negative temperature coefficient resistor is non-linear (exponential curve), which can only achieve approximately linear compensation within a certain temperature range, failing to cover the entire temperature range, and exhibiting poor linearity and non-adjustable compensation effect. Since exponential circuits are based on logarithmic circuits, they also suffer from the aforementioned temperature sensitivity problem, limiting their application in wide temperature range and high-precision scenarios. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a logarithmic circuit structure with temperature compensation, which does not rely on the device characteristics of the temperature compensation element, has good compensation linearity, adjustable gain, supports large signal input, and can achieve stable compensation over the entire temperature range.

[0005] The present invention further proposes an exponential circuit structure with temperature compensation.

[0006] The temperature-compensated logarithmic circuit structure according to the present invention includes: a first logarithmic circuit, wherein the input terminal of the first logarithmic circuit receives the input voltage V. i and reference voltage V rII The first logarithmic circuit is an uncompensated logarithmic circuit; the temperature compensation circuit includes a single-ended to differential converter circuit, wherein the output terminal of the first logarithmic circuit is connected to the input terminal of the single-ended to differential converter circuit to input a temperature-sensitive voltage V to the single-ended to differential converter circuit. lg The output of the single-ended to differential conversion circuit outputs a first differential signal V. lg / 2 and the second differential signal -V lg / 2; First exponential circuit, the input of the first exponential circuit receives the first differential signal Vlg / 2, output the first exponential signal V exp1 The second exponential circuit receives the second differential signal -V at its input. lg / 2, output the second exponential signal V exp2 Differential-to-single-ended conversion circuit, wherein the input terminals of the differential-to-single-ended conversion circuit are respectively connected to the first exponential signal V. exp1 Second exponential signal V exp2 The differential-to-single-ended conversion circuit outputs a temperature-independent logarithmic voltage V. lg_wo_VT .

[0007] Therefore, this temperature-compensated logarithmic circuit structure eliminates the PN junction thermoelectric potential contained in the output voltage of the first logarithmic circuit, effectively eliminating the influence of temperature on the logarithmic circuit output. This invention does not rely on the device characteristics of the temperature-compensating element, offers good compensation linearity and adjustable gain, supports large signal input, and can achieve stable compensation across the entire temperature range.

[0008] In some examples of the present invention, the first logarithmic circuit includes a PN junction device and an operational amplifier, the PN junction device and the operational amplifier being adapted to be coupled to the reference voltage V. rII To achieve the input voltage V i The logarithmic operation is performed to output the temperature-sensitive voltage V. lg Wherein, the temperature-sensitive voltage V lg With the temperature parameter V T Proportional.

[0009] In some examples of the present invention, the single-ended to differential conversion circuit includes a 1 / 2 multiplier circuit and an inverting circuit, wherein the 1 / 2 multiplier circuit is adapted to convert the input voltage V lg Converted to the second differential signal -V lg / 2, the inverting circuit is adapted to convert the second differential signal -V lg / 2 is converted into the first differential signal V lg / 2.

[0010] In some examples of the present invention, both the first exponential circuit and the second exponential circuit are uncompensated exponential circuits. The first exponential circuit includes a second logarithmic circuit and a first inverse function circuit. The output terminal of the second logarithmic circuit is connected to the input terminal of the first inverse function circuit. The second exponential circuit includes a third logarithmic circuit and a second inverse function circuit. The output terminal of the third logarithmic circuit is connected to the input terminal of the first inverse function circuit, which is used to perform exponential operations.

[0011] In some examples of the present invention, the differential-to-single-ended conversion circuit is an inverting subtraction circuit, which is adapted to process the first exponential signal V. exp1 Second exponential signal V exp2 Perform difference operations.

