Temperature detection circuit and audio power amplifier

Abstract

The application provides a temperature detection circuit and an audio power amplifier, comprising: a voltage sampling unit, comprising a current source module and a transistor module connected in series, the current source module is composed of N current source branches arranged in parallel, and the transistor module is composed of M transistor branches arranged in parallel; a buffer comparison amplification unit configured to buffer and amplify the sampling voltage from the voltage sampling unit and output a temperature sampling voltage; an analog-to-digital conversion unit configured to convert the temperature sampling voltage from the buffer comparison amplification unit into a digital voltage signal; and a digital signal processing unit configured to output a second control signal for controlling the current source branches and / or the transistor branches, and determine a corrected digital voltage signal based on the digital voltage signal corresponding to the temperature sampling voltage of the N current source branches arranged in parallel and / or the M transistor branches arranged in parallel in different on states.

Description

Technical Field

[0001] This application relates to the field of integrated circuits, and more particularly to a temperature detection circuit and an audio power amplifier. Background Technology

[0002] The temperature detection circuit can sense changes in the temperature of the external environment and output a sampling voltage corresponding to the temperature change. The temperature of the temperature detection circuit is determined based on the obtained sampling voltage.

[0003] Ideally, voltage and temperature have a linear relationship. However, in manufacturing, the curve of the sampled voltage changing with temperature may be deviated, such as by slope deviation or intercept deviation, which affects the accuracy of the temperature determined by the temperature detection circuit. Summary of the Invention

[0004] Some embodiments of this application provide a temperature detection circuit and an audio power amplifier. The following describes this application from multiple aspects, and the embodiments and beneficial effects of the following aspects can be referred to each other.

[0005] In a first aspect, embodiments of this application provide a temperature detection circuit, comprising: a voltage sampling unit, including a current source module and a transistor module connected in series, wherein the current source module is composed of N parallel current source branches, and the transistor module is composed of M parallel transistor branches, wherein at least one of N and M is greater than or equal to 2; a buffer comparison amplification unit, configured to buffer and amplify a first sampling voltage and a second sampling voltage from the voltage sampling unit, and output a temperature sampling voltage; an analog-to-digital conversion unit, configured to convert the temperature sampling voltage from the buffer comparison amplification unit into a digital voltage signal; and a digital signal processing unit, configured to output a second control signal for the current source and / or the transistor, and to determine a corrected digital voltage signal based on the digital voltage signal of the temperature sampling voltage corresponding to the N parallel current source branches and / or the M parallel transistor branches under different on-states from the analog-to-digital conversion unit.

[0006] According to the temperature detection circuit provided in the first aspect of this application, by setting a current source module consisting of N parallel current source branches / a transistor module consisting of M parallel transistor branches, the digital signal processing unit can correct the digital voltage signal output by the temperature detection circuit based on the digital voltage signal of the temperature sampling voltage of the N parallel current source branches / M parallel transistor branches under different on-states. This corrects the slope deviation caused by the input offset voltage and / or current matching degree of the operational amplifier and the transistor matching degree, thereby improving the accuracy of temperature detection by the temperature detection circuit.

[0007] In some embodiments, the second control signal is configured to control the sequential activation of N parallel current source branches, and / or to control the sequential activation of M parallel transistor branches.

[0008] In some embodiments, the digital signal processing unit is configured to output a first control signal, which is configured to control the amount of current output by each current source in the current source module.

[0009] In some embodiments, the voltage sampling unit includes a first voltage sampling unit and a second voltage sampling unit connected in parallel. The first voltage sampling unit includes a first current source module and a first transistor module connected in series and is configured to output a first sampled voltage. The second voltage sampling unit includes a second current source module and a second transistor module connected in series and is configured to output a second sampled voltage. At least one of the first and second current source modules is composed of N current source branches connected in parallel, and / or at least one of the first and second transistor modules is composed of M transistor branches connected in parallel.

[0010] In cases where at least one of the first and second current source modules includes N parallel current source branches, the digital signal processing unit is configured to determine the digital voltage signals Vcs-out1, Vcs-out2, ..., Vcs-outN corresponding to the temperature sampling voltage when each current source branch is in the ON state, and the digital voltage signal Vcs-out0 corresponding to the temperature sampling voltage when all N current source branches are in the ON state; and to determine the corrected digital voltage signal based on the difference between Vcs-out0 and Vcs-out1, Vcs-out2, ..., Vcs-outN, respectively; and / or...

[0011] In the case where at least one of the first transistor module and the second transistor module includes M parallel transistor branches, the digital signal processing unit is configured to determine the digital voltage signals Vt-out1, Vt-out2, ..., Vt-outM corresponding to the temperature sampling voltage when each transistor branch is in the ON state, and the digital voltage signal Vt-out0 corresponding to the temperature sampling voltage when all M transistor branches are in the ON state, and determine the corrected digital voltage signal based on the difference between Vt-out0 and Vt-out1, Vt-out2, ..., Vt-outM respectively.

[0012] In some embodiments, each current source branch includes a current source and a current source switch connected in series, and a second control signal is configured to control the closing or opening of the current source switch corresponding to each current source branch, and / or, each transistor branch includes a transistor and a transistor switch connected in series, and a second control signal is configured to control the closing or opening of the transistor switch corresponding to each transistor branch.

[0013] In some embodiments, the digital signal processing unit is configured to: determine Vcs-out0-1, Vcs-out0-2, ..., Vcs-out0-N as differences between Vcs-out0 and Vcs-out1, Vcs-out2, ..., Vcs-outN respectively; average the differences Vcs-out0-1, Vcs-out0-2, ..., Vcs-out0-N to determine the corrected digital voltage signal Vcs-out; and / or determine Vt-out0-1, Vt-out0-2, ..., Vt-out0-M as differences between Vt-out0 and Vt-out1, Vt-out2, ..., Vt-outM respectively; average the differences Vt-out0-1, Vt-out0-2, ..., Vt-out0-M to determine the corrected digital voltage signal Vt-out. By averaging the differences, the slope deviation caused by the matching degree of the operational amplifier's input offset voltage and / or current, and the transistor matching degree, is eliminated, thereby improving the accuracy of temperature detection in the temperature detection circuit.

