CN112882505A - Temperature protection signal generation circuit and temperature protection point trimming method - Google Patents
Temperature protection signal generation circuit and temperature protection point trimming method Download PDFInfo
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- CN112882505A CN112882505A CN202110255770.0A CN202110255770A CN112882505A CN 112882505 A CN112882505 A CN 112882505A CN 202110255770 A CN202110255770 A CN 202110255770A CN 112882505 A CN112882505 A CN 112882505A
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- G05D23/19—Control of temperature characterised by the use of electric means
Abstract
The non-inverting input end of a comparator in the temperature protection signal generation circuit is selectively connected with a detection signal or a reference signal through a first switch, and the inverting input end of the comparator is connected with the detection signal or the reference signal through a second switch or connected with the output end of the comparator, so that the comparator compares the detection signal with the reference signal to obtain a temperature protection signal. Wherein, a detection signal and a reference signal are obtained through detection, and a reference voltage target value is obtained through calculation based on the reference signal and the detection signal; the reference signal is adjusted according to the reference voltage target value and the first reference signal, or adjusted according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature. The temperature protection signal generation circuit and the temperature protection point trimming method provided by the invention have the advantages of simple circuit structure, simple and easy trimming process and higher trimming precision.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a temperature protection signal generation circuit and a temperature protection point trimming method.
Background
In electronic equipment, if the temperature of a system or a chip is too high or too low, the service life and reliability of components or chips in the system are affected, and a temperature protection point is usually required to be set, and when the temperature is exceeded or lowered, the temperature protection is carried out, so that over-temperature protection (for example, the power supply is disconnected at high temperature) or under-temperature regulation control (for example, heating of a heating device is controlled at low temperature) is realized.
In the over-temperature protection, as shown in fig. 1, the comparator U1 compares the detection signal V2 with the reference signal V1 to provide an over-temperature protection signal OTP, and the system or the chip performs over-temperature protection (for example, power off) according to the over-temperature protection signal OTP, wherein at least one of the detection signal V2 and the reference signal V1 is a temperature-sensitive signal, so that the temperature-voltage characteristic curves of the detection signal V2 and the reference signal V1 have an intersection, and the temperature of the intersection corresponds to the state transition point of the over-temperature protection signal OTP provided at the output terminal of the comparator U1 and corresponds to the temperature protection point Totp.
In practical applications, the states of the comparator U1, the detection signal V2, and the reference signal V1 often deviate from the ideal state, so that the actual temperature protection point Totp deviates from the target temperature protection point set according to the ideal value, and the reliability of temperature protection is reduced.
The requirement of the test of the temperature protection point in the prior art controls the temperature to simulate, and the temperature control cost is high, so that the repair and adjustment cost of the temperature protection point is high.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a temperature protection signal generation circuit and a temperature protection point trimming method, so as to conveniently realize trimming of an actual temperature protection point of the temperature protection signal generation circuit and reduce trimming cost of the temperature protection point.
According to an aspect of the present invention, there is provided a temperature protection signal generation circuit including: a comparator, a first switch, a second switch, and a reference signal conditioning circuit, wherein,
the reference signal adjusting circuit receives a reference voltage and outputs a reference signal,
the non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch, the inverting input terminal of the comparator receives the reference signal or the detection signal through the second switch or is connected to the output terminal of the comparator,
at least one of the detection signal and the reference signal is a temperature-sensitive voltage signal, and the comparator outputs a temperature protection signal according to the comparison between the detection signal and the reference signal.
Optionally, in a trimming environment, the temperature protection signal generation circuit detects to obtain a detection signal and a reference signal, and when the inverting input terminal of the comparator is connected to the output terminal of the comparator through the second switch, the temperature protection signal generation circuit makes the non-inverting input terminal of the comparator receive the reference signal through the first switch to detect to obtain a first reference signal at the output terminal of the comparator;
and obtaining a reference voltage target value of the temperature protection signal generation circuit under a trimming environment through calculation processing based on the detection signal and the reference signal, and adjusting the reference signal according to the reference voltage target value and the first reference signal so as to enable the reference signal to correspond to a reference signal under a target protection temperature.
