Temperature measurement circuit and electronic device

Abstract

The present disclosure provides a temperature measurement circuit and an electronic device. The temperature measurement circuit comprises a ground terminal, a first power input terminal, at least two temperature detection circuits, a detection control circuit and a controller. The first power input terminal is used to connect a first power supply. The temperature detection circuit comprises a thermistor and a controllable switch, and the thermistor and the controllable switch are connected in series between the first power input terminal and the ground terminal. The detection control circuit is connected to the controllable switch of the at least two temperature detection circuits respectively. The controller comprises a detection port and a pulse output port, and the at least two temperature detection circuits are connected to the detection port respectively. The pulse output port is connected to the detection control circuit, and the pulse output port is used to output pulse signals with different duty cycles to control the conduction of the controllable switch of the at least two temperature detection circuits through the detection control circuit. In this way, comprehensive temperature detection can be achieved, and the reliability of the electronic device is improved.

Description

Technical Field

[0001] This disclosure relates to the field of electronic devices, and more particularly to a temperature measuring circuit and electronic device. Background Technology

[0002] With the continuous advancement of science and technology, electronic devices are gradually developing towards miniaturization and portability, thus placing higher demands on the temperature monitoring of components within these devices. Specifically, by monitoring the temperature of components and combining this with software control, performance, power consumption, and temperature can be optimized to improve the user experience. Furthermore, when an excessively high temperature is detected, temperature management strategies can be activated to lower the device's temperature, thereby extending its lifespan.

[0003] Electronic devices often contain multiple high-temperature components that require temperature monitoring. However, some electronic devices can only monitor the temperature of one component through a single control port of the controller. This limitation on the number of control ports prevents comprehensive temperature monitoring, resulting in poor reliability of the electronic device. Utility Model Content

[0004] This disclosure provides a temperature measuring circuit and electronic device that can achieve comprehensive temperature detection and improve the reliability of electronic devices.

[0005] This disclosure provides a temperature measuring circuit, including:

[0006] Grounding terminal;

[0007] The first power input terminal is used to connect to the first power source;

[0008] At least two temperature detection circuits, each temperature detection circuit including a thermistor and a controllable switch, wherein the thermistor and the controllable switch are connected in series between the first power input terminal and the ground terminal;

[0009] A detection control circuit, wherein the detection control circuit is respectively connected to the controllable switches of at least two of the temperature detection circuits; and

[0010] The controller includes a detection port and a pulse output port, with the at least two temperature detection circuits respectively connected to the detection port; the pulse output port is connected to the detection control circuit and is used to output pulse signals with different duty cycles, so as to control the conduction of the controllable switches of the at least two temperature detection circuits through the detection control circuit.

[0011] In some embodiments of this application, when the controllable switch of the temperature detection circuit is turned on, the detection port of the controller can detect the voltage value of the thermistor in the temperature detection circuit and obtain the resistance value of the thermistor to determine the temperature of the device corresponding to the thermistor. The pulse output port of the controller is used to output pulse signals with different duty cycles to control the conduction of controllable switches of at least two temperature detection circuits through the detection control circuit. Thus, the voltage values ​​of at least two thermistors can be determined through one detection port, and the temperature detection of multiple devices can be achieved through one detection port. In this way, comprehensive temperature detection is achieved using the limited number of ports of the controller, improving the reliability of electronic equipment.

[0012] Furthermore, the detection and control circuit includes at least two voltage drop circuits connected to the controllable switches of the at least two temperature detection circuits, each voltage drop circuit being connected between the pulse output port and the corresponding controllable switch; the voltage drops of the at least two voltage drop circuits are different. In one embodiment, the pulse signal output from the controller's pulse output port is voltage-dropped through the at least two voltage drop circuits, and each of the at least two voltage drop circuits controls the conduction of the controllable switch of the corresponding temperature detection circuit. Because the voltage drops of the at least two voltage drop circuits are different, pulse signals with different duty cycles can correspond to the conduction of different controllable switches, thereby enabling hierarchical or sequential conduction of the controllable switches, which is simple to implement.

[0013] Furthermore, the at least two voltage drop circuits include a first type of voltage drop circuit, which includes a first diode. The anode of the first diode is connected to the pulse output port, and the cathode of the first diode is connected to the corresponding controllable switch. In one embodiment, the first type of voltage drop circuit includes a first diode, and the voltage drop is achieved through the first diode. This circuit is simple and has a low cost.