[0014] In some implementations, the digital signal processing unit is configured to determine the temperature of the temperature detection circuit based on the corrected digital voltage signal and the correspondence between the digital voltage signal and the temperature.

[0015] In some implementations, N parallel current source branches include a first current source branch, a second current source branch, ..., an Nth current source branch. A second control signal is configured to control the sequential activation of the N current source branches, the first current source branch, the second current source branch, ..., the Nth current source branch, and / or M parallel transistor branches include a first transistor branch, a second transistor branch, ..., an Mth transistor branch. The second control signal is configured to control the sequential activation of the M transistor branches, the first transistor branch, the second transistor branch, ..., the Mth transistor branch. This reduces computational load and improves the detection speed of the temperature detection circuit.

[0016] In some implementations, N parallel current source branches include a first current source branch, a second current source branch, ..., an Nth current source branch. A second control signal is configured to sequentially activate the first current source branch, the N current source branches, the second current source branch, the N current source branches, ..., the Nth current source branch, and the Nth current source branch. Alternatively, M parallel transistor branches include a first transistor branch, a second transistor branch, ..., an Mth transistor branch. A second control signal is configured to sequentially activate the first transistor branch, the M transistor branches, the second transistor branch, the M transistor branches, ..., the Mth transistor branch, and the Mth transistor branch. This eliminates the temperature variation affected by the sampling rate.

[0017] In some implementations, one end of the voltage sampling unit is configured to receive the supply voltage, and the other end of the voltage sampling unit is configured to be grounded.

[0018] In some embodiments, the buffered comparison amplification unit includes a first operational amplifier, a second operational amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a first capacitor. The non-inverting input of the first operational amplifier is configured as the first input of the buffered comparison amplification unit, receiving a second sampling voltage. The output of the first operational amplifier is connected to the inverting input of the first operational amplifier and one end of the first resistor. The other end of the first resistor is connected to the second resistor and the non-inverting input of the third operational amplifier. The other end of the second resistor is grounded. The non-inverting input of the second operational amplifier is configured as the second input of the buffered comparison amplification unit, receiving a first sampling voltage. The output of the second operational amplifier is connected to the inverting input of the second operational amplifier and one end of the third resistor. The other end of the third resistor is connected to the inverting input of the third operational amplifier and one end of the fourth resistor. The output of the third operational amplifier is connected to the other end of the fourth resistor and one end of the fifth resistor. The other end of the fifth resistor is connected to one end of the first capacitor, and the connection point serves as the voltage output of the buffered comparison amplification unit, outputting the temperature sampling voltage.

[0019] In some embodiments, the digital signal processing unit is configured to, based on the ratio of the collector current corresponding to the second voltage output terminal to the collector current corresponding to the first voltage output terminal, the ratio of the saturation current corresponding to the second voltage output terminal to the saturation current corresponding to the first voltage output terminal, and the total input offset voltage generated by the first operational amplifier, the second operational amplifier, and the third operational amplifier, respectively determine the digital voltage signals Vcs-out0, Vcs-out1, Vcs-out2, ..., Vcs-outN corresponding to the temperature sampling voltages of N current source branches, the first current source branch, the second current source branch, ..., the Nth current source branch when they are in the on state, and / or, respectively determine the digital voltage signals Vt-out0, Vt-out1, Vt-out2, ..., Vt-outM corresponding to the temperature sampling voltages of M transistor branches, the first transistor branch, the second transistor branch, ..., the Mth transistor branch when they are in the on state.

[0020] In some embodiments, the digital signal processing unit is configured to determine a total input offset voltage based on the ratio of the second resistor to the first resistor, the first input offset voltage of the first operational amplifier, the second input offset voltage of the second operational amplifier, and the third input offset voltage of the third operational amplifier, wherein the total input offset voltage is linearly related to temperature.

[0021] In some implementations, at least one of N and M is 2, 3, or 4.

[0022] Secondly, embodiments of this application provide an audio power amplifier including a temperature detection circuit as described in any of the first aspects. Attached Figure Description

[0023] Figure 1 A schematic diagram of a temperature detection circuit according to some embodiments is shown;

[0024] Figure 2 A schematic diagram of a temperature detection circuit according to some embodiments of this application is shown;

[0025] Figure 3(a) shows Figure 2 A schematic diagram of the temperature detection circuit in which all three current source branches are in the on state;

[0026] Figure 3(b) shows Figure 2 A schematic diagram of the temperature detection circuit in the circuit with the first current source branch in the on state;

[0027] Figure 3(c) shows Figure 2 A schematic diagram of the temperature detection circuit in the middle when the second current source branch is in the on state;

[0028] Figure 3(d) showsFigure 2 A schematic diagram of the temperature detection circuit in the third current source branch when it is in the on state;

[0029] Figure 4 A schematic diagram of a temperature detection circuit according to other embodiments of this application is shown. Figure 1 ;

[0030] Figure 5 A schematic diagram of a temperature detection circuit according to other embodiments of this application is shown. Figure 2 . Detailed Implementation

[0031] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0032] Temperature detection circuits can be used as temperature sensors in mobile terminals (such as mobile phones). During operation, the speaker located within the mobile terminal needs to transmit its impedance value to the processor in real time. This allows the processor to control the music amplitude based on impedance changes, ensuring the speaker operates within a reliable range and protecting it. However, temperature affects impedance calculations. Therefore, a temperature detection circuit monitors the temperature of the chip housing the audio amplifier, thus eliminating the impact of temperature variations on the speaker's impedance.

