CN111628483A

CN111628483A - H-bridge driving circuit with over-temperature protection function and electrical system

Info

Publication number: CN111628483A
Application number: CN202010384070.7A
Authority: CN
Inventors: 郭小建; 曹震霆; 邓超明
Original assignee: Shanghai Siludi Medical Laboratory Co ltd
Current assignee: Shanghai Siludi Medical Laboratory Co ltd
Priority date: 2020-05-09
Filing date: 2020-05-09
Publication date: 2020-09-04

Abstract

The application provides an H-bridge driving circuit with an over-temperature protection function and an electrical system, wherein a temperature detection circuit is provided with a temperature sensor which is arranged on a heating component of a controlled electrical appliance; the output end of the temperature detection circuit is electrically connected with one signal input end of the control signal regulating circuit; the signal output end of the control signal regulating circuit is electrically connected with the signal input end of the first driving chip and the signal input end of the second driving chip respectively; the signal output end of the first driving chip and the signal output end of the second driving chip are respectively and electrically connected with an upper bridge arm and a lower bridge arm of the H-bridge circuit; the output end of the upper bridge arm and the output end of the lower bridge arm; the voltage stabilization output circuit is electrically connected with the first driving chip and the second driving chip respectively. The H-bridge driving circuit can effectively avoid the limitation of the conventional bootstrap circuit on the on and off of the switching device, and can also avoid the problem of too high complexity of the algorithm of the driving chip caused by the addition of the temperature detection module.

Description

H-bridge driving circuit with over-temperature protection function and electrical system

Technical Field

The application relates to the technical field of H-bridge drive circuits, in particular to an H-bridge drive circuit with an over-temperature protection function and an electrical system.

Background

In the existing H-bridge driving circuit, the driving voltage of the switching device in the H-bridge circuit is provided by a bootstrap circuit composed of a driving chip, a diode and a capacitor. The first end of a diode in the bootstrap circuit is electrically connected with a preset voltage end, the first end of the diode and the first end of a capacitor are electrically connected with a voltage input end of the driving chip, and the first end of the capacitor is electrically connected with a series node of the switching devices. When the bootstrap circuit in the above form supplies a driving voltage to the switching device, it is necessary to set a charging and discharging time, so that a duty ratio of a PWM (pulse width modulation) signal received by the driving chip cannot reach 100%, and the diode cannot be continuously charged; moreover, the frequency of the PWM signal needs to be matched with the bootstrap circuit, and if the frequency is low, the duty ratio is too high, which easily causes the switching device to be turned off.

In addition, a temperature detection module is arranged on the existing H-bridge driving circuit according to needs and is used for detecting the temperature of the controlled electric appliance. The temperature detection module is usually electrically connected with the driving chip, detected temperature information is sent to the driving chip, and the driving chip controls the on-off of the switch device according to the temperature information, so that the function of over-temperature protection of the controlled electric appliance is realized. However, adding a temperature detection module to the original H-bridge driving circuit requires a large change to the H-bridge driving circuit, and also increases the complexity of the algorithm of the driving chip itself.

Disclosure of Invention

The present application provides an H-bridge driving circuit with an over-temperature protection function and an electrical system to overcome the above technical drawbacks.

In a first aspect, an embodiment of the present application provides an H-bridge driving circuit with an over-temperature protection function, which is characterized by including a temperature detection circuit, a first driving chip, a second driving chip, a control signal adjustment circuit, an H-bridge circuit, and a voltage stabilization output circuit;

the temperature detection circuit is provided with a temperature sensor which is arranged on a heating component of the controlled electric appliance and is used for detecting the temperature of the controlled electric appliance; the output end of the temperature detection circuit is electrically connected with one signal input end of the control signal regulating circuit, and the temperature detection circuit is used for outputting a corresponding temperature control signal according to temperature information detected by the temperature sensor;

the signal output end of the control signal regulating circuit is electrically connected with the signal input end of the first driving chip and the signal input end of the second driving chip respectively; the control signal regulating circuit is used for outputting a switch control signal according to the temperature control signal and at least one other signal;

the signal output end of the first driving chip and the signal output end of the second driving chip are respectively and electrically connected with the upper bridge arm and the lower bridge arm of the H-bridge circuit and used for controlling the on-off of the switching devices in the upper bridge arm and the lower bridge arm according to the switching control signals;

the output end of the upper bridge arm and the output end of the lower bridge arm are used for being electrically connected with a controlled electric appliance and supplying power to the controlled electric appliance;

and the output end of the voltage stabilizing output circuit is electrically connected with the first voltage input end of the first driving chip and the first voltage input end of the second driving chip respectively and used for providing stable preset voltage.

In one embodiment of the present application, the temperature detection circuit further includes a first resistor, a second resistor, a third resistor, and a first comparator;

the first resistor is connected with the temperature sensor in series; the serial node of the first resistor and the temperature sensor is electrically connected with a first signal input end of the first comparator;

the second resistor is connected with the third resistor in series; the serial node of the second resistor and the third resistor is electrically connected with the second signal input end of the first comparator;

the signal output end of the first comparator is used as the output end of the temperature detection circuit and is electrically connected with one signal input end of the control signal adjusting circuit.

In one embodiment of the present application, the temperature detection circuit further includes a fourth resistor and a fifth resistor;

the serial node of the first resistor and the temperature sensor is electrically connected with the first signal input end of the first comparator through a fourth resistor;

and a series node of the second resistor and the third resistor is electrically connected with the second signal input end of the first comparator through a fifth resistor.

In one embodiment of the present application, the control signal adjusting circuit includes first to fourth nand gate chips, and a first and gate chip; the at least one other signal comprises a first type of switch control signal and a second type of switch control signal;

the first input end of the first NAND gate chip is electrically connected with the first voltage end, the second input end of the first NAND gate chip is used for receiving the first switch control signal, and the output end of the first NAND gate chip is electrically connected with the first input end of the third NAND gate chip;

the first input end and the second input end of the second NAND gate chip are respectively used for receiving the first switch control signal and the second switch control signal; the output end of the second NAND gate chip is electrically connected with the second input end of the fourth NAND gate chip and the first signal input end of the second driving chip respectively;

the second input end of the third NAND gate chip is used for receiving a second switch control signal; the output end of the third NAND gate chip is electrically connected with the first input end of the fourth NAND gate chip and the first signal input end of the first driving chip respectively;

the output end of the fourth NAND gate chip and the output end of the temperature detection circuit are respectively and electrically connected with the first input end and the second input end of the first AND gate chip; the output end of the first AND gate chip is electrically connected with the second signal input end of the first driving chip and the second signal input end of the second driving chip respectively.

In one embodiment of the present application, the regulated output circuit is a boost circuit independent of the H-bridge circuit, a charge-discharge circuit independent of the H-bridge circuit, or a bootstrap circuit independent of the H-bridge circuit.

In one embodiment of the application, the voltage stabilization output circuit comprises a first driver, a first inductor, a first diode, a sixth resistor and a seventh resistor which are sequentially connected in series;

the first end and the second end of the first driver, one end of the first inductor and one end of the seventh resistor are connected with a power supply; the third end of the first driver is electrically connected with the series node of the first inductor and the first diode; the fourth end of the first driver is electrically connected with a series node of the sixth resistor and the seventh resistor;

and the series node of the first diode and the sixth resistor is used as the output end of the voltage-stabilizing output circuit and is respectively and electrically connected with the first voltage input end of the first driving chip and the first voltage input end of the second driving chip.

In one embodiment of the present application, the signal output end of the first driving chip includes a first signal output end, a second signal output end and a floating power supply bias end, the upper bridge arm includes a first switching device and a second switching device, and a second end of the first switching device is connected in series with a first end of the second switching device;

the first signal output end of the first driving chip is electrically connected with the control end of the first switching device, the floating power supply bias end of the first driving chip is electrically connected with the series node of the first switching device and the second switching device, and the second signal output end of the first driving chip is electrically connected with the control end of the second switching device.

