OLED light source driving control circuit and OLED lamp

Abstract

The application provides an OLED light source driving control circuit and an OLED lamp, the driving control circuit comprises a DC / DC constant voltage module, an external transceiver, a first internal transceiver, a micro-processing module, a linear constant current module and an OLED screen light source; the micro-processing module communicates with the first internal transceiver, feeds back the detected output voltage to the DC / DC constant voltage module, and controls the operation of the DC / DC constant voltage module; the first internal transceiver is connected with the linear constant current module through a differential bus; the linear constant current module comprises a plurality of linear constant current chips, each linear constant current chip is provided with a second internal transceiver, and the differential bus interfaces of the second internal transceivers are respectively connected on the differential bus communication lines connected with the differential bus interface of the first internal transceiver. The application has stronger anti-interference ability, and effectively improves the circuit conversion efficiency of the overall driving system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile lamps, in particular to the technical field of automobile OLED lamps, and specifically to an OLED light source driving control circuit and an OLED lamp. BACKGROUND

[0002] LED, as the preferred light source of automobile signal lamps, has been widely and maturely applied to various functional automobile signal lamps. However, as a point light source, when LED is applied to a signal lamp of a certain function of an automobile rear lamp, a plurality of LEDs are generally required to realize one function. The light emitting effect of the plurality of LEDs is difficult to achieve good light emitting uniformity without the cooperation of a good optical reflection system and a light distribution lens. The organic light emitting diode (OLED) product has two advantages: on the one hand, its self-luminous characteristic does not require any light source system support, and the thickness of the OLED light emitting body is only 1.4 millimeters. The future tail lamp can even be pasted like a sticker on the parking space, without occupying the space of the trunk, and has a greater advantage in volume compared with ordinary LED products. On the other hand, compared with the point light source of LED, OLED has the characteristics of surface light source and diffuse reflection, and the light quality is uniform, which can realize stepless dimming and will not project any shadow. Because of the advantages of OLED, such as lightness, thinness, softness and good light quality, OLED can be well used in the field of automobile lighting in terms of energy saving and design. The OLED panel is getting thinner and thinner, and the screen body color is changing from single color to multi color, from rigid panel to flexible panel, etc., which makes the OLED lighting technology mature.

[0003] The existing vehicle lamp OLED driving control system adopts a pure linear constant current mode for the driving part, and a single-chip microcomputer IO port directly connects a switch group to turn on and off the PWM dimming port of the multi-channel linear constant current chip in an independent control light source mode. For details, see the patent with the patent number ZL201720614078.1. This driving mode has low driving efficiency, occupies many single-chip microcomputer resource IO ports, and has complex connection harnesses, which is not conducive to scalability and platformization. Moreover, the EMC anti-interference ability is poor, and when there is strong electromagnetic interference from the outside world, the OLED driving and control circuit is easily disturbed, which causes the OLED to abnormally emit light. SUMMARY

[0004] In order to solve the above-mentioned and other potential technical problems, embodiments of the present application provide an OLED light source driving control circuit, which comprises a DC / DC constant voltage module, an external transceiver, a first internal transceiver, a micro-processing module, a linear constant current module and an OLED screen light source; the DC / DC constant voltage module is connected with a positive pole of a car power line and outputs power to the external transceiver, the first internal transceiver, the micro-processing module and the linear constant current module respectively; one end of the external transceiver is connected with a car communication line and the other end is connected with the micro-processing module, receives a control signal transmitted by the car communication line and transmits the control signal to the micro-processing module, so that the micro-processing module executes a control instruction corresponding to the control signal; the micro-processing module communicates with the first internal transceiver, detects an output voltage of the linear constant current module, feeds back the detected output voltage to the DC / DC constant voltage module, so that the DC / DC constant voltage module adjusts the output voltage output to the linear constant current module, and controls the DC / DC constant voltage module to work according to the detected voltage or the voltage fed back by the linear constant current module; the first internal transceiver is connected with the linear constant current module through a differential bus, and is used for transmitting signals between the micro-processing module and the linear constant current module; the linear constant current module comprises a plurality of linear constant current chips, each of the linear constant current chips is provided with a second internal transceiver, differential bus interfaces of the second internal transceivers are connected on differential bus communication lines connected with the differential bus interfaces of the first internal transceiver, so as to communicate with the differential bus interfaces of the first internal transceiver; the OLED screen light source comprises a plurality of OLED screens corresponding to the linear constant current chips respectively, and each OLED screen is controlled to emit light through an output channel of the linear constant current chip, and each output channel corresponds to an OLED light emitting area; ground terminals of the DC / DC constant voltage module, the external transceiver, the first internal transceiver, the micro-processing module, the linear constant current module and the OLED screen light source are connected with a negative pole of the car power line respectively.

[0005] In an embodiment of the present application, a reverse connection prevention circuit is further connected on a line between the DC / DC constant voltage module and the car power line.

[0006] In an embodiment of the present application, the reverse connection prevention circuit comprises a reverse connection prevention diode or a reverse connection prevention PMOS circuit.

[0007] In an embodiment of the present application, the external transceiver is a LIN transceiver and the car communication line is a LIN communication line; or the external transceiver is a CAN transceiver and the car communication line is a CAN communication line.

[0008] In an embodiment of the present application, the external transceiver is integrated in the micro-processing module, and a voltage stabilizer LDO is also integrated in the micro-processing module.

[0009] In an embodiment of the present application, each linear constant current chip has multiple output channels corresponding to multiple light emitting areas in an OLED screen.

[0010] In an embodiment of the present application, the number of linear constant current chips multiplied by the number of output channels on a linear constant current chip is greater than or equal to the number of OLED screens multiplied by the number of light emitting areas on an OLED screen.

[0011] In an embodiment of the present application, an over-temperature detection circuit is arranged near the OLED screen light source and connected to the micro-processing module, for detecting the temperature of the OLED screen light source and transmitting the detected temperature to the micro-processing module.

