CN210199961U - Over-temperature early warning circuit - Google Patents
Over-temperature early warning circuit Download PDFInfo
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- CN210199961U CN210199961U CN201920894336.5U CN201920894336U CN210199961U CN 210199961 U CN210199961 U CN 210199961U CN 201920894336 U CN201920894336 U CN 201920894336U CN 210199961 U CN210199961 U CN 210199961U
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Abstract
The utility model relates to an excess temperature early warning circuit, the circuit includes: the device comprises a detection circuit, a control circuit and an early warning circuit; the output end of the detection circuit is connected with the first port of the control circuit and is used for detecting the state of an external chip and sending a state signal to the control circuit; the first port of the control circuit is connected with the input end of the early warning circuit and used for generating a control signal according to the state signal and sending the control signal to the early warning circuit; the output end of the early warning circuit is connected with the second port of the control circuit and used for controlling the on-off of the control circuit and sending an over-temperature early warning signal. The utility model provides a technical scheme sends the overtemperature early warning signal or cuts off partial power when the chip surpasses the temperature of settlement, thereby reaches the purpose that the chip high temperature of lowering the temperature avoided damaging, has guaranteed the safety of circuit, adopts less electronic component, has reduced design cost.
Description
Technical Field
The utility model relates to a protection circuit especially relates to an excess temperature early warning circuit.
Background
With the rapid development of the integrated circuit industry, the integrated level of the chip is higher and better, and the power consumption is higher and higher, so that the temperature of the chip can rise rapidly when the integrated circuit is used for a long time or under some abnormal conditions (such as short circuit).
The temperature of the chip has non-negligible influence on the performance of the chip, the stability of the chip is influenced by high temperature, and the chip cannot normally work even being damaged by overheating.
Therefore, it is desirable to provide an over-temperature warning circuit to solve the deficiencies of the prior art.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem in the prior art, the utility model provides an excess temperature early warning circuit when the chip surpassed the temperature of settlement, sent excess temperature early warning signal or cut off partial high-power supply, thereby reached the purpose that the high damage of chip temperature was avoided to the cooling, guaranteed the safety of circuit, adopted less electronic component, reduced design cost.
The utility model provides an excess temperature early warning circuit, include: the device comprises a detection circuit, a control circuit and an early warning circuit;
the output end of the detection circuit is connected with the first port of the control circuit and is used for detecting the state of an external chip and sending a state signal to the control circuit;
the first port of the control circuit is connected with the input end of the early warning circuit and used for generating a control signal according to the state signal and sending the control signal to the early warning circuit;
the output end of the early warning circuit is connected with the second port of the control circuit and used for controlling the on-off of the control circuit and sending an over-temperature early warning signal.
Further, the detection circuit includes: a reference voltage source U1, a thermistor R1 and a resistor R7,
one end of the thermistor R1 is respectively connected with one end of the resistor R7 and the reference voltage source U1, and the other end of the thermistor R1 is connected with a first port of the control circuit;
the other end of the resistor R7 is connected to a first power supply terminal.
Further, the detection circuit further includes: the resistance of the resistor R3 is,
one end of the resistor R3 is connected with the other end of the thermistor R1, and the other end is grounded.
Further, the control circuit includes: a switching device D1, a resistor R2 and a resistor R5,
a first end of the switching device D1 is connected with an output end of the early warning circuit, a second end of the switching device D1 is respectively connected with one end of the resistor R2 and one end of the resistor R5, and a third end of the switching device D1 is grounded;
the other end of the resistor R2 is connected with the input end of the early warning circuit;
the other end of the resistor R5 is connected with a reference voltage source U1 of the detection circuit.
Further, the control circuit further includes: the resistance of the resistor R8 is,
the resistor R8 has one end connected to the first end of the switching device D1 and the other end connected to a second power supply terminal.
Further, the switching device D1 is a triode or a MOS transistor.
Further, the early warning circuit includes: the voltage of the voltage comparator U2 is,
the input end of the voltage comparator U2 is connected with the first port of the control circuit, the output end of the voltage comparator U2 is connected with the second port of the control circuit, the first end of the voltage comparator U2 is connected with the third power supply terminal, and the second end of the voltage comparator U2 is grounded.
Further, the output end of the voltage comparator U2 is used for outputting an over-temperature warning signal.