In an embodiment of the application, the H-bridge driving circuit further includes a first voltage regulator tube, a positive terminal of the first voltage regulator tube is electrically connected to the second terminal of the first switching device, and a negative terminal of the first voltage regulator tube is electrically connected to the control terminal of the first switching device.

In an embodiment of the application, the H-bridge driving circuit further includes a second voltage regulator tube, a positive terminal of the second voltage regulator tube is electrically connected to the second terminal of the second switching device, and a negative terminal of the second voltage regulator tube is electrically connected to the control terminal of the second switching device.

In one embodiment of the present application, the signal output end of the second driving chip includes a first signal output end, a second signal output end and a floating power supply bias end, the lower bridge arm includes a third switching device and a fourth switching device, and a second end of the third switching device is connected in series with a first end of the fourth switching device;

the first signal output end of the second driving chip is electrically connected with the control end of the third switching device, the floating power supply bias end of the second driving chip is electrically connected with the series node of the third switching device and the fourth switching device, and the second signal output end of the second driving chip is electrically connected with the control end of the fourth switching device.

In an embodiment of the application, the H-bridge driving circuit further includes a third voltage-regulator tube, a positive terminal of the third voltage-regulator tube is electrically connected to the second terminal of the third switching device, and a negative terminal of the third voltage-regulator tube is electrically connected to the control terminal of the third switching device.

In an embodiment of the application, the H-bridge driving circuit further includes a fourth voltage regulator tube, a positive terminal of the fourth voltage regulator tube is electrically connected to the second terminal of the fourth switching device, and a negative terminal of the fourth voltage regulator tube is electrically connected to the control terminal of the fourth switching device.

In one embodiment of the present application, the H-bridge driver circuit further comprises a bypass circuit, the bypass circuit comprising a second driver and a first capacitor;

the voltage input end of the second driver and the first end of the first capacitor are electrically connected with the first voltage end; the second end of the first capacitor is electrically connected with the reference voltage end, and the voltage of the reference voltage end is smaller than that of the first voltage end.

In a second aspect, an embodiment of the present application further provides an electrical system, which includes a controlled electrical appliance and the H-bridge driving circuit having the over-temperature protection function provided in the embodiment of the present application;

in an H-bridge circuit of the H-bridge driving circuit, the output end of an upper bridge arm and the output end of a lower bridge arm are electrically connected with a controlled electric appliance and used for supplying power to the controlled electric appliance;

the temperature sensor of the temperature detection circuit in the H-bridge drive circuit is arranged on a heating component of the controlled electrical appliance.

In one embodiment of the present application, the controlled appliance includes a semiconductor refrigerator; in an H-bridge circuit of the H-bridge driving circuit, the output end of an upper bridge arm is electrically connected with a first connecting end of the semiconductor refrigerator, and the output end of a lower bridge arm is electrically connected with a second connecting end of the semiconductor refrigerator.

The technical scheme provided by the embodiment of the application at least has the following beneficial effects:

in the embodiment of the application, the first driving chip and the second driving chip may receive a switching control signal sent by the control signal adjusting circuit, where the switching control signal includes a PWM signal. The voltage-stabilizing output circuit replaces the function of the existing bootstrap circuit, because the output end of the voltage-stabilizing output circuit is only electrically connected with the first voltage input end of the first driving chip and the first voltage input end of the second driving chip, under the condition that the temperature of the controlled electric appliance does not exceed the threshold temperature, the voltage-stabilizing output circuit can provide stable preset voltage for the first driving chip and the second driving chip, the limitation of the existing bootstrap circuit on the on-off of a switching device is avoided, the H-bridge circuit can be controlled by PWM signals with any duty ratio and any frequency, when the H-bridge circuit is driven by the PWM signals with 100% duty ratio, the power of the controlled electric appliance can be rapidly improved, and when the H-bridge circuit is driven by the PWM signals with low frequency (less than or equal to 1Hz), the service life of the controlled electric appliance can be prevented from being influenced. And compared with a bootstrap circuit mode, the connection mode of the voltage stabilization output circuit and the driving chip is simpler.

In addition, the temperature detection circuit does not need to be electrically connected with the driving chips (the first driving chip and the second driving chip), but is directly electrically connected with the control signal adjusting circuit. The temperature detection circuit can output a corresponding temperature control signal to the voltage stabilization output circuit according to temperature information detected by the temperature sensor, and the control signal adjusting circuit can output a switch control signal according to the temperature control signal and at least one other signal, so that the on-off of a switch device in the H-bridge circuit is controlled, and the function of over-temperature protection of the controlled electric appliance is realized. The connection mode of the temperature detection circuit and the driving chip does not need to greatly change the original H-bridge driving circuit, and meanwhile, the complexity of the algorithm of the driving chip is simplified.

To sum up, the H bridge drive circuit that can realize overtemperature protection that this application provided need not to do under the condition of great change to original H bridge drive circuit, both can avoid the restriction of current bootstrap circuit to switching device's switching on and turn-off effectively, can avoid again because of increasing the problem that the temperature detection module leads to the too complicated degree of driver chip algorithm, has compromise two at least actual demands. .

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is an architecture diagram of an H-bridge driving circuit with an over-temperature protection function according to an embodiment of the present application;

fig. 2 is a schematic connection diagram of the first driver chip, the second driver chip and the H-bridge circuit in fig. 1 provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of a connection between a temperature sensor and a controlled appliance provided by an embodiment of the present application;

fig. 4 is a schematic structural diagram of a regulated output circuit in fig. 1 according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a signal terminal relationship of a NAND gate chip according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram of a signal terminal relationship of a first and gate chip according to an embodiment of the present application;

fig. 7 is an internal structural diagram of a first driver chip and a second driver chip provided in an embodiment of the present application;

fig. 8 is an architecture diagram of an electrical system according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts or parts having the same or similar functions throughout. In addition, if a detailed description of the known art is not necessary for illustrating the features of the present application, it is omitted. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.

Firstly, English acronyms possibly related in the specification or the drawings of the specification are simply explained:

MOS: metal Oxide Semiconductor, field effect transistor.

IGBT: insulated Gate Bipolar Transistor (IGBT).

TEC: thermo Electric Cooler, semiconductor refrigerator.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

The embodiment of the application provides an H-bridge driving circuit (hereinafter referred to as H-bridge driving circuit) with an over-temperature protection function, as shown in fig. 1 and 2, the H-bridge driving circuit includes a temperature detection circuit 3, a first driving chip 1, a second driving chip 2, a control signal adjusting circuit 4 and an H-bridge circuit 5.

The temperature detection circuit 3 has a temperature sensor P2, a temperature sensor P2 is provided on a heat generating component of the controlled appliance P1, and a temperature sensor P2 is used to detect the temperature of the controlled appliance P1.

The output end of the temperature detection circuit 3 is electrically connected with one signal input end of the control signal adjusting circuit 4, and the temperature detection circuit 3 is used for outputting a corresponding temperature control signal according to the temperature information detected by the temperature sensor P2.

And the signal output end of the control signal adjusting circuit 4 is electrically connected with the signal input end of the first driving chip 1 and the signal input end of the second driving chip 2 respectively. The control signal adjusting circuit 4 is used for outputting a switch control signal according to the temperature control signal and at least one other signal.

And the signal output end of the first driving chip 1 and the signal output end of the second driving chip 2 are respectively and electrically connected with the upper bridge arm and the lower bridge arm of the H-bridge circuit 5 and are used for controlling the on-off of the switching devices in the upper bridge arm and the lower bridge arm according to the switching control signals.

And the output end of the upper bridge arm and the output end of the lower bridge arm are used for being electrically connected with a controlled electric appliance P1 and supplying power to the controlled electric appliance P1.