[0033] Figure 1 A schematic diagram of a temperature detection circuit according to some embodiments is shown. The temperature detection circuit includes a voltage sampling unit 10, a buffer comparison amplification unit 20, and an analog-to-digital conversion unit 30. The voltage sampling unit 10 includes a first voltage sampling unit 101 and a second voltage sampling unit 102 connected in parallel. The first voltage sampling unit 101 includes a first current source CS1 and a first transistor T1 connected in series, and their connection point serves as the first voltage terminal of the first voltage sampling unit 101, outputting a first sampling voltage V. BE1 The second voltage sampling unit 102 includes a second current source CS2 and a second transistor T2 connected in series. Their connection point serves as the second voltage terminal of the second voltage sampling unit 102, outputting a second sampling voltage V. BE2 One end of the first voltage sampling unit 101 and the second voltage sampling unit 102 is configured to receive the power supply voltage, and the other end of the first voltage sampling unit 101 and the second voltage sampling unit 102 is configured to be grounded.

[0034] The buffer comparison amplification unit 20 is configured to compare the first sampled voltage V from the voltage sampling unit 10. BE1 Second sampling voltage V BE2 The voltage is buffered and amplified to output the temperature sampling voltage.

[0035] In some embodiments, the buffer comparator amplification unit 20 may include a first operational amplifier A1, a second operational amplifier A2, a third operational amplifier A3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a first capacitor C1. By setting the first operational amplifier A1 and the second operational amplifier A2, the input stability of the non-inverting input terminal of the third operational amplifier A3 can be ensured. In other embodiments, the buffer comparator amplification unit 20 may also include only one operational amplifier, namely the third operational amplifier A3.

[0036] The non-inverting input of the first operational amplifier A1 is configured as the first input of the buffered comparator amplification unit 20, receiving the second sampling voltage V. BE2 The output terminal of the first operational amplifier A1 is connected to its inverting input terminal and one end of the first resistor R1. The other end of the first resistor R1 is connected to the second resistor R2 and the non-inverting input terminal of the third operational amplifier A3. The other end of the second resistor R2 is grounded. The non-inverting input terminal of the second operational amplifier A2 is configured as the second input terminal of the buffered comparator amplification unit 20, receiving the first sampled voltage V. BE1 The output terminal of the second operational amplifier A2 is connected to its inverting input terminal and one end of the third resistor R3. The other end of the third resistor R3 is connected to the inverting input terminal of the third operational amplifier A3 and one end of the fourth resistor R4. The output terminal of the third operational amplifier A3 is connected to the other end of the fourth resistor R4 and one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to one end of the first capacitor C1, and its connection point serves as the voltage output terminal of the buffered comparator amplifier unit 20, outputting the temperature sampling voltage.

[0037] The analog-to-digital conversion unit 30 is configured to convert the temperature sampling voltage from the buffered comparison amplification unit 20 into a digital voltage signal.

[0038] Ideally, the digital voltage signal corresponding to the temperature sampling voltage should have a linear relationship with the temperature. However, the inventors discovered that due to the influence of the manufacturing process (e.g., the inability to ensure that components in a batch are completely identical), a slope deviation can occur. This slope deviation is mainly caused by the following four non-ideal factors: ① The input offset voltage V of the first operational amplifier A1, the second operational amplifier A2, and the third operational amplifier A3. OS1 V OS2 V OS3 ② The first sampling voltage V flows through BE1 The current I1 and the current flowing through the second sampling voltage V BE2The matching degree of the current I2; ③ The matching degree of the first transistor T1 and the first transistor T2; ④ The matching degree of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4.

[0039] The aforementioned slope deviation cannot be eliminated by single-point calibration. Single-point calibration refers to calibrating the chip based on the ambient temperature during mass production testing. While this method is low-cost and widely used, it can only calibrate intercept deviation, not slope deviation, resulting in poor accuracy. Two-point calibration can also be used; however, although it can eliminate slope deviation, it is difficult to implement and costly. Two-point calibration involves performing a high-temperature test in addition to the room-temperature test required for single-point calibration during mass production testing. The slope change of the detection temperature with room temperature is fitted using a two-point method, thereby calibrating both slope and intercept deviations.

[0040] To eliminate the slope deviation caused by the input offset voltage of the operational amplifier and the matching degree of the two currents, some embodiments of this application provide a temperature detection circuit.

[0041] Figure 2 A schematic diagram of a temperature detection circuit according to some embodiments of this application is shown. The temperature detection circuit includes a voltage sampling unit 10, a buffer comparison and amplification unit 20, an analog-to-digital conversion unit 30, and a digital signal processing unit 40. The difference from the above embodiments is that the second voltage sampling unit 102 in the voltage sampling unit 10 and the digital signal processing unit 40 replace the second current source CS2 in the second voltage sampling unit 102 with a second current source module 1021.

[0042] refer to Figure 2 The second voltage sampling unit 102 includes a second current source module 1021 and a second transistor T2 connected in series. The connection point serves as the second voltage terminal of the second voltage sampling unit 102, outputting a second sampling voltage V. BE2 The second current source module 1021 consists of N parallel current source branches, where N is greater than or equal to 2. In some embodiments, each current source branch includes a current source (e.g., a digitally controlled current source, DCCS) and a current source switch connected in series. For example, the N parallel current source branches include a first current source branch, a second current source branch, ..., the Nth current source branch. The first current source branch includes a current source CS. 21 and current source switch S 21 The second current source branch includes the current source CS. 22 and current source switch S 22 The Nth current source branch includes the current source CS.2N and current source switch S 2N In other words, in this embodiment, the second voltage sampling unit 102 includes at least two current source branches, while in the above embodiment, the second voltage sampling unit 102 includes only one current source branch.

[0043] Please refer to the description of the buffer comparison amplification unit 20 and the analog-to-digital conversion unit 30 in the above embodiments, and they will not be repeated here.

[0044] A digital signal processing unit (e.g., a digital signal processor, DSP) 40 is configured to output a first control signal and a second control signal. The first control signal is configured to control the current I1 and I2 output by each current source. 21 I 22 ... I 2N The second control signal is configured to control the sequential switching on of N parallel current source branches; in other words, the second control signal is configured to control the current source switch S. 21 S 22 S 2N The closing or opening of (current source switch S) 21 S 22 S 2N (Controlled by the second control signal).

[0045] It should be noted that "in sequence" can be understood as following a preset order, which can mean connecting one current source branch at a time or connecting multiple current source branches at a time, without making a specific limitation here.