[0012] In an embodiment of the present application, the over-temperature detection circuit comprises a PCB circuit board, a thermistor, a pull-up voltage dividing resistor and an A / D sampling circuit arranged on the PCB circuit board; the thermistor and the pull-up voltage dividing resistor are connected, one end of the A / D sampling circuit is connected to a line between the thermistor and the pull-up voltage dividing resistor, and the other end is connected to an A / D sampling port of the micro-processing module.

[0013] In an embodiment of the present application, the dynamic effect of the OLED light source is controlled through the differential bus; the differential bus protocol used by the differential bus is a high-speed digital communication bus protocol based on the combination of UART protocol and local differential bus physical layer structure.

[0014] In an embodiment of the present application, the first internal transceiver and the second internal transceiver internally provided by each linear constant current chip transmit control signals, and the micro-processing module and the linear constant current module transmit control signals through the first internal transceiver.

[0015] In an embodiment of the present application, the OLED screen voltage corresponding to the OLED light emitting area on each channel in each linear constant current chip is collected through the differential bus communication line; when the OLED screen voltage rises within a preset range, the micro-processing module outputs a feedback signal to adjust the output voltage of the DC / DC constant voltage module, so that each linear constant current chip has sufficient voltage to raise the OLED screen voltage; when the OLED screen voltage rises beyond the preset range, the micro-processing module outputs a feedback signal to raise the output voltage of the DC / DC constant voltage module to a preset limit voltage, so as to maintain a preset constant output limit power to provide driving for the OLED screen light source.

[0016] The embodiment of the present application also provides an OLED lamp adopting the OLED light source driving control circuit as described above.

[0017] As described above, the OLED light source driving control circuit and the OLED lamp of the present application have the following beneficial effects:

[0018] 1. The differential bus communication mode is adopted in the present application, and the differential bus protocol is an optimized and improved high-speed digital communication bus protocol based on the combination of UART protocol and local differential bus physical layer structure. Compared with the traditional I2C or SPI communication line, the differential bus communication protocol and mode have stronger anti-interference ability because the signal in the form of voltage difference of two differential lines is used as the transmission signal. This anti-interference ability can bring convenience to the circuit layout of the driving control circuit. Because of the weak anti-interference ability of the original I2C and SPI communication mode, the linear constant current module with a communication interface and the micro processing module need to be arranged on the same PCB board to avoid the introduction of external interference caused by the long communication line. However, by using the differential bus communication protocol, the linear constant current module with a communication interface and the micro processing module can be distributed on different PCB boards, which is convenient for the control circuit design and arrangement of some compact car lamps.

[0019] 2. The DC / DC constant voltage module is used to pre-process the body voltage in the present application, which effectively improves the circuit conversion efficiency of the overall driving system, reduces the power consumption and heat of the driving consumption, and can effectively reduce the driving board area.

[0020] 3. The circuit form combining the front-end DC / DC constant voltage module with the rear-end linear constant current module is adopted in the present application, which can effectively reduce the radiation interference of the switching power supply type circuit to the outside, so that the EMC electromagnetic compatibility test is more easily passed.

[0021] 4. The first internal transceiver and the linear constant current module with a second internal transceiver are used to communicate through the differential bus in the present application, which simplifies the control circuit architecture and reduces the PCB area ratio, and saves the number of I / O ports or PWM ports required by the MCU.

[0022] 5. The EN enable signal is used to close the DC / DC constant voltage module when the OLED fails, which can reduce the OLED failure shutdown current and make the lamp more easily meet the current demand of the vehicle body BCM for fault diagnosis.

[0023] 6. The present application can avoid the situation that the OLED screen body voltage rises due to aging problems, the output voltage of the original rear-end linear constant current drive is insufficient (voltage difference is not enough), the OLED current becomes small, and the constant luminous flux output of the OLED is maintained, so that a certain preset constant output limit power is provided for the OLED light source to avoid the overheat of the whole lamp system.

[0024] 7、The present application can reduce the current size flowing through the OLED or turn off the OLED light source, avoiding the damage of high temperature to the OLED.

[0025] 8、The present application can realize the independent control of the light emitting area of multiple OLED light sources or multiple LED light sources through a relatively simple control circuit architecture, realizing the functions of rich dynamic effects, text information display, etc. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 The figure shows the principle structure schematic diagram of the OLED light source driving control circuit of the present application.

[0028] Figure 2 The figure shows the specific circuit structure schematic diagram of the OLED light source driving control circuit of the present application when LIN communication is used.

[0029] Figure 3 The figure shows the specific circuit structure schematic diagram of the OLED light source driving control circuit of the present application when CAN communication is used.

[0030] Figures 4 to 7 The figure shows another circuit structure schematic diagram of the OLED light source driving control circuit of the present application with the same effect.

[0031] Figure 8 The figure shows a layout schematic diagram of the OLED screen body in the OLED light source driving control circuit of the present application.

[0032] Figure 9 The figure shows the connection schematic diagram of the over-temperature detection circuit in the OLED light source driving control circuit of the present application.

[0033] Figure 10 The figure shows the circuit structure schematic diagram of the over-temperature detection circuit in the OLED light source driving control circuit of the present application.

[0034] Figure 11 The figure shows an example diagram of the DC / DC constant voltage module in the OLED light source driving control circuit of the present application.

[0035] Figure 12 The figure shows a hardware application example diagram of the OLED light source driving control circuit of the present application.

[0036] Figure 13-1 and Figure 13-2 Figures 1 and 2 respectively show the overall structure of the OLED light source driving control circuit of the present application when using LED light sources.