Optionally, in a trimming environment, the temperature protection signal generation circuit detects to obtain a detection signal and a reference signal, and when the inverting input terminal of the comparator is connected to the output terminal of the comparator through the second switch, the temperature protection signal generation circuit makes the non-inverting input terminal of the comparator receive the detection signal through the first switch to detect at the output terminal of the comparator to obtain a second detection signal;
and obtaining a reference voltage target value of the temperature protection signal generation circuit under a trimming environment through calculation processing based on the detection signal and the reference signal, and adjusting the reference signal according to the reference voltage target value and a second detection signal so as to enable the reference signal to correspond to a reference signal under a target protection temperature.
Optionally, the reference signal adjusting circuit includes an input terminal receiving the reference voltage and an output terminal outputting the reference signal, and the reference signal adjusting circuit includes:
a first resistor and a second resistor connected in series between the input of the reference signal conditioning circuit and ground in that order, an intermediate node of the first resistor and the second resistor being the output of the reference signal conditioning circuit,
at least one of the first resistor and the second resistor is a variable resistor, and a level value of the reference signal is adjusted by adjusting the variable resistor.
Optionally, the temperature protection signal generating circuit further includes:
the base electrode of the triode is connected with the collector electrode, the collector electrode of the triode is connected with the output end of the current source, the emitting electrode of the triode is grounded, and the collector electrode of the triode provides the detection signal.
Optionally, the number of the triodes is multiple, and the triodes are sequentially connected in series between the output end of the current source and the ground, and the collector of at least one of the triodes provides the detection signal.
Optionally, the reference signal adjusting circuit includes an input terminal receiving the reference voltage and an output terminal outputting the reference signal, and the reference signal adjusting circuit includes:
a plurality of resistors connected in series between the input of the reference signal conditioning circuit and ground; and
a third switch including a common terminal connected to the output terminal of the reference signal adjusting circuit and a plurality of stationary contact terminals connected to each adjacent node of the plurality of resistors.
According to another aspect of the present invention, there is provided a temperature protection point trimming method, including:
respectively detecting a detection signal and a reference signal under a trimming environment, and enabling a non-inverting input end of a comparator to receive the reference signal to obtain a first reference signal through detection at an output end of the comparator or enabling the non-inverting input end of the comparator to receive the detection signal to obtain a second detection signal through detection at the output end of the comparator when an inverting input end of the comparator is connected to the output end of the comparator; the temperature protection carries out temperature protection according to a temperature protection signal obtained by comparing the detection signal with the reference signal;
calculating and obtaining a reference voltage target value based on the reference signal, the detection signal and the temperature characteristic thereof and a target protection temperature;
and adjusting the reference signal according to the reference voltage target value and the first reference signal, or adjusting the reference signal according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature.
Optionally, the reference signal is a voltage signal with a zero temperature coefficient or a positive temperature coefficient, and the detection signal is a voltage signal with a negative temperature coefficient, a zero temperature coefficient or a positive temperature coefficient.
Optionally, the reference signal is provided at an intermediate node of a first resistor and a second resistor connected in series between the reference voltage output path and ground, at least one of the first resistor and the second resistor being a variable resistor, and the reference signal is adjusted by adjusting a resistance value of the variable resistor.
Optionally, the detection signal is a voltage signal between a base and an emitter of a triode, the triode is connected between an output end of the current source and ground, and the base of the triode is connected with a collector.
Optionally, the temperature protection signal is obtained by a comparator,
the non-inverting input of the comparator receives the reference signal or the detection signal through a first switch,
the inverting input terminal of the comparator receives the reference signal or the detection signal through a second switch or is connected to the output terminal of the comparator,
at least one of the second detection signal, the first reference signal and the temperature protection signal is selectively obtained at the output end of the comparator by selecting the conduction paths of the first switch and the second switch.
Optionally, the step of adjusting the reference signal according to the reference voltage target value and the first reference signal specifically includes:
the inverting input end of the comparator is connected to the output end of the comparator, the non-inverting input end of the comparator receives the reference signal, so that the first reference signal is obtained through detection at the output end of the comparator, and the first reference signal obtained through detection after the reference signal is adjusted is matched with the reference voltage target value through adjustment of the reference signal.
Optionally, the step of adjusting the reference signal according to the reference voltage target value and the second detection signal specifically includes:
the reference signal is adjusted to match a reference signal with Vref- (V2 '-V2), where Vref is the reference voltage target value, V2' is the second detection signal, V2 is the detection signal, and the second detection signal is a signal obtained by processing the detection signal by a comparator.
