Integrated chip, system for driving PDLC (polymer dispersed liquid crystal) dimming film by inverter and automobile

Abstract

The invention provides an integrated chip, a system for driving a PDLC (polymer dispersed liquid crystal) dimming film by an inverter and an automobile, one integrated chip is connected between each PDLC dimming film and the inverter and is integrated with a first switch unit, a first end of the first switch unit is connected with a first input pin, a second end of the first switch unit is connected with an output pin, and a second end of the first switch unit is connected with a second input pin; the first output end of the inverter is connected with the first input pin, and the PDLC dimming film is connected with the output pin and the second output end of the inverter; and the control unit controls the first switch unit to be switched on to enable the PDLC dimming film to be connected with the inverter, or controls the first switch unit to be switched off to enable the PDLC dimming film to be disconnected from the inverter. According to the integrated chip provided by the invention, independent connection and independent control between each PDLC dimming film and the inverter are realized, and the production cost is reduced. Meanwhile, open circuit detection, over-current detection and over-temperature detection are carried out on each PDLC dimming film, and fault information is fed back to the system, so that the reliability of the system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of power supply, and in particular relates to a system for driving a PDLC dimming film using an integrated chip and an inverter, and a car. Background Art

[0002] With the development of automobile intelligence, various parts on the car are also developing in the direction of intelligence. For example, dimming glass, smart seats, air suspension, laser radar, etc. Taking dimming glass as an example, the principle is to install a layer of liquid crystal dimming film (PDLC) between the glass. When the power is on, the polymer liquid crystal material in the liquid crystal dimming film is arranged in an orderly manner, and the glass becomes transparent, while the glass becomes frosted when the power is off. Among them, in order to increase the service life of the PDLC dimming film, it is necessary to avoid the PDLC dimming film working under DC voltage, that is, it is necessary to provide AC voltage to the PDLC dimming film.

[0003] In the existing inverter-driven PDLC dimming film system, the driving circuit controls the inverter circuit to provide the PDLC dimming film with an operating voltage. If it is necessary to control multiple PDLC dimming films at the same time, it is necessary to increase the inverter circuit and the corresponding driving circuit by multiple times, which will lead to an increase in production costs. In view of the above problems, those skilled in the art can easily think of a solution of using discrete devices to connect the inverter and the multiple PDLC dimming films to reduce production costs. However, during the operation of the PDLC dimming film, it is necessary to set up multiple functional circuits for the discrete devices for open circuit detection, overcurrent protection, etc. Therefore, in the solution of using discrete devices to connect the inverter and the multiple PDLC dimming films, it is necessary to integrate the discrete devices constituting each functional circuit separately, and to meet the normal communication between each integrated chip during operation, which will increase the complexity of the solution and increase the production cost. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a system and a car that integrates a chip and an inverter to drive a PDLC dimming film, wherein:

[0005] An integrated chip is applied to a system where an inverter drives a PDLC dimming film. An integrated chip is connected between each PDLC dimming film and the inverter. The integrated chip is integrated with:

[0006] a first switch unit, wherein a first end of the first switch unit is connected to a first input pin, and a second end of the first switch unit is connected to an output pin,

[0007] The first output end of the inverter is connected to the first input pin, and the PDLC dimming film is connected to the output pin and the second output end of the inverter.

[0008] A control unit controls the first switch unit to be turned on or off, so as to control the connection state between the PDLC dimming film and the inverter.

[0009] Furthermore, the integrated chip is also integrated with:

[0010] a second switch unit, wherein a first end of the second switch unit is connected to the output pin, a second end of the second switch unit is connected to a second input pin, and a second output end of the inverter is connected to the second input pin,

[0011] The control unit controls the first switch unit and the second switch unit to be turned on or off, so as to control the connection state between the PDLC dimming film and the inverter.

[0012] Furthermore, the integrated chip is also provided with:

[0013] An open circuit detection circuit generates an open circuit signal according to the integral signal and the first reference signal, wherein the open circuit signal indicates that the PDLC dimming film and the inverter are in an open circuit state, and the integral signal indicates the integral of the current of the first switch unit;

[0014] An error reporting unit, the output end of which is connected to an error reporting pin, and the control unit controls the error reporting unit to output a first error reporting signal to the system through the error reporting pin according to the open circuit signal.

[0015] Further, the open circuit detection circuit generates the integral signal according to the current of the first switch unit within a first range, and the control unit adjusts the conduction degree of the first switch unit to amplify the integral signal.