In the H-bridge driving circuit with the over-temperature protection function provided in the embodiment of the present application, the temperature detection circuit 3 employs the temperature sensor P2, as shown in fig. 3, the temperature sensor P2 is closely attached to the controlled electrical appliance P1, the temperature sensor P2 can detect the temperature of the controlled device P1 and feed back the voltage corresponding to the temperature, the temperature detection circuit 3 compares the voltage fed back by the temperature sensor P2 with the expected protection temperature voltage to obtain a corresponding control signal, and controls the on and off of the H-bridge circuit 5, thereby achieving the expected over-temperature protection function.

The working process of the H-bridge driving circuit with the over-temperature protection function provided in the embodiment of the present application will be further described in the following embodiments.

In one embodiment of the present application, the temperature detection circuit 3 further includes a first resistor, a second resistor, a third resistor, and a first comparator. The first resistor is connected in series with the temperature sensor P2; the series node of the first resistor and the temperature sensor P2 is electrically connected to the first signal input terminal of the first comparator. The second resistor is connected with the third resistor in series; and the serial node of the second resistor and the third resistor is electrically connected with the second signal input end of the first comparator. The signal output end of the first comparator is used as the output end of the temperature detection circuit 3 and is electrically connected with one signal input end of the control signal adjusting circuit 4.

Taking fig. 1 as an example, the first resistor is a resistor R9, the second resistor is a resistor R14, the third resistor is a resistor R15, and the first comparator is a comparator U6. One end of the resistor R9 is electrically connected to the voltage terminal VREF, the other end of the resistor R9 is electrically connected to one end of the temperature sensor P2, and the other end of the temperature sensor P2 is electrically connected to the reference voltage terminal GND. One end of the resistor R14 is electrically connected to the voltage terminal VREF, the other end of the resistor R14 is electrically connected to one end of the resistor R15, and the other end of the resistor R15 is electrically connected to the reference voltage terminal GND.

The voltage input terminal of the comparator U6 is electrically connected to a power supply terminal, and for example, in fig. 1, the voltage input terminal of the comparator U6 is electrically connected to a power supply terminal VCC with a voltage of 3.3V. The voltage output terminal of the comparator U6 is electrically connected to the reference voltage terminal.

It should be noted that the two voltage terminals VREF in the drawings may refer to the same voltage terminal or may refer to two independent voltage terminals. The voltage value of the voltage terminal VREF may depend on the actual design requirement, for example, the voltage value of the voltage terminal VREF may be 2.5V.

Alternatively, the reference voltage terminals GND in the drawings may be the same voltage terminal or may be independent voltage terminals. The voltage value of the reference voltage terminal GND may be determined according to actual design requirements, for example, the reference voltage terminal GND may be a ground terminal.

Optionally, the temperature sensor P2 is a platinum thermistor (PT 1000). Of course, the temperature sensor P2 can be other types of temperature sensors capable of feeding back the temperature of the controlled appliance.

In one embodiment of the present application, the temperature detection circuit 3 further includes a fourth resistor and a fifth resistor. The series node of the first resistor and the temperature sensor P2 is electrically connected to the first signal input terminal of the first comparator through a fourth resistor. And a series node of the second resistor and the third resistor is electrically connected with the second signal input end of the first comparator through a fifth resistor.

Taking fig. 1 as an example, the fourth resistor is a resistor R11, and the fifth resistor is a resistor R13. A series node of the resistor R9 and the temperature sensor P2 is electrically connected to a first input terminal (one terminal denoted by a symbol —) of the comparator U6 through a resistor R11; the series node of the resistor R14 and the resistor R15 is electrically connected to the second input terminal (the terminal indicated by the symbol +) of the comparator U6 through the resistor R13.

In one embodiment of the present application, the temperature detection circuit 3 further includes a capacitor C7, a capacitor C8, and a resistor R10. One end of the capacitor C7 is electrically connected to the voltage input terminal of the comparator U6, and the other end of the capacitor C7 is electrically connected to the reference voltage terminal GND. One end of the capacitor C8 is electrically connected to the signal output terminal of the first comparator, and the other end of the capacitor C8 is electrically connected to the reference voltage terminal GND. One end of the resistor R10 is electrically connected to a power supply terminal, and taking fig. 1 as an example, one end of the resistor R10 is electrically connected to a power supply terminal VCC with a voltage of 3.3V; the other end of the resistor R10 is electrically connected to the signal output terminal of the first comparator.

In the temperature detection circuit 3, when the temperature of the controlled electric appliance P1 exceeds the threshold temperature, the signal output end of the comparator U6 outputs low level to the control signal adjusting circuit 4; when the temperature of the controlled electric appliance P1 does not exceed the threshold temperature, the signal output end of the comparator U6 outputs a high level to the control signal adjusting circuit 4.

Taking the voltage values, the resistance values and the capacitance values shown in fig. 1 as examples, when the voltage at the second signal input terminal of the comparator U6 is greater than the voltage at the first signal input terminal of the comparator U6, the signal output terminal of the comparator U6 outputs a high level of 3.3V, otherwise outputs a low level of 0V.

Assuming that the threshold temperature of the controlled appliance P1 is 120 ℃, when the controlled appliance P1 reaches the threshold temperature, the temperature of the temperature sensor P2 is 119.3 ℃, and the resistance value of the temperature sensor P2 is 1460.68 omega. The resistance of the resistor R9 is 10K omega, and the resistance of the resistor R14 is 24K omega, the resistance of the resistor R15 is 3.5K omega, and the voltage V at the first signal input terminal of the comparator U6_in-0.318129V, the voltage V of the second signal input terminal of the comparator U6_in+0.318182V, the voltage at the first signal input terminal and the voltage at the second signal input terminal of the comparator U6 can be considered to be equal; when the temperature of the controlled electric appliance P1 is more than 120 ℃ so that the temperature of the temperature sensor P2 is more than 119.3 ℃, the voltage of the first signal input end of the comparator U6 is more than that of the second signal input end; when the temperature of the controlled appliance P1 is less than 120 ℃ resulting in the temperature of the temperature sensor P2 being less than 119.3 ℃, the voltage of the first signal input terminal of the comparator U6 is less than the voltage of the second signal input terminal.

According to the principle of the comparator U6, when the temperature of the temperature sensor P2 is less than 119.3 ℃, the voltage V of the first signal input end of the comparator U6_in-Less than the voltage V of the input terminal_in+The signal output end of the comparator U6 outputs a high level of 3.3V; when the temperature of the temperature sensor P2 is higher than 119.3 ℃, the voltage V of the first signal input end of the comparator U6_in-Greater than the voltage V at the input end_in+And the signal output end of the comparator U6 outputs a low level 0V.

In one embodiment of the present application, the control signal conditioning circuit 4 includes first to fourth nand gate chips, and a first and gate chip U5. The at least one other signal includes a first type of switch control signal and a second type of switch control signal.

Fig. 5 shows a schematic diagram of signal end relationships of the first nand chip U1A, the second nand chip U1B, the third nand chip U1C and the fourth nand chip U1D, where the a1 end is a first input end of the nand chip, the B1 end is a second input end of the nand chip, and the Y1 end is an output end of the nand chip. The first voltage terminal may be a power supply terminal VCC of fig. 1 with a voltage of 3.3V.

Alternatively, the model of the four nand gate chips may be 74hc 00. Of course, the nand gate chip can be in other types. In the nand gate chip, when the input signals at the a1 terminal and the B1 terminal are both high, the output signal at the Y1 terminal is low; otherwise, the output signal at the terminal Y1 is high.

Fig. 6 shows a schematic diagram of the signal end relationship of the first and chip U5, in which an a end is a first input end of the first and chip U5, a B end is a second input end of the first and chip U5, and a Y end is an output end of the first and chip U5. As will be understood by those skilled in the art, in the first and gate chip U5, when the input signals at the a terminal and the B terminal are both high, the output signal at the Y terminal is high; otherwise, the output signal at the Y terminal is at a low level.

