LED driving chip, communication control method and circuit thereof

Abstract

This invention provides an LED driver chip and its communication control method and circuit. The communication control method used in the LED driver chip includes: when a frame header signal is received through the signal input port of the LED driver chip, outputting the frame header signal through the signal output port of the LED driver chip without performing any processing on the frame header signal; and when it is determined that the frame header signal is a data frame header signal, switching the LED driver chip to a working mode of receiving data signals and performing data signal shaping processing; and when a data signal is received through the signal input port of the LED driver chip, performing data signal shaping processing based on the frequency information of the data signal contained in the data frame header signal, and outputting the shaped data signal through the signal output port of the LED driver chip.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more specifically to an LED driver chip and its communication control method and circuit. Background Technology

[0002] With the development of light-emitting diode (LED) display devices, mini LED display technology is gaining increasing popularity. MiniLED display technology allows for independent brightness adjustment and control of different MiniLEDs based on the displayed image, thereby improving image quality. However, a large number of MiniLEDs require a large number of driver chips, and significant data transmission is needed between these chips.

[0003] Traditional communication schemes typically include clock and data lines, such as the Serial Peripheral Interface (SPI) and the Integrated Circuit Bus (I2C). When there are many devices, this requires extensive wiring, which is difficult and costly. Single-wire communication schemes can simplify wiring and solve these problems. However, single-wire communication schemes lack a synchronous clock signal. Ensuring data synchronization while transmitting data accurately and efficiently remains a challenge for single-wire communication. Summary of the Invention

[0004] A communication control method for use in an LED driver chip according to an embodiment of the present invention includes: when a frame header signal is received through the signal input port of the LED driver chip, outputting the frame header signal through the signal output port of the LED driver chip without performing any processing on the frame header signal, and when it is determined that the frame header signal is a data frame header signal, switching the LED driver chip to a working mode of receiving data signals and performing data signal shaping processing; and when a data signal is received through the signal input port of the LED driver chip, performing data signal shaping processing based on the frequency information of the data signal contained in the data frame header signal, and outputting the shaped data signal through the signal output port of the LED driver chip.

[0005] A communication control circuit for use in an LED driver chip according to an embodiment of the present invention includes: a decoding control unit configured to output a frame header signal through a signal output port of the LED driver chip when a frame header signal is received through a signal input port of the LED driver chip, and to switch the LED driver chip to a working mode of receiving data signals and performing data signal shaping processing when it is determined that the frame header signal is a data frame header signal; and a data shaping unit configured to perform data signal shaping processing based on the frequency information of the data signal contained in the data frame header signal when a data signal is received through a signal input port of the LED driver chip, and to output the shaped data signal through a signal output port of the LED driver chip. Attached Figure Description

[0006] The invention can be better understood from the following description of specific embodiments of the invention in conjunction with the accompanying drawings, wherein:

[0007] Figure 1 A connection diagram of a backlight system using single-wire communication is shown.

[0008] Figure 2 A schematic diagram of the data format used in single-wire communication is shown.

[0009] Figure 3A The data signal is shown in Figure 1 The diagram shows a step-by-step reduction of the pulse width during transmission in the backlight system.

[0010] Figure 3B The data signal is shown in Figure 1 The diagram shows a step-by-step increase in pulse width during transmission in the backlight system.

[0011] Figure 4 A schematic block diagram of an LED driver chip and a communication control circuit used therein, according to an embodiment of the present invention, is shown.

[0012] Figure 5 It shows Figure 4 The flowchart shown illustrates the communication control method implemented by the communication control circuit.

[0013] Figure 6 It shows Figure 1 The backlight system shown adopts Figure 4 The diagram shows the waveforms of the synchronization header signal and data header signal input to each stage of the LED driver chip.

[0014] Figure 7 It shows Figure 1 The backlight system shown adopts Figure 4 The diagram shows the waveforms of the data frame header signal and data signal input to each stage of the LED driver chip. Detailed Implementation

[0015] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific configuration and algorithm presented below, but covers any modifications, substitutions, and improvements to elements, components, and algorithms without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description in order to avoid unnecessarily obscuring the invention. Furthermore, it should be noted that the term "A connected to B" as used herein can mean "A and B are directly connected" or "A and B are indirectly connected via one or more other elements."

