LED driver chip, LED control circuit, backlight module and display device

Abstract

The present application provides an LED driver chip, an LED control circuit, a backlight module and a display device, and relates to the technical field of electronic circuits. The LED driver chip includes: a data signal control circuit and a boost circuit; the data signal control circuit is connected to the boost circuit; the output end of the boost circuit is configured to be connected to the input end of the H-bridge circuit outside the LED driver chip; the data signal control circuit is used to select the target boost ratio of the boost circuit, so that the boost circuit performs a boost process on the voltage received by itself based on the target boost ratio, and transmits the boosted voltage to the H-bridge circuit, so that the H-bridge circuit drives the connected LED. Compared with the method of directly boosting the voltage to the required voltage, the cross-voltage of each boost can be reduced, and the energy loss during voltage conversion can be reduced, thereby improving the output efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to an LED driver chip, an LED control circuit, a backlight module and a display device. Background Art

[0002] LED (light emitting diode) dimming control driver chip (hereinafter referred to as LED driver chip) usually has the characteristics of high current control accuracy and flexible dimming mode. Since LED driver chip has high voltage output (that is, the output voltage required to drive LED is higher than the input voltage of LED driver chip), the voltage difference between it and the input voltage is large, and there is a large energy loss during voltage conversion, which leads to low output efficiency. Summary of the invention

[0003] The present application provides an LED driver chip, an LED control circuit, a backlight module and a display device to solve the problem that the existing LED driver chip has large energy loss during voltage conversion, thereby resulting in low efficiency.

[0004] In a first aspect, the present application provides an LED driver chip, comprising: a data signal control circuit and a boost circuit; the data signal control circuit is connected to the boost circuit; the output end of the boost circuit is configured to be connected to the input end of an H-bridge circuit outside the LED driver chip; the data signal control circuit is used to select a target boost ratio of the boost circuit, so that the boost circuit boosts the voltage it receives based on the target boost ratio, and transmits the boosted voltage to the H-bridge circuit, so that the H-bridge circuit drives the connected LED.

[0005] In the embodiment of the present application, the voltage can be boosted in sequence by the boost circuit and the H-bridge circuit to obtain the voltage required to drive the LED (hereinafter referred to as the required voltage). Therefore, for the LED driver chip, it is not necessary to directly convert the voltage to the required voltage, but first convert it to the voltage boosted by the target boost ratio (hereinafter referred to as the intermediate voltage), and then use the H-bridge circuit to convert the intermediate voltage to the required voltage. In this way, through multi-stage voltage conversion, compared with the method of directly boosting the voltage to the required voltage, the cross-voltage of each boost can be reduced, and the energy loss during voltage conversion can be reduced, thereby improving the output efficiency.

[0006] In combination with the technical solution provided in the first aspect above, in some possible implementations, the LED driver chip also includes: an H-bridge control circuit; an enable end of the H-bridge control circuit is connected to the data signal control circuit, and the control end of the H-bridge control circuit is configured to be connected to the enable end of the H-bridge circuit; the H-bridge control circuit is used to change the topology of the H-bridge circuit connected to itself under the control of the data signal control circuit, so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

[0007] In the embodiment of the present application, the H-bridge circuit can be controlled by the H-bridge control circuit, so that the topological structure of the H-bridge circuit can be changed, so that the H-bridge circuit can boost the intermediate voltage output by the boost circuit according to the set multiple, so that the voltage output by the H-bridge circuit can meet the driving requirements of the LED (that is, reach the required voltage), thereby improving the reliability of the solution.

[0008] In combination with the technical solution provided in the first aspect above, in some possible implementations, the LED driver chip further includes: a switch control circuit, an enable end of the switch control circuit is connected to the data signal control circuit, each output end of the switch control circuit is configured to be connected to an enable end of an LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit.

[0009] In the embodiment of the present application, the switch control circuit sends an enable signal to each LED branch circuit respectively, so as to realize the control of multiple LED branch circuits. At the same time, since the switch control circuit can control the LED branch circuit to be in a disabled state (i.e., an open circuit state), it can prevent the occurrence of leakage caused by the capacitor in the circuit continuing to discharge to the LED branch circuit when the input voltage is disconnected; it can also control the LED branch circuit to be disabled when the LED branch circuit is short-circuited, so as to solve the short-circuit problem of the LED branch circuit.