[0014] Furthermore, the at least two voltage drop circuits include a second type of voltage drop circuit, which includes a second diode and a Zener diode, wherein the second diode and the Zener diode are connected in series between the pulse output port and the corresponding controllable switch;

[0015] The anode of the second diode is connected to the pulse output port, and the cathode of the second diode is connected to the corresponding controllable switch; the cathode of the Zener diode is connected to the pulse output port, and the anode of the Zener diode is connected to the corresponding controllable switch. In one embodiment, the second type of voltage drop circuit includes a second diode and a Zener diode, and the voltage drop is achieved through the second diode and the Zener diode. This circuit is simple and more reliable.

[0016] Furthermore, the number of the second type of voltage drop circuits is at least two, and the Zener diodes of the at least two second type of voltage drop circuits have different Zener values. In one embodiment, the Zener diodes of the at least two second type of voltage drop circuits have different Zener values, which makes the voltage drops of the at least two second type of voltage drop circuits different, thus achieving the different voltage drops of the at least two second type of voltage drop circuits is a simple method.

[0017] Furthermore, the detection and control circuit also includes a voltage conversion circuit connected between the pulse output port and the at least two voltage drop circuits. The voltage conversion circuit converts pulse signals with different duty cycles into DC signals with different voltage values ​​and provides DC signals to the at least two voltage drop circuits. In one embodiment, by converting pulse signals with different duty cycles into DC signals with different voltage values ​​and providing DC signals to the at least two voltage drop circuits, the conduction of the controllable switch can be controlled via the DC signals, thus facilitating the controllable switch's operation.

[0018] Furthermore, the voltage conversion circuit includes a pulse modulation circuit and a filtering circuit. The pulse modulation circuit is connected between the pulse output port and the filtering circuit. The filtering circuit is connected to the at least two voltage drop circuits to provide a DC signal to the at least two voltage drop circuits. In one embodiment, the pulse modulation circuit can convert the pulse signal into a modulated voltage signal, and the filtering circuit can filter the modulated voltage signal into a DC signal to provide a DC signal to the at least two voltage drop circuits.

[0019] Furthermore, the temperature measuring circuit also includes a second power input terminal for connecting to a second power supply; the pulse modulation circuit includes a master controllable switch and a first resistor, the master controllable switch and the first resistor being connected in series between the second power input terminal and the ground terminal; the filter circuit is connected between the master controllable switch and the first resistor; the pulse output port is connected to the master controllable switch for controlling the on / off state of the master controllable switch. In one embodiment, the pulse signal can be converted into a modulated voltage signal using the master controllable switch and the first resistor, which is a simple implementation method; and / or

[0020] The filtering circuit includes a first filtering capacitor and a second resistor, which are connected in series between the pulse modulation circuit and the ground terminal. One end of each voltage drop circuit is connected between the first filtering capacitor and the second resistor, and the other end is connected to the corresponding controllable switch. In one embodiment, the modulated voltage signal can be converted into a DC signal using the first filtering capacitor and the second resistor, which is a simple implementation method.

[0021] Furthermore, the temperature detection circuit also includes a second filter capacitor, one end of which is connected between the controllable switch and the detection and control circuit, and the other end is connected to the ground terminal. In one embodiment, the second filter capacitor can act as a filter, enabling the controllable switch to receive a stable control voltage.

[0022] This disclosure provides an electronic device, including a temperature measuring circuit as described in any of the above embodiments.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0025] Figure 1 The diagram shown is a circuit block diagram of an electronic device provided in one embodiment of this disclosure;

[0026] Figure 2 As shown Figure 1 The circuit diagram of the temperature detection circuit in the temperature measurement circuit of the electronic device.

[0027] Figure 3 As shown Figure 1 Circuit diagrams of the detection and control circuits and controllers for the temperature measurement circuits of electronic devices in the system;

[0028] Figure 4 The diagram shown is a control flowchart of a controller for an electronic device provided in one embodiment of this disclosure. Detailed Implementation

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0030] To better understand the technical solutions of this disclosure, the temperature measuring circuit and electronic equipment of this disclosure will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.

[0031] join Figure 1 , Figure 2 and Figure 3As shown, this disclosure provides an electronic device 100, which can be a television, monitor, tablet computer, mobile phone, or similar device. The electronic device 100 includes a temperature sensing circuit 10, which can detect the temperature of devices such as main logic control chips, DDR (Double Data Rate) chips, transformers, MOSFETs, and power management chips.

[0032] This disclosure provides a temperature measuring circuit 10, which includes a ground terminal 11, a first power input terminal 12, at least two temperature detection circuits 13, a detection control circuit 14, and a controller 15.

[0033] The first power input terminal 12 is used to connect to the first power supply 16. The input voltage of the first power supply 16 is +5V. The number of temperature detection circuits 13 can be two, three, four or more, and this disclosure does not impose any limitation. In this embodiment, the number of temperature detection circuits 13 is three, including a first temperature detection circuit 17, a second temperature detection circuit 18 and a third temperature detection circuit 19.

