Patent Publication Number: US-2023147234-A1

Title: Dynamic automotive turn signal circuit and dynamic automotive turn signal system

Description:
CROSS REFERENCE TO THE RELATED APPLICATION 
     The present invention is based on and claims foreign priority to Chinese patent application No. 202111305268.2 filed Nov. 5, 2021, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This application relates to the field of automotive signal technologies, and more specifically, to a dynamic automotive turn signal circuit. 
     BACKGROUND 
     As an important signaling device in automotive lights, turn signals have the important function of alerting surrounding vehicles and pedestrians when the vehicle is turning. According to the regulations, all the light emitting diode (LED) light strings of the turn signals need to be lit within 200 ms. Therefore, more and more automotive turn signals on the market have the dynamic flowing function, and LED turn signals with a dynamic effect can better alert the surrounding vehicles and pedestrians, with a more eye-catching effect in the rainy and foggy weather. 
     The dynamic turn signals on the market mainly implement the dynamic lighting function by a microcontroller unit (MCU), which generates a specific delay to drive an LED driver circuit. More specifically, as shown in  FIG.  1   , when the driver toggles a turn signal switch, a body control module (BCM) of the vehicle generates a 12 V power supply signal with 1 Hz and 50% duty cycle, to drive the LED circuit to work. When the power supply voltage increases, a low dropout (LDO) regulator circuit starts the MCU, which generates a plurality of delay circuits to control the plurality of LED drivers to light up the LEDs, achieving the effect of flowing light up. After waiting for 500 ms, the MCU enters a new start-up cycle. Due to the high cost of the MCU in this method, and the need for software programming and complex peripheral circuit, the dynamic turn signals have high cost. 
     Therefore, it is expected to provide a new type of dynamic automotive turn signal circuit to meet the needs of high accuracy and flexible adjustment and reduce the MCU hardware costs and software development and maintenance costs. 
     SUMMARY 
     This application is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. This application is not intended to identify key features or essential features of the claimed protected subject matter, nor is it intended to limit the scope of the claimed protected subject matter. 
     The purpose of this application is to provide an improved dynamic automotive turn signal circuit to facilitate flexible adjustment and reduce production and maintenance costs. The above and other purposes are implemented by the features of the independent claims. Further forms of implementation are apparent from the dependent claims, the specification and the accompanying drawings. 
     According to a first aspect of this application, a dynamic automotive turn signal circuit is provided, including: at least one drive control module configured to receive a power supply signal from a BCM to start operation, where the drive control module outputs first control signals at different delays through a delay unit as well as an LED light set connected to the drive control module and lit based on the first control signals. 
     Optionally, a plurality of delay units are provided, and the plurality of delay units are in a one-to-one correspondence with the plurality of drive control modules. 
     Optionally, the delay units each may include a first resistor, where a first terminal of the first resistor is connected to the drive control module and a second terminal is connected to a reference low voltage node. 
     Optionally, the first resistors have different resistance values. 
     Optionally, the resistance values of the first resistors increase with an equal difference. 
     Optionally, the LED light set turns off after lit for a fixed time. 
     Optionally, the drive control module outputs second control signals at different delays through the delay unit; and the LED light set turns off based on the second control signals. 
     Optionally, a plurality of delay units are provided, and the plurality of delay units are in a one-to-one correspondence with the plurality of drive control modules. 
     Optionally, the delay unit may further include: a second resistor, where a first terminal of the second resistor is connected to the drive control module and a second terminal is connected to the reference low voltage node. 
     Optionally, the second resistor has different resistance values. 
     Optionally, the drive control module may include: a first comparator, where a first input terminal of the first comparator is connected to the first resistor and a second input terminal is fed with a first voltage; a first switch transistor, where a control terminal of the first switch transistor is connected to an output terminal of the first comparator, a first polarity terminal receives the power supply signal, and a second polarity terminal is connected to the first resistor; a second switch transistor, where a control terminal of the second switch transistor is connected to the output terminal of the first comparator and a first polarity terminal receives the power supply signal; a first capacitor, where a first terminal of the first capacitor is connected to a second polarity terminal of the second switch transistor and a second terminal is connected to a reference low voltage node; a third switch transistor, where a first polarity terminal of the third switch transistor is connected to the first terminal of the first capacitor and a second polarity terminal is connected to the reference low voltage node; and a second comparator, where a first input terminal of the second comparator is connected to the first polarity terminal of the third switch transistor, a second input terminal is fed with a second voltage, an output terminal is connected to the control terminal of the second switch transistor, and the output terminal of the second comparator outputs the first control signal. 