Taking fig. 1 and fig. 2 as an example, the first driver chip 1 is a driver chip U2. The first signal input end of the first driver chip 1 is the IN end of the driver chip U2; the second signal input terminal of the first driver chip 1 is the SD terminal of the driver chip U2. The second driver chip 2 is a driver chip U3. The first signal input end of the second driver chip 2 is the IN end of the driver chip U3; the second signal input terminal of the second driver chip 2 is the SD terminal of the driver chip U3.

It should be noted that the first type of switching control signal is a MODE signal, and the second type of switching control signal is a PWM signal. If the controlled electrical device P1 is a TEC (semiconductor cooler), the first type of switch control signal is a TEC _ MODE signal, and the second type of switch control signal is a TEC _ PWM signal.

The first input end of the first nand gate chip U1A is electrically connected to a first voltage end, the second input end of the first nand gate chip U1A is used for receiving a first switch control signal, and the output end of the first nand gate chip U1A is electrically connected to the first input end of the third nand gate chip U1C.

A first input end and a second input end of the second nand gate chip U1B are respectively used for receiving a first switch control signal and a second switch control signal; the output end of the second nand gate chip U1B is electrically connected to the second input end of the fourth nand gate chip U1D and the first signal input end (IN end) of the second driver chip 2, respectively.

A second input end of the third nand gate chip U1C is used for receiving a second type of switch control signal; the output end of the third nand gate chip U1C is electrically connected to the first input end of the fourth nand gate chip U1D and the first signal input end (IN end) of the first driver chip 1, respectively.

The output end of the fourth nand gate chip U1D and the output end of the temperature detection circuit 3 are electrically connected to the first input end and the second input end of the first and gate chip U5, respectively. The output end of the first and gate chip U5 is electrically connected to the second signal input end (SD end) of the first driver chip 1 and the second signal input end (SD end) of the second driver chip 2, respectively.

The inventor of the present application has also found that in the existing H-bridge driving circuit, the driving voltage of the switching device in the H-bridge circuit 5 is provided by a bootstrap circuit composed of a driving chip, a diode and a capacitor. The first end of a diode in the bootstrap circuit is electrically connected with a preset voltage end, the first end of the diode and the first end of a capacitor are electrically connected with a voltage input end of the driving chip, and the first end of the capacitor is electrically connected with a series node of the two switching devices. When the bootstrap circuit in the above form supplies a driving voltage to the switching device, it is necessary to set a charging and discharging time, so that a duty ratio of a PWM (pulse width modulation) signal received by the driving chip cannot reach 100%, and the diode cannot be continuously charged; moreover, the frequency of the PWM signal needs to be matched with the bootstrap circuit, and if the duty ratio is too high when the frequency is low, the capacitor discharge is easily completed, and the switching device is turned off.

For the above reasons, in one embodiment of the present application, the H-bridge driver circuit further includes a voltage stabilization output circuit 6. The output end of the voltage stabilizing output circuit 6 is electrically connected with the first voltage input end of the first driving chip 1 and the first voltage input end of the second driving chip 2 respectively, and is used for providing stable preset voltage.

In the H-bridge driving circuit with the over-temperature protection function provided in the embodiment of the present application, the first driving chip 1 and the second driving chip 2 may receive a switching control signal sent by the control signal adjusting circuit 4, where the switching control signal includes a PWM signal. The voltage stabilizing output circuit 6 replaces the function of the existing bootstrap circuit, because the output end of the voltage stabilizing output circuit 6 is only electrically connected with the first voltage input end of the first driving chip 1 and the first voltage input end of the second driving chip 2, under the condition that the temperature of the controlled electric appliance P1 does not exceed the threshold temperature, the voltage stabilizing output circuit 6 can provide stable preset voltage for the first driving chip 1 and the second driving chip 2, so that the limitation of the existing bootstrap circuit on the on and off of the switching device is avoided, the H-bridge circuit 5 can be controlled by any duty ratio and any frequency PWM signal, when the H-bridge circuit 5 is driven by the PWM signal with 100% duty ratio, the power of the controlled electric appliance P1 can be rapidly increased, and when the H-bridge circuit 5 is driven by the PWM signal with low frequency (less than or equal to 1Hz), the service life of the controlled electric appliance P1 can be prevented from being affected. Moreover, compared with the mode of a bootstrap circuit, the connection mode of the voltage stabilization output circuit 6 and the driving chip is simpler.

In addition, the temperature detection circuit 3 is not necessarily electrically connected to the driver chips (the first driver chip 1 and the second driver chip 2), but is directly electrically connected to the control signal adjustment circuit 4. The temperature detection circuit 3 can output a corresponding temperature control signal to the voltage stabilization output circuit 6 according to the temperature information detected by the temperature sensor P2, and the control signal adjusting circuit 4 can output a switch control signal according to the temperature control signal and at least one other signal, so as to control the on-off of a switch device in the H-bridge circuit 5, and realize the over-temperature protection function of the controlled electric appliance P1. The connection mode of the temperature detection circuit 3 and the driving chip does not need to greatly change the original H-bridge driving circuit, and meanwhile, the complexity of the algorithm of the driving chip is simplified.

To sum up, the H bridge drive circuit that can realize overtemperature protection that this application provided need not to do under the condition of great change to original H bridge drive circuit, both can avoid the restriction of current bootstrap circuit to switching device's switching on and turn-off effectively, can avoid again because of increasing the problem that the temperature detection module leads to the too complicated degree of driver chip algorithm, has compromise two at least actual demands.

In one embodiment of the present application, the regulated output circuit 6 is a boost circuit independent of the H-bridge circuit 5, a charge-discharge circuit independent of the H-bridge circuit 5, or a bootstrap circuit independent of the H-bridge circuit 5.

Alternatively, when the regulated output circuit 6 is a booster circuit independent of the H-bridge circuit 5, the regulated output circuit 6 includes a first driver, and a first inductor, a first diode, a sixth resistor, and a seventh resistor connected in series in this order.

the series node of the first diode and the sixth resistor is used as the output end of the voltage stabilization output circuit 6, and is electrically connected with the first voltage input end of the first driving chip 1 and the first voltage input end of the second driving chip 2 respectively.

Taking the first driver shown in fig. 4 as an example, the first terminal of the first driver is the SHND terminal (i.e., the enable signal input terminal) of the driver U4, the second terminal of the first driver is the VIN terminal of the driver U4, the third terminal of the first driver is the SW terminal of the driver U4, and the fourth terminal of the first driver is the FB terminal of the driver U4. The SHND terminal and the VIN terminal of the driver U4 are electrically connected to a 3.3V power supply.

The driver U4 in fig. 4 is model AP 3015. Of course, other types of boost chips can be used for the driver U4, provided that the function of the driver U4 can be satisfied.

The first inductor is inductor L1, the first diode is diode D5, the sixth resistor is resistor R7, and the seventh resistor is resistor R8. One end of an inductor L1 is electrically connected with a 3.3V power supply, the other end of the inductor L1 is electrically connected with the positive electrode end of a diode D5, the negative electrode end of a diode D5 is electrically connected with one end of a resistor R7, the other end of a resistor R7 is electrically connected with one end of a resistor R8, and the other end of a resistor R8 is electrically connected with the 3.3V power supply. A series node of the diode D5 and the resistor R7, which is an output terminal of the voltage regulator output circuit 6, is electrically connected to the first voltage input terminal of the first driver chip 1 and the first voltage input terminal of the second driver chip 2, respectively.

Optionally, the regulated output circuit 6 further includes a diode D4. The SHND terminal and the VIN terminal of the driver U4, and the other terminal of the resistor R8 are electrically connected to a 3.3V power supply through a diode D4. Specifically, the regulated output circuit 6 further includes a diode D4, and the positive terminal of the diode D4 is electrically connected to the 3.3V power supply. The SHND terminal and the VIN terminal of the driver U4, and the other terminal of the resistor R8 are electrically connected to the negative terminal of the diode D4.