[0034] The temperature detection circuit 13 includes a thermistor 20 and a controllable switch 21, wherein the controllable switch 21 can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The thermistor 20 and the controllable switch 21 are connected in series between the first power input terminal 12 and the ground terminal 11. The thermistor 20 can be placed near the device or on the device body to determine the temperature near the device or on the device body. In one embodiment, the temperature sensing circuit 10 also includes a resistor R1, the resistance of which can be a fixed value. The resistor R1 is connected between the first power input terminal 12 and at least two temperature detection circuits 13. This allows the resistor R1, together with the thermistor NTC1 of the first temperature detection circuit 17, the thermistor NTC2 of the second temperature detection circuit 18, and the thermistor NTC3 of the third temperature detection circuit 19, to form a voltage divider network to divide the first power supply 16. In this embodiment, the first end of resistor R1 is connected to the first power input terminal 12, the second end of resistor R1 is connected to the first end of the thermistor 20, the second end of the thermistor 20 is connected to the drain terminal (i.e., D terminal) of the MOSFET, the source terminal (i.e., S terminal) of the MOSFET is connected to the ground terminal 11, and the gate terminal (i.e., G terminal) of the MOSFET is connected to the detection and control circuit 14. In this way, the switching on and off of the MOSFET can be realized through the detection and control circuit 14.

[0035] The detection control circuit 14 is connected to the controllable switches 21 of at least two temperature detection circuits 13. In this embodiment, the detection control circuit 14 is connected to the gate terminal of the MOS transistor Q1 of the first temperature detection circuit 17, the gate terminal of the MOS transistor Q2 of the second temperature detection circuit 18, and the gate terminal of the MOS transistor Q3 of the third temperature detection circuit 19.

[0036] The controller 15 includes a detection port 22 and a pulse output port 23, with at least two temperature detection circuits 13 respectively connected to the detection port 22. In this embodiment, the detection port 22 can be connected between a resistor R1 and the thermistor 20 of the temperature detection circuit 13. Specifically, the detection port 22 can be connected between a resistor R1 and the thermistor NTC1 of the first temperature detection circuit 17, between a resistor R1 and the thermistor NTC2 of the second temperature detection circuit 18, and between a resistor R1 and the thermistor NTC3 of the third temperature detection circuit 19. The pulse output port 23 is connected to the detection control circuit 14 and is used to output pulse signals with different duty cycles to control the conduction of the controllable switches 21 of at least two temperature detection circuits 13 through the detection control circuit 14. The controllable switches of at least two temperature detection circuits 13 can be controlled to conduct in stages or sequentially. Figure 2Taking the illustrated embodiment as an example, the hierarchical conduction of the controllable switches of at least two temperature detection circuits 13 means that a pulse signal with a first duty cycle can turn on the MOSFET Q1 of the first temperature detection circuit 17, turn off the MOSFET Q2 of the second temperature detection circuit 18, and turn off the MOSFET Q3 of the third temperature detection circuit 19. A pulse signal with a second duty cycle can turn on the MOSFET Q1 of the first temperature detection circuit 17, turn on the MOSFET Q2 of the second temperature detection circuit 18, and turn off the MOSFET Q3 of the third temperature detection circuit 19. A pulse signal with a third duty cycle can turn on the MOSFET Q1 of the first temperature detection circuit 17, turn on the MOSFET Q2 of the second temperature detection circuit 18, and turn on the MOSFET Q3 of the third temperature detection circuit 19. The sequential activation of the controllable switches in at least two temperature detection circuits 13 means that a pulse signal with a first duty cycle can activate MOSFET Q1 in the first temperature detection circuit 17, deactivate MOSFET Q2 in the second temperature detection circuit 18, and deactivate MOSFET Q3 in the third temperature detection circuit 19. A pulse signal with a second duty cycle can deactivate MOSFET Q1 in the first temperature detection circuit 17, activate MOSFET Q2 in the second temperature detection circuit 18, and deactivate MOSFET Q3 in the third temperature detection circuit 19. A pulse signal with a third duty cycle can deactivate MOSFET Q1 in the first temperature detection circuit 17, deactivate MOSFET Q2 in the second temperature detection circuit 18, and activate MOSFET Q3 in the third temperature detection circuit 19. The pulse output port 23 can be used to output PWM signals with different duty cycles.