[0046] In some embodiments, the digital signal processing unit 40 is configured to determine the temperature of the temperature detection circuit based on the digital voltage signal corresponding to the corrected temperature sampling voltage and the correspondence between the digital voltage signal and the temperature.

[0047] According to the temperature detection circuit provided in this application, by setting a second current source module 1021 composed of N parallel current source branches, the digital signal processing unit can correct the digital voltage signal output by the temperature detection circuit based on the digital voltage signal corresponding to the temperature sampling voltage of the N parallel current source branches under different on-states. This corrects the slope deviation caused by the input offset voltage of the operational amplifier and the current matching degree, thereby improving the accuracy of temperature detection by the temperature detection circuit.

[0048] In some embodiments, N is 2, 3, or 4. This setting allows for the correction of slope deviations caused by the input offset voltage and current matching of the operational amplifier at a relatively low cost, thereby improving the accuracy of temperature detection in the temperature detection circuit.

[0049] The following example uses N=3, combined with Figures 3(a) to 3(d) This application describes some embodiments in which a second current source module 1021 is provided to eliminate slope deviation caused by the input offset voltage of the operational amplifier and the matching degree of the current.

[0050] Assuming R4 = R2 = pR and R1 = R3 = R, from the virtual short characteristic of the operational amplifier, we can obtain:

[0051]

[0052] In formula (1), V BE1 V is the first sampling voltage. BE2 This is the second sampling voltage.

[0053] From formula (1), we can obtain the following: In formula (2), I1 is the collector current of the first transistor T1; I 2N I is the collector current of the second transistor T2 corresponding to the Nth current source branch in the second current source module 1021 when it is in the ON state; S1 I is the saturation current of the first transistor T1; S2 V is the saturation current of the second transistor T2; T Thermoelectric voltage, k is the Boltzmann constant, and q is the electron charge.

[0054] For ease of understanding, the following formula derivation does not consider the mismatch between the first transistor T1 and the second transistor T2, that is, I S1 =I S2 .

[0055] From formula (2), we can obtain that

[0056] Assume I 21 =2αI1,I 22 =2βI1,I 23 = 2γI1, where α, β, and γ are the collector current mismatch coefficients caused by current source mismatch. The collector current mismatch coefficient can be understood as the collector current I flowing through the first current source branch... 21 If there is a 1% mismatch, then α = 1.01.

[0057] In some embodiments, the total input offset voltage V generated by the first operational amplifier A1, the second operational amplifier A2, and the third operational amplifier A3 is... os123 The ratio p of the second resistor R2 to the first resistor R1 and the first input offset voltage V of the first operational amplifier A1 can be used as a reference. os1 The second input offset voltage V of the second operational amplifier A2 os2 and the third input offset voltage V of the third operational amplifier A3 os3 Sure.

[0058] Total input offset voltage V os123 Specifically, it can be determined using the following formula:

[0059] V OS123 =-(p+1)V OS3 +pV OS2 -pV OS1 (4)

[0060] In formula (4), V OS1 V is the first input offset voltage of the first operational amplifier A1. OS2 V is the second input offset voltage of the second operational amplifier A2. OS3 This is the third input offset voltage of the third operational amplifier A3.

[0061] In some embodiments, the total input offset voltage V os123 It is considered to have a linear relationship with temperature, that is,

[0062] V OS123 =-(p+1)V OS3 +pV OS2 -pV OS1 =k o 'T=k o V T (5)

[0063] In formula (5), k o The temperature coefficient of the input offset voltage.

[0064] Figure 3(a) shows Figure 2 The diagram shows the temperature detection circuit with all three current source branches in the ON state. As shown in Figure 3(a), all three current source branches are in the ON state, i.e., the current source switch S... 21 S 22 S 23 It is under control and in a closed state.

[0065] From formulas (3) and (5), we can obtain the digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches are in the on state. cs-out0 ,Right now,

[0066] V cs-out0 =pV T In2(α+β+γ)-(p+1)V OS3 +p V OS2 -p V OS1 =(pIn2+pIn(α+β+γ)+k o V T (6)

[0067] Figure 3(b) shows Figure 2 The diagram shows the temperature detection circuit in Figure 3(b) with only the first current source branch in the on state. As shown in Figure 3(b), the first current source branch is in the on state, i.e., the current source switch S is in the on state. 21 S is in a closed state under control. 22 S 23 The controlled device is in a disconnected state.

[0068] From formulas (3) and (5), we can obtain the digital voltage signal V corresponding to the temperature sampling voltage when the first current source branch is in the on state. cs-out1 ,Right now,

[0069] V cs-out1 =pV T In2(α)-(p+1)V OS3 +pV OS2 -pV OS1 =(pIn2+pIn(α)+k o V T (7)

[0070] Subtracting formula (7) from formula (6) yields the digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches are in the on state. cs-out0 The digital voltage signal V corresponding to the temperature sampling voltage when the first current source branch is in the ON state. cs-out1 The difference V cs-out0-1 ,Right now,

[0071]

[0072] Figure 3(c) shows Figure 2 The diagram shows the temperature detection circuit in Figure 3(c) with only the second current source branch in the on state. As shown in Figure 3(c), the second current source branch is in the on state, i.e., the current source switch S... 22 S is in a closed state under control. 21 S 23 The controlled device is in a disconnected state.

[0073] From formulas (3) to (5), the digital voltage signal V corresponding to the temperature sampling voltage when the second current source branch is in the on state can be obtained. cs-out2 ,Right now,

[0074] V cs-out2 =pV T In2(β)-(p+1)V OS3 +pV OS2 -pV OS1 =(pIn2+pIn(β)+k o V T (9)

[0075] Subtracting formula (9) from formula (6) yields the digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches are in the on state. cs-out0 The digital voltage signal V corresponding to the temperature sampling voltage when the second current source branch is in the ON state. cs-out2 The difference V cs-out0-2 ,Right now,

[0076]

[0077] Figure 3(d) shows Figure 2 The diagram shows the temperature detection circuit in Figure 3(d) with only the third current source branch in the on state. As shown in Figure 3(d), the third current source branch is in the on state, i.e., the current source switch S... 23 S is in a closed state under control. 21 S 22 The controlled device is in a disconnected state.