Optionally, the regulated output circuit 6 further includes a capacitor C4. The other end of the resistor R8 is electrically connected to a 3.3V power supply via a capacitor C4 and a diode D4 in this order. Specifically, the other end of the resistor R8 is electrically connected to one end of the capacitor C4, and the other end of the capacitor C4 is electrically connected to the negative terminal of the diode D4.

Optionally, the regulated output circuit 6 further includes a capacitor C5. One end of the capacitor C5 is electrically connected to a series node of the diode D5 and the resistor R7; the other end of the capacitor C5 is electrically connected to the other end of the resistor R8.

It should be noted that the voltage stabilizing output circuit 6 may also have other structures on the premise that the preset voltage capable of being stably output is satisfied. When the voltage stabilization output circuit 6 is a charge and discharge circuit independent of the H-bridge circuit 5 or a bootstrap circuit independent of the H-bridge circuit 5, on the premise that a stable preset voltage can be output, the present application does not limit the specific structures of the charge and discharge circuit and the bootstrap circuit.

In one embodiment of the present application, the signal output terminal of the first driving chip 1 includes a first signal output terminal, a second signal output terminal, and a floating power supply bias terminal, the upper bridge arm includes a first switching device Q1 and a second switching device Q2, and a second terminal of the first switching device Q1 is connected in series with a first terminal of the second switching device Q2.

The first signal output end of the first driver chip 1 is electrically connected to the control end of the first switching device Q1, the floating power bias end of the first driver chip 1 is electrically connected to the series node of the first switching device Q1 and the second switching device Q2, and the second signal output end of the first driver chip 1 is electrically connected to the control end of the second switching device Q2.

Alternatively, the first switching device Q1 and the second switching device Q2 may be at least one of a triode, a MOS transistor, and an IGBT transistor. In fig. 1 and 2, the first switching device Q1 and the second switching device Q2 are both N-channel MOS transistors.

The control terminal of the first switching device Q1 is the gate of the N-channel MOS transistor, the first terminal of the first switching device Q1 is the drain of the N-channel MOS transistor, and the second terminal of the first switching device Q1 is the source of the N-channel MOS transistor.

The control terminal of the second switching device Q2 is the gate of the N-channel MOS transistor, the first terminal of the second switching device Q2 is the drain of the N-channel MOS transistor, and the second terminal of the second switching device Q2 is the source of the N-channel MOS transistor.

A first terminal of the first switching device Q1 is electrically connected to a power supply terminal having a voltage of 24V; a second terminal of the first switching device Q1 is electrically connected to a first terminal of the second switching device Q2 as a series node of the first switching device Q1 and the second switching device Q2; a second terminal of the second switching device Q2 is electrically connected to the reference voltage terminal GND.

Taking fig. 1 and fig. 2 as an example, the first driver chip 1 is a driver chip U2. The driver chip U2 is a half bridge driver chip model IR 2104. Of course, on the premise that the function of the driver chip U2 can be satisfied, the driver chip U2 may also be a half-bridge driver chip of another type. The first voltage input end of the first driver chip 1 is the VB end of the driver chip U2; the first signal output end of the first driver chip 1 is the HO end of the driver chip U2; the floating power supply bias end of the first driving chip 1 is the VS end of the driving chip U2; the second signal output terminal of the first driver chip 1 is the LO terminal of the driver chip U2.

The VB terminal of the driving chip U2 is electrically connected to the output terminal of the regulated output circuit 6. Optionally, the H-bridge driver circuit further includes a resistor R2. The VB terminal of the driver chip U2 is electrically connected to the output terminal of the regulator output circuit 6 through a resistor R2.

The HO terminal of the driver chip U2 is electrically connected to the control terminal of the first switching device Q1. Optionally, the H-bridge driver circuit further includes a resistor R1. The HO terminal of the driver chip U2 is electrically connected to the control terminal of the first switching device Q1 through a resistor R1.

The VS terminal of the driving chip U2 is electrically connected to the series node of the first switching device Q1 and the second switching device Q2.

The LO terminal of the driver chip U2 is electrically connected to the control terminal of the second switching device Q2. Optionally, the H-bridge driver circuit further includes a resistor R3. The LO terminal of the driver chip U2 is electrically connected to the control terminal of the second switching device Q2 through a resistor R3.

In one embodiment of the present application, the driver chip U2 further has a VCC terminal and a COM terminal. The VCC terminal of the driver chip U2 is electrically connected to a power supply with a voltage of 12V. The COM terminal of the driving chip U2 is electrically connected to the reference voltage terminal GND.

Optionally, the H-bridge driver circuit further comprises a capacitor C2. The VCC terminal of the driving chip U2 is also electrically connected to the reference voltage terminal GND through the capacitor C2.

In one embodiment of the present application, the H-bridge driving circuit further includes a first regulator tube D1, a positive terminal of the first regulator tube D1 is electrically connected to the second terminal of the first switching device Q1, and a negative terminal of the first regulator tube D1 is electrically connected to the control terminal of the first switching device Q1.

The first regulator tube D1 can ensure that the voltage Vgs between the control terminal and the second terminal of the first switching device Q1 does not exceed a threshold voltage (e.g., 12V), which acts to protect the first switching device Q1.

In one embodiment of the present application, the H-bridge driving circuit further includes a second regulator tube D2, a positive terminal of the second regulator tube D2 is electrically connected to the second terminal of the second switching device Q2, and a negative terminal of the second regulator tube D2 is electrically connected to the control terminal of the second switching device Q2.

In one embodiment of the present application, the signal output terminal of the second driving chip 2 includes a first signal output terminal, a second signal output terminal and a floating power supply bias terminal, the lower bridge arm includes a third switching device Q3 and a fourth switching device Q4, a second terminal of the third switching device Q3 is connected in series with a first terminal of the fourth switching device Q4;

the first signal output end of the second driver chip 2 is electrically connected to the control end of the third switching device Q3, the floating power bias end of the second driver chip 2 is electrically connected to the series node of the third switching device Q3 and the fourth switching device Q4, and the second signal output end of the second driver chip 2 is electrically connected to the control end of the fourth switching device Q4.

Alternatively, the third switching device Q3 and the fourth switching device Q4 may be at least one of a triode, a MOS transistor, and an IGBT transistor. The third switching device Q3 and the fourth switching device Q4 in fig. 1 and 2 are both N-channel MOS transistors.

The control end of the third switching device Q3 is the gate electrode of an N-channel MOS transistor, the first end of the third switching device Q3 is the drain electrode of the N-channel MOS transistor, and the second end of the third switching device Q3 is the source electrode of the N-channel MOS transistor.

The control end of the fourth switching device Q4 is the gate electrode of an N-channel MOS transistor, the first end of the fourth switching device Q4 is the drain electrode of the N-channel MOS transistor, and the second end of the fourth switching device Q4 is the source electrode of the N-channel MOS transistor.

A first terminal of the third switching device Q3 is electrically connected to a power supply terminal having a voltage of 24V; a second terminal of the third switching device Q3 is electrically connected to a first terminal of the fourth switching device Q4 as a series node of the third switching device Q3 and the fourth switching device Q4; a second terminal of the fourth switching device Q4 is electrically connected to the reference voltage terminal GND.

Taking fig. 1 and fig. 2 as an example, the second driver chip 2 is a driver chip U3. The driver chip U3 is a half bridge driver chip model IR 2104. Of course, on the premise that the function of the driver chip U3 can be satisfied, the driver chip U3 may also be a half-bridge driver chip of another type. The first voltage input end of the second driver chip 2 is the VB end of the driver chip U3; the first signal output end of the second driver chip 2 is the HO end of the driver chip U3; the floating power supply bias end of the second driving chip 2 is the VS end of the driving chip U3; the second signal output terminal of the second driver chip 2 is the LO terminal of the driver chip U3.

