LED display driving circuit, display driving chip and display device

Abstract

The embodiment of the utility model provides an LED display driving circuit, a display driving chip and a display device. The LED display driving circuit comprises a reference current generation module, a driving current generation module and a driving module, the reference current generation module comprises a positive temperature coefficient resistor and a negative temperature coefficient resistor, and the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor. The reference current generating module can generate reference current of a zero temperature coefficient according to reference voltage and the zero temperature coefficient resistor, the driving current generating module can mirror the reference current into driving current, and the driving module can drive an LED according to the driving current. According to the LED display driving circuit, the stability of LED display can be improved, and the complexity of the circuit can be reduced.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the technical field of LED display, and particularly to an LED display driving circuit, a display driving chip, and a display device. Background Art

[0002] Currently, in analog circuit design, the temperature effect is an issue that cannot be ignored. The temperature effect causes the performance of the designed circuit to change non-linearly with temperature. In the research of display technology, the pixel circuit drives the light-emitting diode (LED) display, ensuring good linearity between the output current and the input signal, maintaining the stability of the output current, and reducing or even eliminating the influence of external disturbances on the circuit.

[0003] Once the driving of the LED is affected by the temperature effect, the LED will emit light abnormally, resulting in a decrease in the stability of the LED display. Summary of the Utility Model

[0004] Embodiments of the present disclosure provide an LED display driving circuit, a display driving chip, and a display device, which can improve the stability of the LED display and reduce the circuit complexity.

[0005] In a first aspect, the present disclosure provides an LED display driving circuit, including: a reference current generation module, a driving current generation module, and a driving module.

[0006] The input end of the reference current generation module receives a reference voltage with zero temperature coefficient. The output end of the reference current generation module is connected to the input end of the driving current generation module. The output end of the driving current generation module is connected to the input end of the driving module. The output end of the driving module is connected to the LED.

[0007] The reference current generation module includes a positive temperature coefficient resistor and a negative temperature coefficient resistor, where the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor.

[0008] The reference current generation module is configured to generate a reference current with zero temperature coefficient according to the reference voltage and the zero temperature coefficient resistor. The driving current generation module is configured to mirror the reference current into a driving current. The driving module is configured to drive the LED according to the driving current.

[0009] In some embodiments of the present disclosure, the reference current generation module further includes an operational amplifier, a first transistor, and a first current source.

[0010] The non-inverting input terminal of the operational amplifier is connected to the reference voltage. The inverting input terminal of the operational amplifier is connected to the first terminal of the positive temperature coefficient resistor, the first terminal of the negative temperature coefficient resistor, and the first terminal of the first transistor. The output terminal of the operational amplifier is connected to the control terminal of the first transistor. The second terminal of the first transistor is connected to the output terminal of the first current source. The input terminal of the first current source is connected to the power supply. The second terminals of the positive temperature coefficient resistor and the negative temperature coefficient resistor are grounded.

[0011] In some embodiments of the present disclosure, the first current source unit includes a second transistor.

[0012] The first terminal of the second transistor is connected to the power supply. The control terminal and the second terminal of the second transistor are connected to the second terminal of the first transistor.

[0013] In some embodiments of the present disclosure, the temperature coefficient of the zero temperature coefficient resistor is A*Rp + B*Rn, where A is the temperature coefficient of the positive temperature coefficient resistor, Rp is the resistance value of the positive temperature coefficient resistor, B is the temperature coefficient of the negative temperature coefficient resistor, and Rn is the resistance value of the negative temperature coefficient resistor.

[0014] In some embodiments of the present disclosure, the drive current generation module includes a second current source.

[0015] The input terminal of the second current source is connected to the power supply. The output terminal of the second current source is connected to the input terminal of the drive module. The second current source and the first current source form a current mirror structure.

[0016] In some embodiments of the present disclosure, the second current source includes a third transistor.

[0017] The first terminal of the third transistor is connected to the power supply. The control terminal of the third transistor is connected to the control terminal of the first current source. The second terminal of the third transistor is connected to the input terminal of the drive module.

[0018] In some embodiments of the present disclosure, the drive current generation module includes a plurality of second current sources. The second current sources are connected in parallel. Each second current source is controlled by a control signal to output or not output current.

[0019] The drive current generation module is further configured to adjust the magnitude of the drive current according to the control signals of the second current sources.

[0020] In some embodiments of the present disclosure, the drive module includes a digital-to-analog converter and a pixel circuit.