[0037] Element number explanation

[0038] 110 DC / DC constant voltage module

[0039] 120 external transceiver

[0040] 121 LIN transceiver

[0041] 122 CAN transceiver

[0042] 130 micro-processing module

[0043] 140 first internal transceiver

[0044] 150 linear constant current module

[0045] 151 second internal transceiver

[0046] 160 OLED screen light source

[0047] 170 over-temperature detection circuit

[0048] 171 PCB circuit board

[0049] 172 A / D sampling circuit

[0050] 180 light fixture control module

[0051] 190 LED light source DETAILED DESCRIPTION

[0052] The present application will be described in more detail by the following specific examples. Other advantages and effects of the present application can be easily understood by those skilled in the art from this disclosure. The present application can also be implemented or applied in other different specific embodiments, and the details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0053] Please refer to Figure 1 to 13. It is to be understood that the structures, proportions, sizes, etc. shown in the drawings accompanying the present specification are merely intended to assist in the understanding of the present disclosure and are not intended to limit the scope of the present application, and therefore, any modification, change in proportion relationship, or adjustment in size, which does not affect the effects and purposes of the present application, should still fall within the scope of the present application. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in the present specification are merely intended to facilitate the understanding of the present disclosure, and are not intended to limit the scope of the present application, and any change in relative relationship or adjustment without substantial change in technical content should also be considered as the scope of the present application.

[0054] The purpose of the embodiment is to provide an OLED light source driving control circuit and an OLED lamp, which can be widely applied to electronic power supply driving and control systems of automobile OLED lamps, can improve the problems of large heat, large control panel area, and poor EMC anti-interference ability of the original OLED lamp linear driving system, and can simplify the control system in the OLED lamp, simplify the connection wire harness on the control loop, facilitate cascading expansion, and increase the independently controllable OLED light-emitting area, without changing the model of the single-chip microcomputer and directly cascading the number of rear-end OLED linear constant-current driving chips, which is beneficial to the platformization of the OLED control part.

[0055] The present application solves the shortcomings of the traditional OLED lamp driving circuit for vehicles using a single type of linear driving circuit, such as using a linear constant-current driving, low driving circuit efficiency, excessive heat, large driving control panel area, and poor anti-interference ability. In order to improve the driving conversion efficiency and reduce the internal environment temperature of the whole lamp, a new circuit architecture of front-end DC / DC + rear-end linear is adopted: the front-end is a DC / DC constant voltage mode, the output voltage is controlled at a value slightly higher than the OLED itself voltage, and the linear driving of the multiple rear-ends is powered to improve the working efficiency of the whole system driving circuit and reduce the heat of the OLED driving.

[0056] The principles and implementation modes of the OLED light source driving control circuit and the OLED lamp of the present application will be described in detail below, so that those skilled in the art can understand the OLED light source driving control circuit and the OLED lamp of the present application without creative labor.

[0057] The embodiment of the present application provides an OLED light source driving control circuit, which comprises a DC / DC constant voltage module 110, an external transceiver 120, a first internal transceiver 140, a micro processing module 130, a linear constant current module 150 and an OLED screen body light source 160.

[0058] In the embodiment, the DC / DC constant voltage module 110 is connected with the positive pole of the automobile power line and respectively outputs power supply to the external transceiver 120, the first internal transceiver 140, the micro processing module 130 and the linear constant current module 150.

[0059] The DC / DC constant voltage module 110 not only outputs power supply to the linear constant current module 150, but also outputs power supply VCC to the external transceiver 120, the micro processing module 130 and the first internal transceiver 140.

[0060] In the embodiment, the interface between the automobile body and the OLED car lamp is one power line VBat, one ground wire GND, one LIN communication line or two CAN communication lines (CANH line and CANL line).

[0061] In the embodiment, the DC / DC constant voltage module 110 is further connected with an anti-reverse connection circuit on the line between the DC / DC constant voltage module 110 and the automobile power line.

[0062] The anti-reverse connection circuit comprises but is not limited to an anti-reverse connection diode or an anti-reverse connection PMOS circuit. For example, the anti-reverse connection circuit adopts an anti-reverse connection diode D1, one end of the anti-reverse connection diode D1 is connected with the power line VBat, and the other end is connected with the input end of the DC / DC constant voltage module 110.

[0063] In the embodiment, one end of the external transceiver 120 is connected with the automobile communication line, and the other end is connected with the micro processing module 130, receives the control signal transmitted by the automobile communication line and transmits the control signal to the micro processing module 130, so that the micro processing module 130 executes the control instruction corresponding to the control signal.

[0064] The external transceiver 120 communicates with the micro processing module 130 (MCU) through the Rx communication port and the Tx communication port.

[0065] Specifically, in the embodiment, as shown in the figure, Figure 2 the external transceiver 120 is a LIN transceiver 121, the automobile communication line is a LIN communication line, and the communication between the OLED lamp and the automobile body follows the LIN communication protocol; or as shown in the figure, Figure 3As shown, the external transceiver 120 is a CAN transceiver 122, the automobile communication line is a CAN communication line (CANH line and CANL line), and the communication between the OLED lamp and the automobile body complies with the CAN communication protocol.

[0066] In this embodiment, the micro-processing module 130 communicates with the first internal transceiver 140, detects the output voltage of the linear constant current module 150, feeds back the detected output voltage to the DC / DC constant voltage module 110 for the DC / DC constant voltage module 110 to adjust the output voltage output to the linear constant current module 150, and controls the operation of the DC / DC constant voltage module 110 according to the detected voltage or the voltage fed back by the linear constant current module 150.

[0067] Specifically, the micro-processing module 130 selects the highest voltage UOUT(max) in the multiple output channels according to the detected output voltage of each channel of the linear constant current module 150, and then sets the feedback signal FB output to the DC / DC constant voltage module 110 according to the highest voltage for the DC / DC constant voltage module 110 to adjust the output voltage output to the linear constant current module 150, and controls the operation of the DC / DC constant voltage module 110 according to the detected output voltage of the linear constant current module 150. The form of the feedback signal FB can be an analog voltage value, a PWM signal, etc.

[0068] In this embodiment, as shown in Figure 4 and Figure 5 The external transceiver 120 can be integrated in the micro-processing module 130, and a voltage stabilizing source LDO is also integrated in the micro-processing module 130. When the transceiver is integrated in the micro-processing module 130, an anti-reverse connection diode D2 is added for anti-reverse connection protection, forming an anti-reverse connection circuit for the micro-processing module 130.