[0078] From formulas (3) and (5), we can obtain the digital voltage signal V corresponding to the temperature sampling voltage when the third current source branch is in the on state. cs-out3 ,Right now,

[0079] V cs-out3 =pV T In2(γ)-(p+1)V OS3 +pV OS2 -pV OS1 =(pIn2+pIn(γ)+k o V T (11)

[0080] Subtracting formula (11) from formula (6) yields the digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches are in the on state. cs-out0 The digital voltage signal V corresponding to the temperature sampling voltage when the third current source branch is in the ON state. cs-out3 The difference V cs-out0-3 ,Right now,

[0081]

[0082] The difference V determined above cs-out0-1 V cs-out0-2 V cs-out0-3 The average value is taken to determine the digital voltage signal V corresponding to the corrected temperature sampling voltage. cs-out That is, from formulas (8), (10), and (12), we can obtain that

[0083]

[0084]

[0085] Assuming α, β, and γ are all greater than 1, when α-1 approaches infinity, In(1+α-1) and α-1 are equivalent infinitesimals, denoted as In(1+α-1)~α-1. Similarly, we can obtain In(1+β-1)~β-1 and In(1+γ-1)~γ-1. Then, in formula (13), In(1+α-1)~α-1, In(1+β-1)~β-1, In(1+γ-1)~γ-1, thus,

[0086] V cs-out =p In3V T (14)

[0087] From formula (14), it can be seen that, since V cs-out It is only related to the ratio p of the second resistor R2 to the first resistor R1, eliminating the slope deviation caused by the input offset voltage of the operational amplifier and the matching degree of the two currents.

[0088] The digital signal processing unit 40 is configured to process the digital voltage signal V corresponding to the corrected temperature sampling voltage. cs-out And the correspondence between digital voltage signals and temperature, to determine the temperature T of the temperature detection circuit. s This improves the accuracy of the temperature detection circuit.

[0089] It should be noted that the digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches are in the ON state. cs-out0 And the digital voltage signal V corresponding to the temperature sampling voltage when the first current source branch is in the ON state. cs-out1 The digital voltage signal V corresponding to the temperature sampling voltage when the second current source branch is in the ON state. cs-out2 The digital voltage signal V corresponding to the temperature sampling voltage when the third current source branch is in the ON state. cs-out3 The order in which this is determined is not specifically limited. In some embodiments, it may be according to V cs-out0 Vcs-out1 V cs-out2 V cs-out3 The order is determined, and in other embodiments, it can also be determined according to V. cs-out3 V cs-out2 V cs-out1 V cs-out0 The order can be any other order, as long as the above digital voltage signal can be obtained.

[0090] To eliminate the temperature change affected by the sampling rate, in some embodiments, the following steps can also be followed: (1) Determine the digital voltage signal corresponding to the temperature sampling voltage when one current source branch is in the on state; (2) Determine the digital voltage signal corresponding to the temperature sampling voltage when all three current source branches are in the on state; (3) Determine the digital voltage signal corresponding to the temperature sampling voltage when another current source branch is in the on state; (4) Determine the digital voltage signal corresponding to the temperature sampling voltage when all three current source branches are in the on state; (5) Determine the digital voltage signal corresponding to the temperature sampling voltage when the remaining current source branch is in the on state; (6) Determine the digital voltage signal corresponding to the temperature sampling voltage when all three current source branches are in the on state.

[0091] It should be noted that if the sampling speed is fast enough, the temperature change affected by the sampling speed can be ignored. Therefore, it is not necessary to repeat the determination of the digital voltage signal corresponding to the temperature sampling voltage when all three current source branches are in the on state.

[0092] It should be noted that although the above derivation process takes N=3 as an example, those skilled in the art will understand that it is equally applicable to cases where N is greater than or less than 3, and will not be elaborated here.

[0093] In some other embodiments, Figure 2 Based on the embodiment shown, the first current source CS1 in the first voltage sampling unit 101 can be replaced with a first current source module, whose connection point serves as the first voltage terminal of the first voltage sampling unit 101, outputting the first sampling voltage V. BE1 The first current source module may include N current source branches connected in parallel, or it may include more than N, or less than N but N is greater than or equal to 2 current source branches connected in parallel; no specific limitation is made here. By setting two current source modules, the slope deviation caused by the input offset voltage of the operational amplifier and the matching degree of the current can also be eliminated, thereby improving the detection accuracy of the temperature detection circuit. It should be noted that the first current source module can refer to the description of the second current source module 1021 above, and will not be repeated here.

[0094] In some other embodiments, it is also possible toFigure 1 At least one transistor in the first voltage sampling unit 101 and the second voltage sampling unit 102 is replaced with a transistor module. This eliminates slope deviations caused by the input offset voltage of the operational amplifier and the matching degree of the transistors, thereby improving the detection accuracy of the temperature detection circuit. The transistor module comprises M parallel transistor branches, where M is greater than or equal to 2.

[0095] Figure 4 A schematic diagram of a temperature detection circuit according to other embodiments of this application is shown. Figure 1 .and Figure 2 The embodiment shown differs in that the second voltage sampling unit 102 includes a second current source module 1021 and a second transistor module 1022 connected in series. In other words, the second voltage sampling unit 102 includes a second current source module 1021 and a second transistor module 1022 connected in series. Figure 2 The second transistor T2 in the second voltage sampling unit 102 is replaced with the second transistor module 1022. For details not described in detail, please refer to the description in the above embodiments; they will not be repeated here.

[0096] The second transistor module 1022 is composed of M parallel transistor branches, where M is greater than or equal to 2. In some embodiments, each transistor branch includes a transistor (e.g., a bipolar junction transistor, BJT) and a transistor switch connected in series. For example, the M parallel transistor branches include a first transistor branch, a second transistor branch, ..., the Mth transistor branch. The first transistor branch includes a transistor T... 21 and transistor switch S' 21 The second transistor branch includes transistor TS. 22 and transistor switch S' 22 ...; The Mth transistor branch includes transistor T 2M and transistor switch S' 2M It should be noted that M can be equal to N, or they can be different.