[0037] The temperature measurement circuit 10 provided in this disclosure allows the controller 15 to detect the voltage value of the thermistor 20 in the temperature detection circuit 13 when the controllable switch 21 of the temperature detection circuit 13 is turned on, and obtain the resistance value of the thermistor 20 to determine the temperature of the device corresponding to the thermistor 20. The controller 15's pulse output port 23 is used to output pulse signals with different duty cycles to control the conduction of at least two controllable switches of the temperature detection circuit 13 through the detection control circuit 14. This allows the voltage values ​​of at least two thermistors 20 to be determined through one detection port 22, enabling temperature detection of multiple devices through a single port 22. This achieves comprehensive temperature detection using the limited number of ports on the controller 15, thus utilizing limited control resources for over-temperature protection of devices and improving the reliability of the electronic device 100. Simultaneously, it reduces the cost of the electronic device, achieves a better power consumption and temperature control scheme, and enhances the user experience of the electronic device.

[0038] In one embodiment, the detection control circuit 14 includes at least two voltage drop circuits 24 connected to controllable switches 21 corresponding to at least two temperature detection circuits 13. One voltage drop circuit 24 can correspond to one temperature detection circuit 13. Each voltage drop circuit 24 is connected between the pulse output port 23 and the corresponding controllable switch 21. The voltage drops of the at least two voltage drop circuits 24 are different, meaning that the voltage drop of each of the at least two voltage drop circuits 24 is different. In this embodiment, the number of voltage drop circuits 24 is three, including a first voltage drop circuit 25, a second voltage drop circuit 26, and a third voltage drop circuit 27. The first voltage drop circuit 25 is connected between the pulse output port 23 and the gate of the MOS transistor Q1 of the first temperature detection circuit 17; the second voltage drop circuit 26 is connected between the pulse output port 23 and the gate of the MOS transistor Q2 of the second temperature detection circuit 18; and the third voltage drop circuit 27 is connected between the pulse output port 23 and the gate of the MOS transistor Q3 of the third temperature detection circuit 19. The voltage drops of the first voltage drop circuit 25, the second voltage drop circuit 26, and the third voltage drop circuit 27 are all different. The pulse signal output from the pulse output port 23 of the controller 15 is voltage-dropped through at least two voltage drop circuits 24. Each of the at least two voltage drop circuits 24 controls the conduction of the controllable switch 21 of the corresponding temperature detection circuit 13. Because the voltage drops of the at least two voltage drop circuits 24 are different, pulse signals with different duty cycles can correspond to the conduction of different controllable switches 21, thereby enabling the controllable switches 21 to conduct in stages or sequentially, which is a simple implementation method.

[0039] In one embodiment, at least two voltage drop circuits 24 include a first type of voltage drop circuit. This first type of voltage drop circuit includes a first diode D1, with the anode of the first diode D1 connected to the pulse output port 23 and the cathode of the first diode D2 connected to the corresponding controllable switch 21. The first type of voltage drop circuit includes the first diode D1, achieving voltage drop through this diode, resulting in a simple circuit with low cost. In this embodiment, the first voltage drop circuit 25 is a first type of voltage drop circuit, and the cathode of the first diode D1 can be connected to the gate of the MOS transistor Q1 in the first temperature detection circuit 17.

[0040] In one embodiment, at least two voltage drop circuits 24 include a second type of voltage drop circuit, which includes a second diode 34 and a Zener diode 28. The second diode 34 and the Zener diode 28 are connected in series between the pulse output port 23 and the corresponding controllable switch 21. The anode of the second diode 34 is connected to the pulse output port 23, and the cathode of the second diode 34 is connected to the corresponding controllable switch 21. The cathode of the Zener diode 28 is connected to the pulse output port 23, and the anode of the Zener diode 28 is connected to the corresponding controllable switch 21. Alternatively, the anode of the Zener diode 28 can be connected to the anode of the second diode 34, or the cathode of the second diode 34 can be connected to the cathode of the Zener diode 28. The second type of voltage drop circuit, including the second diode 34 and the Zener diode 28, achieves voltage drop through these components, resulting in a simpler and more reliable circuit.

[0041] In one embodiment, there are at least two second-type voltage drop circuits, and the Zener diodes 28 of the at least two second-type voltage drop circuits have different Zener values. The different Zener values ​​of the Zener diodes 28 in the at least two second-type voltage drop circuits result in different voltage drops in the at least two second-type voltage drop circuits, thus simplifying the process of achieving different voltage drops in the at least two second-type voltage drop circuits. In this embodiment, the second voltage drop circuit 26 and the third voltage drop circuit 27 are second-type voltage drop circuits. The second diode D2 and the Zener diode Z1 of the second voltage drop circuit 26 are connected in series between the pulse output port 23 and the corresponding controllable switch 21. The second diode D3 and the Zener diode Z2 of the third voltage drop circuit 27 are connected in series between the pulse output port 23 and the corresponding controllable switch 21. The Zener value of the Zener diode Z1 in the second voltage drop circuit 26 is different from the Zener value of the Zener diode Z2 in the third voltage drop circuit 27. The pulse output port 23 of the controller 15 is used to output pulse signals with different duty cycles. A voltage gating network is formed by the first diode D1, the second diode 34 and the Zener diode 28 to cyclically control the on and off of the controllable switch 21. The on and off of the controllable switch 21 realizes the time-division detection of the thermistors 20 of different temperature detection circuits 13. Thus, the voltage values ​​of at least two thermistors can be determined through one detection port 22.