The non-inverting input end of the comparator in the temperature protection signal generation circuit provided by the invention is selectively connected with the detection signal or the reference signal through the first switch, and the inverting input end is connected with the detection signal or the reference signal through the second switch or is connected with the output end of the comparator, so that the detection signal and the reference signal are compared through the comparator to obtain the temperature protection signal. The detection signal and the reference signal are obtained by detection, and the reference voltage target value is obtained by calculation based on the reference signal and the detection signal. The reference signal is adjusted according to the reference voltage target value and the first reference signal, or adjusted according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature. The temperature protection signal generation circuit and the temperature protection point trimming method provided by the invention have the advantages of simple circuit structure, simple and easy trimming process and higher trimming precision. The invention is convenient for detecting and repairing the temperature protection point at normal temperature, provides powerful guarantee for the accuracy of temperature protection and reduces the cost for repairing and repairing the temperature protection point.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:
fig. 1 shows a schematic diagram of a temperature protection signal generation circuit according to the prior art;
fig. 2A, 2B and 2C illustrate temperature-voltage characteristics of partial signals of a temperature protection signal generation circuit according to an embodiment of the present invention;
FIG. 3 illustrates a schematic diagram of a temperature protection signal generation principle of a temperature protection signal generation circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a detection principle of a part of signals of a temperature protection signal generation circuit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a temperature protection signal generating circuit according to an embodiment of the present invention;
fig. 6 shows a schematic diagram of a reference signal adjustment principle of a temperature protection signal generation circuit according to an embodiment of the present invention.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.
Fig. 2A, 2B, and 2C illustrate temperature-voltage characteristics of partial signals of the temperature protection signal generation circuit according to the embodiment of the present invention.
As shown in fig. 2A, 2B and 2C, fig. 2A corresponds to the reference signal V1 being a zero temperature coefficient voltage signal and the detection signal V2 being a negative temperature coefficient voltage signal; FIG. 2B shows that the reference signal V1 is a positive temperature coefficient voltage signal and the detection signal V2 is a zero temperature coefficient voltage signal; FIG. 2C shows that the reference signal V1 is a positive temperature coefficient voltage signal and the detection signal V2 is a negative temperature coefficient voltage signal; the temperature-voltage characteristic curves of the reference signal V1 and the detection signal V2 are made to intersect with each other, and the intersection point corresponds to the temperature protection point Totp.
The temperature protection point trimming method of the embodiment of the invention detects the level values of the reference signal V1 and the detection signal V2 under the trimming environment to respectively obtain the first reference signal and the second detection signal, and calculates a reference voltage target value under the temperature protection circuit trimming environment (the reference voltage target value does not eliminate the influence of the detuning value of the comparator) according to the reference signal V1, the detection signal V2, the temperature characteristic thereof and the target protection temperature, adjusts the reference signal according to the reference voltage target value and the first reference signal, or adjusting the reference signal according to the reference voltage target value and the second detection signal so that the reference signal corresponds to the reference signal at the target protection temperature, the trimming error caused by the change of the detection signal due to the difference between the trimming environment temperature and the target protection temperature can be eliminated, and the influence of the detuning value of the comparator can be eliminated. Referring to fig. 2A, 2B and 2C, even if the temperature characteristic curve of the reference signal V1 is shifted up and down, the intersection of the temperature-voltage characteristic curves of the reference signal V1 and the sensing signal V2 is shifted to coincide with the target temperature protection signal. The temperature characteristic specifically refers to a temperature coefficient, which may be one of a positive temperature coefficient, a negative temperature coefficient, and a zero temperature coefficient.
The trimming environment is any suitable environment, generally 25 ℃ at normal temperature can be selected, and the temperature protection point trimming method provided by the embodiment of the invention utilizes a temperature-voltage characteristic curve to perform trimming, so that the parameters of hardware providing the reference signal V1 and the detection signal V2 are not easy to change along with the temperature, namely the slope of the temperature-voltage characteristic curve of the reference signal V1 and the detection signal V2 is not changed along with the temperature, no special requirement is made on the temperature of the detection environment for detecting and obtaining the first reference signal and the second detection signal, the detection is convenient and effective, and the corresponding trimming is simple and effective.