[0016] Figure 1 A connection diagram of a backlight system using single-wire communication is shown. Figure 1 In the backlight system 100 shown, LED driver chips 1 to N are connected in series; controller 102 sends control signals to LED driver chips 1 to N through a single-wire bus to control LED driver chips 1 to N simultaneously; each LED driver chip includes a signal input port and a signal output port, and may contain multiple LED driver circuits.

[0017] Figure 2 A schematic diagram illustrating the data format used in single-wire communication is shown. For example... Figure 2 As shown, data can be transmitted in binary format, either 0 or 1, and pulse width can be used to represent binary data 0 or 1. For example, a signal with a pulse width of 25% can be used as data 0, and a signal with a pulse width of 75% can be used as data 1. When the LED driver chip receives a data signal, it can sample the data signal after a certain delay (e.g., 50% of the cycle) after receiving the rising edge of the data signal to obtain the transmitted binary data.

[0018] exist Figure 1 In the backlight system 100 shown, the data signal experiences a certain delay each time it passes through an LED driver chip. When the rise / fall delays of the data signal are inconsistent, the pulse width of the data signal will change. Figure 3A and Figure 3B The data signals are shown respectively. Figure 1 The diagram illustrates the gradual decrease and increase of pulse width during step-by-step transmission in a backlight system. Data inputs 1 to N represent data inputs 1 to N of the LED driver chip, respectively. Figure 3AAs shown, when the rising edge delay of the data signal is higher than the falling edge delay, the pulse width of the data signal gradually decreases as the data signal is transmitted from LED driver chip 1 to LED driver chip N. Figure 3B As shown, when the rising edge delay of the data signal is lower than the falling edge delay, the pulse width of the data signal increases step by step as the data signal is transmitted from LED driver chip 1 to LED driver chip N.

[0019] exist Figure 1 In the backlight system 100 shown, data signals may become abnormal or even be lost after multiple transmission stages, causing LED driver chips located later in the series to fail to receive correct data signals. When the communication frequency is low, the impact of this problem is relatively small and can be ignored; however, as the bandwidth of data transmission increases and the communication frequency rises, the impact of this problem increases, affecting the reliability of data transmission. Currently, with a fixed communication frequency pre-set, each LED driver chip can shape the received input signal before outputting it to prevent LED driver chips located later in the series from failing to receive data signals or receiving incorrect data signals. However, a fixed communication frequency limits the application.

[0020] In view of the above, an embodiment of the present invention is proposed for use in... Figure 1 In the single-wire communication scheme of the backlight system 100 shown, the controller 102 first sends a data frame header signal at a lower transmission frequency before sending the data signal at a higher transmission frequency. Because the transmission frequency of the data frame header signal is low, LED driver chips 1 to N can all receive the complete and correct data frame header signal and can perform shaping processing on the subsequently received data signals based on the frequency information of the data signal contained in the data frame header signal, so that the output format of the data signal conforms to the specification. Thus, Figure 1 In the backlight system 100 shown, LED driver chips located in any series position can obtain the correct data signal, thus improving the reliability of data transmission.

[0021] Figure 4 A schematic block diagram of an LED driver chip and a communication control circuit used therein, according to an embodiment of the present invention, is shown. Figure 5 It shows Figure 4 The flowchart below shows the communication control method implemented by the communication control circuit. Figure 4 and Figure 5 This paper describes in detail a single-wire communication scheme used in an LED driver chip according to an embodiment of the present invention.

[0022] like Figure 4As shown, the communication control circuit 400 used in the LED driver chip includes a decoding control unit 402 and a data shaping unit 404. The decoding control unit 402 is configured to output the frame header signal through the signal output port of the LED driver chip when it receives the frame header signal through the signal input port of the LED driver chip, determine whether the frame header signal is a data frame header signal, a synchronization frame header signal, or an instruction frame header signal, and switch the LED driver chip to a working mode that receives and shapes data signals when it determines that the frame header signal is a data frame header signal (i.e., execute step S502). The data shaping unit 404 is configured to shape the data signal based on the frequency information of the data signal contained in the data frame header signal when it receives the data signal through the signal input port of the LED driver chip, and output the shaped data signal through the signal output port of the LED driver chip (i.e., execute step S504).