[0012] The temperature-compensated exponential circuit structure according to the present invention includes: a third exponential circuit, the third exponential circuit comprising a fourth logarithmic circuit and a third inverse function circuit, wherein the input terminal of the fourth logarithmic circuit is connected to a reference voltage V. rII and the feedback voltage signal V emitted by the third inverse function circuit lgi The temperature compensation circuit includes a single-ended to differential converter circuit, wherein the output terminal of the fourth logarithmic circuit is connected to the input terminal of the single-ended to differential converter circuit to input a temperature-sensitive voltage V to the single-ended to differential converter circuit. lg The output terminals of the single-ended to differential conversion circuit respectively output the first differential signal V. lg / 2 and the second differential signal -V lg / 2; First exponential circuit, the input of the first exponential circuit receives the first differential signal V lg / 2, output the first exponential signal V exp1 The second exponential circuit receives the second differential signal -V at its input. lg / 2, output the second exponential signal V exp2 Differential-to-single-ended conversion circuit, wherein the input terminals of the differential-to-single-ended conversion circuit are respectively connected to the first exponential signal V. exp1 Second exponential signal V exp2 The output of the differential-to-single-ended converter circuit is connected to the first input of the third inverse function circuit, so that the first input of the third inverse function receives a temperature-independent logarithmic voltage V. lg_wo_VT The second input terminal of the third inverse function circuit is also connected to the input voltage V. i The output of the third inverse function circuit is an exponential voltage V that is independent of temperature. exp_wo_VT The third exponential circuit is an exponential circuit without temperature compensation.

[0013] In some examples of the present invention, the third inverse function circuit outputs a temperature-independent exponential voltage V from the output terminal through resistor matching. exp_wo_VT The feedback voltage signal V is split from the middle. lgi It is transmitted to the input terminal of the fourth logarithmic circuit.

[0014] In some examples of the present invention, the third inverse function circuit achieves the input voltage V through resistor matching. i With temperature-sensitive voltage Vlg It is directly proportional; or the third inverse function circuit makes the input voltage V proportional to the resistance matching. i With temperature-sensitive voltage V lg equal.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 It is based on a schematic diagram of a basic logarithmic circuit in the prior art; Figure 2 This is a schematic diagram of an improved logarithmic circuit based on existing technology that eliminates the influence of saturation current without temperature compensation. Figure 3 It is a schematic diagram of an exponential circuit based on an improved logarithmic circuit and an inverse function circuit in the prior art; Figure 4 This is a schematic diagram of a first exponential circuit according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the second exponential circuit according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a single-ended to differential conversion circuit according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a differential-to-single-ended conversion circuit according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the temperature compensation circuit structure according to an embodiment of the present invention; Figure 9 This is a schematic diagram of a logarithmic circuit structure with temperature compensation according to an embodiment of the present invention; Figure 10 This is a schematic diagram of an exponential circuit structure with temperature compensation according to an embodiment of the present invention; Figure 11 This is a simulation diagram showing the relationship between time and voltage in the temperature compensation circuit structure according to an embodiment of the present invention; Figure 12 This is a simulation diagram showing the relationship between time and voltage in a logarithmic circuit structure with temperature compensation according to an embodiment of the present invention. Figure 13 This is a simulation diagram showing the relationship between time and voltage in an exponential circuit structure with temperature compensation according to an embodiment of the present invention.

[0017] Figure label: 100. Temperature compensation circuit structure; 10. Single-ended to differential conversion circuit; 20. Differential to single-ended conversion circuit; 30. First exponential circuit; 31. Second logarithmic circuit; 32. First inverse function circuit; 40. Second exponential circuit; 41. Third logarithmic circuit; 42. Second inverse function circuit; 200. Logarithmic circuit structure with temperature compensation; 201. First logarithmic circuit; 300. Exponential circuit structure with temperature compensation; 301. Third exponential circuit; 3011. Fourth logarithmic circuit; 3012. Third inverse function circuit. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below, and the embodiments described with reference to the accompanying drawings are exemplary.

[0019] The following is for reference. Figures 4-8 The temperature compensation circuit structure according to an embodiment of the present invention is described.

[0020] In the prior art, the structure of a basic logarithmic circuit is as follows: Figure 1 As shown, it mainly consists of an operational amplifier, a PN junction device Q, and a resistor. The operational amplifier can be a discrete component or a module in an integrated circuit, and the PN junction device Q utilizes its current-voltage exponential characteristic to achieve signal conversion. According to the operational amplifier's "virtual short" and "virtual open" analysis methods, ignoring the base current, the current flowing through the emitter of Q satisfies formula (1): (1) In the formula, I s V is the reverse saturation current of the PN junction. olg V is the output voltage. T Thermoelectric potential (V) T =qkT, approximately 26mV at 27℃; k is Boltzmann constant, T is Kelvin temperature, q is electron charge), I s and V T Both change with temperature, V BE This is the forward voltage of the PN junction device.