The utility model provides a technical scheme compares with closest prior art and has following advantage:
the utility model provides a technical scheme utilizes detection circuitry to detect the state of outside chip, then sends for control circuit, and control circuit generates control signal according to state signal, sends to early warning circuit, sends out excess temperature early warning signal, controls control circuit's break-make simultaneously through early warning circuit. The utility model provides a technical scheme passes through the temperature of detection circuitry control outside chip, when the chip surpassed the temperature of settlement, sends overtemperature early warning signal or cuts off partial power, thereby reaches the purpose of avoiding the too high damage of chip temperature of lowering the temperature, has guaranteed the safety of circuit, adopts less electronic component, has reduced design cost.
Drawings
Fig. 1 is a block diagram of an over-temperature warning circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an over-temperature warning circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of another over-temperature warning circuit provided in the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
As shown in fig. 1, the utility model provides an excess temperature early warning circuit, this excess temperature early warning circuit includes: detection circuitry, control circuit and early warning circuit.
The output end of the detection circuit is connected with the first port of the control circuit and used for detecting the state of an external chip and sending a state signal to the control circuit.
The state of the external chip comprises a normal temperature state, namely the temperature is not higher than a preset temperature value, and an over-temperature state, namely the temperature is higher than the preset temperature value. The first port of the control circuit is connected with the input end of the early warning circuit and used for generating a control signal according to the state signal and sending the control signal to the early warning circuit.
The output end of the early warning circuit is connected with the second port of the control circuit and used for controlling the on-off of the control circuit and sending an over-temperature early warning signal.
Specifically, as shown in fig. 2, the over-temperature warning circuit is specifically composed of the following electronic components.
The circuit is used for monitoring the temperature of an external chip, and sending an over-temperature early warning signal or automatically cutting off a part of high-power supply when the chip is in an over-temperature state, so that the aim of reducing the temperature and avoiding the damage of electronic equipment due to over-high temperature is fulfilled.
In the figure, VIN1 is a first power supply, VIN2 is a second power supply, and VIN3 is a third power supply, which are all externally supplied voltages, and may be the same power supply or different power supplies, and the voltage values of the power supplies are determined according to actual conditions.
R3, R2 and R5 are all voltage dividing resistors, and the values are determined according to the set temperature and the voltage reference of an external chip.
The detection circuit specifically includes: a reference voltage source U1, a thermistor R1 and a resistor R7.
The specific connection structure is as follows: one end of the thermistor R1 is respectively connected with one end of the resistor R7 and the reference voltage source U1, and the other end of the thermistor R1 is connected with the first end of the control circuit; the other end of the resistor R7 is connected to a first power supply terminal.
The reference voltage source U1 provides a voltage reference V for the circuit through the VOUT pin of U1OUT2。
The thermistor R1 is arranged near the external chip to be monitored, and the resistance value of the thermistor R1 changes correspondingly when the temperature of the external chip changes, so that the state of the external chip is monitored. In the present application, R1 is a negative temperature coefficient thermistor (NTC).
The resistor R7 is a pull-up resistor, and its resistance depends on the voltage reference of the selected reference voltage source U1.
Further, the detection circuit further includes: resistor R3.
The specific connection structure is as follows: one end of the resistor R3 is connected to the other end of the thermistor R1, and the other end is grounded.
The resistor R3 is used for dividing voltage with the thermistor R1, and the resistance value is determined according to the set temperature and voltage reference of an external chip.
Further, the detection circuit further includes: resistor R9.
The specific connection structure is as follows: one end of the resistor R9 is connected to the reference voltage source U1, and the other end is grounded.
R9 is connected to the TEST pin of reference voltage source U1.
The control circuit specifically includes: a switching device D1, a resistor R2, and a resistor R5.
The specific connection structure is as follows: the first end of the switching device D1 is connected with the output end of the early warning circuit, the second end of the switching device D1 is respectively connected with one end of the resistor R2 and one end of the resistor R5, and the third end of the switching device D1 is grounded; the other end of the resistor R2 is connected with the input end of the early warning circuit; the other end of the resistor R5 is connected to a reference voltage source U1 of the detection circuit.
The switching device D1 may be a triode, a MOS transistor, or another device with a switching function. Fig. 2 shows an N-channel type MOS transistor.
The triode is also called bipolar transistor and transistor triode, and is a semiconductor device for controlling current. In the over-temperature early warning circuit provided by the application, the triode plays a role of a switch, wherein the drain voltage is defined as OT _ FB.
The MOS pipe is metal (metal), oxide, semiconductor (semiconductor) field effect transistor, has the advantage that input impedance is high, the noise is low, thermal stability is good, and the MOS pipe plays the effect of switch in the excess temperature early warning circuit that this application provided.