[0042] In one embodiment, the detection control circuit 14 further includes a voltage conversion circuit 29, which is connected between the pulse output port 23 and at least two voltage drop circuits 24. The voltage conversion circuit 29 converts pulse signals with different duty cycles into DC signals with different voltage values ​​and provides DC signals to the at least two voltage drop circuits 24. Different duty cycles of the pulse signals correspond to different voltage values ​​of the DC signals. The conversion is simple and straightforward. By converting pulse signals with different duty cycles into DC signals with different voltage values ​​and providing DC signals to the at least two voltage drop circuits 24, the conduction of the controllable switch 21 can be controlled via the DC signals, thus facilitating the controllable switch 21's operation.

[0043] In one embodiment, the voltage conversion circuit 29 includes a pulse modulation circuit 30 and a filter circuit 31. The pulse modulation circuit 30 is connected between the pulse output port 23 and the filter circuit 31, and can generate a modulated voltage signal Vp0. The pulse signal can be converted into the modulated voltage signal Vp0 by the pulse modulation circuit. The filter circuit 31 is connected to at least two voltage drop circuits 24 and is used to provide a DC signal to the at least two voltage drop circuits 24. The modulated voltage signal Vp0 can be filtered into a DC signal Vp1 by the filter circuit 31 to provide a DC signal to the at least two voltage drop circuits 24.

[0044] In one embodiment, the temperature measuring circuit 10 further includes a second power input terminal 32 for connecting to a second power supply. The input voltage of the second power supply is +VCC. The pulse modulation circuit 30 includes a master controllable switch 33 and a first resistor R2, which are connected in series between the second power input terminal 32 and the ground terminal 11. A filter circuit 31 is connected between the master controllable switch 33 and the first resistor R2. A pulse output port 23 is connected to the master controllable switch 33 and is used to control the on / off state of the master controllable switch 33.

[0045] In this embodiment, the main controllable switch 33 can be a MOSFET Q4. The second power input terminal 32 is connected to the first end of the first resistor R2, the second end of the first resistor R2 is connected to the drain terminal (D terminal) of the MOSFET Q4, the source terminal (S terminal) of the MOSFET Q4 is connected to the ground terminal 11, and the gate terminal (G terminal) of the MOSFET Q4 is connected to the pulse output port 23. A filter circuit 31 is connected between the drain terminal of the MOSFET Q4 and the second end of the first resistor R2. The pulse output port 23 is used to output pulse signals with different duty cycles, causing the MOSFET Q4 to have different conduction times, forming a modulated voltage signal Vp0 with a voltage amplitude of +VCC and a pulse width opposite to the output waveform of the pulse output port 23. The pulse signal can be converted into a modulated voltage signal using the main controllable switch 33 and the first resistor R2, a simple implementation method.

[0046] In one embodiment, the filter circuit 31 includes a first filter capacitor C1 and a second resistor R3, which are connected in series between the pulse modulation circuit 30 and the ground terminal 11. One end of each voltage drop circuit 24 is connected between the first filter capacitor C1 and the second resistor R3, and the other end is connected to the corresponding controllable switch 21. The modulated voltage signal can be converted into a DC signal using the first filter capacitor C1 and the second resistor R3, which is a simple implementation method.

[0047] In this embodiment, the first end of the second resistor R3 is connected between the drain terminal of the MOSFET Q4 and the second end of the first resistor R2, and the second end of the second resistor R3 is connected to the first end of the first filter capacitor C1. The second end of the first filter capacitor C1 is connected to the ground terminal 11. The filter circuit 31 can filter the modulated voltage signal Vp0 into a DC signal Vp1. The DC signal Vp1 can pass through at least two voltage drop circuits 24 to form a control voltage for the controllable switch 21. In this embodiment, the DC signal Vp1 passes through the first voltage drop circuit 25 to obtain the control voltage V1, which is the control voltage of the MOSFET Q1 of the first temperature detection circuit 17. The DC signal Vp1 passes through the second voltage drop circuit 26 to obtain the control voltage V2, which is the control voltage of the MOSFET Q2 of the second temperature detection circuit 18. The DC signal Vp1 passes through the third voltage drop circuit 27 to obtain the control voltage V3, which is the control voltage of the MOSFET Q3 of the third temperature detection circuit 19.