[0021] Further derivation yields the input voltage V of the basic logarithmic circuit. i With output voltage V lg The relationship is shown in formula (2): (2) It can be seen that the output voltage V lg Simultaneously affected by V T and I s The effect of temperature, of which I sLocated in the logarithmic term, it is more difficult to compensate.

[0022] To eliminate I s The impact of existing technologies, such as Figure 2 The improved logarithmic circuit shown (without temperature compensation) introduces a reference voltage V. r V is obtained through a logarithmic circuit with the same structure. r Perform logarithmic operations, then use a subtraction circuit ( Figure 2 (Dashed box) Eliminates I based on the principle that "division and logarithmic subtraction are equivalent". s The terms ultimately lead to formula (3): (3) At this time, the output voltage V lg With input voltage V i It exhibits a logarithmic relationship, but the linear coefficient is still V, which is temperature-dependent. T V lg It is directly proportional to temperature T, and the temperature drift problem has not been completely solved.

[0023] For V T The resulting temperature drift, currently available technologies typically... Figure 2 A negative temperature coefficient resistor (thermistor) is cascaded into the circuit to attempt to offset V through the temperature change of the resistor value. T However, the resistance-temperature characteristic curve of a negative temperature coefficient resistor is a non-linear exponential curve, which cannot cover the industrial standard temperature range (such as -40℃ to 85℃) and cannot achieve linear compensation across the entire temperature range. At the same time, its compensation coefficient is fixed and cannot be adjusted according to actual needs, and its linearity is poor, which can easily introduce additional errors and make it difficult to meet the requirements of high-precision circuits.

[0024] Exponential circuits are typically constructed based on the inverse function of logarithmic circuits. For example... Figure 3 As shown (the exponential circuit without temperature compensation), in Figure 2 Cascade inverse function circuits based on logarithmic circuits ( Figure 3 (Dashed box), using inverse function relationships to implement exponential operations. In the inverse function circuit, the input voltage V... i With the output voltage V of the logarithmic circuit lg Through resistors R of equal resistance value vi Connection (R) vi1 =R vi2 =R vi In inverse function circuits, As the input signal of the basic logarithmic circuit (" / / " indicates parallel connection), V can be obtained according to the characteristics of the operational amplifier. i =-V lg After substituting the logarithmic circuit output relationship, we derive formula (4): (4) As can be seen, the output V of the exponential circuit exp The denominator of the exponent term still includes V. T It is significantly affected by temperature. If the same "cascaded negative temperature coefficient resistor" compensation scheme as the logarithmic circuit is used, it will face the same defects: poor compensation over the entire temperature range, poor linearity, and the compensation coefficient cannot be adjusted.

[0025] Combination Figures 4-8 As shown, the temperature compensation circuit structure 100 according to the present invention may mainly include: a single-ended to differential conversion circuit 10, a first exponential circuit 30, a second exponential circuit 40, and a differential to single-ended conversion circuit 20, wherein the input terminal of the single-ended to differential conversion circuit 10 receives the input voltage V of the temperature compensation circuit 100. i The output terminals respectively output the first differential signal V i / 2 and the second differential signal -V i / 2, the input terminal of the first exponential circuit 30 receives the first differential signal V. i / 2, output the first exponential signal V exp1 The input terminal of the second exponential circuit 40 receives the second differential signal -V. i / 2, output the second exponential signal V exp2 The input terminals of the differential-to-single-ended converter 20 are respectively connected to the first exponential signal V. exp1 Second exponential signal V exp2 The output terminal outputs a compensated voltage Vo, and Vo satisfies the following relationship: Vo = (V exp1 -V exp2 ) / k, to achieve control over temperature parameter V T The compensation is given by k, which is a constant determined by the circuit parameters.

[0026] Combination Figure 6 As shown, the single-ended to differential converter circuit 10 includes a 1 / 2 multiplier circuit and an inverting circuit. The 1 / 2 multiplier circuit is suitable for converting the input voltage V... i Converted to the second differential signal -V i / 2, The inverting circuit is suitable for converting the second differential signal -V i / 2 is converted into the first differential signal V. i / 2.