     Optionally, a time interval between the first signal of the first control signals and the last signal of the first control signals generated by the drive control module receiving the power supply signal is no longer than 200 ms at most. 
     Optionally, a delay range among the first control signals generated by the drive control module is 0 ms to 200 ms. 
     According to a second aspect of this application, a dynamic automotive turn signal system is provided, including: a power supply configured to provide a power supply voltage; a BCM configured to receive the power supply voltage and output a power supply signal; and the dynamic automotive turn signal circuit described above, electrically connected to the BCM to receive the power supply signal. 
     According to the dynamic automotive turn signal circuit and the dynamic automotive turn signal system provided in this application, a high-precision delay circuit is disposed by using an external resistor, to achieve the dynamic flowing turn signals. In addition, the external resistor can be used to configure a turn-on delay and a turn-off delay of the internal driver chip, such that the channel turn-on time and turn-off time can be flexibly adjusted, reducing the MCU hardware costs and software development, production and maintenance costs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To describe the technical solutions in the embodiments of this application or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show some embodiments of this application, and those of ordinary skill in the art may still derive other accompanying drawings from these accompanying drawings without creative efforts. 
         FIG.  1    is a schematic circuit diagram of a dynamic automotive turn signal in the prior art. 
         FIG.  2    is a control timing diagram of a dynamic automotive turn signal in the prior art. 
         FIG.  3    is a schematic structural diagram of a circuit according to an embodiment of this application. 
         FIG.  4    is a schematic structural diagram of a circuit of a drive control module according to the embodiment in  FIG.  3   . 
     
    
    
     The same reference numerals below indicate same features or at least features with same functions. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solutions in the embodiments of this application are described below with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are merely some rather than all of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts should fall within the protection scope of this application. 
     It should be understood that A and B are connected/coupled in the embodiments of this application means that A and B are connected in series or in parallel, or that A and B are connected through another device, which is not limited in the embodiments of this application. 
       FIG.  1    is a schematic circuit diagram of a dynamic automotive turn signal in the prior art. As shown in  FIG.  1   , dynamic automotive turn signal system  100  includes BCM  101  and a dynamic automotive turn signal circuit. The existing dynamic automotive turn signal circuit includes MCU  102 , six driver circuit modules ( 1031 - 1036 ), and six LED light strings ( 1041 - 1046 ). In an example, when a driver toggles a turn signal switch, the BCM  100  generates a 12 V voltage signal with 1 Hz and 50% duty cycle, to drive an LED circuit to work. When a power supply voltage increases, the MCU  101  starts and generates a plurality of delay signals, to control the plurality of driver circuit modules to generate drive currents to light the LED light strings. Different delay signals have different delays, such that the flowing light effect is realized. When the power supply voltage is set low, the LED module is powered down and enters into a new start-up cycle after waiting for 500 ms. According to regulations, all the LED light strings need to be lit within 200 ms, therefore. Therefore, delays of the channels need to be adjusted accordingly for turn signal modules of different light strings. 
       FIG.  2    is a control timing diagram of a dynamic automotive turn signal in the prior art. As shown in  FIG.  2   , when a driver toggles a turn signal switch, BCM  100  generates a 12 V voltage signal with 1 Hz and 50% duty cycle. When the power supply voltage increases, MCU  101  starts and generates six delay signals. For example, a control signal for the first LED light string controls the LED light string to be lit directly, a control signal for the second LED light string is sent out 40 ms later to control the LED light string to be lit, a control signal for the third LED light string is sent out 80 ms later, until a control signal for the sixth LED light string is sent out 200 ms later and the sixth LED light string is lit. All the light strings are lit within 200 ms according to the regulations. 
     The dynamic automotive turn signal is controlled by using the MCU in the prior art. After receiving the voltage signal from the BCM, the MCU needs to send different delay control signals according to the requirements. This step needs to be implemented through programming, which greatly increases the production and maintenance costs of the dynamic automotive turn signal. 