[0048] In one embodiment, the temperature detection circuit 13 further includes a second filter capacitor 35. One end of the second filter capacitor 35 is connected between the controllable switch 21 and the detection control circuit 14, and the other end is connected to the ground terminal 11. The second filter capacitor 35 can act as a filter, so that the controllable switch 21 can obtain a stable control voltage. In this embodiment, one end of the second filter capacitor C2 of the first temperature detection circuit 17 can be connected between the gate terminal of the MOSFET Q1 and the detection control circuit 14; one end of the second filter capacitor C3 of the second temperature detection circuit 18 can be connected between the gate terminal of the MOSFET Q2 and the detection control circuit 14; and one end of the second filter capacitor C4 of the third temperature detection circuit 19 can be connected between the gate terminal of the MOSFET Q3 and the detection control circuit 14.

[0049] In one embodiment, the first temperature detection circuit 17 further includes a third resistor R4, a fourth resistor R5, and a fifth resistor R6. The third resistor R4 is connected in parallel with the second filter capacitor C2, the fourth resistor R5 is connected in parallel with the second filter capacitor C3, and the fifth resistor R6 is connected in parallel with the second filter capacitor C4. When the controllable switch 21 is turned off, the voltage across the second filter capacitors C2, C3, and C4 can be discharged.

[0050] See Figure 2 , Figure 3 and Figure 4 As shown, in this embodiment, the number of temperature detection circuits 13 is taken as an example of three. The pulse output port 23 of the controller 15 can first output a PWM signal with a 70% duty cycle. At this time, the detection port 22 of the controller 15 can detect a first voltage value. The controller 15 can determine the resistance value of the thermistor NTC1 based on the detected first voltage value. After determining the resistance value of the thermistor NTC1, the pulse output port 23 of the controller 15 outputs a PWM signal with a 40% duty cycle. At this time, the detection port 22 of the controller 15 can detect a second voltage value. The controller 15 can determine the resistance value of the thermistor NTC2 based on the detected second voltage value and the resistance value of the thermistor NTC1. After determining the resistance value of the thermistor NTC2, the pulse output port 23 of the controller 15 outputs a PWM signal with a 0% duty cycle. The detection port 22 of the controller 15 can detect a third voltage value. The controller 15 can determine the resistance value of the thermistor NTC3 based on the detected third voltage value, the resistance values ​​of the thermistors NTC1 and NTC2.

[0051] The input voltage +VCC of the second power supply can be 5V. The conduction voltage of MOSFETs Q1, Q2, and Q3 is 1V. The voltage drop of the first diode D1 in the first voltage drop circuit 25, the second diode D2 in the second voltage drop circuit 26, and the second diode D3 in the third voltage drop circuit 27 is 0.2V. The Zener diode Z1 in the second voltage drop circuit 26 has a Zener voltage of 1V, and the Zener diode Z2 in the third voltage drop circuit 27 has a Zener voltage of 3V.

[0052] When the pulse output port 23 of the controller 15 outputs a PWM signal with a 70% duty cycle, the modulation voltage signal Vp0 is a PWM signal with an amplitude of 5V and a pulse width of 30%. After being filtered by the filter circuit 31, the voltage value of the DC signal Vp1 obtained is 5V×0.3=1.5V.

[0053] The control voltage V1 after the DC signal Vp1 is reduced by the first diode D1 of the first voltage drop circuit 25 is 1.3V, that is, V1 = 1.5V - 0.2V = 1.3V. The control voltage V1 is the control voltage of the MOS transistor Q1 of the first temperature detection circuit 17.

[0054] The control voltage V2 after the DC signal Vp1 is reduced by the second diode D2 and the Zener diode Z1 in the second voltage drop circuit 26 is 0.3V, that is, V1 = 1.5V - 0.2V - 1V = 0.3V. The control voltage V2 is the control voltage of the MOS transistor Q2 in the second temperature detection circuit 18.

[0055] The DC signal Vp1 is isolated by the 3V Zener diode Z2 of the third voltage drop circuit 27, so that the control voltage V3 is 0V. The control voltage V3 is the control voltage of the MOS transistor Q3 of the third temperature detection circuit 19.