[0023] In some embodiments, the frequency of the data frame header signal can be a multiple of the frequency of the data signal, such as 1 / 2, 1 / 3, 1 / 4, 1 / 8, 1 / 16, etc. The decoding control unit 402 can obtain the frequency information of the data signal based on the frequency of the data frame header signal and provide this information to the data shaping unit 404. The data shaping unit 404 can then shape the data signal received subsequently through the signal input port of the LED driver chip based on the frequency information before outputting it, ensuring that the output data signal conforms to specifications.

[0024] In some embodiments, the format of the frame header signal can be used to distinguish data frame header signals, synchronization frame header signals, and command frame header signals. For example, different combinations of pulse width and pulse duty cycle can be used to distinguish different frame header signals, or different combinations of one or more pulse widths can be used to distinguish different frame header signals.

[0025] In some embodiments, the decoding control unit 402 may short-circuit the signal input port and signal output port of the LED driver chip when no signal is received through the signal input port of the LED driver chip (i.e., when the signal input port of the LED driver chip is in an idle state).

[0026] In some embodiments, when the decoding control unit 402 receives the data frame header signal through the signal input port of the LED driver chip, it can maintain the short-circuit state between the signal input port and the signal output port of the LED driver chip, so as to output the data frame header signal without performing any processing on the data frame header signal.

[0027] In some embodiments, the decoding control unit 402 can maintain the short-circuit state between the signal input port and the signal output port of the LED driver chip when it receives a synchronization frame header signal or a command frame header signal through the signal input port of the LED driver chip, so as to output the synchronization frame header signal or the command frame header signal without performing any processing on the synchronization frame header signal or the command frame header signal. It should be noted that, in Figure 1 In the backlight system 100 shown, the controller 102 can send the synchronization header signal or the instruction header signal at a lower transmission frequency (e.g., the same transmission frequency as the data header signal). Since the transmission frequency of the synchronization header signal or the instruction header signal is low, all LED driver chips 1 to N can receive the complete and correct synchronization header signal or instruction header signal. Therefore, when the synchronization header signal or the instruction header signal is received, it is directly output to the next stage without the need for shaping.

[0028] In some embodiments, the decoding control unit 402 can short-circuit the signal input port and signal output port of the LED driver chip again after the LED driver chip has completed the transmission of data signals.

[0029] Figure 6 It shows Figure 1 The backlight system shown adopts Figure 4 The diagram shows example waveforms of the synchronization header signal and data header signal input to each stage of the LED driver chip. Data inputs 1 to N represent data inputs to LED driver chips 1 to N, respectively. Figure 6 As shown, the synchronization frame header signal and the data frame header signal are in Figure 1 The backlight system 100 shown has low transmission delay between LED driver chips at each level, and LED driver chips at each level can receive synchronization frame header signals and data frame header signals approximately synchronously. Therefore, it can achieve accurate and efficient data transmission while ensuring the consistency of synchronous control between LED driver chips at each level.

[0030] Figure 7 It shows Figure 1 The backlight system shown adopts Figure 4 The diagram shows example waveforms of the data frame header signals and data signals input to each stage of the LED driver chip. Data inputs 1 to N represent data inputs to LED driver chips 1 to N, respectively. Figure 7 As shown, in some cases, after shaping the data signal, the data shaping unit 404 can also delay the shaped data signal by one or more bits before outputting it. Additionally, in some cases, the data signal may include a start data signal and a main data signal; the start data signal may be a data signal with a predetermined data format and bit length (e.g., data signal 1010). Figure 1 The LED driver chips at each stage in the backlight system 100 shown can obtain their own position based on the number of shifts between the data frame header signal and the start data signal. Figure 1 The serial connection position in the backlight system 100 shown.

[0031] In summary, the communication control method and circuit used in LED driver chips according to embodiments of the present invention can achieve accurate and efficient data transmission while ensuring the synchronization of data transmission.

[0032] This invention can be implemented in other specific forms without departing from its spirit and essential characteristics. For example, the algorithm described in a particular embodiment can be modified without departing from the basic spirit of the invention. Therefore, the present embodiments are to be regarded as exemplary rather than limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and all changes falling within the meaning and scope of the claims and their equivalents are thus included within the scope of the invention.

Claims

1. A communication control method used in an LED driver chip, comprising: When a frame header signal is received through the signal input port of the LED driver chip, the frame header signal is output through the signal output port of the LED driver chip without any processing of the frame header signal. If the frame header signal is determined to be a data frame header signal, the LED driver chip is switched to a working mode of receiving data signals and performing shaping processing on the data signals. as well as When the data signal is received through the signal input port of the LED driver chip, the data signal is shaped based on the frequency information of the data signal contained in the data frame header signal, and the shaped data signal is output through the signal output port of the LED driver chip.