[0069] As shown in Figure 6 and Figure 7 The micro-processing module 130 can also only have a voltage stabilizing source LDO integrated therein, and the external transceiver 120 is connected outside the micro-processing module 130.

[0070] In this embodiment, the first internal transceiver 140 is connected to the linear constant current module 150 through a differential bus, for transmitting signals between the micro-processing module 130 and the linear constant current module 150. The first internal transceiver 140 is an internal CAN transceiver.

[0071] The differential bus is used to control the dynamic effect of the OLED light source. The differential bus protocol is a high-speed digital communication bus protocol based on the UART protocol and the local differential bus physical layer structure.

[0072] The micro-processing module 130 communicates with the first internal transceiver 140 through the Rx and Tx communication ports. The first internal transceiver 140 is connected to the communication port of each linear constant current chip in the back-end linear constant current module 150 through the differential bus to control the switching, dimming and delay of each channel of the OLED light source.

[0073] The micro-processing module 130 can output a feedback signal FB to the DC / DC constant voltage module to adjust the output voltage of the DC / DC constant voltage module 110 in a timely manner. Meanwhile, the micro-processing module 130 can output an enable signal EN to the DC / DC constant voltage module 110 to turn off the operation of the DC / DC constant voltage module 110.

[0074] In this embodiment, the linear constant current module 150 includes a plurality of linear constant current chips, each of which has a second internal transceiver 151. The differential bus interface of the second internal transceiver 151 is connected to the differential bus communication line connected to the differential bus interface of the first internal transceiver 140 to communicate with the differential bus interface of the first internal transceiver 140.

[0075] The first internal transceiver 140 and the second internal transceiver 151 internally provided in each linear constant current chip transmit control signals. The micro-processing module 130 and the linear constant current module 150 transmit control signals through the first internal transceiver 140.

[0076] The second internal transceiver 151 is also an internal CAN transceiver.

[0077] Therefore, the OLED light source drive control circuit in this embodiment uses a DC / DC constant voltage circuit as the front-end first-level circuit, and adjusts the input voltage to a suitable range of the rear-end OLED voltage through a high-efficiency driving method (for example: 12V is reduced to 6V, and the conversion efficiency is about 80% through DC / DC driving, which is much higher than the simple linear constant current conversion efficiency of 30%), and then connects to various constant current driving chips at the second level to accurately control the current flowing through the OLED. From the perspective of the driving system, it effectively improves the circuit conversion efficiency of the overall driving system, reduces the power consumption and heat consumed by the driving, and can effectively reduce the area of ​​the driving board; and because a hybrid circuit of a front-end DC / DC constant voltage drive and a rear-end linear constant current drive is adopted, the rear-end second-level linear constant current circuit can effectively alleviate the external radiation interference of the previous stage DC / DC constant voltage circuit. Compared with the traditional DC / DC constant current drive, it can effectively reduce the external radiation interference of the switching power supply circuit, making it easier to pass the external radiation and external conduction tests in the EMC electromagnetic compatibility test.

[0078] OLED is used as a taillight light source, its purpose is to reflect the sense of technology and super cool feeling. It can realize the independent control and lighting of a single OLED graphic area. However, if there are a large number of OLED chips, it will bring a burden on the pin requirements of the single-chip microcomputer. The first generation of drivers uses a shift register chip with serial to parallel output to realize the conversion of one SPI communication to several parallel output controls, thereby expanding the number of I / O ports. In addition to the linear constant current driver, this control architecture also requires the addition of multiple shift register chips and peripheral circuits, which increases the complexity and board area of ​​the control circuit. The OLED light source drive control circuit in this embodiment uses a linear constant current driver chip with communication function, and uses the differential bus communication protocol built into the linear constant current driver chip to communicate with the microprocessor module 130 through the first internal transceiver 140 (internal CAN transceiver). Through a few simple communication lines, a variety of OLED graphic display effects are achieved, simplifying the control circuit architecture to reduce the PCB board rate and saving the number of I / O ports or PWM ports required for the MCU. At the same time, compared with the use of I2C or SPI lines, this differential bus protocol is an optimized and improved high-speed digital communication bus protocol based on the combination of the UART protocol and the local differential bus physical layer structure. It has strong anti-electromagnetic interference capabilities and is particularly beneficial for OLED automotive lamps, which require independent control of each light-emitting area. The strong anti-interference capability helps dynamic OLED automotive lamps implement dynamic effects according to preset states, realizing rich dynamic effects, text information display and other functions.

[0079] Therefore, it can be seen that the original OLED drive and control system adopts a serial-to-parallel output shift register chip to realize one-way SPI communication to several-way parallel output control to expand the number of I / O ports. This control architecture needs to additionally increase multiple shift register chips and peripheral circuits except for linear constant current drive, which increases the complexity and PCB area of the control circuit. The OLED light source drive control circuit in the embodiment adopts a linear constant current drive chip with communication function. The linear constant current drive chip is used to transmit control signals through the differential bus communication port and the internal CAN transceiver. The control signals are converted by the internal CAN transceiver and communicated with the micro-processing module 130. Through a few communication lines, diversified OLED graphic display effects are realized, the control circuit architecture is simplified, the PCB area is reduced, and the number of I / O ports or PWM ports required by the micro-processing module 130 is saved. Compared with the traditional I2C or SPI communication line, the differential bus communication method has stronger anti-interference ability. At the same time, the open circuit or short circuit fault of the OLED load can be fed back to the micro-processing module 130 through the communication interface of the internal CAN transceiver through the differential bus communication port of the linear constant current drive chip. Then the micro-processing module 130 outputs an enable signal EN to shut down the DC / DC constant voltage module 110 of the previous stage, so as to reduce the OLED fault shutdown current, and make the lamp more easily meet the current demand of the vehicle body BCM for fault diagnosis.