The VB terminal of the driving chip U3 is electrically connected to the output terminal of the regulated output circuit 6. Optionally, the H-bridge driver circuit further includes a resistor R5. The VB terminal of the driver chip U3 is electrically connected to the output terminal of the regulator output circuit 6 through a resistor R5.

The HO terminal of the driving chip U3 is electrically connected to the control terminal of the third switching device Q3. Optionally, the H-bridge driver circuit further includes a resistor R4. The HO terminal of the driver chip U3 is electrically connected to the control terminal of the third switching device Q3 through a resistor R4.

The VS terminal of the driving chip U3 is electrically connected to the series node of the third switching device Q3 and the fourth switching device Q4.

The LO terminal of the driver chip U3 is electrically connected to the control terminal of the fourth switching device Q4. Optionally, the H-bridge driver circuit further includes a resistor R6. The LO terminal of the driver chip U3 is electrically connected to the control terminal of the fourth switching device Q4 through a resistor R6.

In one embodiment of the present application, the driver chip U3 further has a VCC terminal and a COM terminal. The VCC terminal of the driver chip U3 is electrically connected to a power supply with a voltage of 12V. The COM terminal of the driving chip U3 is electrically connected to the reference voltage terminal GND.

Optionally, the H-bridge driver circuit further comprises a capacitor C3. The VCC terminal of the driving chip U3 is also electrically connected to the reference voltage terminal GND through the capacitor C3.

In one embodiment of the present application, the H-bridge driving circuit further includes a third regulator tube D3, a positive terminal of the third regulator tube D3 is electrically connected to the second terminal of the third switching device Q3, and a negative terminal of the third regulator tube D3 is electrically connected to the control terminal of the third switching device Q3.

In one embodiment of the present application, the H-bridge driving circuit further includes a fourth regulator tube D6, a positive terminal of the fourth regulator tube D6 is electrically connected to the second terminal of the fourth switching device Q4, and a negative terminal of the fourth regulator tube D6 is electrically connected to the control terminal of the fourth switching device Q4.

In one embodiment of the present application, as shown in fig. 1, the H-bridge driving circuit further includes a bypass circuit 7, and the bypass circuit 7 includes a second driver and a first capacitor.

The voltage input end of the second driver is electrically connected with the first end of the first capacitor and the first voltage end; the second end of the first capacitor is electrically connected with the reference voltage end, and the voltage of the reference voltage end is smaller than that of the first voltage end.

Taking fig. 1 as an example, the second driver is the driver U1E, and the voltage input terminal of the second driver is the VCC terminal of the driver U1E. The first capacitance is capacitance C1. The first voltage terminal is a power supply terminal VCC with a voltage of 3.3V.

In the embodiment of the application, the first capacitor can be used as a bypass capacitor, and can bypass the high-frequency signal to the reference voltage end GND, so that the high-frequency signal is prevented from entering each nand gate chip.

It should be noted that the structure and the operation principle of the driving chip U2 and the driving chip U3 are the same. Taking the driver chip U2 as an example, the internal structure of the driver chip U2 is shown in fig. 7. For convenience of description, a logic high level is represented by "1" and a logic low level is represented by "0".

The logical relationship between the input signal and the output signal at each end of the driver chip U2 can be represented by table 1.

SD	IN	HO	LO
				0	0	0, HO and VS conduction	0, LO is conducted with COM
0	1	0, HO and VS conduction	0, LO is conducted with COM
				1	0	0, HO and VS conduction	1, LO is conducted with VCC, i.e., +12V
1	1	1, HO is conducted with VB, i.e. +34V	0, LO is conducted with COM

TABLE 1

When the input of the SD end is 1, the driving chip U2 and the driving chip U4 work normally, the output of the HO end is consistent with the output of the IN end, and the output of the LO end is opposite to the output of the IN end; when the input of the SD terminal is 0, the driver chip U2 and the driver chip U4 are turned off, and the outputs of the HO terminal and the LO terminal are both 0, independent of the IN terminal. When the driving chip U2 outputs a high level, a power source terminal of 34V is connected to the control terminal of the first switching device Q1 through the resistor R2 and the resistor R1. At this time, the first regulator tube D1 may ensure that the voltage Vgs between the control terminal and the second terminal of the first switching device Q1 does not exceed a threshold voltage (e.g., 12V), which serves to protect the first switching device Q1. Of course, the third regulator tube D3 may also serve the same function as the third switching device Q3.

For the H-bridge circuit 5, those skilled in the art will appreciate that the first switching device Q1 and the fourth switching device Q4 may form one path, and the second switching device Q2 and the third switching device Q3 may form another path. The two paths may be off at the same time, or one of the paths may be off and the other on.

The two paths may not be simultaneously conductive. Specifically, in order to prevent two switching devices in the same bridge arm from being turned on simultaneously due to the switching control signal being inverted, a protection time (dead time) may be set. The driving chip U2 and the driving chip U3 can automatically control dead time, and thus it can be ensured that the first switching device Q1 and the second switching device Q2 (or the third switching device Q3 and the fourth switching device Q4) are not simultaneously turned on when the signal output from the IN terminal is inverted.

Based on the same inventive concept, the embodiment of the application also provides an electrical system. As shown in fig. 8, the electrical system includes a controlled appliance P1 and an H-bridge driving circuit with an over-temperature protection function provided in the above embodiments of the present application. In the H-bridge circuit 5 of the H-bridge drive circuit, the output end of the upper arm and the output end of the lower arm are electrically connected to the controlled electrical appliance P1, and are used for supplying power to the controlled electrical appliance P1. The temperature sensor P2 of the temperature detection circuit 3 in the H-bridge drive circuit is provided on a heat generating component of the controlled electric appliance P1.

The electrical system provided by the embodiment of the present application has the same inventive concept and the same advantages as the previous embodiments, and the contents not shown in detail in the electrical system may refer to the previous embodiments, and are not described herein again.

In one embodiment of the present application, the controlled appliance P1 includes a semiconductor cooler. In an H-bridge circuit 5 of the H-bridge driving circuit, the output end of an upper bridge arm is electrically connected with a first connecting end of a semiconductor refrigerator, and the output end of a lower bridge arm is electrically connected with a second connecting end of the semiconductor refrigerator.

When the H-bridge driving circuit with the over-temperature protection function is applied to an electrical system, the over-temperature protection function can be realized, and the over-low temperature protection function can be realized.

The significance of the over-high temperature protection function lies in that: the controlled electric appliance P1 is prevented from being damaged due to overhigh temperature.

It will be understood by those skilled in the art that under experimental conditions, when the temperature of the controlled appliance P1 is much lower than room temperature (e.g. the temperature of the controlled appliance P1 is less than 5 ℃), condensed water is formed on the surface of the controlled appliance P1, and the more condensed water is formed in the longer time, which increases the risk of damage to parts inside the product. The significance of the low temperature protection function is therefore: avoid the damage of the parts inside the product caused by the formation of more condensed water on the surface of the controlled electric appliance P1.

The threshold temperature of the controlled appliance P1 may be determined according to actual design needs. When the H-bridge driving circuit with the over-temperature protection function provided by the embodiment of the application is used for realizing the over-temperature protection function, the temperature of the electric controller P1 exceeds the threshold temperature, which indicates that the temperature of the controlled electric appliance P1 is higher than the threshold temperature; when the H-bridge driving circuit with the over-temperature protection function provided by the embodiment of the application is used for realizing the over-temperature protection function, the temperature of the electric controller P1 exceeds the threshold temperature, and the temperature of the controlled electric appliance P1 is lower than the threshold temperature.