2. The communication control method for use in an LED driver chip according to claim 1, further comprising: When no signal is received through the signal input port of the LED driver chip, short-circuit the signal input port and the signal output port of the LED driver chip.

3. The communication control method for use in an LED driver chip according to claim 2, further comprising: When the data frame header signal is received through the signal input port of the LED driver chip, the signal input port and signal output port of the LED driver chip are kept short-circuited so that the data frame header signal is output without any processing of the data frame header signal.

4. The communication control method for use in an LED driver chip according to claim 2, further comprising: When a synchronization frame header signal or a command frame header signal is received through the signal input port of the LED driver chip, the signal input port and the signal output port of the LED driver chip are kept short-circuited so that the synchronization frame header signal or the command frame header signal can be output without any processing of the synchronization frame header signal or the command frame header signal.

5. The communication control method for use in an LED driver chip according to claim 2, further comprising: After the LED driver chip completes the transmission of the data signal, the signal input port and signal output port of the LED driver chip are shorted again.

6. The communication control method for use in an LED driver chip according to claim 1, further comprising: The shaped data signal is delayed by one or more bits before being output.

7. The communication control method for use in an LED driver chip according to claim 1, wherein, The data signal includes a start data signal and a main data signal, wherein the start data signal is a data signal with a predetermined data format and bit length.

8. The communication control method for use in an LED driver chip according to claim 4, wherein, The transmission frequency of any one of the data frame header signal, the synchronization frame header signal, and the instruction frame header signal is lower than the transmission frequency of the data signal.

9. A communication control circuit used in an LED driver chip, comprising: The decoding control unit is configured to output the frame header signal through the signal output port of the LED driver chip when the frame header signal is received through the signal input port of the LED driver chip, and to switch the LED driver chip to a working mode of receiving data signals and performing shaping processing on the data signals when it is determined that the frame header signal is a data frame header signal. as well as The data shaping unit is configured to, when receiving the data signal through the signal input port of the LED driver chip, perform shaping processing on the data signal based on the frequency information of the data signal contained in the data frame header signal, and output the shaped data signal through the signal output port of the LED driver chip.

10. The communication control circuit for use in an LED driver chip according to claim 9, wherein, The decoding control unit is further configured to obtain frequency information of the data signal based on the frequency of the data frame header signal, and to provide the frequency information of the data signal to the data shaping unit.

11. The communication control circuit for use in an LED driver chip according to claim 9, wherein, The decoding control unit is further configured to short-circuit the signal input port and signal output port of the LED driver chip when no signal is received through the signal input port of the LED driver chip.

12. The communication control circuit for use in an LED driver chip according to claim 11, wherein, The decoding control unit is further configured to maintain the short-circuit state of the signal input port and the signal output port of the LED driver chip when the data frame header signal is received through the signal input port of the LED driver chip, so as to output the data frame header signal without performing any processing on the data frame header signal.

13. The communication control circuit for use in an LED driver chip according to claim 11, wherein, The decoding control unit is further configured to maintain the short-circuit state of the signal input port and the signal output port of the LED driver chip when a synchronization frame header signal or an instruction frame header signal is received through the signal input port of the LED driver chip, so as to output the synchronization frame header signal or the instruction frame header signal without performing any processing on the synchronization frame header signal or the instruction frame header signal.

14. The communication control circuit for use in an LED driver chip according to claim 11, wherein, The decoding control unit is further configured to short-circuit the signal input port and signal output port of the LED driver chip again after the LED driver chip completes the transmission of the data signal.

15. The communication control circuit for use in an LED driver chip according to claim 9, wherein, The data shaping unit is further configured to delay the shaped data signal by one or more bits before outputting it.

16. The communication control circuit for use in an LED driver chip according to claim 9, wherein, The data signal includes a start data signal and a main data signal, wherein the start data signal is a data signal with a predetermined data format and bit length.

17. The communication control circuit for use in an LED driver chip according to claim 13, wherein, The transmission frequency of any one of the data frame header signal, the synchronization frame header signal, and the instruction frame header signal is lower than the transmission frequency of the data signal.

18. An LED driver chip, comprising the communication control circuit used in the LED driver chip according to any one of claims 9 to 17.

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