[0080] In the embodiment, each linear constant current chip in the linear constant current module 150 has 1-n output channels (for example, n=12) for connecting the positive pole of the OLED light source, and the negative pole of the OLED light source is connected with GND (the OLED light source is common cathode, and the linear constant current chip required must be high-side driving). The linear constant current chips 1-N can be all hung on the differential bus communication line (the differential bus protocol is an optimized and improved high-speed digital communication bus protocol based on the UART protocol and the local differential bus physical layer structure), and the channel number of the OLED light source is expanded in this way (according to the actual demand of the OLED individually controllable light-emitting area number). The linear constant current chip collects the voltage value of the OLED light source on each channel, and transmits it to the first internal transceiver 140 through the second internal transceiver and the differential bus communication line, and the first internal transceiver 140 converts the signal and transmits it to the micro-processing module 130. If an abnormal voltage is detected, it can be judged as OLED short circuit or open circuit, and the micro-processing module 130 can output an EN signal to close the front-end DC / DC constant voltage module 110 to stop power supply to the rear-end linear constant current module 150. On the other hand, the micro-processing module 130 can also collect the OLED light source voltage through the differential bus communication line. If the OLED voltage changes within a certain range (not short circuit and open circuit), the MCU can output an FB feedback signal to the DC / DC constant voltage module 110 to adjust the output voltage value of the DC / DC constant voltage module 110 to adapt to the voltage change of the rear-end OLED due to aging, and compensate the darkening or brightening of the OLED due to aging.

[0081] In the embodiment, the OLED screen light source 160 includes a plurality of OLED screens corresponding to each linear constant current chip, and each OLED screen is controlled to emit light through the output channel of the linear constant current chip.

[0082] In the embodiment, each linear constant current chip has a plurality of output channels corresponding to a plurality of light-emitting areas in an OLED screen.

[0083] The output end of each linear constant current chip is connected with the positive pole of each light-emitting area of the OLED, and the negative pole of each light-emitting area of the OLED is connected with GND.

[0084] In the embodiment, the OLED screen body voltage corresponding to each OLED light emitting area on each channel in each linear constant current chip is collected through the differential bus communication line. When the OLED screen body voltage rises within a preset range, the micro processing module 130 outputs a feedback signal to adjust the output voltage of the DC / DC constant voltage module 110, so that each linear constant current chip has sufficient voltage to raise the OLED screen body voltage. When the OLED screen body voltage rises beyond the preset range, the micro processing module 130 outputs a feedback signal to raise the output voltage of the DC / DC constant voltage module 110 to a preset limit voltage, so as to maintain a preset constant output limit power to provide driving for the OLED screen body light source.

[0085] Specifically, in order to adapt to the change of the screen body electrical characteristic parameters of the OLED screen body after high temperature and solar radiation aging, and avoid the OLED lamp from becoming dim due to environmental factors, the OLED light source driving control circuit in the embodiment is designed as follows: the micro processing module 130 of the OLED light source driving control circuit in the embodiment is connected with the first internal transceiver 140 (internal CAN transceiver), the first internal transceiver 140 is connected with the communication port of each linear constant current chip, the micro processing module 130 converts signals through the first internal transceiver 140 (internal CAN transceiver), and collects the OLED screen body voltage corresponding to each OLED light emitting area on each channel of the linear constant current chip through the differential bus communication line (the differential bus protocol is an optimized and improved high-speed digital communication bus protocol based on the UART protocol and the local differential bus physical layer structure). When the OLED screen body voltage rises within a certain range (which can be customized, for example, +30%), the micro processing module 130 outputs a feedback signal to adjust the output voltage (follow-up voltage control) of the front-end DC / DC constant voltage module, so that the rear-end linear constant current module 150 has sufficient voltage to raise the OLED screen body voltage to maintain the original current value to light up, avoid the insufficient output voltage (voltage difference is not enough) of the original set rear-end linear constant current driving due to the voltage rise of the screen body caused by aging problems, so as to maintain the constant luminous flux output of the OLED, that is, avoid the dimming of the whole lamp due to the change of the electrical characteristics of the OLED screen body caused by environmental factors. When the OLED screen body voltage rises beyond the defined range, the micro processing module 130 outputs a feedback signal to adjust the output of the front-end DC / DC constant voltage module, so that the OLED front-end DC / DC constant voltage module can output a certain set limit voltage to maintain a certain preset constant output limit power to provide driving for the OLED light source, and avoid the whole lamp system from overheating.

[0086] For example, if an OLED light source participates in the whole lamp lighting distribution regulatory assessment, if a single luminous area in the OLED light source is damaged, it may affect the regulatory compliance of the whole lamp lighting distribution. In this case, the damage of a single luminous area requires the function of shutting down all OLED screens to indicate that the lamp is damaged. The original traditional OLED drive control circuit does not have this fault shutdown function. In the OLED light source drive control circuit of this embodiment, the output voltage of each channel of each linear constant current chip that supplies power to the OLED is transmitted back to the internal CAN transceiver through the differential bus interface of the linear constant current chip. The internal CAN transceiver then converts the signal and transmits it to the microprocessor module 130. If the voltage change has the characteristics of an OLED short circuit or open circuit, it can be detected by the microprocessor module 130. The microprocessor module 130 then outputs an enable EN signal to the front-end DC / DC constant voltage module 110, which is used to shut down the operation of the DC / DC constant voltage module 110 and stop supplying power to the back-end linear constant current module 150 to shut down all OLEDs. At the same time, the microprocessor module 130 provides a fault alarm signal that is transmitted to the vehicle body via the CAN / LIN communication line.

[0087] In this embodiment, the number of linear constant current chips multiplied by the number of output channels on one linear constant current chip is greater than or equal to the number of OLED screens multiplied by the number of light-emitting areas on one OLED screen.