Fig. 3 shows a schematic diagram of a temperature protection signal generation principle of the temperature protection signal generation circuit according to the embodiment of the present invention.
As shown in fig. 3, in the temperature protection signal generating circuit according to the embodiment of the present invention, a first resistor R1 and a second resistor R2 are connected in series between the bandgap reference voltage signal output terminal of the bandgap reference voltage signal generating circuit 10 and the ground in sequence, and a reference signal V1 output is provided at an intermediate node between the first resistor R1 and the second resistor R2.
The transistor Q1 has a base connected to a collector, a collector connected to the output of the current source a1, and an emitter connected to ground to provide the detection signal V2 at the collector of the transistor Q1, which outputs a voltage Vbe between its base and emitter. In an alternative embodiment, the transistor Q1 is a negative temperature coefficient transistor, and the Vbe voltage between the base and the emitter of the transistor Q1 is generally characterized by a temperature of 1.5 to 2 mV/deg.c, i.e., for every rise in temperature, the Vbe voltage drops by 1.5 to 2 mV. In an alternative embodiment, the detection signal V2 is provided by a device connected between the current source and ground, and the voltage temperature coefficient of the device may be one of a positive temperature coefficient, a negative temperature coefficient, and a zero temperature coefficient, i.e., the present invention is not particularly limited to the provision of the detection signal V2. In one embodiment of the present invention, the detection signal V2 is provided by a thermistor connected between a current source and ground.
The comparator U1 has a non-inverting input terminal receiving the detection signal V2 and an inverting input terminal receiving the reference signal V1, and the comparator U1 compares the detection signal V2 with the reference signal V1 and outputs the over-temperature protection signal OTP.
In the present embodiment, the second resistor R2 is a variable resistor, so as to adjust the voltage division of the first resistor R1 and the second resistor R2 by adjusting the resistance value of the second resistor R2, and adjust the level value of the reference signal V1 relative to the bandgap reference voltage Vgb (in the present embodiment, the bandgap reference voltage, which may also be other reference voltages in alternative embodiments), so as to adjust the temperature protection point. In an alternative embodiment, the first resistor R1 is designed as a variable resistor, or the first resistor R1 and the second resistor R2 are both selected as variable resistors, and a plurality of adjusting nodes are preset, so that more optional preset values of the reference signal V1 are provided, digital adjustment is facilitated, and the speed of trimming the temperature protection point is improved.
Fig. 4 is a schematic diagram illustrating a detection principle of a part of signals of a temperature protection signal generation circuit according to an embodiment of the present invention.
As shown in fig. 4, the temperature protection signal generating circuit according to the embodiment of the present invention connects the inverting input terminal and the output terminal of the comparator U1, configures the comparator U1 as a voltage follower, connects the reference signal V1 to the non-inverting input terminal of the comparator U1, directly detects the reference signal V1 through the comparator U1 to obtain the first reference signal, and does not need to provide any other detecting unit, thereby avoiding an increase in cost, and the first reference signal obtained by detecting the reference signal V1 through the comparator U1 includes the detuning value of the comparator U1, thereby overcoming the influence of the detuning value of the comparator U1.
Similarly, in another embodiment, the second detection signal may be obtained by detecting the detection signal V2 through the voltage follower function of the comparator U1, and the second detection signal includes the detuning value of the comparator U1, so as to overcome the influence of the detuning value of the comparator U1, and the influence of the detuning value of the comparator U1 may be eliminated according to the first reference signal or the second detection signal including the detuning value of the comparator U1 and the reference voltage target value obtained by calculation, without modifying the detuning influence of the comparator U1, so as to improve the modification efficiency of the temperature protection point, improve the accuracy of the over-temperature protection signal provided by the temperature protection signal generating circuit, and improve the reliability of the over-temperature protection.
Fig. 5 shows a schematic structural diagram of a temperature protection signal generation circuit according to an embodiment of the present invention.
As shown in fig. 5, the temperature protection signal generating circuit according to the embodiment of the present invention includes a comparator U1, a first switch S1, a second switch S2, a first resistor R1, a second resistor R2, and a transistor Q1.