[0010] In combination with the technical solution provided in the first aspect above, in some possible implementations, the LED driver chip also includes: a constant current PWM (pulse width modulation) current control circuit, an enable end of the constant current PWM current control circuit is connected to the data signal control circuit, each output end of the constant current PWM current control circuit is configured to be connected to an LED branch circuit, and the constant current PWM current control circuit is used to control the current size of each of the LED branch circuits under the control of the data signal control circuit.

[0011] In the embodiment of the present application, the current magnitude of each LED branch circuit is controlled by a constant current PWM control current circuit, so that each LED branch circuit can be dimmed more precisely.

[0012] In combination with the technical solution provided in the first aspect above, in some possible implementations, each of the LED branch circuits includes a first switch, a third resistor and multiple LEDs connected in series; each output end of the constant current PWM control current circuit is respectively configured to be connected to an enable end of the first switch, and the voltage acquisition interface of the constant current PWM control current circuit is configured to be connected to the third resistor. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor, so as to control the current size of each of the LED branch circuits.

[0013] In the embodiment of the present application, the constant current PWM control current circuit can determine the current of the LED branch circuit by detecting the voltage of the third resistor, and then adjust the current of the LED branch circuit by adjusting the conduction degree of the first switch. In this way, the current of the LED branch circuit will not directly flow through the constant current PWM control current circuit. Therefore, even if the current in the LED branch circuit is large, it will not cause the constant current PWM control current circuit to overheat, thereby improving the safety of the LED driver chip.

[0014] In combination with the technical solution provided in the first aspect above, in some possible implementations, the LED driver chip further includes: a switch control circuit and a constant current PWM control current circuit, the enable end of the switch control circuit is connected to the data signal control circuit, each output end of the switch control circuit is configured to be connected to the enable end of an LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit; the enable end of the constant current PWM control current circuit is connected to the data signal control circuit, each output end of the constant current PWM control current circuit is configured to be connected to an LED branch circuit, and the constant current PWM control current circuit is used to control the current size of each of the LED branch circuits under the control of the data signal control circuit.

[0015] In a second aspect, the present application provides an LED control circuit, comprising: an LED branch circuit, an H-bridge circuit, and an LED driver chip as described in the first aspect and / or in combination with any possible implementation of the first aspect; the output end of the boost circuit of the driver chip is connected to the input end of the H-bridge circuit, the output end of the H-bridge circuit is connected to the first end of the LED branch circuit, and the second end of the LED branch circuit is grounded; the output end of the H-bridge circuit is grounded through a first capacitor.

[0016] In the embodiment of the present application, the input boost circuit is boosted in sequence by a boost circuit and an H-bridge circuit, so that the voltage output by the H-bridge circuit meets the requirements of the LED branch circuit. Compared with directly boosting the input voltage to the required voltage value, the cross-voltage of each boost can be reduced, thereby achieving the effect of improving the output efficiency.

[0017] In combination with the technical solution provided in the second aspect above, in some possible implementations, the LED driver chip is an LED driver chip including an H-bridge control circuit, the output end of the H-bridge circuit is connected to the first end of the LED branch circuit through a first resistor, and the enable end of the H-bridge circuit is connected to the control end of the H-bridge control circuit; the output end of the H-bridge circuit is grounded through the first capacitor; the first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driver chip are respectively connected to the two ends of the first resistor, and the data signal control circuit is also used to control the H-bridge control circuit to adjust the topology of the H-bridge circuit according to the voltage across the first resistor, so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

[0018] In the embodiment of the present application, the voltage across the first resistor is monitored to determine the current of the LED branch circuit. The H-bridge circuit is controlled by the H-bridge control circuit, so that the topology of the H-bridge circuit can be changed, and the H-bridge circuit can also achieve constant voltage output or constant current output, so that the present solution can be applied to more scenarios and improve the applicability of the present solution.

[0019] In combination with the technical solution provided in the second aspect above, in some possible implementations, the LED driver chip is an LED driver chip including an H-bridge control circuit, the enable end of the H-bridge circuit is connected to the control end of the H-bridge control circuit, the second end of the LED branch circuit is grounded through a second resistor; the output end of the H-bridge circuit is grounded through the first capacitor; the first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driver chip are respectively connected to the two ends of the second resistor, and the data signal control circuit is also used to control the H-bridge control circuit according to the voltage across the second resistor to adjust the topology of the H-bridge circuit so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

[0020] In the embodiment of the present application, the voltage across the second resistor is monitored to determine the current of the LED branch circuit. The H-bridge circuit is controlled by the H-bridge control circuit, so that the topology of the H-bridge circuit can be changed, and the H-bridge circuit can also achieve constant voltage output or constant current output, so that the present solution can be applied to more scenarios and improve the applicability of the present solution.