[0088] Specifically, Figure 8 This is a schematic diagram for explaining the OLED screen and the light-emitting area corresponding to the OLED light source in the OLED light source driving control circuit of this embodiment (but not limited to this diagram, this diagram is only for example). Figure 8 There are M OLED screens, each of which has m independently controllable light-emitting areas (here Figure 8 Where m=3, i.e., each OLED screen has three independently controllable light-emitting areas), OLED1-1 represents the leftmost light-emitting area of ​​the first OLED screen, OLED1-2 represents the middle light-emitting area of ​​the first OLED screen, and OLED1-3 represents the rightmost light-emitting area of ​​the first OLED screen; of course, m can be greater than 3, so each OLED screen can have m independent light-emitting areas greater than 3. It should be noted that: N represents N linear constant current chips, and n represents the number of output channels in each linear constant current chip. The relationship is: N×n≥M×m, that is, the total number of output channels of the linear constant current chipset must be greater than or equal to the light-emitting areas of all OLED screens that need to be independently controlled.

[0089] In this embodiment, if Figure 9As shown, an over-temperature detection circuit 170 is provided in the OLED screen light source 160 and is connected to the micro-processing module 130 for detecting the temperature of the OLED screen light source 160 and transmitting the detected temperature to the micro-processing module 130 .

[0090] An over-temperature detection circuit 170 can be set in the hottest area inside the lamp body. The temperature change inside the lamp body is transmitted to the microprocessing module 130 through the over-temperature detection circuit 170. The microprocessing module 130 can adjust the output control strategy in a timely manner to reduce the current flowing through the OLED light source or turn off the OLED light source to avoid damage to the OLED light source due to high temperature.

[0091] Specifically, if Figure 10 As shown, in this embodiment, the overtemperature detection circuit 170 includes a PCB circuit board 171, a thermistor, a pull-up voltage divider resistor, and an A / D sampling circuit 172 installed on the PCB circuit board 171; wherein, the thermistor and the pull-up voltage divider resistor are connected, and one end of the A / D sampling circuit 172 is connected to the line between the thermistor and the pull-up voltage divider resistor, and the other end is connected to the microprocessor module 130.

[0092] In this embodiment, the over-temperature protection principle is as follows:

[0093] The thermistor is soldered on a PCB with polarity leads. This PCB is physically installed and fixed in an area close to the OLED screen to sense the temperature of the area near the OLED. In terms of circuit structure, this overtemperature detection circuit 170 is composed of a pull-up voltage divider resistor, a thermistor, and an A / D sampling circuit 172. The pull-up voltage divider resistor is connected to a constant voltage VCC. The lower end of the pull-up voltage divider resistor is connected to the thermistor, and the other end of the thermistor circuit is connected to ground GND. The connection point between the thermistor and the pull-up resistor, i.e., the voltage at the voltage divider point, is sampled by the A / D sampling circuit 172 of the microprocessor module 130 (MCU) and input into the microprocessor module 130 (MCU). When the thermistor's resistance changes due to temperature changes, the microprocessor module 130 (MCU) can sense this change in the voltage at the voltage divider point. The microprocessor module 130 (MCU) then outputs an FB feedback signal (which can be a PWM signal ranging from 0% to 100%) to the front-end DC / DC constant voltage module 110 for timely adjustment, thereby reducing the current flowing through the OLED light source or directly shutting down the OLED light source.

[0094] Among them, the ground ends of the DC / DC constant voltage module 110, the external transceiver 120, the first internal transceiver 140, the microprocessor module 130, the linear constant current module 150 and the OLED screen light source 160 are respectively connected to the negative pole of the car power line.

[0095] The working principle of the OLED light source driving control circuit in this embodiment is as follows:

[0096] The body inputs two types of signals to the OLED light source driving control circuit, one is the power line of VBat and GND, where VBat is the positive pole of the power line and GND is the negative pole of the power line, and the positive and negative poles form a current loop of the entire OLED light source driving control circuit and are responsible for power supply of the entire OLED light source driving control circuit; the other is the communication signal line LIN (one LIN line input) or CAN (divided into two lines CANH and CANL input), which is responsible for the control function of the OLED light source driving control circuit, for example: the body transmits whether the OLED needs to be powered on through the LIN or CAN communication line, or the body inputs a certain preset signal through the LIN or CAN, and different light-emitting areas of the OLED perform dynamic display according to a certain specific dynamic effect to represent a certain special scene definition of the body (such as "welcome mode", when the car key is close, the OLED rear lamp will display a certain preset dynamic effect to welcome the owner).

[0097] The reverse connection prevention circuit provides reverse connection prevention for the entire OLED light source driving control circuit, which can be composed of a diode or a PMOS reverse connection prevention circuit with the same effect, and is used to prevent damage to the system after the positive and negative poles of the power supply are reversely connected. The DC / DC constant voltage module 110 can be a DC / DC in the form of a step-down BUCK, and the E522.10 chip model, and can also be composed of a step-up and step-down SEPIC and ZETA constant voltage circuit and other similar function DC / DC chips.

[0098] As shown in Figure 11 , an example diagram of the DC / DC constant voltage module 110 is shown. The DC / DC constant voltage module 110 can be composed of an input filter circuit, a DC / DC driving chip (taking E522.10 of ELMOS as an example), and a peripheral circuit (see Figure 11 for details of the DC / DC constant voltage module 110 example circuit structure) constituting its constant voltage topology architecture (BUCK step-down topology or SEPIC step-up and step-down topology or ZETA form step-up and step-down topology), and an output filter circuit: the input filter circuit is used to alleviate the ripple of the DC / DC switching power supply type circuit, Figure 11 The DC / DC step-down constant voltage circuit Figure 11 is an example of this type, but it is not limited to this BUCK step-down type and can be expanded to a step-up and step-down SEPIC or ZETA form constant voltage circuit: Figure 11 C1, L1, and C2 constitute the input filter circuit; U1, D1, L2, and C5 constitute the DC / DC BUCK step-down topology structure; C8, C6, and C7 constitute the output filter circuit; Figure 11The rest of the devices constitute the peripheral circuit of the DC / DC constant voltage BUCK circuit. The negative electrode of D1 in the OLED light source driving control circuit is connected to the VIN-D1 port in Figure 11 The power output of the DC / DC constant voltage output module in the OLED light source driving control circuit is the DC / DC-VOUT port in Figure 11 The DC / DC constant voltage module 110 outputs a constant voltage to the power input end of the rear-end linear constant current module 150. Through the front-end first constant voltage, the voltage applied to the two ends of the second linear constant current chip set can be reduced, the power consumption of the second linear constant current chip can be reduced, the efficiency of the entire driving control system can be improved through the front-end DC / DC+rear-end linear circuit architecture, the heat generated by power consumption can be reduced, and the size of the PCB board can be reduced.