[0027] Combination Figure 4 and Figure 5As shown, both the first exponential circuit 30 and the second exponential circuit 40 are uncompensated exponential circuits. The first exponential circuit 30 includes a second logarithmic circuit 31 and a first inverse function circuit 32. The output of the second logarithmic circuit 31 is connected to the input of the first inverse function circuit 32. The second exponential circuit 40 includes a third logarithmic circuit 41 and a second inverse function circuit 42. The output of the third logarithmic circuit 41 is connected to the input of the second inverse function circuit 42. The second logarithmic circuit 31 and the third logarithmic circuit 41 are input with a reference voltage V. rI The first differential signal V i The second differential signal -Vi / 2 is input to the first inverse function circuit 32, and the second differential signal -Vi / 2 is input to the second inverse function circuit 42 to perform exponential operations.

[0028] Combination Figure 7 As shown, the differential-to-single-ended conversion circuit 20 is an inverting subtraction circuit, which is suitable for performing differential operations on the first exponential signal Vexp1 and the second exponential signal Vexp2.

[0029] The temperature compensation principle of this invention is based on the Taylor expansion properties of exponential functions and hyperbolic tangent functions. Regarding exponential functions... and Performing Taylor expansions on each formula yields formula (5): (5) Adding the two equations together, we get equation (6): (6) Under the condition of Taylor series expansion, i.e. In the case of the non-constant terms in equation (6) , ...etc. are all high-order small quantities, approximately equal to 0, so (7) Observation (4), although V T It's very small, but as long as Choosing an appropriate value can also be done in V. i When taking a larger value, it makes When equation (4) is applied to equation (7), it is not required that... V i It can be a large signal. This condition is satisfied in the following derivation. Established.

[0030] In equation (4), let the input voltages be respectively and The outputs of equation (4) are respectively and ,have (8) According to equation (7), there is also (9) Solving equations (8) and (9) simultaneously yields the following results: (10) Similarly, it can be derived and solved. (11) Subtract the two signals (12) The derivation of equations (8) to (12) above borrows from the analytical approach of Gilbert's multiplication circuit, with the core difference being: 1) In the Gilbert circuit, small-signal AC currents are added and subtracted, and the sum of currents is a variable; here, voltages are added and subtracted, and as shown in equations (7) and (9), the sum of voltages is a constant.

[0031] 2) In the principle of the Gilbert circuit, the input voltage V i The denominator is only V T In order to satisfy linearization and The condition, V i The absolute value must be much smaller than V. T According to the aforementioned content V T The voltage is approximately 26mV, which limits the Gilbert circuit to small-signal processing; here, at V... i An additional gain is introduced into the denominator. When the linearization exponent and hyperbolic tangent function are used, V is better than the Gilbert circuit. i The range can be increased times.

[0032] Combination Figure 8 As shown, the core of the temperature compensation circuit structure 100 in this embodiment of the invention is achieved through mathematical derivation and circuit design, and its output signal V o The input signal V of the temperature compensation circuit 100 is implemented. i With thermoelectric potential V T Ratio operation (Vo∝V) i / V T ), thereby canceling out V in the logarithmic / exponential circuit T Temperature influence. Its structure is as follows: Figure 8 As shown, it includes a single-ended to differential conversion circuit 10, a first exponential circuit 30, a second exponential circuit 40, and a differential to single-ended conversion circuit 20. The functions and principles of each module are as follows: Single-ended to differential conversion circuit 10 (s2d): such as Figure 6As shown, it consists of a 1 / 2 inverting proportional circuit and an inverting circuit. The input voltage V of the temperature compensation circuit 100 is... i The signal is converted into a second differential signal -V by a 1 / 2 inverting amplifier circuit (resistor ratio 1:2). i / 2, then through an inverting circuit (resistor ratio 1:1) the second differential signal -V i / 2 is inverted to form the first differential signal V. i / 2, ultimately outputting a pair of first differential signals V with equal amplitude and opposite phase. i / 2 and the second differential signal -V i / 2 provides differential inputs for the first exponential circuit 30 and the second exponential circuit 40.

[0033] First exponential circuit 30 and second exponential circuit 40: (e.g.) Figure 4 and Figure 5 As shown, the first exponential circuit 30 is formed by cascading an uncompensated second logarithmic circuit 31 and a first inverse function circuit 32. The second exponential circuit 40 is formed by cascading an uncompensated third logarithmic circuit 41 and a second inverse function circuit 42. The first exponential circuit 30 and the second exponential circuit 40 perform exponential operations on the input first differential signal and the second differential signal, respectively, and output signals that are exponentially related to the input signals and contain V. T The first exponential signal V of the term exp1 Second exponential signal V exp2 This provides the original exponent signal for subsequent subtraction operations.