The first resistor R1 and the second resistor R2 are reference voltage adjusting circuits, and are sequentially connected in series between a bandgap reference voltage signal output terminal (bandgap reference voltage output path) of the bandgap reference voltage signal generating circuit 10 and ground, and the intermediate node of the first resistor R1 and the second resistor R2 provides a reference signal V1 for the reference signal output terminal. In the present embodiment, the resistor R2 is a variable resistor so as to adjust the level value of the reference signal V1.
The transistor Q1 is a temperature sensitive device, the base is connected with the collector, the emitter is grounded, the collector is connected with the output end of the current source a1, the current source a1 drives the collector to output the PN junction voltage thereof, i.e. the voltage Vbe between the base and the emitter, and the Vbe is the detection signal V2, in this embodiment, the transistor Q1 is one, in an optional embodiment, the transistor Q1 is multiple and is sequentially connected in series between the output end of the current source a1 and the ground, and the detection signal V2 is provided at the collector of at least one of the multiple transistors Q1. The triodes Q1 are connected in series, and the voltage values provided by the collectors of different triodes Q1 are different, so that the voltage value can be used for adjusting the level value of the detection signal V2, the adjustment of the cross point of the detection signal V2 and the reference signal V1 can be realized, and the adjustment of a temperature protection point can be realized.
The common terminal of the first switch S1 is connected to the non-inverting input terminal of the comparator U1, the stationary contact S11 of the first switch S1 receives the detection signal V2, and the stationary contact S12 receives the reference signal V1. The common terminal of the second switch S2 is connected to the inverting input terminal of the comparator U1, the stationary contact S21 of the second switch S2 is connected to the intermediate node of the first resistor R1 and the second resistor R2, and the stationary contact S22 is connected to the output terminal of the comparator U1. As can be seen from fig. 3 to 5, the non-inverting input terminal of the comparator U1 is coupled to the detection signal terminal to receive the detection signal V2 by selecting the conduction path of the first switch S1, and the inverting input terminal of the comparator U1 is coupled to the reference signal terminal to receive the reference signal V1 by selecting the conduction path of the second switch S2. In this connection state, the acquisition of the detection signal V2 and the reference signal V1 can be detected, and the acquisition of the detection signal V2 and the reference signal V1 can also be detected without the above connection relationship. During trimming, the inverting input end of the comparator U1 is connected with the output end by selecting the conduction path of the second switch S2, the comparator U1 is configured as a voltage follower, and the reference signal V1 is connected to the non-inverting input end of the comparator U1 by selecting the conduction path of the switch S1 so as to obtain a first reference signal V1' through detection at the output end of the comparator U1. The reference voltage target value Vref is obtained by calculation according to the temperature characteristics of the detection signal V2 and the reference signal V1, the value of the first reference signal V1 'is adjusted by adjusting the resistance value of the second resistor R2, the first reference signal V1' is modified to the reference voltage target value Vref, so that the first reference signal obtained by detection after the reference signal is adjusted is matched with the reference voltage target value, namely, the modification error caused by the change of the detection signal due to the difference between the modification environment temperature and the target protection temperature is eliminated, the influence of the modified value of the comparator is eliminated, and the modification of the temperature protection point is realized. The matching of the first reference signal detected after the adjustment of the reference signal with the reference voltage target value means that the first reference signal obtained after the adjustment is equal to the reference voltage target value or that the difference between the first reference signal obtained after the adjustment and the reference voltage target value is within an allowable range.
In the present embodiment, the reference signal V1 is a divided voltage of the bandgap reference voltage, so that the divided voltage value does not change with temperature when the resistance value of the second resistor R2 is adjusted. In another embodiment, the reference signal V1 is derived from a voltage dividing resistor set with a positive temperature coefficient or a negative temperature coefficient, and the voltage dividing resistor set may include a first resistor R1 and a second resistor R2, and at this time, the trimming value from the voltage dividing resistor set needs to be taken into account when performing trimming, so as to achieve precise trimming.