[0021] In combination with the technical solution provided in the second aspect above, in some possible implementations, the LED driver chip is an LED driver chip including a switch control circuit, and the LED branch circuits include multiple ones; each output end of the switch control circuit is connected to the enable end of each LED branch circuit, and the switch control circuit is used to send an enable signal to each of the LED branch circuits under the control of the data signal control circuit.

[0022] In combination with the technical solution provided in the second aspect above, in some possible implementations, the LED driver chip is an LED driver chip including a constant current PWM control current circuit, each input end of the constant current PWM control current circuit is connected to one of the LED branch circuits, and the constant current PWM control current circuit is used to control the current size of each of the LED branch circuits under the control of the data signal control circuit.

[0023] In the embodiment of the present application, the current magnitude of each LED branch circuit is controlled by a constant current PWM control current circuit, so that each LED branch circuit can be dimmed more precisely.

[0024] In combination with the technical solution provided in the second aspect above, in some possible implementations, the second end of the LED branch circuit is grounded through the constant current PWM control current circuit.

[0025] In combination with the technical solution provided in the second aspect above, in some possible implementations, each of the LED branch circuits includes a first switch, a third resistor and multiple LEDs connected in series; the enable end of each of the first switches is respectively connected to an output end of the constant current PWM control current circuit, and the end of the third resistor away from the ground is connected to the voltage acquisition interface of the constant current PWM control current circuit. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor, so as to control the current size of each of the LED branch circuits.

[0026] In the embodiment of the present application, the constant current PWM control current circuit determines the current of the LED branch circuit by detecting the voltage of the third resistor, and then adjusts the current of the LED branch circuit by adjusting the conduction degree of the first switch. In this way, the current of the LED branch circuit will not directly flow through the constant current PWM control current circuit, so even if the current in the LED branch circuit is large, it will not cause the constant current PWM control current circuit to overheat.

[0027] In a third aspect, the present application provides a backlight module, comprising an LED control circuit as described in the second aspect above and / or in combination with any one of the second aspect above.

[0028] In a fourth aspect, the present application provides a display device, comprising the backlight module as described in the third aspect above.

[0029] In a fifth aspect, the present application provides a light-emitting device, comprising an LED control circuit as described in the second aspect above and / or in combination with any one of the second aspect above. 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 use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a structural block diagram of the first LED driver chip shown in the embodiment of the present application;

[0032] Figure 2 This is a structural block diagram of a second LED driver chip shown in an embodiment of the present application;

[0033] Figure 3 A circuit structure diagram of an H-bridge circuit shown in an embodiment of the present application;

[0034] Figure 4 This is a structural block diagram of a third LED driver chip shown in an embodiment of the present application;

[0035] Figure 5 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0036] Figure 6 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0037] Figure 7 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0038] Figure 8 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0039] Fig. 9 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0040] Fig.10 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0041] Fig.11A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0042] Fig.12 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0043] Fig.13 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0044] Fig.14 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0045] Fig.15 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0046] Fig.16 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0047] Fig.17 A circuit structure diagram of an LED control circuit shown in an embodiment of the present application;

[0048] Fig.18 This is a circuit structure diagram of an LED control circuit shown in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The terms “first”, “second”, “third”, etc. are only used for distinguishing descriptions and do not indicate the order of arrangement, nor can they be understood as indicating or implying relative importance.

[0050] In the description of the present application, it should be noted that the terms "inside", "outside", "left", "right", "up", "down", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the products of the present application are usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0051] In the description of this application, unless otherwise clearly specified and limited, the terms "setting" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0052] The technical solution of the present application will be described in detail below with reference to the accompanying drawings.

[0053] like Figure 1As shown, the present application provides an LED driver chip, such as Figure 1 As shown, the LED driver chip includes a data signal control circuit and a boost circuit.