[0099] The communication signal of the internal transceiver of each linear constant current chip (for example, the TPS929XX series of TI) in the linear constant current module 150 is connected to the communication port of the first internal transceiver 140 (internal CAN transceiver) through a differential bus (ICANH and ICANL lines) to transmit control signals; the input signal port of the first internal transceiver 140 is connected to the communication port of the micro processing module 130 to receive the control signals transmitted by the micro processing module 130. In this way, the micro processing module 130 can convert signals through the internal CAN transceiver and output instructions through the differential bus to independently control the power output channels of each linear constant current chip. The control method includes: switching each channel and individually dimming, switching, and delay or time interval control of each channel. Each linear constant current chip has n power output channels CH1-n, each output channel is connected to the positive electrode of an OLED independently controlled light emitting area lead to provide a constant current for the OLED to emit light, and the negative electrodes of all OLED independent light emitting areas are connected to the ground GND. The DC / DC constant voltage module 110 can also provide a constant voltage VCC power supply to the micro processing module 130 and the LIN transceiver 121 for power supply. The LIN transceiver 121 receives the communication signal LIN of the vehicle body, converts and transmits the vehicle body instructions to the micro processing module 130 through the LIN transceiver 121, and the micro processing module 130 receives the signal instructions and then converts the signals through the internal CAN transceiver 122 and transmits the control signals to the rear-end linear constant current chips through the differential bus, thereby realizing independent control of each channel, i.e., independent control of each light emitting area.

[0100] In addition, the micro-processing module 130 collects the voltage value output by each channel of the linear constant current chip through the differential bus via the internal CAN transceiver. If the voltage value is abnormal, such as an open circuit or a short circuit of the OLED, the micro-processing module 130 can collect the abnormal value and output an enable signal EN to turn off the operation of the front-end DC / DC constant voltage module 110. If the voltage value collected by the micro-processing module 130 via the internal CAN transceiver through the differential bus increases or decreases within a certain preset value range, the micro-processing module 130 can output a feedback signal FB to the DC / DC constant voltage module 110 to adjust the output voltage, thereby compensating for the decrease or increase of the OLED current caused by the voltage change of the OLED screen body due to aging.

[0101] As shown in Figure 12 , because the front-end DC / DC constant voltage module is used for voltage preprocessing and the differential bus with strong anti-interference capability is used for control signal transmission, the anti-reverse connection diode D1, the DC / DC constant voltage module 110, the external transceiver 120, the micro-processing module 130, and the first internal transceiver 140 in the OLED light source driving control circuit architecture of the embodiment can be combined into a lamp control module 180. The lamp control module 180 can be designed as a standardized and platformized independent control module. The lamp control module 180 is separated from the OLED light source driving control circuit architecture and becomes a physically independent control module. The hardware circuit design of the lamp control module 180 can be applied to different vehicle lamp fixtures, and different software can be written into the control module for different light control effects. The lamp control module 180 can be arranged outside the vehicle lamp as a standard master control module Master, and the linear constant current module 150 and the OLED screen light source 160 in the OLED light source driving control circuit architecture of the embodiment can be independently arranged inside the lamp. The linear constant current module 150 is used as a slave driving circuit Slave and is designed differently according to different lamp shapes.

[0102] In addition, it should be noted that, as shown in Figure 13-1 and Figure 13-2 , the above OLED light source driving control circuit is also applicable to the LED light source 190. For example, when a vehicle lamp composed of multiple LED light sources has the functional requirements of dynamic display or independent control of each LED light source for switching, dimming, text or information display, the light source driving control circuit scheme of the application can be used to realize the functions. As shown in Figure 13-1 and Figure 13-2 , the linear constant current chip in Figure 13-1 is high-side driven, Figure 13-2 the linear constant current chip is low-side driven, and both can be applied to the LED light source 190.

[0103] The embodiment of the present application also provides an OLED lamp adopting the OLED light source driving control circuit as described above. The OLED light source driving control circuit has been described in detail above, and will not be repeated here.

[0104] To sum up, the differential bus communication mode is adopted in the present application, which has stronger anti-interference ability than the traditional I2C or SPI communication line; the circuit mode combining the front-end DC / DC constant voltage module and the rear-end linear constant current module is adopted, which effectively improves the circuit conversion efficiency of the overall driving system, reduces the power consumption and heat consumed by driving, and can effectively reduce the driving board area; the present application can effectively reduce the radiation interference of the switching power supply circuit to the outside, making the EMC electromagnetic compatibility test more easily passed; the present application simplifies the control circuit architecture to reduce the PCB area ratio, saves the number of I / O ports or PWM ports required by the MCU, and can also reduce the OLED fault shutdown current, so that the lamp is more easily to meet the current demand of the vehicle body BCM for fault diagnosis of the whole vehicle factory; the present application can avoid the problem that the OLED current becomes small due to the insufficient output voltage (voltage difference is not enough) of the rear-end linear constant current drive caused by the voltage rise of the screen body due to aging, so as to maintain the constant luminous flux output of the OLED, can maintain a certain preset constant output limit power to provide driving for the OLED light source, and avoid the overheat of the whole lamp system; the present application can reduce the current flowing through the OLED or turn off the OLED light source, to avoid the damage of high temperature to the OLED. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.