     The present disclosure provides an improved dynamic automotive turn signal circuit. A high-precision delay circuit is disposed by using an external resistor, to achieve the dynamic flowing turn signals. In addition, the external resistor can be used to configure a turn-on delay and a turn-off delay of the internal driver chip, such that the channel turn-on time and turn-off time can be flexibly adjusted, reducing the MCU hardware costs and software development, production and maintenance costs. 
       FIG.  3    is a schematic structural diagram of a circuit according to an embodiment of this application. As shown in  FIG.  3   , dynamic automotive turn signal system  200  includes BCM  201  and a dynamic automotive turn signal circuit. In an example, the dynamic automotive turn signal circuit includes first drive control module  2031 , second drive control module  2032 , third drive control module  2033 , fourth drive control module  2034 , fifth drive control module  2035 , sixth drive control module  2036 , first LED light set  2041 , second LED light set  2042 , third LED light set  2043 , fourth LED light set  2044 , fifth LED light set  2045 , sixth LED light set  2046 , first delay unit  2051 , second delay unit  2052 , third delay unit  2053 , fourth delay unit  2054 , fifth delay unit  2055 , and sixth delay unit  2056 . In an example, when a driver toggles a turn signal switch, the BCM  201  outputs a power supply signal to the first drive control module  2031 . The first delay unit  2051  includes first resistor R 1  and second resistor R 2 , the first resistor R 1  serves as a delay unit for circuit turn-on and the second resistor R 2  serves as a delay unit for circuit turn-off. Resistance values of the first resistor R 1  and the second resistor R 2  are set, and a time for the first drive control module  2031  to output the voltage signal or cut off the voltage signal may be set. After receiving the power supply signal for a certain time, the first drive control module  2031  outputs the first control signal to the first LED light set  2041 , to light the first LED light set  2041 . The control logic of the second drive control module  2032  to the sixth drive control module  2036  is the same as that of the first drive control module  2031 , and details are not repeated here. 
     Optionally, each drive control module corresponds to one delay unit, and the delay unit includes the first resistor and the second resistor. The drive control module delays the circuit turn-on time through the first resistor and delays the turn-off time through the second resistor. In an example, the first resistors corresponding to the drive control modules have different resistance values, and may be resistors with equally incremental resistance values obtained by calculation. The circuits are lit at 40 ms intervals after powering up at the same time, achieving the effect of flowing light. The resistors may alternatively have incremental resistance values obtained by calculation. Because the automotive turn signal in the strip design has an arc shape, the time intervals for lighting the LED light sets may be set unequal. For example, in the arc area, the LED light set is lit with a shorter time interval, achieving a smoother flowing light effect. 
     It can be understood that the above description is an example of the drive control module in the embodiments of this application, the embodiments of this application are not limited hereto, and there may be other ways of extension and variation. 
     For example, the plurality of drive control modules may be integrated in a chip, and delays for outputting the voltage signals or cutting off the voltage signals may be set by using one resistor, to send a plurality of control signals to control different LED light strings. 