[0034] Differential to single-ended conversion circuit 20 (d2s): such as Figure 7 As shown, an inverting subtraction circuit is used. This circuit receives the first exponential signal V output by the first exponential circuit. exp1 The second exponential signal V output by the second exponential circuit exp2 Subtraction is achieved by utilizing the "virtual short" and "virtual open" characteristics of the operational amplifier, and the output is the same as V. i / V T A proportional voltage Vo performs the core calculations for temperature compensation. Meanwhile, the differential-to-single-ended conversion circuit can introduce additional gain by adjusting the ratio of the feedback resistor to the input resistor, further enhancing circuit flexibility. Swapping the input of d2s will invert the result, but this has no fundamental impact on the final outcome.

[0035] After processing by the above circuit units, equation (12) can be used Figure 8 It means that, in In this case, the V of the temperature compensation circuit 100 o The output is This achieves the input voltage V of the temperature compensation circuit 100. i In molecules, V TIn the denominator, and with adjustable gain, V i Unaffected by V T Restriction can be the purpose of a large signal. The larger V is i The larger the input range, the more effective the adjustment of V. r R fb R fs as well as The value of can be used to adjust the gain of this compensation circuit.

[0036] Combination Figures 4-9 As shown, the temperature-compensated logarithmic circuit structure 200 according to the present invention can mainly include: the temperature compensation circuit structure 100 and a first logarithmic circuit 201, wherein the input terminal of the first logarithmic circuit 201 receives an input voltage V. i and reference voltage V rII The output of the first logarithmic circuit 201 is connected to the input of the temperature compensation circuit structure 100 to output a temperature-sensitive voltage V to the temperature compensation circuit structure 100. lg After processing, the temperature compensation circuit structure 100 outputs a logarithmic voltage V that is independent of temperature. lg_wo_VT The first logarithmic circuit 201 is a logarithmic circuit without temperature compensation.

[0037] The first logarithmic circuit 201 includes a PN junction device and an operational amplifier, the PN junction device and the operational amplifier being adapted to be coupled to a reference voltage V. rII Achieve input voltage V i Logarithmic operation to output temperature-sensitive voltage V lg Among them, the temperature-sensitive voltage V lg With temperature parameter V T Proportional.

[0038] like Figure 9 As shown, part II to the left of the dashed line is the first logarithmic circuit 201, and part I to the right of the dashed line is the temperature compensation circuit structure 100. Both parts I and II utilize... They are respectively denoted as and The reference voltage V used r Let them be denoted as V rI and V rII The inverse function circuit used in I Record . Figure 9 This implements the use of the result of equation (3) as the input of equation (12), and the output does not include V. T Logarithmic voltage V lg_wo_VT As shown in equation (13).

[0039] (13) As long as the result of equation (3) V lg satisfy V i satisfy By applying the linearization condition, V can be compensated over the entire temperature range. T The effect of this makes the output of the logarithmic circuit independent of the temperature of the PN junction; The smaller the ratio, the more the linearization condition is satisfied, and the better the linearity of the result. The op-amp's output will not exceed VDD or fall below VSS; if the absolute value of the output is too large, saturation will occur. Figure 9 The output V of section II lg There is a defined range, and reasonable adjustments are made. The ratio of these two values ​​easily satisfies the linearization conditions described above.

[0040] In equation (13), V lg_wo_VT The signal is a logarithmic signal with full temperature compensation, and V has been eliminated from its expression. T Term, only related to input voltage V i It is proportional to the logarithm, realizing logarithmic operation compensation across the entire temperature range.

[0041] Combination Figures 4-10 As shown, the temperature-compensated exponential circuit structure 300 according to the present invention can mainly include: the temperature compensation circuit structure 100 and a third exponential circuit 301. The third exponential circuit 301 includes a fourth logarithmic circuit 3011 and a third inverse function circuit 3012. The input terminal of the fourth logarithmic circuit 3011 is connected to a reference voltage V. rII and the feedback voltage signal V emitted by the third inverse function circuit 3012 lgi The output of the fourth logarithmic circuit 3011 is connected to the input of the temperature compensation circuit structure 100. The output of the temperature compensation circuit structure 100 is connected to the input of the third inverse function circuit 3012. The input of the third inverse function circuit 3012 is also connected to the input voltage V. i The output of the third inverse function circuit 3012 is an exponential voltage V that is independent of temperature. exp_wo_VT Among them, the third exponential circuit 301 is an exponential circuit without temperature compensation.