[0105] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. An OLED light source drive control circuit, characterized in that: The OLED light source drive control circuit includes: a DC / DC constant voltage module, an external transceiver, a first internal transceiver, a microprocessor module, a linear constant current module and an OLED screen light source; The DC / DC constant voltage module is connected to the positive pole of the car power line and outputs power to the external transceiver, the first internal transceiver, the microprocessor module and the linear constant current module respectively; One end of the external transceiver is connected to the vehicle communication line, and the other end is connected to the micro-processing module, receiving the control signal transmitted by the vehicle communication line and transmitting the control signal to the micro-processing module, so that the micro-processing module executes the control instruction corresponding to the control signal; The micro-processing module communicates with the first internal transceiver, detects the output voltage of the linear constant current module, feeds back the detected output voltage to the DC / DC constant voltage module so that the DC / DC constant voltage module can adjust the output voltage output to the linear constant current module, and controls the operation of the DC / DC constant voltage module according to the detected voltage or the voltage fed back by the linear constant current module; wherein: the micro-processing module selects the highest voltage among the plurality of output channels according to the output voltage of each channel of the linear constant current module detected, and then sets a feedback signal output according to the highest voltage and feeds it back to the DC / DC constant voltage module so that the DC / DC constant voltage module can adjust the output voltage output to the linear constant current module; The first internal transceiver is connected to the linear constant current module via a differential bus, and is used to transmit signals between the microprocessor module and the linear constant current module; The linear constant current module includes a plurality of linear constant current chips, each of the linear constant current chips has a second internal transceiver, and the differential bus interface of the second internal transceiver is respectively connected to the differential bus communication line connected to the differential bus interface of the first internal transceiver to communicate with the differential bus interface of the first internal transceiver; An OLED screen light source comprises a plurality of OLED screens corresponding to the linear constant current chips, wherein the output channels of the linear constant current chips are used to control the emission of each OLED screen, and each output channel corresponds to an OLED light-emitting area; The ground terminals of the DC / DC constant voltage module, the external transceiver, the first internal transceiver, the microprocessor module, the linear constant current module, and the OLED screen light source are respectively connected to the negative pole of the car power line; The OLED screen voltage corresponding to the OLED light-emitting area on each channel of each linear constant current chip is collected through the differential bus communication line. When the OLED screen voltage increases within a preset range, the micro-processing module outputs a feedback signal to adjust the output voltage of the DC / DC constant voltage module so that each linear constant current chip has sufficient voltage to increase the OLED screen voltage. When the OLED screen voltage increases beyond the preset range, the micro-processing module outputs a feedback signal to increase the output voltage of the DC / DC constant voltage module to a preset limit voltage, so as to maintain a preset constant output limit power to provide drive for the OLED screen light source; The microprocessor module is connected to the first internal transceiver, and the first internal transceiver is connected to the communication port of each linear constant current chip. The microprocessor module converts the signal through the first internal transceiver and collects the OLED screen voltage corresponding to the OLED light-emitting area on each channel of the linear constant current chip through the differential bus communication line. When the OLED screen voltage rises within a preset range, the microprocessor module outputs a feedback signal to adjust the output voltage of the front-end DC / DC constant voltage module driver, so that the rear-end linear constant current module has sufficient voltage for the OLED with the increased screen voltage to maintain the original current value and light up, thereby maintaining the constant luminous flux output of the OLED; when the OLED screen voltage rises beyond the preset range, the microprocessor module outputs a feedback signal to adjust the front-end DC / DC constant voltage module driver output, so that the output of the OLED front-end DC / DC constant voltage module floats up to a set ratio of the limit voltage, so as to maintain the preset constant output limit power to provide drive for the OLED light source.

2. The OLED light source driving control circuit according to claim 1, characterized in that: The line between the DC / DC constant voltage module and the car power line is also connected to an anti-reverse connection circuit.

3. The OLED light source driving control circuit according to claim 2, characterized in that: The anti-reverse connection circuit includes an anti-reverse connection diode or an anti-reverse connection PMOS circuit.

4. The OLED light source driving control circuit according to claim 1, wherein: The external transceiver is a LIN transceiver, and the vehicle communication line is a LIN communication line; or the external transceiver is a CAN transceiver, and the vehicle communication line is a CAN communication line.

5. The OLED light source driving control circuit according to claim 1, characterized in that: The external transceiver is integrated into the micro-processing module, and a voltage regulator LDO is also integrated into the micro-processing module.

6. The OLED light source driving control circuit according to claim 1, characterized in that: Each of the linear constant current chips has multiple output channels, which are correspondingly connected to multiple light-emitting areas in an OLED screen.

7. The OLED light source driving control circuit according to claim 6, characterized in that: The number of linear constant current chips multiplied by the number of output channels on a linear constant current chip ≥ the number of OLED screens multiplied by the number of light-emitting areas on an OLED screen.

8. The OLED light source driving control circuit according to claim 6, wherein: An over-temperature detection circuit is provided near the light source of the OLED screen and is connected to the micro-processing module for detecting the temperature of the light source of the OLED screen and transmitting the detected temperature to the micro-processing module.

9. The OLED light source driving control circuit according to claim 8, characterized in that: The overtemperature detection circuit includes a PCB circuit board, a thermistor, a pull-up voltage divider resistor, and an A / D sampling circuit installed on the PCB circuit board; wherein the thermistor and the pull-up voltage divider resistor are connected, and one end of the A / D sampling circuit is connected to the circuit between the thermistor and the pull-up voltage divider resistor, and the other end is connected to the A / D sampling port of the microprocessor module.

10. The OLED light source driving control circuit according to claim 1, wherein: The dynamic effect of the OLED light source is controlled by the differential bus; the differential bus protocol adopted by the differential bus is a high-speed digital communication bus protocol based on the combination of the UART protocol and the local differential bus physical layer structure.

11. The OLED light source driving control circuit according to claim 1, wherein: The first internal transceiver transmits control signals to the second internal transceiver inside each linear constant current chip, and the microprocessor module and the linear constant current module transmit control signals through the first internal transceiver.

12. An OLED lamp, characterized in that: The OLED light source driving control circuit according to any one of claims 1 to 11 is used.

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