[0021] The input end of the digital-to-analog converter is connected to the output end of the driving current generation module, the output end of the digital-to-analog converter is connected to the input end of the pixel circuit, and the output end of the pixel circuit is connected to the LED.

[0022] In a second aspect, the present disclosure provides a display driving chip, including any LED display driving circuit provided in the first aspect.

[0023] In a third aspect, the present disclosure provides a display device, including an LED and any LED display driving circuit provided in the first aspect.

[0024] The positive electrode of the LED is connected to the output end of the LED display driving circuit, and the negative electrode of the LED is connected to the common voltage.

[0025] In the technical solution of the embodiment of the present disclosure, the LED display driving circuit includes a reference current generation module, a driving current generation module, and a driving module. The reference current generation module includes a positive temperature coefficient resistor and a negative temperature coefficient resistor, and the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor. The reference current generation module can generate a reference current with zero temperature coefficient according to the reference voltage and the zero temperature coefficient resistor. The driving current generation module can mirror the reference current into a driving current, and the driving module can drive the LED according to the driving current. The LED display driving circuit provided by the present disclosure has the following beneficial effects:

[0026] First, since the reference current has zero temperature coefficient, the driving current also has zero temperature coefficient. Thus, the LED display driving circuit can drive the LED according to the driving current with zero temperature coefficient, which can reduce the temperature sensitivity of the LED display driving circuit, thereby improving the stability of LED display.

[0027] Second, the zero temperature coefficient resistor formed by the parallel positive temperature coefficient resistor and negative temperature coefficient resistor has a change trend with temperature similar to that of the reference voltage. Then, the change of the zero temperature coefficient resistor with temperature can offset the change of the reference voltage with temperature. Therefore, a reference current with a larger zero temperature range can be obtained, which can improve the stability of the reference current, thereby further improving the stability of LED display.

[0028] Third, since the stability of the reference current is relatively high, the trimming process can be reduced when generating the driving current, thereby reducing the complexity of the LED display driving circuit.

[0029] The above description is only an overview of the technical solution of the embodiment of the present application. In order to be able to understand the technical means of the embodiment of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the embodiment of the present application more obvious and understandable, the following specifically illustrates the specific implementation manners of the present application. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0031] Figure 1 FIG. is a schematic structural diagram of an LED display driving circuit provided by an embodiment of the present disclosure.

[0032] Figure 2 FIG. is a schematic circuit diagram of an LED display driving circuit provided by an embodiment of the present disclosure.

[0033] Figure 3 FIG. is a schematic diagram of the temperature characteristic curves of a zero temperature coefficient resistor and a reference voltage provided by an embodiment of the present disclosure.

[0034] Figure 4 FIG. is a schematic circuit diagram of another LED display driving circuit provided by an embodiment of the present disclosure.

[0035] Figure 5 FIG. is a schematic circuit diagram of yet another LED display driving circuit provided by an embodiment of the present disclosure

[0036] Figure 6 FIG. is a schematic circuit diagram of yet another LED display driving circuit provided by an embodiment of the present disclosure.

[0037] Figure 7 FIG. is a schematic structural diagram of a display device provided by an embodiment of the present disclosure. Detailed Description of the Embodiments

[0038] In order to make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts also belong to the scope of protection of the present disclosure.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Further will be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless expressly defined herein otherwise. As used herein, a statement that two or more parts are "connected" together shall mean that the parts are directly joined together or joined through one or more intervening components.

[0040] Reference to "embodiments" in this disclosure means that a particular feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of this application. The phrase "embodiments" appearing in various places in the specification is not necessarily all referring to the same embodiment, nor are they independent or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described in this disclosure can be combined with other embodiments.

[0041] Furthermore, the terms "first", "second", etc. in the description and claims of this disclosure or in the above-mentioned drawings are used to distinguish different objects and not to describe a particular order, and may explicitly or implicitly include one or more of such features.

[0042] The term "and / or" in this disclosure is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0043] In the description of this disclosure, unless otherwise stated, the meanings of "a plurality" and "at least two" refer to more than two (including two). Similarly, "multiple groups" and "at least two groups" refer to more than two groups (including two groups).

[0044] To enable those skilled in the art of this technology to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings.

[0045] Currently, in analog circuit design, the temperature effect is a non-negligible problem, and the temperature effect will cause the performance of the designed circuit to change non-linearly with temperature.