[0042] The third inverse function circuit 3012 outputs a temperature-independent exponential voltage V from its output terminal through resistor matching. exp_wo_VT The feedback voltage signal V is split from the middle. lgi The data is transmitted to the input of the fourth logarithmic circuit 3011.

[0043] The third inverse function circuit 3012 achieves the input voltage V through resistor matching. i With temperature-sensitive voltage V lgIt is directly proportional; or the third inverse function circuit 3012 makes the input voltage V proportional through resistor matching. i With temperature-sensitive voltage V lg equal.

[0044] like Figure 10 As shown, part I is still Figure 8 The temperature compensation circuit, part II is Figure 5 The difference between the exponential circuit and the logarithmic circuit in Part II is that the output of the logarithmic circuit in Part II is first processed... Figure 8 The temperature compensation circuit is then used, followed by the input inverse function circuit.

[0045] according to Figure 5 The principle and formula (4) are used in parts I and II. They are respectively denoted as and The reference voltage V used r Let them be denoted as V rI and V rII The inverse function circuit used They are respectively denoted as and Therefore, it is possible to obtain a value that does not include V. T exponential voltage V exp_wo_VT As shown in equation (14).

[0046] (14) As long as V i satisfy By applying the linearization condition, V can be compensated over the entire temperature range. T The effect of this makes the output of the exponential circuit independent of the temperature of the PN junction.

[0047] Compared with the prior art, the present invention has the following significant advantages: 1) Full temperature range compensation: Abandoning the nonlinear compensation scheme that relies on negative temperature coefficient resistors, V is achieved through circuit structure. i / V T The ratio operation eliminates V from a mathematical perspective. T The temperature effect can be stabilized within the industrial standard temperature range (-40℃~85℃), overcoming the shortcomings of existing technologies that only provide local temperature compensation.

[0048] 2) High linearity: The output characteristics of the temperature compensation circuit structure 100 strictly follow Vo∝V i / V T The linear relationship is achieved without additional nonlinear errors; at the same time, the linearization conditions can be flexibly met by adjusting the resistance ratio, ensuring that the linearity of logarithmic / exponential operations is better than that of existing schemes.

[0049] 3) Adjustable gain: By adjusting the reference voltage (V) rI V rII ) and resistance ratio (R fb / R fs It can flexibly adjust the gain of the temperature compensation circuit, logarithmic circuit and exponential circuit to adapt to the signal amplitude requirements of different scenarios and solve the problem of "fixed compensation coefficient" in existing technologies.

[0050] 4) Supports large signal input: Existing Gilbert circuits are limited by V T Limited to approximately 26mV, it can only process small signals; this invention, through V i An additional resistance gain is introduced into the denominator ( This allows the input signal range to be expanded. fb / R fs It can handle input signals of ±2V or even greater amplitude, expanding the application scenarios of the circuit.

[0051] 5) Regular and easy-to-implement circuit structure: The core units of the temperature compensation circuit structure 100, the exponential circuit structure 300 with temperature compensation, and the logarithmic circuit structure 200 with temperature compensation all include a single-ended to differential conversion circuit 10, a first exponential circuit 30, a second exponential circuit 40, and a differential to single-ended conversion circuit 20. That is, the core units of the temperature compensation circuit structure 100, the exponential circuit structure 300 with temperature compensation, and the logarithmic circuit structure 200 with temperature compensation have high repeatability, which can reduce the layout mismatch problem in integrated circuit design. At the same time, the temperature compensation circuit structure 100, the exponential circuit structure 300 with temperature compensation, and the logarithmic circuit structure 200 with temperature compensation only use conventional components such as operational amplifiers, resistors, and PN junction devices, without the need for special customized components, which reduces the difficulty and cost of hardware implementation.

[0052] Furthermore, the following are simulations and analyses of temperature-compensated circuit structure 100, temperature-compensated exponential circuit structure 300, and temperature-compensated logarithmic circuit structure 200, respectively: Example 1: Implementation and Simulation of Temperature Compensation Circuit Structure 100 1. Circuit parameter settings The industrial standard temperature range is -40℃, 25℃, and 85℃; the input resistance R of the second logarithmic circuit 31 and the third logarithmic circuit 41 is... lg =100kΩ, temperature compensation circuit structure 100 R fsub / R sub =20kΩ / 100Ω, R fb / R fs =4kΩ / 1kΩ; Reference voltage: V r =1V; Input voltage: V i =rt, where r = 1V / s, and t is 0~2s.