In this embodiment, the detection signal V2 is a negative temperature coefficient voltage signal, during temperature protection comparison, the detection signal V2 is connected to the non-inverting input terminal of the comparator U1, the reference signal V1 (the value of the reference signal V1 at this time is modified due to the resistance change of the second resistor R2) is connected to the inverting input terminal of the comparator U1, and when the temperature exceeds a temperature protection point, the temperature protection signal OTP output by the comparator U1 is inverted from a high level to a low level. In an alternative embodiment, the detection signal V2 is connected to the inverting input terminal of the comparator U1, the reference signal V1 is connected to the non-inverting input terminal of the comparator U1, and the temperature protection signal OTP output by the comparator U1 is inverted from low level to high level when the temperature exceeds the temperature protection point. In another embodiment, the corresponding switch S2 further includes a third fixed contact for receiving the input of the detection signal V2 and providing different ways of inverting the temperature protection signal OTP, so as to apply to different ways of inverting the temperature protection signal by the temperature protection execution device, and improve the applicability of the temperature protection signal generation circuit of the present invention.
In an alternative embodiment, for example, the target protection temperature is 135 degrees celsius, and V2-600 mV, V1-400 mV are measured in a trimming environment at a normal temperature of 25 degrees celsius, i.e., 600mv for the detection signal and 400mv for the reference signal, and at the same time, with every 1 c rise in temperature, 2mv for the Vbe voltage of transistor Q1, the temperature protection point corresponding to the current V1 value is calculated to be (600mV-400mV)/2mV/° C +25 ℃ + 125 ℃, the temperature is 10 ℃ different from the 135 ℃ of the required target temperature protection point, the voltage difference between the corresponding reference signal and the detection signal at 25 degrees celsius is also 10 deg.c by 2 mV/20 mV, namely, the reference signal V1 corresponding to the first reference signal needs to be modified to 380mV, that is, the target value of the reference voltage of the temperature protection signal generation circuit under the modification environment is 380mV based on the detection signal V2 and the reference signal V1. In addition, the trimming error caused by the change of the detection signal due to the difference between the trimming ambient temperature and the target protection temperature is eliminated and the influence of the trimming value of the comparator is eliminated by adjusting the resistance value of the second resistor R2 in consideration of the trimming value of the comparator.
In another embodiment of the present invention, in conjunction with FIG. 5, the acquisition detection signal V2 and the reference signal V1 are detected. Then, the non-inverting input terminal of the comparator U1 is coupled to the detection signal terminal to receive the detection signal V2 by selecting the conduction path of the first switch S1, the inverting input terminal of the comparator U1 is coupled to the output terminal of the comparator U1 by selecting the conduction path of the second switch S2, and the comparator U1 is configured as a voltage follower to detect at the output terminal of the comparator U1 to obtain a second detection signal V2 ', and the second detection signal V2' is equal to the sum of the detection signal V2 and the offset value of the comparator. At the time of trimming, a reference voltage target value Vref is obtained by calculation based on the temperature characteristics of the detection signal V2 and the reference signal V1. According to the reference voltage target value Vref, the detection signal V2 and the second detection signal V2 ', the resistance value of the second resistor R2 is adjusted, so that the value of the reference signal V1 (i.e. the divided voltage value of the first resistor R1 and the second resistor R2 after the resistance value of R2 is adjusted) is adjusted, the adjusted reference signal V1 is matched with Vref- (V2' -V2), and the trimming of the temperature protection point is realized. Wherein Vref is the reference voltage target value, V2' is the second detection signal, and V2 is the detection signal. The matching of the adjusted reference signal V1 and Vref- (V2 ' -V2) means that the adjusted reference signal V1 is equal to Vref- (V2 ' -V2) or the difference between the adjusted reference signal V1 and Vref- (V2 ' -V2) is within the allowable range. When performing the temperature protection comparison, the non-inverting input terminal of the comparator may be coupled to the detection signal V2, and the inverting input terminal of the comparator may be coupled to the adjusted reference signal V1. In this embodiment, the temperature characteristics of the reference signal V1 and the detection signal V2 can also be obtained through detection by the comparator U1, so that the influence of process deviation can be reduced, and the accuracy of the temperature protection signal provided by the temperature protection signal generating circuit can be further improved.
Fig. 6 shows a schematic diagram of a reference signal adjustment principle of a temperature protection signal generation circuit according to an embodiment of the present invention.