[0046] In the research of display technology, the pixel circuit is used as the drive of LED display, which ensures good linearity between the output current and the input signal, maintains the stability of the output current, and reduces or even eliminates the influence of the circuit by external disturbances. Once the drive of the LED is affected by the temperature effect, it will cause abnormal light emission of the LED, resulting in reduced stability of the LED display.

[0047] To solve the above technical problems, the present disclosure provides an LED display driving circuit, including a reference current generating module, a driving current generating module, and a driving module. The reference current generating module includes a positive temperature coefficient resistor and a negative temperature coefficient resistor, and the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor. The reference current generating module can generate a reference current with zero temperature coefficient according to the reference voltage and the zero temperature coefficient resistor. The driving current generating module can mirror the reference current into a driving current, and the driving module can drive the LED according to the driving current. The LED display driving circuit provided by the present disclosure has the following beneficial effects:

[0048] First, since the reference current has zero temperature coefficient, the driving current also has zero temperature coefficient. Thus, the LED display driving circuit can drive the LED according to the driving current with zero temperature coefficient, which can reduce the temperature sensitivity of the LED display driving circuit, thereby improving the stability of the LED display.

[0049] Second, the zero temperature coefficient resistor formed by the parallel positive temperature coefficient resistor and negative temperature coefficient resistor has a change trend with temperature similar to that of the reference voltage. Then, the change of the zero temperature coefficient resistor with temperature can offset the change of the reference voltage with temperature, so a reference current with a larger zero temperature range can be obtained, which can improve the stability of the reference current, thereby further improving the stability of the LED display.

[0050] Third, due to the high stability of the reference current, the trimming process can be reduced when generating the driving current, thereby reducing the complexity of the LED display driving circuit.

[0051] The technical solutions of the present disclosure will be described in detail below with several specific embodiments.

[0052] Figure 1 FIG. is a schematic structural diagram of an LED display driving circuit provided by an embodiment of the present disclosure. As Figure 1 shown, the LED display driving circuit 100 includes a reference current generating module 110, a driving current generating module 120, and a driving module 130. The reference current generating module 110 includes a positive temperature coefficient resistor and a negative temperature coefficient resistor, and the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor.

[0053] Among them, the input end of the reference current generation module 110 receives a reference voltage Vref with zero temperature coefficient. The output end of the reference current generation module 110 is connected to the input end of the drive current generation module 120. The output end of the drive current generation module 120 is connected to the input end of the drive module 130. The output end of the drive module 130 is connected to the LED.

[0054] The reference current generation module 110 is configured to generate a reference current Iref with zero temperature coefficient according to the reference voltage Vref and a zero temperature coefficient resistor. The drive current generation module 120 is configured to mirror the reference current Iref into a drive current Idrv. The drive module 130 is configured to drive the LED according to the drive current Idrv.

[0055] Exemplarily, Figure 2 is a circuit schematic diagram of an LED display driving circuit provided by an embodiment of the present disclosure. As Figure 2 shown, the reference current generation module 110 includes an operational amplifier OPA, a first transistor M1, a first current source source1, a positive temperature coefficient resistor Rptc, and a negative temperature coefficient resistor Rntc.

[0056] Among them, the non-inverting input end of the operational amplifier OPA is connected to the reference voltage Vref. The inverting input end of the operational amplifier OPA is connected to the first end of the positive temperature coefficient resistor Rptc, the first end of the negative temperature coefficient resistor Rntc, and the first end of the first transistor M1. The output end of the operational amplifier OPA is connected to the control end of the first transistor M1. The second end of the first transistor M1 is connected to the output end of the first current source source1. The input end of the first current source source1 is connected to the power supply. The second ends of the positive temperature coefficient resistor Rptc and the negative temperature coefficient resistor Rntc are grounded.

[0057] Specifically, the power supply can provide a power supply voltage VDD. The input end of the first current source source1 can receive the power supply voltage VDD. The first transistor M1 is an N-type metal oxide semiconductor field effect transistor (N-Metal Oxide Semiconductor Field Effect Transistor, NMOS).

[0058] The gate of the first transistor M1 is connected to the output end of the operational amplifier OPA. The source of the first transistor M1 is connected to the inverting input end of the operational amplifier OPA, the first end of the positive temperature coefficient resistor Rptc, and the first end of the negative temperature coefficient resistor Rntc. The drain of the first transistor M1 is connected to the output end of the first current source source1.