[0053] 2. Simulation Results and Analysis Simulation results are as follows Figure 11 As shown, the input voltage V is within the range of -40℃ to 85℃. i At -2V to 2V, the output voltage of the temperature compensation circuit structure 100 exhibits a strictly linear change with no significant temperature drift; without gain correction, the linearity error is less than 0.5%, verifying the advantages of the temperature compensation circuit in "full temperature range compensation" and "high linearity".

[0054] Example 2: Implementation and Simulation of a Temperature-Compensated Logarithmic Circuit Structure 200 1. Circuit parameter settings Temperatures within the industrial standard temperature range are -40℃, 25℃, and 85℃; Resistance parameter: R lg =100kΩ, (R) fsub / R sub ) I =20kΩ / 100Ω, (R) fsub / R sub ) II =4kΩ / 100Ω, (R) fb / R fs ) I =4kΩ / 1kΩ; Reference voltage: V rI =1V, V rII =1V; Input voltage: V i =rt, where r = 1V / s, and t is 0~2s.

[0055] 2. Simulation Results and Analysis Simulation results are as follows Figure 12 As shown: When the input voltage V i Logarithmic output V at different temperatures within the 0~2V input range. lg_wo_VT The curves completely overlap, with no temperature drift; The logarithmic relationship between the output and input has a good fit of over 99.8%, demonstrating excellent linearity. This verifies the full temperature compensation effect and high linearity of the temperature-compensated logarithmic circuit structure 200.

[0056] Example 3: Implementation and Simulation of an Exponential Circuit Structure 300 with Temperature Compensation 1. Circuit parameter settings Temperatures within the industrial standard temperature range are -40℃, 25℃, and 85℃; Resistance parameter: R lg =100kΩ, (R) fsub / R sub ) I =20kΩ / 100Ω, (R) fsub / R sub ) II =4kΩ / 100Ω, (R) fb / R fs ) I =4kΩ / 1kΩ, (R) fb / R fs II = 1kΩ / 1kΩ; Reference voltage: V rI =1V, V rII =0.5V; Input voltage: V i =rt, where r = 1V / s, and t is 0~2s.

[0057] 2. Simulation Results and Analysis Simulation results are as follows Figure 13 As shown: When the input voltage V i Within the input range of -2V to 2V, the exponential output V at different temperatures exp_wo_VT The curves are highly consistent, with a temperature drift error of less than 1%. The goodness of fit between the output and the input is higher than 99.7%, which verifies the full temperature compensation effect and high linearity of the temperature-compensated exponential circuit structure 300, and also proves that the circuit can handle large signal inputs.

[0058] The simulations of the three embodiments described above were performed using Matlab Simscape circuit simulation software (version R2019a), with an Intel Core i7-1260P 2.10GHz CPU, 32GB of RAM, and Windows 1124H2 Home Edition operating system. The simulations of these three embodiments verified the technical effects of the present invention: the temperature compensation circuit structure 100 can achieve linear compensation across the entire temperature range; the logarithmic circuit structure 200 with temperature compensation and the exponential circuit structure 300 with temperature compensation can output temperature-independent logarithmic and exponential signals, respectively, and support large signal inputs, completely solving the shortcomings of existing technologies and meeting the application requirements of high precision, wide temperature range, and large signal scenarios.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0061] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A logarithmic circuit structure with temperature compensation, characterized in that, include: The first logarithmic circuit (201) receives the input voltage V at its input terminal. i and reference voltage V rII The first logarithmic circuit (201) is a logarithmic circuit without temperature compensation; Temperature compensation circuit, the temperature compensation circuit includes: A single-ended to differential converter circuit (10) is provided, wherein the output terminal of the first logarithmic circuit (201) is connected to the input terminal of the single-ended to differential converter circuit (10) to input a temperature-sensitive voltage V to the single-ended to differential converter circuit. lg The output terminal of the single-ended to differential conversion circuit (10) outputs the first differential signal V. lg / 2 and the second differential signal -V lg / 2; The first exponential circuit (30) receives the first differential signal V at its input terminal. lg / 2, output the first exponential signal V exp1 ; The second exponential circuit (40) receives the second differential signal -V at its input terminal. lg / 2, output the second exponential signal V exp2 ; Differential to single-ended conversion circuit (20), the input terminals of the differential to single-ended conversion circuit (20) are respectively connected to the first exponential signal V exp1 Second exponential signal V exp2 The differential-to-single-ended conversion circuit (20) outputs a temperature-independent logarithmic voltage V. lg_wo_VT .