[0016] Furthermore, there is also provided: a charge pump circuit for providing a driving voltage for the first switching unit, the input end of the charge pump circuit is connected to the first input pin and the second input pin, the second output end of the inverter is connected to the second input pin, and the output end of the charge pump circuit is connected to the control unit.

[0017] Furthermore, it is also provided with:

[0018] an overcurrent detection circuit, generating an overcurrent signal according to a current sampling signal representing the current of the first switch unit and a second reference signal;

[0019] An over-temperature detection circuit generates an over-temperature signal according to a temperature sampling signal representing the temperature of the integrated chip and a third reference signal;

[0020] The control unit controls the error reporting unit to output a second error reporting signal to the system according to the over-current signal, and the control unit controls the error reporting unit to output a third error reporting signal to the system according to the over-temperature signal.

[0021] Preferably, the first switch unit includes: a first power tube and a second power tube, the drain of the first power tube is connected to the first input pin, the source is connected to the source of the second power tube, and the drain of the second power tube is connected to the output pin.

[0022] Preferably, the second switch unit includes: a third power tube and a fourth power tube, the drain of the third power tube is connected to the first switch unit, the source is connected to the source of the fourth power tube, and the drain of the fourth power tube is connected to the second input pin.

[0023] Preferably, the open circuit detection circuit comprises: a first comparison circuit, an integration circuit and a second comparison circuit, wherein:

[0024] The first comparison circuit outputs a valid enable signal according to a sampling voltage representing the current of the first switch unit, a first comparison threshold, and a second comparison threshold;

[0025] When the integration circuit receives the valid enable signal, the integration circuit integrates the sampled voltage to output the integration signal.

[0026] The second comparison circuit compares the integrated signal with the first reference signal to output the open-circuit signal;

[0027] The first comparison threshold is greater than the second comparison threshold, the first comparison threshold and the second comparison threshold are both positive or negative, and the control unit increases the on-resistance of the first switch unit according to the effective enable signal.

[0028] Preferably, the error reporting unit includes a fifth power tube, a control end of the fifth power tube is connected to the control unit, and a first end is connected to the error reporting pin, the control unit controls the duty cycle of the fifth power tube to be a first threshold value according to the open circuit signal, the control unit controls the duty cycle of the fifth power tube to be a second threshold value according to the over-current signal, and the control unit controls the duty cycle of the fifth power tube to be a third threshold value according to the over-temperature signal.

[0029] A system for driving a PDLC dimming film with an inverter comprises N integrated chips as described above, an inverter and N PDLC dimming films, wherein one integrated chip is connected between the inverter and each PDLC dimming film, and N is a natural number greater than or equal to 1.

[0030] A car, characterized by comprising the system for driving the PDLC dimming film by the inverter as described above.

[0031] The integrated chip proposed in the present invention can realize one inverter driving multiple PDLC dimming films, saving production costs, and in the driving process, the corresponding PDLC dimming films can be independently controlled by the integrated chip to realize independent control of each PDLC dimming film. At the same time, each integrated chip integrates functional circuits such as open circuit detection, overcurrent detection, and overtemperature detection. Only one chip can meet the requirements of the PDLC dimming film during operation, thereby reducing production costs and the complexity of the solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The inverter-driven PDLC dimming film system proposed by the present invention;

[0033] Figure 2 A structural diagram of an integrated chip proposed by the present invention;

[0034] Figure 3 A structural diagram of another integrated chip proposed by the present invention;

[0035] Figure 4 A further detailed structural diagram of the integrated chip;

[0036] Figure 5 This is a block diagram of the circuit for open circuit detection. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0038] like Figure 1 and Figure 2 As shown, the present invention proposes an integrated chip, which is applied to a system where an inverter drives a PDLC dimming film. Each PDLC dimming film and the inverter are connected via an integrated chip. The specific integrated chip is integrated with:

[0039] A first switch unit, wherein a first end of the first switch unit is connected to the first input pin, and a second end of the first switch unit is connected to the output pin;

[0040] The first output end of the inverter is connected to the first input pin, and the PDLC dimming film is connected to the output pin and the second output end of the inverter.

[0041] The control unit controls the connection state between the PDLC dimming film and the inverter by controlling the first switch unit to be turned on or off; wherein, when the first switch unit is turned on, the inverter is connected to the PDLC dimming film, and the inverter supplies power to the PDLC dimming film; when the first switch unit is turned off, the inverter and the PDLC dimming film are disconnected, and the inverter stops supplying power to the PDLC dimming film.