Further, the control circuit further includes: resistor R8.
The specific connection structure is as follows: the resistor R8 has one end connected to the first end of the switching device D1 and the other end connected to the second power supply terminal.
R8 is a pull-up resistor that provides an initial on state for switching device D1.
The early warning circuit specifically includes: a voltage comparator U2.
The specific connection structure is as follows: the input end of the voltage comparator U2 is connected with the first port of the control circuit, the output end is connected with the second port of the control circuit, the first end is connected with the third power supply terminal, and the second end is grounded.
IN fig. 2, the input terminal is the IN pin IN U2, the output terminal is the OUT pin IN U2, the first terminal is the VS pin IN U2, and the second terminal is the GND pin IN U2.
The input voltage of U2 is defined as VIN _ N and the output voltage is defined as VOUT1(also for an external overtemperature warning signal).
Further, the output end of the voltage comparator U2 is used for outputting an over-temperature warning signal.
That is, when the temperature of the external chip is higher than the preset temperature, the output end of the voltage comparator U2 will output an over-temperature early warning signal, and at the same time, the switching device D1 is controlled to be turned off, so as to achieve the purpose of reducing the temperature.
The external chip and the over-temperature early warning circuit can be located on the same circuit board, namely the distance between the thermistor R1 and the external chip is smaller than the threshold distance, and the thermistor R1 can quickly and accurately show the state of the external chip through the change of temperature.
Fig. 3 is a schematic diagram of another over-temperature warning circuit provided in the embodiment of the present application. The connection relationship of the electronic device is substantially the same as that of the embodiment shown in fig. 2, except that the pull-up resistors in fig. 3 are R6 and R7 (instead of R7 in fig. 2), and the voltage dividing resistors are R3 and R4 (instead of R3 in fig. 2). The others are not changed and are not described in detail herein.
The working principle of the circuit is as follows:
VIN value 12V, reference voltage V provided by U1OUT21.25V NMOS tube is selected for D1, 1.8V NMOS tube is selected for D1, and the on-state voltage is greater than 0.45V. The voltage comparator U2 is a voltage comparator with a reference voltage of 400 mV.
The values of the resistances (in ohm Ω): r7 ═ R8 ═ 10K, R6 ═ 0, R9 ═ 100K, R3 ═ 1K, R4 ═ 100, and R2 ═ 3.57K, R5 ═ 4.7K.
At 25 ℃, namely the external chip is in a normal temperature state, the selected negative temperature coefficient thermistor R1 is 10K; r1 ═ 1.5K at 85 ℃; r1 ═ 3.6K at 55 ℃.
VOUT2The voltage division is carried out by connecting R1, R3 and R4 in series, when the NMOS tube is conducted, R2, R3 and R4 are combinedIs connected to the ground; when the NMOS tube is closed, R2, R5 and R1 form a parallel connection VOUT2。VOUT1As an over-temperature early warning signal, the output signal is an over-temperature early warning signal when the output signal is at a low level, and the output signal is a normal signal when the output signal is at a high level.
At the initial stage of power-on, the external chip temperature is 25 ℃ (assumed) at normal temperature, R1 is 10K, and VIN _ N<400mv, at this time VOUT1The output level of the voltage regulator is high level, which indicates that the temperature of the external chip is normal, the NMOS tube is conducted, the OT _ FB level is low, and the R2, the R3 and the R4 are connected in parallel and grounded. The value of VIN _ N at this time becomes:
when the temperature of the external chip gradually rises to 85 ℃, the resistance value of the thermistor R1 is reduced, wherein R1 is 1.5K, VIN _ N is 397mV (a critical value comparator is about to output in an inversion mode), and V is at the momentOUT1The output level of the voltage comparator U2 is low level which indicates that the temperature of the external chip is too high, the voltage comparator U2 outputs an over-temperature early warning signal, the NMOS is closed, the OT _ FB level is high, and the R2, the R5 and the R1 are connected in parallel to form a VOUT2. The value of VIN _ N at this time becomes:
and since the NMOS is turned off, part of the high-power supply is cut off, the temperature of the external chip is gradually reduced, and VIN _ N is gradually reduced along with the reduction of the temperature of the external chip, but is not smaller than 400 mV. Only when the external chip temperature drops to 53 ℃, R1 ═ 3.6K, VIN _ N ═ 397mV (the critical value comparator will invert again), when V is now presentOUT1The output level is high level, the external chip displays normal temperature, the NMOS tube is conducted, the OT _ FB level is low, and the R2, the R3 and the R4 form parallel connection and are grounded. The value of VIN _ N at this time becomes:
and only when the temperature rises to 85 ℃ again, the over-temperature early warning signal can be sent out again.