[0097] In some embodiments, N and M are 2, 3, or 4. This setting allows for the correction of slope deviations caused by the operational amplifier's input offset voltage, current matching, and transistor matching, while maintaining a relatively low cost, thereby improving the accuracy of temperature detection in the temperature sensing circuit.

[0098] The digital signal processing unit 40 (e.g., a digital signal processor, DSP) is configured to output a first control signal and a second control signal. The first control signal is configured to control the current I1 and I2 output by each current source. 21 I 22... I 2N The second control signal is configured to control the sequential switching on of N parallel current source branches; in other words, the second control signal is configured to control the current source switch S. 21 S 22 S 2N The closing or opening of (current source switch S) 21 S 22 S 2N Controlled by a second control signal, and configured to control the sequential switching on of M parallel transistor branches; in other words, the second control signal is configured to control transistor switch S'. 21 S' 22 、…、S' 2M The closing or opening of the current source switch (S') 21 S' 22 、…、S' 2M (Controlled by the second control signal).

[0099] In some embodiments, the digital signal processing unit 40 is configured to determine the temperature of the temperature detection circuit based on the digital voltage signal corresponding to the corrected temperature sampling voltage and the correspondence between the digital voltage signal and the temperature.

[0100]

[0101] In formula (15), I1 is the collector current of the first transistor T1; I 2N I is the collector current of the second transistor module 1022 corresponding to the Nth current source branch in the second current source module 1021 being in the ON state; S1 I is the saturation current of the first transistor T1; S2M V represents the saturation current of the transistor corresponding to the Mth transistor branch in the second transistor module 1022 when it is in the ON state; T Thermoelectric voltage, k is the Boltzmann constant, and q is the electron charge.

[0102] Assume N = M = 3, R4 = R2 = pR, R1 = R3 = R, and I 21 =2αI1,I 22 =2βI1,I 23 =2γI1, and I S1 =uI S21 =vI S22 =wI S23 , where α, β, γ are the current mismatch coefficients caused by current source mismatch; u, v, w are the saturation current mismatch coefficients caused by transistor mismatch.

[0103] By rearranging formula (15), we can obtain:

[0104] The second control signal can simultaneously control the sequential connection of the current source branch and the transistor branch, or it can control the sequential connection of the current source branch first and then the sequential connection of the transistor branch, or it can control the sequential connection of the transistor branch first and then the sequential connection of the current source branch. No specific limitation is made here.

[0105] In some embodiments, the total input offset voltage V generated by the first operational amplifier A1, the second operational amplifier A2, and the third operational amplifier A3 is... os123 The ratio p of the second resistor R2 to the first resistor R1 and the first input offset voltage V of the first operational amplifier A1 can be used as a reference. os1 The second input offset voltage V of the second operational amplifier A2 os2 and the third input offset voltage V of the third operational amplifier A3 os3 Confirmed. Please refer to formula (4) for the specific calculation formula.

[0106] In some embodiments, the total input offset voltage V os123 It is considered to have a linear relationship with temperature. Please refer to formula (5) for the specific calculation formula.

[0107] The following example illustrates how the second control signal simultaneously controls the sequential activation of the current source branch and the transistor branch.

[0108] From formulas (16) and (5), we can determine:

[0109] ① The digital voltage signal V corresponding to the temperature sampling voltage when all three current source branches and three transistor branches are in the ON state. cst-out0 =(pIn2+pIn(α+β+γ)+pIn(u+v+w)+k o V T (17)

[0110] ② The digital voltage signal V corresponding to the temperature sampling voltage when the first current source branch and the first transistor branch are in the ON state. tcs-out1 =(pIn2+pIn(α)+pIn(u)+k o V T (18)

[0111] ③ The digital voltage signal V corresponding to the temperature sampling voltage when the second current source branch and the second transistor branch are in the ON state. tcs-out2 =(pIn2+pIn(β)+pIn(v)+k o V T (19)

[0112] ④ The digital voltage signal V corresponding to the temperature sampling voltage when the third current source branch and the third transistor branch are in the ON state. tcs-out3 =(pIn2+pIn(γ)+pIn(w)+k o V T (20)

[0113] It should be noted that this application does not impose specific limitations on the order of determining the above-mentioned digital voltage signals, as long as the above-mentioned digital voltage signals can be obtained.

[0114] Subtract formula (17) from formulas (18), (19), and (20) respectively to determine the difference V. cst-out0-1 V cst-out0-2 V cst-out0-3 .

[0115] In some embodiments, the digital signal processing unit 40 is further configured to process the difference V cst-out0-1 V cst-out0-2 V cst-out0-3 Averaging is performed to determine the digital voltage signal V corresponding to the corrected temperature sampling voltage. cst-out ,Right now,

[0116] V cst-out =p In3V T (twenty one)

[0117] Please refer to the description in the above embodiments for the specific calculation process, which will not be repeated here.

[0118] From formula (21), it can be seen that, since V cst-out It is only related to the ratio p of the second resistor R2 to the first resistor R1, eliminating the slope deviation caused by the input offset voltage of the operational amplifier, the matching degree of the two currents, and the matching degree of the two transistors.

[0119] According to other embodiments of the present application, the temperature detection circuit provides a second current source module 1021 composed of N parallel current source branches and a second transistor module 1022 composed of M parallel transistor branches. This enables the digital signal processing unit to correct the digital voltage signal output by the temperature detection circuit based on the digital voltage signals of the temperature sampling voltages of the N parallel current source branches and the M parallel transistor branches under different on-states. This eliminates the slope deviation caused by the input offset voltage of the operational amplifier, the matching degree of the two currents, and the matching degree of the two transistors, thereby further improving the accuracy of temperature detection by the temperature detection circuit.