[0059] The positive temperature coefficient resistor Rptc has a temperature coefficient of A and A > 0, and the resistance value of the positive temperature coefficient resistor Rptc is Rp. The negative temperature coefficient resistor Rntc has a temperature coefficient of B and B < 0, and the resistance value of the negative temperature coefficient resistor Rntc is Rn. Then, the temperature coefficient of the resistance after the parallel connection of the positive temperature coefficient resistor Rptc and the negative temperature coefficient resistor Rntc is A*Rp + B*Rn. Since A > 0 and B < 0, by selecting a positive temperature coefficient resistor Rptc and a negative temperature coefficient resistor Rntc with specific resistance values and temperature coefficients, A*Rp + B*Rn can be made equal to 0, thereby obtaining a zero temperature coefficient resistor.

[0060] In other embodiments, the reference current generation module 110 may further include a plurality of positive temperature coefficient resistors Rptc and / or a plurality of negative temperature coefficient resistors Rntc. Each positive temperature coefficient resistor Rptc is connected in parallel, and each negative temperature coefficient resistor Rntc is connected in parallel. The present disclosure does not specifically limit the number of positive temperature coefficient resistors Rptc and the number of negative temperature coefficient resistors Rntc in the reference current generation module 110.

[0061] For example, the reference current generation module 110 includes N1 positive temperature coefficient resistors Rptc connected in parallel and N2 negative temperature coefficient resistors Rntc connected in parallel, where both N1 and N2 are integers greater than 1. The temperature coefficient of the resistance after the parallel connection of the N1 positive temperature coefficient resistors Rptc connected in parallel and the N2 negative temperature coefficient resistors Rntc connected in parallel can be expressed as:

[0062]

[0063] where Ai represents the temperature coefficient of the i-th positive temperature coefficient resistor Rptc, Rpi represents the resistance value of the i-th positive temperature coefficient resistor Rptc, Bj represents the temperature coefficient of the j-th negative temperature coefficient resistor Rntc, and Rnj represents the resistance value of the j-th negative temperature coefficient resistor Rntc.

[0064] In this way, by selecting positive temperature coefficient resistors Rptc and negative temperature coefficient resistors Rntc with certain specific temperature coefficients and specific resistance values, the above formula can be made equal to zero, thereby obtaining a zero temperature coefficient resistor.

[0065] The reference voltage Vref can be loaded on the zero temperature coefficient resistor through the clamping function of the operational amplifier OPA. Since the reference voltage Vref is a zero temperature coefficient voltage, it is equivalent to loading a zero temperature coefficient voltage on the zero temperature coefficient resistor. Therefore, a zero temperature coefficient current, that is, the reference current Iref, can be obtained.

[0066] It should be noted that in the embodiments of the present disclosure, only NMOS is used as an example to illustrate the first transistor M1. In practical applications, the first transistor M1 can also be a PMOS, or other types of transistors such as triodes. And if other types of transistors are used, the connection relationships between the components inside the reference current generation module 110 need to be adjusted accordingly.

[0067] Exemplarily, continue to refer to Figure 2 , the drive current generation module 120 includes a second current source source2. The input end of the second current source source2 is connected to the power supply, the output end of the second current source source2 is connected to the input end of the drive module 130, and the second current source source2 and the first current source source1 form a current mirror structure.

[0068] The current in the branch where the first current source source1 is located is the reference current Iref. Since the second current source source2 and the first current source source1 form a current mirror structure, the second current source source2 can mirror, mirror amplify or mirror reduce the reference current Iref proportionally to obtain the drive current Idrv. For example, Idrv = Iref, M * Iref or Iref / M, where M is an integer greater than 1. Since the reference current Iref is a zero temperature coefficient current, the drive current Idrv is also a zero temperature coefficient current.

[0069] Exemplarily, continue to refer to Figure 2 , the drive module 130 includes a digital-to-analog converter DAC and a pixel circuit Pixel. The input end of the digital-to-analog converter DAC is connected to the output end of the drive current generation module 120, the output end of the digital-to-analog converter DAC is connected to the input end of the pixel circuit Pixel, and the output end of the pixel circuit Pixel is connected to the LED.

[0070] The digital-to-analog converter DAC can receive the zero temperature coefficient drive current Idrv and perform digital-to-analog conversion on the drive current Idrv to obtain an analog drive signal. After receiving the analog drive signal, the pixel circuit Pixel drives the LED according to the analog drive signal to make the LED emit light or not emit light.

[0071] In this way, the drive module 130 drives the LED according to the zero temperature coefficient drive current Idrv, which can reduce the sensitivity of the drive module 130 to temperature, improve the stability of the LED display drive circuit 100, and thus improve the stability of the LED display.