As shown in fig. 6, the reference signal adjusting circuit of the temperature protection signal generating circuit according to the embodiment of the present invention, i.e. the first resistor R1 and the second resistor R2, in the embodiment, the second resistor R2 is a variable resistor and includes 3 preset adjusting nodes corresponding to one end of the resistors R21, R22 and R23 far away from each other and led out to three stationary contact terminals of the switch S3, the common terminal of the switch S3 is connected to the output terminal of the reference signal adjusting circuit, the node actually outputting the reference signal V1 is selected by selecting the conduction path of the switch S3 to adjust the level of the reference signal V1, in the embodiment, the output node is selected without changing the total resistance of the first resistor R1 and the second resistor R2 between the output path of the reference voltage Vgb and the ground, the level corresponding to each preset adjusting node is well linearized, which facilitates the linearized adjustment of the reference signal V1, the implementation is convenient.
In an alternative embodiment, at least one of the first resistor R1 and the second resistor R2 is a variable resistor.
The temperature protection signal generation circuit provided by the invention compares a reference signal and a detection signal through a comparator to provide a temperature protection signal, controls the inverting input end of the comparator to be connected with the output end of the comparator through a second switch, constructs the comparator into a voltage follower, selects the non-inverting input end of the comparator to access the reference signal or the detection signal through a first switch, obtains a first reference signal or a second detection signal through the detection of the comparator, calculates a reference voltage target value actually corresponding to the temperature protection signal generation circuit according to the temperature characteristics of the first reference signal or the second detection signal, the reference signal and the detection signal and the environment temperature during detection, adjusts the reference signal to enable the reference signal to correspond to the reference signal under the target protection temperature, and ensures that the overturning point of the temperature protection signal provided by the temperature protection signal generation circuit is matched with the target temperature point, the reliability of temperature protection by adopting the temperature protection signal is guaranteed.
According to the temperature protection point trimming method, the reference voltage target value is calculated according to the second detection signal or the first reference signal obtained by detecting the detection signal and the reference signal and according to the second detection signal or the first reference signal and the temperature characteristics of the detection signal and the reference signal, trimming is convenient and effective, and the accuracy of the temperature protection signal obtained by comparing the detection signal and the reference signal is improved.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (14)
1. A temperature protection signal generation circuit, comprising: a comparator, a first switch, a second switch, and a reference signal conditioning circuit, wherein,
the reference signal adjusting circuit receives a reference voltage and outputs a reference signal,
the non-inverting input terminal of the comparator receives the reference signal or the detection signal through the first switch, the inverting input terminal of the comparator receives the reference signal or the detection signal through the second switch or is connected to the output terminal of the comparator,
at least one of the detection signal and the reference signal is a temperature-sensitive voltage signal, and the comparator outputs a temperature protection signal according to the comparison between the detection signal and the reference signal.
2. The temperature protection signal generation circuit of claim 1,
under the trimming environment, the temperature protection signal generation circuit detects and obtains a detection signal and a reference signal, and when the inverting input end of the comparator is connected to the output end of the comparator through the second switch, the temperature protection signal generation circuit enables the non-inverting input end of the comparator to receive the reference signal through the first switch so as to detect and obtain a first reference signal at the output end of the comparator;
and obtaining a reference voltage target value of the temperature protection signal generation circuit under a trimming environment through calculation processing based on the detection signal and the reference signal, and adjusting the reference signal according to the reference voltage target value and the first reference signal so as to enable the reference signal to correspond to a reference signal under a target protection temperature.
3. The temperature protection signal generation circuit of claim 1,
under a trimming environment, the temperature protection signal generation circuit detects to obtain a detection signal and a reference signal, and when the inverting input end of the comparator is connected to the output end of the comparator through the second switch, the temperature protection signal generation circuit enables the non-inverting input end of the comparator to receive the detection signal through the first switch so as to detect at the output end of the comparator to obtain a second detection signal;
and obtaining a reference voltage target value of the temperature protection signal generation circuit under a trimming environment through calculation processing based on the detection signal and the reference signal, and adjusting the reference signal according to the reference voltage target value and a second detection signal so as to enable the reference signal to correspond to a reference signal under a target protection temperature.
4. The temperature protection signal generation circuit of claim 2 or 3, wherein the reference signal conditioning circuit comprises an input terminal receiving the reference voltage and an output terminal outputting the reference signal, the reference signal conditioning circuit comprising:
a first resistor and a second resistor connected in series between the input of the reference signal conditioning circuit and ground in that order, an intermediate node of the first resistor and the second resistor being the output of the reference signal conditioning circuit,
at least one of the first resistor and the second resistor is a variable resistor, and a level value of the reference signal is adjusted by adjusting the variable resistor.