[0042] Furthermore, in order to achieve rapid discharge of the PDLC dimming film when the power is off, as Figure 3 As shown, the integrated chip is also integrated with: a second switch unit, the first end of the second switch unit is connected to the second end of the first switch unit, the second end of the second switch unit is connected to the second input pin, the second output end of the inverter is connected to the second input pin, and the control unit controls the connection state between the PDLC dimming film and the inverter by controlling the conduction and cutoff of the first switch unit and the second switch unit. Wherein, when the first switch unit is turned on and the second switch unit is turned off, the PDLC dimming film is connected to the inverter, and the inverter supplies power to the PDLC dimming film; when the first switch unit is turned off and the second switch unit is turned on, the PDLC is disconnected from the inverter, the inverter stops supplying power to the PDLC dimming film, and the PDLC dimming film is quickly discharged through the second switch unit.

[0043] Furthermore, in order to realize the normal operation of the PDLC dimming film, the integrated chip is also integrated with:

[0044] An open circuit detection circuit, wherein the open circuit detection circuit generates an open circuit signal representing an open circuit connection state between the PDLC dimming film and the inverter according to an integral signal representing an integral of the current of the first switch unit and a first reference signal;

[0045] An overcurrent detection circuit generates an overcurrent signal according to a current sampling signal representing the current of the first switch unit and a second reference signal;

[0046] An over-temperature detection circuit generates an over-temperature signal according to a temperature sampling signal representing the temperature of the integrated chip and a third reference signal;

[0047] An error reporting unit, the output end of which is connected to an error reporting pin. When the open circuit detection circuit detects an open circuit connection between the PDLC dimming film and the inverter, the control unit controls the error reporting unit to output a first error signal to the system through the error reporting pin according to the open circuit signal; when the overcurrent detection circuit detects an overcurrent in the process of the inverter supplying power to the PDLC dimming film, the control unit controls the error reporting unit to output a second error signal to the system through the error reporting pin according to the overcurrent signal; when the overtemperature detection circuit detects that the integrated chip is overtemperature, the control unit controls the error reporting unit to output a third error signal to the system through the error reporting pin according to the overtemperature signal.

[0048] Furthermore, a charge pump circuit is also provided in the indispensable integrated chip, the input end of the charge pump circuit is connected to the first input pin and the second input pin, and the output end is connected to the control unit. The charge pump circuit converts the output of the inverter and provides a driving voltage for the first switch unit and the second switch unit.

[0049] In summary, the integrated chip proposed in the present invention can realize one inverter driving multiple PDLC dimming films, saving production costs, and in the driving process, the corresponding PDLC dimming films can be independently controlled by the integrated chip to achieve independent control of each PDLC dimming film. At the same time, each integrated chip integrates functional circuits such as open circuit detection, overcurrent detection, and overtemperature detection. Only one chip can meet the needs of the PDLC dimming film during operation, thereby reducing production costs and the complexity of the solution.

[0050] Preferably, in one embodiment, Figure 4 As shown, the first switch unit includes a first power tube M1 and a second power tube M2, and the second switch unit includes a third power tube M3 and a fourth power tube M4. The drain of the first power tube M1 is connected to the first input pin, the source is connected to the source of the second power tube M2, the drain of the second power tube M2 is connected to the output pin, the drain of the third power tube M3 is connected to the output pin, the source is connected to the source of the fourth power tube M4, and the drain of the fourth power tube M4 is connected to the second input pin. The first power tube M1 and the second power tube M2, the third power tube M3 and the fourth power tube M4 form a dual MOS back-to-back structure, thereby preventing the body diode of the power tube from forming a current path when the first switch unit or the second switch unit is turned off.