[0072] Although the reference voltage Vref in the embodiments of the present disclosure is a zero-temperature coefficient voltage, it is only within a certain temperature range. When the temperature exceeds this temperature range, the reference voltage Vref still has a certain change. The zero-temperature coefficient resistor provided by the present disclosure is also within a certain temperature range. When the temperature exceeds this temperature range, the resistance value also has a certain fluctuation.

[0073] Figure 3 It is a schematic diagram of the temperature characteristic curves of the zero-temperature coefficient resistor and the reference voltage provided by the embodiments of the present disclosure. As Figure 3 shown in part (a) thereof, when the temperature is higher than the upper limit of the temperature range of the zero-temperature coefficient, the reference voltage Vref decreases as the temperature increases. When the temperature is lower than the lower limit of the temperature range of the zero-temperature coefficient, the reference voltage Vref decreases as the temperature decreases.

[0074] The zero-temperature coefficient resistor formed by the parallel positive temperature coefficient resistor Rptc and negative temperature coefficient resistor Rntc in the present disclosure is Rztc, and the zero-temperature coefficient resistor formed by the traditional series positive temperature coefficient resistor Rptc and negative temperature coefficient resistor Rntc is Rztc'.

[0075] When the temperature is higher than the upper limit of the temperature range of the zero-temperature coefficient, the resistance value of the zero-temperature coefficient resistor Rztc decreases as the temperature increases. When the temperature is lower than the lower limit of the temperature range of the zero-temperature coefficient, the resistance value of the zero-temperature coefficient resistor Rztc decreases as the temperature decreases. As Figure 3 shown in part (b) thereof.

[0076] When the temperature is higher than the upper limit of the temperature range of the zero-temperature coefficient, the resistance value of the zero-temperature coefficient resistor Rztc' increases as the temperature increases. When the temperature is lower than the lower limit of the temperature range of the zero-temperature coefficient, the zero-temperature coefficient resistor Rztc' increases as the temperature decreases. As Figure 3 shown in part (c) thereof.

[0077] In this way, the change trend of the zero-temperature coefficient resistor Rztc with temperature is similar to the change trend of the reference voltage Vref. Then, the change of the zero-temperature coefficient resistor Rztc with temperature can offset the change of the reference voltage Vref with temperature. Therefore, a reference current Iref with a larger zero-temperature range can be obtained, which can improve the stability of the reference current Iref, and thus can further improve the stability of LED display.

[0078] In addition, due to the high stability of the reference current Iref, the trimming process can be reduced when generating the drive current Idrv, thereby reducing the complexity of the LED display drive circuit 100.

[0079] In some embodiments, the drive current generation module 120 includes a second current source source2, as Figure 2 shown.

[0080] In other embodiments, the drive current generation module 120 may include a plurality of second current sources source2, wherein the second current sources source2 are connected in parallel, and each second current source source2 is controlled by a control signal to output or not output current. The drive current generation module 120 is further configured to adjust the magnitude of the drive current Idrv according to the control signals of the second current sources source2.

[0081] Exemplarily, the control signal may be an enable signal. Figure 4 The circuit schematic diagram of another LED display driving circuit provided by an embodiment of the present disclosure is shown in Figure 4 shown, and the enable terminals of the second current sources source2 are connected to an enable signal.

[0082] As Figure 4 shown, the drive current generation module 120 includes two second current sources source2, denoted as the second current source source2_1 and the second current source source2_2 respectively. Among them, the second current source source2_1 and the second current source source2_2 are connected in parallel, and the second current source source2_1 and the second current source source2_2 are connected between the power supply and the input end of the drive module 130. The enable terminal of the second current source source2_1 may receive a first enable signal, that is, a first control signal, and the control terminal of the second current source source2_2 may receive a second enable signal, that is, a second control signal.

[0083] The first current source source, the second current source source2_1, and the second current source source2_2 form a current mirror structure. When the first enable signal is an enable signal, the second current source source2_1 can mirror the reference current Iref as the first sub-drive current Idrv1. When the second enable signal is an enable signal, the second current source source2_2 can mirror the reference current Iref as the second sub-drive current Idrv2. When the first enable signal is a non-enable signal, the second current source source2_1 stops working. When the second enable signal is a non-enable signal, the second current source source2_2 stops working.