[0120] Figure 5 A schematic diagram of a temperature detection circuit according to other embodiments of this application is shown. Figure 2The temperature detection circuit includes a voltage sampling unit 10, a buffer comparison and amplification unit 20, an analog-to-digital conversion unit 30, and a digital signal processing unit 40. Figure 4 The embodiment shown differs in that the first current source CS1 in the first voltage sampling unit 101 is replaced with a first current source module 1011, the first transistor T1 in the first voltage sampling unit 101 is replaced with a first transistor module 1012, and the connection point between the first current source module 1011 and the first transistor module 1012 is used as the first voltage terminal of the first voltage sampling unit 101 to output the first sampling voltage V. BE1 .

[0121] The first current source module 1011 may include Y current source branches connected in parallel, and the second current source module 1021 may include N current source branches connected in parallel. Each current source branch includes a current source and a current source switch. The number of N and Y may be the same or different.

[0122] The first transistor module 1012 may include Z parallel transistor branches, and the second transistor module 1022 may include M parallel transistor branches, each transistor branch including a transistor and a transistor switch. The numbers M and Z may be the same or different.

[0123] It should be noted that the number of branches in the current source module and the transistor module can be the same or different. For example, N and M, Y and Z can be the same or different.

[0124] In some embodiments, N, M, Y, and Z are 2, 3, or 4. This setting allows for the correction of slope deviations caused by the operational amplifier's input offset voltage, current matching, and transistor matching, while maintaining a relatively low cost, thereby improving the accuracy of temperature detection in the temperature sensing circuit.

[0125] For any parts not described in detail, please refer to the description in the above embodiments, which will not be repeated here.

[0126] The digital signal processing unit 40 (e.g., a digital signal processor, DSP) is configured to output a first control signal and a second control signal. The first control signal is configured to control the current I output by each current source. 11 I 12 ..., I 1Y I 21 I 22 ... I 2NThe second control signal is configured to sequentially connect the Y parallel current source branches in the first current source module 1011 and the N parallel current source branches in the second current source module 1021. In other words, the second control signal is configured to control the current source switch S. 11 S 12 S 1Y S 21 S 22 S 2N The closing or opening of (current source switch S) 21 S 22 S 2Y S 21 S 22 S 2N Controlled by a second control signal, and configured to control the sequential activation of Z parallel transistor branches in the first transistor module 1012 and M parallel transistor branches in the second transistor module 1022; in other words, the second control signal is configured to control transistor switch S'. 11 S' 12 、…、S' 1Z S' 21 S' 22 、…、S' 2M The closing or opening of the current source switch (S') 11 S' 12 、…、S' 1Z S' 21 S' 22 、…、S' 2M (Controlled by the second control signal).

[0127] According to other embodiments of the present application, the temperature detection circuit is configured with a first current source module 1011 consisting of Y parallel current source branches, a second current source module 1021 consisting of N parallel current source branches, and a first transistor module 1012 consisting of Z parallel transistor branches and a second transistor module 1022 consisting of M parallel transistor branches. This enables the digital signal processing unit to correct the digital voltage signal output by the temperature detection circuit based on the digital voltage signals of the temperature sampling voltages of the Y / N parallel current source branches and the Z / M parallel transistor branches under different on-states. This also eliminates the slope deviation caused by the input offset voltage of the operational amplifier, the matching degree of the two currents, and the matching degree of the two transistors, thereby further improving the accuracy of temperature detection by the temperature detection circuit.

[0128] Various embodiments of the mechanisms disclosed in this application can be implemented in hardware, software, firmware, or a combination of these implementation methods.

[0129] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0130] It should be noted that all units / modules mentioned in the device embodiments of this application are logical units / modules. Physically, a logical unit / module can be a physical unit / module, a part of a physical unit / module, or a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important factor; the combination of functions implemented by these logical units / modules is the key to solving the technical problems proposed in this application. Furthermore, to highlight the innovative aspects of this application, the above-described device embodiments of this application have not introduced units / modules that are not closely related to solving the technical problems proposed in this application. This does not mean that the above-described device embodiments do not contain other units / modules.

[0131] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0132] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.

Claims

1. A temperature detection circuit, characterized in that, include: The voltage sampling unit includes a current source module and a transistor module connected in series. The current source module consists of N current source branches connected in parallel, and the transistor module consists of M transistor branches connected in parallel. At least one of N and M is greater than or equal to 2. The voltage sampling unit includes a first voltage sampling unit and a second voltage sampling unit connected in parallel. The first voltage sampling unit includes a first current source module and a first transistor module connected in series and is configured to output a first sampling voltage. The second voltage sampling unit includes a second current source module and a second transistor module connected in series and is configured to output a second sampling voltage. At least one of the first current source module and the second current source module is composed of N current source branches connected in parallel, and / or at least one of the first transistor module and the second transistor module is composed of M transistor branches connected in parallel. The buffered comparison amplification unit is configured to buffer and amplify the sampled voltage from the voltage sampling unit and output a temperature sampling voltage. An analog-to-digital conversion unit is configured to convert the temperature sampling voltage from the buffered comparison amplification unit into a digital voltage signal; The digital signal processing unit is configured to output a second control signal for controlling the current source branch and / or the transistor branch, and to determine a corrected digital voltage signal based on the digital voltage signal of the temperature sampling voltage corresponding to the N parallel current source branches and / or the M parallel transistor branches under different on-states from the analog-to-digital conversion unit. The second control signal is configured to control the sequential activation of the N parallel current source branches, and / or to control the sequential activation of the M parallel transistor branches.

2. The temperature detection circuit according to claim 1, characterized in that, The digital signal processing unit is configured to output a first control signal, which is configured to control the amount of current output by each current source in the current source module.