[0051] More preferably, in order to reduce production costs and complexity, an open circuit detection circuit is provided at the first switch unit, and the open circuit detection circuit performs open circuit detection only when the current of the first switch unit is within the first range. At the same time, since the working current of the PDLC dimming film is relatively small, the open circuit detection circuit is unable to perform effective detection when sampling and integrating the current of the first switch unit. Therefore, when the open circuit detection circuit performs open circuit detection, the control unit will adjust the conduction degree (on resistance) of the first switch unit to amplify the sampling signal, thereby achieving effective detection. Specifically, as Figure 5 As shown, the open circuit detection circuit includes:

[0052] A first comparison circuit, wherein a first input terminal of the first comparison circuit receives a sampling voltage representing a current of the first switch unit, a second input terminal receives a first comparison threshold, a third input terminal receives a second comparison threshold, and an output terminal of the first comparison circuit is connected to an enable terminal of the integration circuit;

[0053] The integration circuit integrates the sampled voltage when receiving a valid enable signal to output an integration signal;

[0054] The second comparison circuit compares the integrated signal with the first reference signal to output an open-circuit signal;

[0055] Among them, the first comparison threshold is greater than the second comparison threshold, and the second comparison threshold and the first comparison threshold are both positive or negative. That is, when the sampling voltage is within the range of the first comparison threshold to the second comparison threshold (characterizing that the current of the first switch unit is within the first range), the integration circuit integrates the current to generate an integral signal. At the same time, when the control unit receives a valid enable signal, it will reduce the driving voltage of the first switch unit to increase the on-resistance of the first switch unit, thereby increasing the sampling voltage (i.e., amplifying the integral signal). It should be noted that, under the premise that the resistance of the PDLC dimming film is large, the on-resistance of the first switch unit is adjusted, and the influence on the working current of the PDLC dimming film is negligible.

[0056] The first comparison circuit and the second comparison circuit can be implemented by comparators, logic gates, etc., and the integration circuit can be implemented by capacitors, which are all conventional technical means in the field and are not described here. For example, the first comparison circuit can be set to output a high-level signal when the sampling voltage is between the second comparison threshold and the first comparison threshold, and the high-level signal is a valid enable signal; the second comparison circuit can be set to output a low-level signal when the integration signal is less than the reference signal, and the low-level signal indicates an open circuit connection between the inverter and the PDLC dimming film.

[0057] In other embodiments, two open circuit detection circuits may be provided at the first switch unit, wherein one open circuit detection circuit performs open circuit detection when the current of the first switch unit is positive, and the other open circuit detection circuit performs open circuit detection when the current of the first switch unit is negative.

[0058] Preferably, in one embodiment, the error reporting unit includes a fifth power tube M5, the gate of the fifth power tube M5 is connected to the control unit, the source is grounded, and the drain is connected to the error reporting pin, the control unit controls the duty cycle of the fifth power tube M5 to be a first threshold value according to the open circuit signal, the control unit controls the duty cycle of the fifth power tube M5 to be a second threshold value according to the overcurrent signal, and the control unit controls the duty cycle of the fifth power tube M5 to be a third threshold value according to the overtemperature signal. That is, the control unit prompts the system of different faults by controlling the duty cycle change of the fifth power tube M5.

[0059] Furthermore, the integrated chip is also provided with an enable pin connected to the control unit. The system controller sends a command signal to the control unit through the enable pin. The control unit controls the conduction and cutoff of the first switch unit and the second switch unit according to the command signal, thereby controlling the connection between the inverter and the PDLC dimming film, and timely protecting the PDLC dimming film in the event of over-current or over-temperature faults.

[0060] It should be noted that the integrated chip proposed in the present invention is not a simple chip formed by connecting and integrating the functional circuits composed of various existing independent components. Instead, various components are manufactured on a substrate through multiple process flows, and in this process, the various components are connected through electrical connection processes to form switch units and functional circuits, thereby finally forming an integrated chip.

[0061] like Figure 1 As shown, the present invention also proposes a system for an inverter to drive a PDLC dimming film, comprising N integrated chips mentioned above, an inverter and N PDLC dimming films, an integrated chip is connected between the inverter and each PDLC dimming film, and N is a natural number greater than or equal to 1.

[0062] In addition, the present invention also provides a car, which includes the inverter-driven PDLC dimming film system provided above.

[0063] It should be noted that the specific implementation and corresponding illustrations given are merely a way of describing the implementation method of the present invention, and do not limit the specific structure of the implementation scheme of the present invention. Various changes or modifications can be made to these implementation schemes without departing from the principle and essence of the present invention, but these changes and modifications fall within the scope of protection of the present invention.