The main working principle of the circuit is that the voltage at the input end of the voltage comparator is compared with the reference voltage (400mV) of the voltage comparator, the output signal of the voltage comparator is used as a switch, R2 is switched to be grounded or R2 and R5 are switched to be 1.25V, so that the amplitude of the input voltage of the voltage comparator is suddenly changed into a smaller or larger value, a certain hysteresis effect is achieved, and the voltage comparator can stably output. And when the temperature rises to the set value (85 ℃), VOUT1The output level is low level, and an over-temperature early warning signal is sent out or a part of a high-power supply is automatically cut off, so that the aim of reducing the temperature and avoiding the damage of electronic equipment due to over-high temperature is fulfilled.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (8)
1. An over-temperature early warning circuit, comprising: the device comprises a detection circuit, a control circuit and an early warning circuit;
the output end of the detection circuit is connected with the first port of the control circuit and is used for detecting the state of an external chip and sending a state signal to the control circuit;
the first port of the control circuit is connected with the input end of the early warning circuit and used for generating a control signal according to the state signal and sending the control signal to the early warning circuit;
the output end of the early warning circuit is connected with the second port of the control circuit and used for controlling the on-off of the control circuit and sending an over-temperature early warning signal.
2. The over-temperature warning circuit according to claim 1, wherein the detection circuit comprises: a reference voltage source U1, a thermistor R1 and a resistor R7,
one end of the thermistor R1 is respectively connected with one end of the resistor R7 and the reference voltage source U1, and the other end of the thermistor R1 is connected with a first port of the control circuit;
the other end of the resistor R7 is connected to a first power supply terminal.
3. The over-temperature warning circuit according to claim 2, wherein the detection circuit further comprises: the resistance of the resistor R3 is,
one end of the resistor R3 is connected with the other end of the thermistor R1, and the other end is grounded.
4. The over-temperature warning circuit according to claim 1, wherein the control circuit comprises: a switching device D1, a resistor R2 and a resistor R5,
a first end of the switching device D1 is connected with an output end of the early warning circuit, a second end of the switching device D1 is respectively connected with one end of the resistor R2 and one end of the resistor R5, and a third end of the switching device D1 is grounded;
the other end of the resistor R2 is connected with the input end of the early warning circuit;
the other end of the resistor R5 is connected with a reference voltage source U1 of the detection circuit.
5. The over-temperature warning circuit according to claim 4, wherein the control circuit further comprises: the resistance of the resistor R8 is,
the resistor R8 has one end connected to the first end of the switching device D1 and the other end connected to a second power supply terminal.
6. The over-temperature warning circuit according to claim 4 or 5, wherein the switching device D1 is a transistor or a MOS transistor.
7. The over-temperature warning circuit according to claim 1, wherein the warning circuit comprises: the voltage of the voltage comparator U2 is,
the input end of the voltage comparator U2 is connected with the first port of the control circuit, the output end of the voltage comparator U2 is connected with the second port of the control circuit, the first end of the voltage comparator U2 is connected with the third power supply terminal, and the second end of the voltage comparator U2 is grounded.
8. The over-temperature warning circuit according to claim 7, wherein an output terminal of the voltage comparator U2 is configured to output an over-temperature warning signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920894336.5U CN210199961U (en) | 2019-06-13 | 2019-06-13 | Over-temperature early warning circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920894336.5U CN210199961U (en) | 2019-06-13 | 2019-06-13 | Over-temperature early warning circuit |
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| Publication Number | Publication Date |
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| CN210199961U true CN210199961U (en) | 2020-03-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201920894336.5U Active CN210199961U (en) | 2019-06-13 | 2019-06-13 | Over-temperature early warning circuit |
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| CN (1) | CN210199961U (en) |
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Address after: 510000 no.2-8, North Street, Nancun Town, Panyu District, Guangzhou City, Guangdong Province Patentee after: Guangzhou huiruisitong Technology Co.,Ltd. Address before: 510000 no.2-8, North Street, Nancun Town, Panyu District, Guangzhou City, Guangdong Province Patentee before: GUANGZHOU HUIRUI SITONG INFORMATION TECHNOLOGY Co.,Ltd. |
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