3. The temperature detection circuit according to claim 1, characterized in that, In the case where at least one of the first current source module and the second current source module includes the N parallel current source branches, the digital signal processing unit is configured to determine the digital voltage signals Vcs-out1, Vcs-out2, ..., Vcs-outN corresponding to the temperature sampling voltage when each of the current source branches is in the on state, and the digital voltage signal Vcs-out0 corresponding to the temperature sampling voltage when all N of the current source branches are in the on state; and, based on the differences between Vcs-out0 and Vcs-out1, Vcs-out2, ..., Vcs-outN, respectively, determine the corrected digital voltage signal, and / or... In the case where at least one of the first transistor module and the second transistor module includes the M parallel transistor branches, the digital signal processing unit is configured to determine the digital voltage signals Vt-out1, Vt-out2, ..., Vt-outM corresponding to the temperature sampling voltage when each of the transistor branches is in the ON state, and the digital voltage signal Vt-out0 corresponding to the temperature sampling voltage when all M transistor branches are in the ON state, and determine the corrected digital voltage signal based on the difference between Vt-out0 and Vt-out1, Vt-out2, ..., Vt-outM respectively.

4. The temperature detection circuit according to claim 1, characterized in that, Each current source branch includes a current source and a current source switch connected in series, and the second control signal is configured to control the closing or opening of the current source switch corresponding to each current source branch, and / or, each transistor branch includes a transistor and a transistor switch connected in series, and the second control signal is configured to control the closing or opening of the transistor switch corresponding to each transistor branch.

5. The temperature detection circuit according to claim 3, characterized in that, The digital signal processing unit is configured to: determine Vcs-out0-1, Vcs-out0-2, ..., Vcs-out0-N as differences between Vcs-out0 and Vcs-out1, Vcs-out2, ..., Vcs-outN respectively; average the differences Vcs-out0-1, Vcs-out0-2, ..., Vcs-out0-N to determine the corrected digital voltage signal Vcs-out; and / or determine Vt-out0-1, Vt-out0-2, ..., Vt-out0-M as differences between Vt-out0 and Vt-out1, Vt-out2, ..., Vt-outM respectively; average the differences Vt-out0-1, Vt-out0-2, ..., Vt-out0-M to determine the corrected digital voltage signal Vt-out.

6. The temperature detection circuit according to claim 1, characterized in that, The digital signal processing unit is configured to determine the temperature of the temperature detection circuit based on the corrected digital voltage signal and the correspondence between the digital voltage signal and temperature.

7. The temperature detection circuit according to claim 5, characterized in that, The N parallel current source branches include a first current source branch, a second current source branch, ..., an Nth current source branch. The second control signal is configured to control the sequential activation of the N parallel current source branches, the first current source branch, the second current source branch, ..., the Nth current source branch, and / or, the M parallel transistor branches include a first transistor branch, a second transistor branch, ..., an Mth transistor branch. The second control signal is configured to control the sequential activation of the M parallel transistor branches, the first transistor branch, the second transistor branch, ..., the Mth transistor branch.

8. The temperature detection circuit according to claim 5, characterized in that, The N parallel current source branches include a first current source branch, a second current source branch, ..., an Nth current source branch. The second control signal is configured to control the sequential activation of the first current source branch, the N parallel current source branches, the second current source branch, the N parallel current source branches, ..., the Nth current source branch, and the N parallel current source branches, and / or, the M parallel transistor branches include a first transistor branch, a second transistor branch, ..., an Mth transistor branch. The second control signal is configured to control the sequential activation of the first transistor branch, the M parallel transistor branches, the second transistor branch, the M parallel transistor branches, ..., the Mth transistor branch, and the M parallel transistor branches.

9. The temperature detection circuit according to claim 1, characterized in that, One end of the voltage sampling unit is configured to receive the power supply voltage, and the other end of the voltage sampling unit is configured to be grounded.

10. The temperature detection circuit according to claim 7 or 8, characterized in that, The buffered comparison amplification unit includes a first operational amplifier, a second operational amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a first capacitor. The non-inverting input of the first operational amplifier is configured as the first input of the buffered comparison amplification unit, receiving the second sampling voltage. The output of the first operational amplifier is connected to the inverting input of the first operational amplifier and one end of the first resistor. The other end of the first resistor is connected to the second resistor and the non-inverting input of the third operational amplifier. The other end of the second resistor is grounded. The non-inverting input of the second operational amplifier is configured as the second input of the buffered comparison amplification unit, receiving the first sampling voltage. The output of the second operational amplifier is connected to the inverting input of the second operational amplifier and one end of the third resistor. The other end of the third resistor is connected to the inverting input of the third operational amplifier and one end of the fourth resistor. The output of the third operational amplifier is connected to the other end of the fourth resistor and one end of the fifth resistor. The other end of the fifth resistor is connected to one end of the first capacitor, and the connection point serves as the voltage output of the buffered comparison amplification unit, outputting the temperature sampling voltage.

11. The temperature detection circuit according to claim 10, characterized in that, The digital signal processing unit is configured to, based on the ratio of the collector current corresponding to the second voltage output terminal to the collector current corresponding to the first voltage output terminal, the ratio of the saturation current corresponding to the second voltage output terminal to the saturation current corresponding to the first voltage output terminal, and the total input offset voltage generated by the first operational amplifier, the second operational amplifier, and the third operational amplifier, respectively determine the digital voltage signals Vcs-out0, Vcs-out1, Vcs-out2, ..., Vcs-outN corresponding to the temperature sampling voltage of the N parallel current source branches, the first current source branch, the second current source branch, ..., the Nth current source branch when it is in the on state, and / or, respectively determine the digital voltage signals Vt-out0, Vt-out1, Vt-out2, ..., Vt-outM corresponding to the temperature sampling voltage of the M parallel transistor branches, the first transistor branch, the second transistor branch, ..., the Mth transistor branch when it is in the on state.

12. The temperature detection circuit according to claim 11, characterized in that, The digital signal processing unit is configured to determine the total input offset voltage based on the ratio of the second resistor to the first resistor, the first input offset voltage of the first operational amplifier, the second input offset voltage of the second operational amplifier, and the third input offset voltage of the third operational amplifier, wherein the total input offset voltage is linearly related to temperature.

13. The temperature detection circuit according to claim 1, characterized in that, At least one of N and M is 2, 3, or 4.

14. An audio power amplifier, characterized in that, Includes the temperature detection circuit as described in any one of claims 1 to 13.

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