[0064] Although the embodiments are described and illustrated separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that the embodiments can be replaced and integrated. If the content is not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0065] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. An integrated chip, applied to a system where an inverter drives a PDLC dimming film, wherein one integrated chip is connected between each PDLC dimming film and the inverter, characterized in that: The integrated chip is integrated with: a first switch unit, wherein a first end of the first switch unit is connected to a first input pin, and a second end of the first switch unit is connected to an output pin, The first output end of the inverter is connected to the first input pin, and the PDLC dimming film is connected to the output pin and the second output end of the inverter. A control unit controls the first switch unit to be turned on or off, so as to control the connection state between the PDLC dimming film and the inverter.

2. The integrated chip according to claim 1, characterized in that: The integrated chip is also integrated with: a second switch unit, wherein a first end of the second switch unit is connected to the output pin, a second end of the second switch unit is connected to a second input pin, and a second output end of the inverter is connected to the second input pin, The control unit controls the first switch unit and the second switch unit to be turned on or off, so as to control the connection state between the PDLC dimming film and the inverter.

3. The integrated chip according to claim 1, characterized in that: The integrated chip is also provided with: An open circuit detection circuit generates an open circuit signal according to the integral signal and the first reference signal, wherein the open circuit signal indicates that the PDLC dimming film and the inverter are in an open circuit state, and the integral signal indicates the integral of the current of the first switch unit; An error reporting unit, the output end of which is connected to an error reporting pin, and the control unit controls the error reporting unit to output a first error reporting signal to the system through the error reporting pin according to the open circuit signal.

4. The integrated chip according to claim 3, characterized in that: The open circuit detection circuit generates the integral signal according to the current of the first switch unit within a first range, and the control unit adjusts the conduction degree of the first switch unit to amplify the integral signal.

5. The integrated chip according to claim 1, characterized in that: Also provided is: a charge pump circuit for providing a driving voltage for the first switch unit, the input end of the charge pump circuit is connected to the first input pin and the second input pin, the second output end of the inverter is connected to the second input pin, and the output end of the charge pump circuit is connected to the control unit.

6. The integrated chip according to claim 3, characterized in that: Also provided are: an overcurrent detection circuit, generating an overcurrent signal according to a current sampling signal representing the current of the first switch unit and a second reference signal; An over-temperature detection circuit generates an over-temperature signal according to a temperature sampling signal representing the temperature of the integrated chip and a third reference signal; The control unit controls the error reporting unit to output a second error reporting signal to the system according to the over-current signal, and the control unit controls the error reporting unit to output a third error reporting signal to the system according to the over-temperature signal.

7. The integrated chip according to claim 1, characterized in that: The first switch unit includes: a first power tube and a second power tube, the drain of the first power tube is connected to the first input pin, the source is connected to the source of the second power tube, and the drain of the second power tube is connected to the output pin.

8. The integrated chip according to claim 2, characterized in that: The second switch unit includes: a third power tube and a fourth power tube, the drain of the third power tube is connected to the first switch unit, the source is connected to the source of the fourth power tube, and the drain of the fourth power tube is connected to the second input pin.

9. The integrated chip according to claim 3 or 4, characterized in that: The open circuit detection circuit comprises: a first comparison circuit, an integration circuit and a second comparison circuit, wherein: The first comparison circuit outputs a valid enable signal according to a sampling voltage representing the current of the first switch unit, a first comparison threshold, and a second comparison threshold; When the integration circuit receives the valid enable signal, the integration circuit integrates the sampled voltage to output the integration signal. The second comparison circuit compares the integrated signal with the first reference signal to output the open-circuit signal; The first comparison threshold is greater than the second comparison threshold, the first comparison threshold and the second comparison threshold are both positive or negative, and the control unit increases the on-resistance of the first switch unit according to the effective enable signal.

10. The integrated chip according to claim 6, characterized in that: The error reporting unit includes a fifth power tube, a control end of the fifth power tube is connected to the control unit, and a first end is connected to the error reporting pin, the control unit controls the duty cycle of the fifth power tube to be a first threshold value according to the open circuit signal, the control unit controls the duty cycle of the fifth power tube to be a second threshold value according to the over-current signal, and the control unit controls the duty cycle of the fifth power tube to be a third threshold value according to the over-temperature signal.

11. A system for driving a PDLC dimming film by an inverter, characterized in that: It comprises N integrated chips as described in any one of claims 1 to 10, an inverter and N PDLC dimming films, one integrated chip is connected between the inverter and each of the PDLC dimming films, and N is a natural number greater than or equal to 1.

12. A car, characterized in that: A system comprising the inverter driving the PDLC dimming film as claimed in claim 11.

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