[0056] Since the on-state voltage of MOSFETs Q1, Q2, and Q3 is 1V, when the pulse output port 23 of controller 15 outputs a PWM signal with a 70% duty cycle, only MOSFET Q1 is turned on. Thermistor NTC1 is grounded through MOSFET Q1, making thermistor NTC1 and resistor R1 form a voltage divider network. MOSFETs Q2 and Q3 are turned off, making the impedance of thermistors NTC2 and NTC3 infinite. The voltage value detected by the detection port 22 of controller 15 is approximately the voltage value of thermistor NTC1. Thus, the resistance value Rntc1 of thermistor NTC1 can be obtained using the voltage divider formula of resistor R1 and thermistor NTC1, and stored in the memory of controller 15.

[0057] When the pulse output port 23 of the controller 15 outputs a PWM signal with a 40% duty cycle, the modulation voltage signal Vp0 is a PWM signal with an amplitude of 5V and a pulse width of 60%. After being filtered by the filter circuit 31, the voltage value of the DC signal Vp1 obtained is 5V × 0.6 = 3V.

[0058] The control voltage V1 after the DC signal Vp1 is reduced by the first diode D1 of the first voltage drop circuit 25 is 3V, that is, V1 = 3V - 0.2V = 2.8V. The control voltage V1 is the control voltage of the MOS transistor Q1 of the first temperature detection circuit 17.

[0059] The control voltage V2 after the DC signal Vp1 is reduced by the second diode D2 and the Zener diode Z1 in the second voltage drop circuit 26 is 1.8V, that is, V1 = 3V - 0.2V - 1V = 1.8V. The control voltage V2 is the control voltage of the MOS transistor Q2 in the second temperature detection circuit 18.

[0060] The DC signal Vp1 is isolated by the 3V Zener diode Z2 of the third voltage drop circuit 27, so that the control voltage V3 is 0V. The control voltage V3 is the control voltage of the MOS transistor Q3 of the third temperature detection circuit 19.

[0061] Since the on-state voltage of MOSFETs Q1, Q2, and Q3 is 1V, when the pulse output port 23 of controller 15 outputs a PWM signal with a 40% duty cycle, both MOSFETs Q1 and Q2 are turned on. Thermistor NTC1 is grounded through MOSFET Q1, and thermistor NTC2 is grounded through MOSFET Q2, so that thermistors NTC1 and NTC2 are connected in parallel and form a voltage divider network with resistor R1. MOSFET Q3 is turned off, making the impedance of thermistor NTC3 infinite. The voltage value detected by the detection port 22 of controller 15 is approximately the voltage divider value of the parallel connection of thermistors NTC1 and NTC2 with resistor R1. Thus, the resistance value Rntc1_2 of the parallel connection of thermistors NTC1 and NTC2 can be calculated. Based on the previously obtained resistance value Rntc1 of thermistor NTC1, the resistance value Rntc2 of thermistor NTC2 can be calculated and stored in the memory of controller 15.

[0062] When the pulse output port 23 of the controller 15 outputs a PWM signal with a 0% duty cycle, the modulation voltage signal Vp0 is a PWM signal with an amplitude of 5V and a pulse width of 100%. After being filtered by the filter circuit 31, the voltage value of the DC signal Vp1 obtained is 5V×1=5V.

[0063] The control voltage V1 after the DC signal Vp1 is reduced by the first diode D1 of the first voltage drop circuit 25 is 4.8V, that is, V1 = 5V - 0.2V = 4.8V. The control voltage V1 is the control voltage of the MOS transistor Q1 of the first temperature detection circuit 17.

[0064] The control voltage V2 after the DC signal Vp1 is reduced by the second diode D2 and the Zener diode Z1 in the second voltage drop circuit 26 is 3.8V, that is, V1 = 5V - 0.2V - 1V = 3.8V. The control voltage V2 is the control voltage of the MOS transistor Q2 in the second temperature detection circuit 18.

[0065] The control voltage V3 after the DC signal Vp1 is reduced by the second diode D3 and the Zener diode Z2 of the third voltage drop circuit 27 is 1.8V, that is, V3 = 5V - 0.2V - 3V = 1.8V. The control voltage V3 is the control voltage of the MOS transistor Q3 of the third temperature detection circuit 19.

[0066] Since the on-state voltage of MOSFETs Q1, Q2, and Q3 is 1V, when the pulse output port 23 of controller 15 outputs a PWM signal with a 0% duty cycle, all MOSFETs Q1, Q2, and Q3 are turned on. Thermistor NTC1 is grounded through MOSFET Q1, thermistor NTC2 is grounded through MOSFET Q2, and thermistor NTC3 is grounded through MOSFET Q3. This allows thermistors NTC1, NTC2, and NTC3 to be connected in parallel and form a voltage divider network with resistor R1. The voltage value detected by the detection port 22 of the controller 15 is approximately the voltage division value of the thermistors NTC1, NTC2, and NTC3 connected in parallel with resistor R1. Thus, the resistance value Rntc1_2_3 of the thermistors NTC1, NTC2, and NTC3 connected in parallel can be calculated. Based on the previously obtained resistance values ​​Rntc1 of thermistor NTC1 and Rntc2 of thermistor NTC2, the resistance value Rntc3 of thermistor NTC3 can be calculated and stored in the memory of the controller 15.