[0084] Among them, the magnitudes of the first sub-drive current Idrv1 and the second sub-drive current Idrv2 may be the same or different, and the present disclosure does not make specific limitations thereto.

[0085] For example, when the first enable signal is an enable signal and the second enable signal is a non - enable signal, the driving current Idrv generated by the driving current generation module 120 is equal to the first sub - driving current Idrv1, that is, Idrv = Idrv1. When the first enable signal is a non - enable signal and the second enable signal is an enable signal, the driving current Idrv generated by the driving current generation module 120 is equal to the second sub - driving current Idrv2, that is, Idrv = Idrv2. When the first enable signal is an enable signal and the second enable signal is an enable signal, the driving current Idrv generated by the driving current generation module 120 is equal to the sum of the first sub - driving current Idrv1 and the second sub - driving current Idrv2, that is, Idrv = Idrv1 + Idrv2.

[0086] In this way, the driving current generation module 120 can obtain driving currents Idrv of different magnitudes according to the first enable signal and the second enable signal.

[0087] In other embodiments, the control signal can be the on - off control signal of the switch in the branch where the second current source source2 is located. Figure 5 The circuit schematic diagram of another LED display driving circuit provided by an embodiment of the present disclosure is shown in Figure 5 As shown, each branch where the second current source source2 is located includes a second current source source2 and a switch K. The control end of each switch K is connected to the control signal, and the switch K can control whether the corresponding branch where the second current source source2 is located outputs current.

[0088] As Figure 5 shown, the driving current generation module 120 includes two second current sources source2, denoted as the second current source source2_1 and the second current source source2_2 respectively. Among them, the second current source source2_1 and the second current source source2_2 are connected in parallel, and the second current source source2_1 and the second current source source2_2 are connected between the power supply and the input end of the driving module 130. The output end of the second current source source2_1 is connected to the first end of the switch K_1, the second end of the switch K_1 is connected to the output end of the driving current generation module 120, and the control end of the switch K_1 receives the first on - off control signal, that is, the first control signal. The output end of the second current source source2_2 is connected to the first end of the switch K_2, the second end of the switch K_2 is connected to the output end of the driving current generation module 120, and the control end of the switch K_2 receives the second on - off control signal, that is, the second control signal.

[0089] The first current source "source", the second current source "source2_1" and the second current source "source2_2" form a current mirror structure. When the first on-off control signal is an on signal, the second current source "source2_1" can mirror the reference current Iref into the first sub-driving current Idrv1. When the second on-off control signal is an on signal, the second current source "source2_2" can mirror the reference current Iref into the second sub-driving current Idrv2. When the first on-off control signal is an off signal, the second current source "source2_1" stops working. When the second on-off control signal is an off signal, the second current source "source2_2" stops working.

[0090] For example, when the first on-off control signal is an on signal and the second on-off control signal is an off signal, the driving current Idrv generated by the driving current generation module 120 is equal to the first sub-driving current Idrv1, that is, Idrv = Idrv1. When the first on-off control signal is an off signal and the second on-off control signal is an on signal, the driving current Idrv generated by the driving current generation module 120 is equal to the second sub-driving current Idrv2, that is, Idrv = Idrv2. When the first on-off control signal is an on signal and the second on-off control signal is an on signal, the driving current Idrv generated by the driving current generation module 120 is equal to the sum of the first sub-driving current Idrv1 and the second sub-driving current Idrv2, that is, Idrv = Idrv1 + Idrv2.

[0091] In this way, the driving current generation module 120 can obtain driving currents Idrv of different magnitudes according to the first on-off control signal and the second on-off control signal.

[0092] It should be noted that Figure 4 and Figure 5 only exemplarily shows that the driving current generation module 120 includes two second current sources "source2". In practical applications, the driving current generation module 120 may also include three or more second current sources "source2". Correspondingly, each of the three or more second current sources "source2" is controlled by a control signal. In this way, the driving current generation module 120 can adjust the magnitude of the driving current Idrv according to three or more control signals.

[0093] The present disclosure does not specifically limit the number of the second current sources "source2" in the driving current generation module 120, nor does it specifically limit the number of received control signals, and only limits that the number of the second current sources "source2" is equal to the number of control signals.

[0094] In the embodiments of the present disclosure, the drive current generation module includes a plurality of second current sources. The drive current generation module can adjust the magnitude of the drive current according to the control signals of the second current sources to obtain drive currents of different magnitudes, so as to be able to adjust the brightness of the LED.