2. The logarithmic circuit structure with temperature compensation according to claim 1, characterized in that, The first logarithmic circuit (201) includes a PN junction device and an operational amplifier, the PN junction device and the operational amplifier being adapted to be coupled to the reference voltage V. rII To achieve the input voltage V i The logarithmic operation is performed to output the temperature-sensitive voltage V. lg Wherein, the temperature-sensitive voltage V lg With the temperature parameter V T Proportional.

3. The logarithmic circuit structure with temperature compensation according to claim 1, characterized in that, The single-ended to differential conversion circuit (10) includes a 1 / 2 multiplier circuit and an inverting circuit. The 1 / 2 multiplier circuit is adapted to convert the temperature-sensitive voltage V... lg Converted to the second differential signal -V lg / 2, the inverting circuit is adapted to convert the second differential signal -V lg / 2 is converted into the first differential signal V lg / 2.

4. The temperature compensation circuit structure according to claim 3, characterized in that, Both the first exponential circuit (30) and the second exponential circuit (40) are uncompensated exponential circuits. The first exponential circuit (30) includes a second logarithmic circuit (301) and a first inverse function circuit (302). The output of the second logarithmic circuit (301) is connected to the input of the first inverse function circuit (302). The second exponential circuit (40) includes a third logarithmic circuit (401) and a second inverse function circuit (402). The output of the third logarithmic circuit (401) is connected to the input of the first inverse function circuit (402) to perform exponential operations.

5. The temperature compensation circuit structure according to claim 4, characterized in that, The differential-to-single-ended conversion circuit (20) is an inverting subtraction circuit, which is suitable for processing the first exponential signal V. exp1 Second exponential signal V exp2 Perform difference operations.

6. An exponential circuit structure with temperature compensation, characterized in that, include: The third exponential circuit (301) includes a fourth logarithmic circuit (3011) and a third inverse function circuit (3012). The input terminal of the fourth logarithmic circuit (3011) is connected to a reference voltage V. rII and the feedback voltage signal V emitted by the third inverse function circuit (3012) lgi ; Temperature compensation circuit, the temperature compensation circuit includes: A single-ended to differential converter circuit (10) is provided, wherein the output terminal of the fourth logarithmic circuit (3011) is connected to the input terminal of the single-ended to differential converter circuit (10) to input a temperature-sensitive voltage V to the single-ended to differential converter circuit (10). lg The output terminals of the single-ended to differential conversion circuit (10) respectively output the first differential signal V. lg / 2 and the second differential signal -V lg / 2; The first exponential circuit (30) receives the first differential signal V at its input terminal. lg / 2, output the first exponential signal V exp1 ; The second exponential circuit (40) receives the second differential signal -V at its input terminal. lg / 2, output the second exponential signal V exp2 ; Differential to single-ended conversion circuit (20), the input terminals of the differential to single-ended conversion circuit (20) are respectively connected to the first exponential signal V exp1 Second exponential signal V exp2 The output of the differential-to-single-ended converter circuit (20) is connected to the first input of the third inverse function circuit (3012) so that the first input of the third inverse function receives a temperature-independent logarithmic voltage V. lg_wo_VT The second input terminal of the third inverse function circuit (3012) is also connected to the input voltage V. i The output of the third inverse function circuit (3012) is an exponential voltage V that is independent of temperature. exp_wo_VT The third exponential circuit (301) is an exponential circuit without temperature compensation.

7. The exponential circuit structure with temperature compensation according to claim 6, characterized in that, The third inverse function circuit (3012) outputs a temperature-independent exponential voltage V from its output terminal through resistor matching. exp_wo_VT The feedback voltage signal V is split from the middle. lgi The data is transmitted to the input of the fourth logarithmic circuit (3011).

8. The exponential circuit structure with temperature compensation according to claim 7, characterized in that, The third inverse function circuit (3012) achieves the input voltage V through resistor matching. i With temperature-sensitive voltage V lg It is directly proportional; or the third inverse function circuit (3012) makes the input voltage V proportional to the resistance matching. i With temperature-sensitive voltage V lg equal.

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