     Based on an exemplary configuration,  FIG.  4    is a schematic structural diagram of the drive control module according to the embodiment in  FIG.  3   . As shown in  FIG.  4   , the drive control module includes first comparator U 1 , second comparator U 2 , first switch transistor Q 1 , second switch transistor Q 2 , third switch transistor Q 3 , and first capacitor C 1 . A first input terminal of the first comparator U 1  is connected to the first resistor R 1  and a second input terminal is fed with a first voltage. A control terminal of the first switch transistor Q 1  is connected to an output terminal of the first comparator U 1 , a first polarity terminal receives the voltage signal, and a second polarity terminal is connected to the first resistor R 1 . A control terminal of the second switch transistor Q 2  is connected to the output terminal of the first comparator U 1  and a first polarity terminal receives the voltage signal. A first terminal of the first capacitor C 1  is connected to a second polarity terminal of the second switch transistor Q 2  and a second terminal is connected to a reference low voltage node. A first polarity terminal of the third switch transistor Q 3  is connected to the first terminal of the first capacitor C 1  and a second polarity terminal is connected to the reference low voltage node. A first input terminal of the second comparator U 2  is connected to the first polarity terminal of the third switch transistor Q 3 , a second input terminal is fed with a second voltage and an output terminal is connected to the control terminal of the second switch transistor Q 2 . The output terminal of the second comparator U 2  outputs a voltage signal with a delay. As shown in  FIG.  4   , a resistance value of the first resistor R 1  is inversely proportional to a charging current IREF to the first capacitor C 1 , and the first capacitor C 1  receives the charging current to generate a capacitor voltage. The third switch transistor Q 3  is connected to a side of and shares a reference point with the first capacitor C 1 , to reset the voltage of the first capacitor C 1 . The control terminal of the third switch transistor Q 3  is connected to the output terminal of the second comparator U 2 . The first input terminal of the second comparator U 2  receives the capacitor voltage and the second input terminal receives the second voltage. The second comparator U 2  receives the voltage of the first capacitor C 1  and compares it with the second voltage. After the first capacitor C 1  is charged by the charging current for a period of time and reaches the second voltage, the second comparator U 2  outputs a signal to turn on the third switch transistor Q 3  to bleed the capacitor voltage of the first capacitor C 1 . At the same time, the second comparator U 2  outputs a square waveform as the output power supply signal. 
     It can be understood that the reference low voltage node described above is a negative terminal of the automotive battery connected to the iron part or the automotive body. The above description is an example of the drive control module in the embodiments of this application, the embodiments of this application are not limited hereto, and there may be other ways of extension and variation. 
     For example, the resistors and capacitors provided in the embodiments of this application may be capacitor elements and resistor elements with lumped parameters, or other equivalent elements that function similarly to the capacitors and resistors. The equivalent structures described herein are, for example, but not limited to, structures that provide inductive impedance and/or capacitive impedance such as microstrip lines, varactors, or conductor structures with certain patterns. 
     Optionally, this application further provides a dynamic automotive turn signal system including: a power supply configured to provide a power supply voltage; a BCM configured to receive the power supply voltage and output a power supply signal; and the dynamic automotive turn signal circuit described above, electrically connected to the BCM to receive the power supply signal. 
     Persons of ordinary skill in the art may realize that with reference to the structures and methods described in the embodiments disclosed in the specification, different configuration methods or adjustment methods may be used to implement the described functions for each structure or a variation thereof, but such implementation should not be considered to be beyond the scope of this application. In addition, it should be understood that in the embodiments of this application, the connections among the components of the comparator in the drawings described above are illustrative examples and do not impose any restrictions on the embodiments of this application. 
     In an example, this application further provides a dynamic automotive turn signal system. Optionally, the dynamic automotive turn signal system includes: a power supply configured to provide a power supply voltage; a BCM configured to receive the power supply voltage and output a start signal; and the dynamic automotive turn signal circuit as described above, electrically connected to the BCM to receive the start signal. 
     Any range or device value presented in this specification can be extended or changed without loss of the effect sought. Furthermore, any embodiment may be combined with another embodiment that is not expressly prohibited. 
     Although the subject matter has been described in language specific to structural features and/or actions of the method, it should be understood that the subject matter defined in the appended claims is not limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples of the claims, and other equivalent specific and actions are intended to fall within the scope of the claims. 
     It should be understood that the benefits and advantages mentioned above may involve one or more embodiments. The embodiments are not limited to those that solve any or all of the problems or have any or all of the benefits and advantages. It should also be understood that a reference to “a” project may refer to one or more of those projects. 
     In addition, terms “include”, “comprise”, or any other variations thereof are intended to cover non-exclusive including, so that a process, a method, an article, or a device including a series of elements not only includes those elements, but also includes other elements that are not explicitly listed, or also includes inherent elements of the process, the method, the article, or the device. Without more restrictions, the elements defined by the sentence “including a . . . ” do not exclude the existence of other identical elements in a process, method, article, or device including the elements. 
     It should be understood that the above description is given as an example only and that various modifications can be made by those skilled in the art. The above description, examples and data provide a complete description of the structure and use of the exemplary embodiments. Although various embodiments with a degree of specificity have been described above, or with reference to one or more individual embodiments, those skilled in the art may make a variety of changes to the disclosed embodiments without departing from the spirit or scope of this specification.