[0095] In some embodiments, Figure 6 FIG. is a circuit schematic diagram of another LED display driving circuit provided by the embodiments of the present disclosure. As Figure 6 shown, the first current source source1 includes a second transistor M2. The first end of the second transistor M2 is connected to the power supply, and the control end and the second end of the second transistor M2 are connected to the second end of the first transistor M1.

[0096] Exemplarily, as Figure 6 shown, the second transistor M2 is a PMOS. The source of the second transistor M2 receives the power supply voltage VDD, and the gate and the drain of the second transistor M2 are connected to the drain of the first transistor M1. The current flowing through the second transistor M2 is the reference current Iref.

[0097] As Figure 6 shown, the second current source source2 includes a third transistor M3. The first end of the third transistor M3 is connected to the power supply, the control end of the third transistor M3 is connected to the control end of the first current source source1, and the second end of the third transistor M3 is connected to the input end of the driving module 130.

[0098] Exemplarily, as Figure 6 shown, the third transistor M3 is a PMOS. The source of the third transistor M3 receives the power supply voltage VDD, the gate of the third transistor M3 is connected to the gate of the second transistor M2, and the drain of the third transistor M3 is connected to the input end of the digital-to-analog converter DAC.

[0099] The third transistor M3 and the second transistor M3 form a current mirror structure. The third transistor M3 can mirror the current flowing through the second transistor M3, that is, mirror the reference current Iref. Specifically, the magnitude of the mirrored current depends on the ratio of the aspect ratio of the third transistor M3 to the aspect ratio of the second transistor M2.

[0100] It should be noted that in the embodiments of the present disclosure, only PMOS is used as an example to exemplarily illustrate the second transistor M2 and the third transistor M3. In practical applications, the second transistor M2 and the third transistor M3 can also be NMOS, or other types of transistors such as triodes. And if other types of transistors are used, the connection relationships between the second transistor M2 and the third transistor M3 and other devices need to be adjusted accordingly.

[0101] In some embodiments, the LED display driving circuit 100 further includes a bandgap reference module. The output terminal of the bandgap reference module is connected to the input terminal of the reference current generation module 110. The bandgap reference module can generate a reference voltage Vref and transmit the reference voltage Vref to the input terminal of the reference current generation module 110.

[0102] An embodiment of the present disclosure further provides a display driving chip, including the LED display driving circuit 100 provided in any of the above embodiments.

[0103] In some embodiments, the display driving chip further includes a bandgap reference module. The output terminal of the bandgap reference module is connected to the input terminal of the LED display driving circuit 100. The bandgap reference module can generate a reference voltage Vref and transmit the reference voltage Vref to the input terminal of the LED display driving circuit 100.

[0104] The display driving chip provided by the embodiment of the present disclosure includes the LED display driving circuit 100 provided in any of the above embodiments, and has the same functional modules and beneficial effects as the LED display driving circuit 100, which will not be elaborated here.

[0105] An embodiment of the present disclosure further provides a display device, including an LED and the LED display driving circuit 100 provided in any of the above embodiments.

[0106] Figure 7 FIG. is a schematic structural diagram of a display device provided by an embodiment of the present disclosure. As Figure 7 shown, the display device 200 includes an LED and an LED display driving circuit 100. Among them, the positive electrode of the LED is connected to the output terminal of the LED display driving circuit 100, and the negative electrode of the LED is connected to the common voltage Vcom.

[0107] Exemplarily, the display device 200 may be an organic light emitting diode (OLED) display, or may be a Micro LED display.

[0108] In some embodiments, the display device 200 further includes a bandgap reference module. The output terminal of the bandgap reference module is connected to the input terminal of the LED display driving circuit 100. The bandgap reference module can generate a reference voltage Vref and transmit the reference voltage Vref to the input terminal of the LED display driving circuit 100.

[0109] Exemplarily, the bandgap reference module and the LED display driving circuit 100 may be integrated in the same chip. For example, the bandgap reference module and the LED display driving circuit 100 may be integrated in the display driving chip.

[0110] In other embodiments, the bandgap reference module and the LED display driving circuit 100 may be integrated on different chips. For example, the LED display driving circuit 100 may be integrated in a display driving chip, and the bandgap reference module may be integrated in a reference voltage chip.

[0111] The display device provided by an embodiment of the present disclosure includes the LED display driving circuit 100 provided by any one of the above embodiments, and has the same functional modules and beneficial effects as the LED display driving circuit 100, which will not be elaborated here.