[0067] Thus, by analyzing the signal changes of pulse signals with different duty cycles output through the pulse output port 23 of the controller 15 over one cycle, the resistance values ​​of thermistors NTC1, NTC2, and NTC3 can be obtained. Based on the correspondence between the resistance values ​​of the selected thermistors and their temperature values, the temperature value can be derived. The controller 15 can set the operating values ​​of each thermistor as needed to achieve power consumption control and temperature optimization for multiple devices.

[0068] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A temperature measuring circuit, characterized in that, include: Grounding terminal; The first power input terminal is used to connect to the first power source; At least two temperature detection circuits, each temperature detection circuit including a thermistor and a controllable switch, wherein the thermistor and the controllable switch are connected in series between the first power input terminal and the ground terminal; A detection control circuit, wherein the detection control circuit is respectively connected to the controllable switches of at least two of the temperature detection circuits; and The controller includes a detection port and a pulse output port, wherein the at least two temperature detection circuits are respectively connected to the detection port; The pulse output port is connected to the detection and control circuit. The pulse output port is used to output pulse signals with different duty cycles, so as to control the conduction of the controllable switches of at least two of the temperature detection circuits through the detection and control circuit.

2. The temperature measuring circuit according to claim 1, characterized in that, The detection and control circuit includes at least two voltage drop circuits connected to the controllable switches of the at least two temperature detection circuits, each voltage drop circuit being connected between the pulse output port and the corresponding controllable switch; the voltage drops of the at least two voltage drop circuits are different.

3. The temperature measuring circuit according to claim 2, characterized in that, The at least two voltage drop circuits include a first type of voltage drop circuit, which includes a first diode. The anode of the first diode is connected to the pulse output port, and the cathode of the first diode is connected to the corresponding controllable switch.

4. The temperature measuring circuit according to claim 2, characterized in that, The at least two voltage drop circuits include a second type of voltage drop circuit, which includes a second diode and a Zener diode. The second diode and the Zener diode are connected in series between the pulse output port and the corresponding controllable switch. The anode of the second diode is connected to the pulse output port, and the cathode of the second diode is connected to the corresponding controllable switch; The cathode of the Zener diode is connected to the pulse output port, and the anode of the Zener diode is connected to the corresponding controllable switch.

5. The temperature measuring circuit according to claim 4, characterized in that, The number of the second type of voltage drop circuits is at least two, and the voltage regulation values ​​of the Zener diodes in the at least two second type of voltage drop circuits are different.

6. The temperature measuring circuit according to claim 2, characterized in that, The detection and control circuit further includes a voltage conversion circuit, which is connected between the pulse output port and the at least two voltage drop circuits. The voltage conversion circuit is used to convert pulse signals with different duty cycles into DC signals with different voltage values ​​and to provide DC signals to the at least two voltage drop circuits.

7. The temperature measuring circuit according to claim 6, characterized in that, The voltage conversion circuit includes a pulse modulation circuit and a filter circuit. The pulse modulation circuit is connected between the pulse output port and the filter circuit. The filter circuit is connected to the at least two voltage drop circuits and is used to provide DC signals to the at least two voltage drop circuits.

8. The temperature measuring circuit according to claim 7, characterized in that, The temperature measuring circuit further includes a second power input terminal for connecting to a second power source; the pulse modulation circuit includes a main controllable switch and a first resistor, the main controllable switch and the first resistor being connected in series between the second power input terminal and the ground terminal; the filter circuit is connected between the main controllable switch and the first resistor; the pulse output port is connected to the main controllable switch for controlling the on / off state of the main controllable switch. and / or The filtering circuit includes a first filtering capacitor and a second resistor, which are connected in series between the pulse modulation circuit and the ground terminal; one end of each voltage drop circuit is connected between the first filtering capacitor and the second resistor, and the other end is connected to the corresponding controllable switch.

9. The temperature measuring circuit according to claim 1, characterized in that, The temperature detection circuit also includes a second filter capacitor, one end of which is connected between the controllable switch and the detection control circuit, and the other end is connected to the ground terminal.

10. An electronic device, characterized in that, Includes the temperature measuring circuit as described in any one of claims 1-9.

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