For example, for an H-bridge driving circuit for implementing an over-temperature protection function, the threshold temperature of the controlled appliance P1 may be set to 120 ℃, when the temperature of the controlled appliance P1 is higher than 120 ℃, that is, it is determined that the temperature of the controlled appliance P1 exceeds the threshold temperature. For the H-bridge driving circuit for implementing the over-temperature protection function, the threshold temperature of the controlled appliance P1 may be set to 10 ℃, when the temperature of the controlled appliance P1 is lower than 10 ℃, that is, it is determined that the temperature of the controlled appliance P1 exceeds the threshold temperature.

The operation of the electrical system when the H-bridge driving circuit is used to implement the over-temperature protection function is briefly described as a specific example.

Assuming that the threshold temperature of the controlled appliance P1 is 120 ℃, when the controlled appliance P1 reaches the threshold temperature, the temperature of the temperature sensor P2 is 119.3 ℃, and the resistance value of the temperature sensor P2 is 1460.68 omega. The resistance of the resistor R9 is 10K omega, the resistance of the resistor R14 is 24K omega, the resistance of the resistor R15 is 3.5K omega, and the voltage V of the first signal input end of the comparator U6_in-0.318129V, the voltage V of the second signal input terminal of the comparator U6_in+0.318182V, the voltage at the first signal input terminal and the voltage at the second signal input terminal of the comparator U6 can be considered to be equal; when the temperature of the controlled electric appliance P1 is more than 120 ℃ so that the temperature of the temperature sensor P2 is more than 119.3 ℃, the voltage of the first signal input end of the comparator U6 is more than that of the second signal input end; when the temperature of the controlled appliance P1 is less than 120 ℃ resulting in the temperature of the temperature sensor P2 being less than 119.3 ℃, the voltage of the first signal input terminal of the comparator U6 is less than the voltage of the second signal input terminal.

Assume that the period of one TEC _ PWM signal is 1 second and the duty cycle is 50%. The first half period (first 0.5 seconds) of the TEC _ PWM signal is low 0 and the second half period (last 0.5 seconds) is high 1.

In the temperature detection circuit 3, when the temperature of the controlled electrical appliance P1 exceeds the threshold temperature, the signal output terminal of the comparator U6 outputs a low level 0 to the second input terminal of the first and gate chip U5; when the temperature of the controlled appliance P1 is lower than the threshold temperature, the signal output terminal of the comparator U6 outputs a high level 1 to the second input terminal of the first and chip U5.

When the TEC _ MODE signal is 0 and the temperature of the controlled appliance P1 is below the threshold temperature:

in the first half period of the TEC _ PWM signal, the first nand gate chip U1A, the second nand gate chip U1B, and the third nand gate chip U1C all output a high level 1, the fourth nand gate chip U1D outputs a low level 0, the signal output terminal of the comparator U6 outputs a high level 1 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a low level 0; the HO terminal and the LO terminal of the driver chip U2, and the HO terminal and the LO terminal of the driver chip U3 both output a low level of 0; the first switching device Q1, the second switching device Q2, the third switching device Q3, and the fourth switching device Q4 are all in an off state; the semiconductor refrigerator is in a non-working state, namely, not heated and not cooled.

In the second half period of the TEC _ PWM signal, the first nand gate chip U1A, the second nand gate chip U1B, and the fourth nand gate chip U1D all output a high level 1, the third nand gate chip U1C outputs a low level 0, the signal output terminal of the comparator U6 outputs a high level 1 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a high level 1; the HO end of the driver chip U2 outputs a low level 0, the LO end of the driver chip U2 outputs a high level 1, the HO end of the driver chip U3 outputs a high level 1, and the LO end of the driver chip U3 outputs a low level 0; the first switching device Q1 and the fourth switching device Q4 are both in an off state, and the second switching device Q2 and the third switching device Q3 are in an on state; the semiconductor refrigerator heats.

Therefore, when the TEC _ MODE signal is 0, the duration of the cooling time of the semiconductor refrigerator can be controlled only by adjusting the duty ratio of the TEC _ PWM signal, so as to achieve the purpose of accurate cooling. When the temperature of the controlled electric appliance P1 is lower than the threshold temperature, the temperature detection circuit 3 does not affect the signal output of the driver chip U2 and the driver chip U3, i.e., does not affect the on and off of each switching device in the H-bridge circuit.

When the TEC _ MODE signal is 0 and the temperature of the controlled appliance P1 is above the threshold temperature:

in the first half period of the TEC _ PWM signal, the first nand gate chip U1A, the second nand gate chip U1B, and the third nand gate chip U1C all output a high level 1, the fourth nand gate chip U1D outputs a low level 0, the signal output terminal of the comparator U6 outputs a low level 0 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a low level 0; the HO terminal and the LO terminal of the driver chip U2, and the HO terminal and the LO terminal of the driver chip U3 both output a low level of 0; the first switching device Q1, the second switching device Q2, the third switching device Q3, and the fourth switching device Q4 are all in an off state; the semiconductor refrigerator is in a non-working state, namely, not heated and not cooled.

In the second half period of the TEC _ PWM signal, the first nand gate chip U1A, the second nand gate chip U1B, and the fourth nand gate chip U1D all output a high level 1, the third nand gate chip U1C outputs a low level 0, the signal output terminal of the comparator U6 outputs a low level 0 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a low level 0; the HO terminal and the LO terminal of the driver chip U2, and the HO terminal and the LO terminal of the driver chip U3 both output a low level of 0; the first switching device Q1, the second switching device Q2, the third switching device Q3, and the fourth switching device Q4 are all in an off state; the semiconductor refrigerator is in a non-working state, namely, not heated and not cooled.

Therefore, when the temperature of the controlled electric appliance P1 is higher than the threshold temperature, the temperature detection circuit 3 may affect the signal output of the driving chip U2 and the driving chip U3, so as to affect the turn-off of each switching device in the H-bridge circuit, avoid the controlled electric appliance P1 from continuing to heat up, and protect the controlled electric appliance P1 from being damaged.

When TEC _ MODE is 1, the controlled appliance P1 cannot heat, and can only stop working or cool, the temperature of the controlled appliance P1 is necessarily lower than the threshold temperature, specifically:

in the first half period of the TEC _ PWM signal, both the first nand gate chip U1A and the fourth nand gate chip U1D output a low level 0, both the second nand gate chip U1B and the third nand gate chip U1C output a high level 1, the signal output terminal of the comparator U6 outputs a high level 1 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a low level 0; the HO terminal and the LO terminal of the driver chip U2, and the HO terminal and the LO terminal of the driver chip U3 both output a low level of 0; the first switching device Q1, the second switching device Q2, the third switching device Q3, and the fourth switching device Q4 are all in an off state; the semiconductor refrigerator is in a non-working state, namely, not heated and not cooled.

In the second half period of the TEC _ PWM signal, the first nand gate chip U1A and the second nand gate chip U1B both output a low level 0, the third nand gate chip U1C and the fourth nand gate chip U1D both output a high level 1, the signal output terminal of the comparator U6 outputs a high level 1 to the second input terminal of the first and gate chip U5, and the first and gate chip U5 outputs a high level 1; the HO end of the driver chip U2 outputs high level 1, the LO end of the driver chip U2 outputs low level 0, the HO end of the driver chip U3 outputs low level 0, and the LO end of the driver chip U3 outputs high level 1; the first switching device Q1 and the fourth switching device Q4 are both in an on state, and the second switching device Q2 and the third switching device Q3 are in an off state; the semiconductor refrigerator cools.

Therefore, when the TEC _ MODE signal is 1, the cooling time of the semiconductor refrigerator can be controlled only by adjusting the duty ratio of the TEC _ PWM signal, so as to achieve the purpose of accurate cooling. When the temperature of the controlled electric appliance P1 is lower than the threshold temperature, the temperature detection circuit 3 does not affect the signal output of the driver chip U2 and the driver chip U3, i.e., does not affect the on and off of each switching device in the H-bridge circuit.

It can be understood by those skilled in the art that when the H-bridge driving circuit is used to implement the over-temperature protection function, the operation of the electrical system is similar to the above-mentioned process, and will not be described herein again.