5. The temperature protection signal generation circuit of claim 4, further comprising:
the base electrode of the triode is connected with the collector electrode, the collector electrode of the triode is connected with the output end of the current source, the emitting electrode of the triode is grounded, and the collector electrode of the triode provides the detection signal.
6. The temperature protection signal generation circuit of claim 5,
the triode is a plurality of triodes and is connected in series between the output end of the current source and the ground in sequence, and the collector of at least one of the triodes provides the detection signal.
7. The temperature protection signal generation circuit of claim 2 or 3, wherein the reference signal conditioning circuit comprises an input terminal receiving the reference voltage and an output terminal outputting the reference signal, the reference signal conditioning circuit comprising:
a plurality of resistors connected in series between the input of the reference signal conditioning circuit and ground; and
a third switch including a common terminal connected to the output terminal of the reference signal adjusting circuit and a plurality of stationary contact terminals connected to each adjacent node of the plurality of resistors.
8. A temperature protection point trimming method is characterized by comprising the following steps:
respectively detecting a detection signal and a reference signal under a trimming environment, and enabling a non-inverting input end of a comparator to receive the reference signal to obtain a first reference signal through detection at an output end of the comparator or enabling the non-inverting input end of the comparator to receive the detection signal to obtain a second detection signal through detection at the output end of the comparator when an inverting input end of the comparator is connected to the output end of the comparator; the temperature protection carries out temperature protection according to a temperature protection signal obtained by comparing the detection signal with the reference signal;
calculating and obtaining a reference voltage target value based on the reference signal, the detection signal and the temperature characteristic thereof and a target protection temperature;
and adjusting the reference signal according to the reference voltage target value and the first reference signal, or adjusting the reference signal according to the reference voltage target value and the second detection signal, so that the reference signal corresponds to the reference signal at the target protection temperature.
9. The temperature protection point trimming method according to claim 8,
the reference signal is a voltage signal with a zero temperature coefficient or a positive temperature coefficient, and the detection signal is a voltage signal with a negative temperature coefficient, a zero temperature coefficient or a positive temperature coefficient.
10. The temperature protection point trimming method according to claim 8,
the reference signal is provided for an intermediate node of a first resistor and a second resistor connected in series between a reference voltage output path and ground, at least one of the first resistor and the second resistor being a variable resistor, and the reference signal is adjusted by adjusting a resistance value of the variable resistor.
11. The temperature protection point trimming method according to claim 8,
the detection signal is a voltage signal between a base electrode and an emitting electrode of the triode, the triode is connected between an output end of the current source and the ground, and the base electrode of the triode is connected with the collector electrode.
12. The temperature protection point trimming method according to claim 8,
the temperature protection signal is obtained by a comparator,
the non-inverting input of the comparator receives the reference signal or the detection signal through a first switch,
the inverting input terminal of the comparator receives the reference signal or the detection signal through a second switch or is connected to the output terminal of the comparator,
at least one of the second detection signal, the first reference signal and the temperature protection signal is selectively obtained at the output end of the comparator by selecting the conduction paths of the first switch and the second switch.
13. The method according to claim 8, wherein the step of adjusting the reference signal according to the reference voltage target value and the first reference signal specifically comprises:
the inverting input end of the comparator is connected to the output end of the comparator, the non-inverting input end of the comparator receives the reference signal, so that the first reference signal is obtained through detection at the output end of the comparator, and the first reference signal obtained through detection after the reference signal is adjusted is matched with the reference voltage target value through adjustment of the reference signal.
14. The method according to claim 8, wherein the step of adjusting the reference signal according to the reference voltage target value and the second detection signal specifically comprises:
adjusting the reference signal to match a reference signal with Vref- (V2 '-V2), where Vref is the reference voltage target value, V2' is a second detection signal, V2 is a detection signal, and the second detection signal is a signal obtained by processing the detection signal by the comparator.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115453319A (en) * | 2022-09-02 | 2022-12-09 | 北京炎黄国芯科技有限公司 | Band-gap reference hysteresis over-temperature detection circuit and electronic equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115453319A (en) * | 2022-09-02 | 2022-12-09 | 北京炎黄国芯科技有限公司 | Band-gap reference hysteresis over-temperature detection circuit and electronic equipment |
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