[0112] Unless otherwise clearly specified in the context, the singular forms of the words used in this specification and the appended claims include the plural, and vice versa. Thus, when referring to the singular, the corresponding plural is generally included. Similarly, the terms "comprising" and "including" will be interpreted as inclusive rather than exclusive. Likewise, the term "including" and "or" should be interpreted as inclusive, unless such an interpretation is clearly prohibited in this specification. Where the term "example" is used in this specification, especially when it is located after a group of terms, the "example" is merely exemplary and explanatory, and should not be considered exclusive or extensive.

[0113] Further aspects and scope of adaptability become apparent from the description provided herein. It should be understood that the various aspects of the present application may be implemented alone or in combination with one or more other aspects. It should also be understood that the description herein and the specific embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0114] The above has described several embodiments of the present disclosure in detail. However, obviously, those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the appended claims.

Claims

1. An LED display drive circuit, characterized in that: include: A reference current generating module, a driving current generating module and a driving module; The input end of the reference current generating module receives a reference voltage with a zero temperature coefficient, the output end of the reference current generating module is connected to the input end of the driving current generating module, the output end of the driving current generating module is connected to the input end of the driving module, and the output end of the driving module is connected to the LED; The reference current generating module includes a positive temperature coefficient resistor and a negative temperature coefficient resistor, wherein the positive temperature coefficient resistor and the negative temperature coefficient resistor are connected in parallel to obtain a zero temperature coefficient resistor; The reference current generating module is configured to generate a reference current with a zero temperature coefficient according to the reference voltage and the zero temperature coefficient resistor; The driving current generating module is configured to mirror the reference current into a driving current; The driving module is configured to drive the LED according to the driving current.

2. The LED display driving circuit according to claim 1, characterized in that: The reference current generating module further includes an operational amplifier, a first transistor and a first current source; The non-inverting input terminal of the operational amplifier is connected to the reference voltage, the inverting input terminal of the operational amplifier is connected to the first end of the positive temperature coefficient resistor, the first end of the negative temperature coefficient resistor and the first end of the first transistor, the output terminal of the operational amplifier is connected to the control end of the first transistor, the second end of the first transistor is connected to the output end of the first current source, the input end of the first current source is connected to a power supply, and the second end of the positive temperature coefficient resistor and the second end of the negative temperature coefficient resistor are grounded.

3. The LED display driving circuit according to claim 2, characterized in that: The first current source unit includes a second transistor; The first end of the second transistor is connected to the power supply, and the control end of the second transistor and the second end of the second transistor are connected to the second end of the first transistor.

4. The LED display driving circuit according to claim 1, characterized in that: The temperature coefficient of the zero temperature coefficient resistor is A*Rp+B*Rn, where A is the temperature coefficient of the positive temperature coefficient resistor, Rp is the resistance value of the positive temperature coefficient resistor, B is the temperature coefficient of the negative temperature coefficient resistor, and Rn is the resistance value of the negative temperature coefficient resistor.

5. The LED display driving circuit according to claim 2 or 3, characterized in that: The driving current generating module includes a second current source; An input end of the second current source is connected to the power supply, an output end of the second current source is connected to an input end of the driving module, and the second current source and the first current source form a current mirror structure.

6. The LED display driving circuit according to claim 5, characterized in that: The second current source includes a third transistor; A first end of the third transistor is connected to the power supply, a control end of the third transistor is connected to the control end of the first current source, and a second end of the third transistor is connected to the input end of the driving module.

7. The LED display driving circuit according to claim 5, characterized in that: The driving current generating module includes a plurality of second current sources; The second current sources are connected in parallel, and each of the second current sources is controlled by a control signal to output or not output current; The driving current generating module is further configured to adjust the magnitude of the driving current according to the control signal of each second current source.

8. The LED display driving circuit according to any one of claims 1 to 4, characterized in that: The driving module includes a digital-to-analog converter and a pixel circuit; The input end of the digital-to-analog converter is connected to the output end of the driving current generating module, the output end of the digital-to-analog converter is connected to the input end of the pixel circuit, and the output end of the pixel circuit is connected to the LED.

9. A display driver chip, characterized in that: The LED display driving circuit comprises the LED display driving circuit according to any one of claims 1 to 8.

10. A display device, characterized in that: comprising an LED and the LED display driving circuit according to any one of claims 1 to 8; The positive electrode of the LED is connected to the output end of the LED display driving circuit, and the negative electrode of the LED is connected to the common voltage.

Images