In the electrical system provided by the embodiment of the application, the first driving chip 1 and the second driving chip 2 may receive the switching control signal sent by the control signal adjusting circuit 4, where the switching control signal includes a PWM signal. The voltage stabilizing output circuit 6 replaces the function of the existing bootstrap circuit, because the output end of the voltage stabilizing output circuit 6 is only electrically connected with the first voltage input end of the first driving chip 1 and the first voltage input end of the second driving chip 2, under the condition that the temperature of the controlled electric appliance P1 does not exceed the threshold temperature, the voltage stabilizing output circuit 6 can provide a stable preset voltage to the first driving chip 1 and the second driving chip 2, which avoids the limitation of the existing bootstrap circuit on the on and off of the switching device, thereby realizing that the H-bridge circuit 5 can be controlled by PWM signals with any duty ratio and any frequency, when the H-bridge circuit 5 is driven by the PWM signals with 100 percent duty ratio, the power of the controlled electric appliance P1 can be rapidly increased, and when the H bridge circuit 5 is driven by the low-frequency (less than or equal to 1Hz) PWM signal, the service life of the controlled electric appliance P1 can be prevented from being influenced. Moreover, compared with the mode of a bootstrap circuit, the connection mode of the voltage stabilization output circuit 6 and the driving chip is simpler.

It should be noted that the voltage value, the resistance value, the capacitance value, and the like referred to in the above description and the drawings of the specification may be modified to other values according to actual needs, and the present application does not limit the voltage value and the capacitance value.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.

Claims

1. An H-bridge drive circuit with an over-temperature protection function is characterized by comprising a temperature detection circuit, a first drive chip, a second drive chip, a control signal regulation circuit, an H-bridge circuit and a voltage stabilization output circuit;

the temperature detection circuit is provided with a temperature sensor which is arranged on a heating component of the controlled electric appliance and is used for detecting the temperature of the controlled electric appliance; the output end of the temperature detection circuit is electrically connected with one signal input end of the control signal regulating circuit, and the temperature detection circuit is used for outputting a corresponding temperature control signal according to the temperature information detected by the temperature sensor;

the signal output end of the first driving chip and the signal output end of the second driving chip are respectively and electrically connected with an upper bridge arm and a lower bridge arm of the H-bridge circuit and are used for controlling the on-off of switching devices in the upper bridge arm and the lower bridge arm according to the switching control signals;

2. The H-bridge driver circuit of claim 1, wherein the temperature detection circuit further comprises a first resistor, a second resistor, a third resistor, and a first comparator;

the first resistor is connected with the temperature sensor in series; a series node of the first resistor and the temperature sensor is electrically connected with a first signal input end of the first comparator;

the second resistor is connected with the third resistor in series; a series node of the second resistor and the third resistor is electrically connected with a second signal input end of the first comparator;

and the signal output end of the first comparator is used as the output end of the temperature detection circuit and is electrically connected with one signal input end of the control signal regulating circuit.

3. The H-bridge driver circuit of claim 2, wherein the temperature detection circuit further comprises a fourth resistor and a fifth resistor;

the serial node of the first resistor and the temperature sensor is electrically connected with the first signal input end of the first comparator through the fourth resistor;

and a series node of the second resistor and the third resistor is electrically connected with a second signal input end of the first comparator through the fifth resistor.

4. The H-bridge driving circuit according to any one of claims 1 to 3, wherein the control signal conditioning circuit comprises first to fourth NAND gate chips, and a first AND gate chip; the at least one other signal comprises a first type of switch control signal and a second type of switch control signal;

the first input end of the first NAND gate chip is electrically connected with a first voltage end, the second input end of the first NAND gate chip is used for receiving a first switch control signal, and the output end of the first NAND gate chip is electrically connected with the first input end of the third NAND gate chip;

the first input end and the second input end of the second NAND gate chip are respectively used for receiving a first switch control signal and a second switch control signal; the output end of the second nand gate chip is electrically connected with the second input end of the fourth nand gate chip and the first signal input end of the second driver chip respectively;

the output end of the fourth NAND gate chip and the output end of the temperature detection circuit are respectively and electrically connected with the first input end and the second input end of the first AND gate chip; and the output end of the first AND gate chip is electrically connected with the second signal input end of the first driving chip and the second signal input end of the second driving chip respectively.

5. The H-bridge driver circuit of claim 1, wherein the regulated output circuit is a boost circuit independent of the H-bridge circuit, a charge-discharge circuit independent of the H-bridge circuit, or a bootstrap circuit independent of the H-bridge circuit.

6. The H-bridge driving circuit according to claim 5, wherein the voltage stabilization output circuit comprises a first driver, and a first inductor, a first diode, a sixth resistor and a seventh resistor which are connected in series in sequence;

the first end and the second end of the first driver, one end of the first inductor and one end of the seventh resistor are connected with a power supply; the third end of the first driver is electrically connected with the series node of the first inductor and the first diode; a fourth terminal of the first driver electrically connected to a series node of the sixth resistor and the seventh resistor;

7. The H-bridge driving circuit according to any one of claims 1 to 3, wherein the signal output end of the first driving chip comprises a first signal output end, a second signal output end and a floating power supply bias end, the upper bridge arm comprises a first switching device and a second switching device, and a second end of the first switching device is connected in series with a first end of the second switching device;

the first signal output end of the first driving chip is electrically connected with the control end of the first switch device, the floating power supply bias end of the first driving chip is electrically connected with the series node of the first switch device and the second switch device, and the second signal output end of the first driving chip is electrically connected with the control end of the second switch device.

8. The H-bridge driving circuit according to claim 7, further comprising a first voltage regulator tube, wherein a positive terminal of the first voltage regulator tube is electrically connected with the second terminal of the first switching device, and a negative terminal of the first voltage regulator tube is electrically connected with the control terminal of the first switching device.

9. The H-bridge driving circuit according to claim 7, further comprising a second voltage regulator tube, wherein a positive terminal of the second voltage regulator tube is electrically connected with the second terminal of the second switching device, and a negative terminal of the second voltage regulator tube is electrically connected with the control terminal of the second switching device.

10. The H-bridge driving circuit according to any one of claims 1 to 3, wherein the signal output end of the second driving chip comprises a first signal output end, a second signal output end and a floating power supply bias end, the lower bridge arm comprises a third switching device and a fourth switching device, and a second end of the third switching device is connected with a first end of the fourth switching device in series;

11. The H-bridge driving circuit according to claim 10, further comprising a third regulator tube, wherein a positive terminal of the third regulator tube is electrically connected to the second terminal of the third switching device, and a negative terminal of the third regulator tube is electrically connected to the control terminal of the third switching device.

12. The H-bridge driving circuit according to claim 10, further comprising a fourth regulator tube, wherein a positive terminal of the fourth regulator tube is electrically connected to the second terminal of the fourth switching device, and a negative terminal of the fourth regulator tube is electrically connected to the control terminal of the fourth switching device.

13. The H-bridge driver circuit of any of claims 1 to 3, further comprising a bypass circuit comprising a second driver and a first capacitance;

a voltage input end of the second driver and a first end of the first capacitor are electrically connected with the first voltage end; the second end of the first capacitor is electrically connected with a reference voltage end, and the voltage of the reference voltage end is smaller than that of the first voltage end.

14. An electrical system comprising a controlled appliance and an H-bridge drive circuit with over-temperature protection as claimed in any one of claims 1 to 13;

and the temperature sensor of the temperature detection circuit in the H-bridge drive circuit is arranged on a heating component of the controlled electric appliance.

15. The electrical system of claim 14, wherein the controlled appliance comprises a semiconductor refrigerator;

in the H-bridge circuit of the H-bridge driving circuit, the output end of an upper bridge arm is electrically connected with a first connecting end of the semiconductor refrigerator, and the output end of a lower bridge arm is electrically connected with a second connecting end of the semiconductor refrigerator.