[0054] The data signal control circuit is connected to the boost circuit; the output end of the boost circuit is configured to be connected to the input end of the H-bridge circuit outside the LED driver chip, and the data signal control circuit is used to select a target boost ratio of the boost circuit so that the boost circuit boosts the voltage it receives based on the target boost ratio, and transmits the boosted voltage to the H-bridge circuit so that the H-bridge circuit drives the connected LED.

[0055] The input boost circuit is boosted in sequence by the boost circuit and the H-bridge circuit, so that compared with directly boosting the input voltage to the required voltage value, the cross-voltage of each boost can be reduced, thereby achieving the effect of improving the output efficiency.

[0056] In one implementation, the data signal control circuit can be any circuit with data processing capabilities, for example, it can be an integrated circuit chip with signal processing capabilities, a general-purpose processor, etc., including but not limited to a CPU (Central Processing Unit), an NP (Network Processor), etc.; it can also be a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0057] In one implementation, the boost circuit may be any circuit with boost capability.

[0058] Optionally, the boost circuit may be a Charger Pump control module. In this embodiment, the Charger Pump control module may detect the input voltage, and determine a target boost ratio from a plurality of preset boost ratios based on a preset target voltage and input voltage ratio. The difference between the preset target voltage and input voltage ratio and the target boost ratio is the smallest, and the preset target voltage and input voltage ratio is greater than the target boost ratio.

[0059] If the boost circuit is a Charger Pump control module, the Charger Pump control module also needs to be connected to multiple capacitors, such as Figure 2The number of external capacitors is set according to actual needs, and the specific number is not limited here.

[0060] For example, if the Charger Pump control module is preset with nine boost ratios of 1, 1.33, 1.5, 1.75, 2, 2.66, 3, 3.5, and 4. If the input voltage is 9V and the target voltage is 48V, the ratio of the target voltage to the input voltage is approximately 5.33. It can be determined that the boost ratio that is less than 5.33 and has the smallest difference from 5.33 is 4. Therefore, the target boost ratio is 4.

[0061] If the input voltage is 9V and the target voltage is 30V, the ratio of the target voltage to the input voltage is approximately 3.33. It can be determined that the boost ratio that is less than 3.33 and has the smallest difference from 3.33 is 3. Therefore, the target boost ratio is 3.

[0062] The examples given here are only for ease of understanding and should not be construed as limiting the present application.

[0063] In one implementation, the LED driver chip further includes an H-bridge control circuit.

[0064] The enable end of the H-bridge control circuit is connected to the data signal control circuit, and the control end of the H-bridge control circuit is configured to be connected to the enable end of the H-bridge circuit; the H-bridge control circuit is used to change the topological structure of the H-bridge circuit connected to itself under the control of the data signal control circuit, so that the voltage output by the H-bridge circuit and the boost circuit meets the driving requirements of the LED.

[0065] The H-bridge circuit can be controlled through the H-bridge control circuit, so that the topology of the H-bridge circuit can be changed, and the H-bridge circuit can also achieve constant voltage output or constant current output, so that the solution can be applied to more scenarios and the applicability of the solution is improved.

[0066] The H-bridge control circuit may be any type of H-bridge control circuit, as long as it can realize the control of the constant current output, constant voltage output, and the topology of the H-bridge circuit. For example, the H-bridge control circuit may be a circuit structure included in a chip such as TLD5190, which is only for ease of understanding and should not be used as a limitation to the present application.

[0067] The H-bridge control circuit may include four control interfaces, which are respectively connected to the gates of four transistors (M1, M2, M3, and M4 in Table 1) of the H-bridge circuit. The specific structure of the H-bridge circuit is as follows: Figure 3 As shown, Vin is used to receive the input voltage, and Vout is used to output the boosted voltage. The three topological structures of the H-bridge circuit (boost, buck, and boost / buck structures) are shown in Table 1.

[0068] Table 1

[0069]

[0070] Among them, ON means conduction, OFF means shutdown, and PWM means pulse width control signal.

[0071] In one embodiment, the LED driver chip further includes a switch control circuit. An enable terminal of the switch control circuit is connected to the data signal control circuit, each output terminal of the switch control circuit is configured to be connected to an enable terminal of an LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit among the LED branch circuits under the control of the data signal control circuit.

[0072] By sending an enable signal to each LED branch circuit respectively through the switch control circuit, multiple LED branch circuits can be controlled. At the same time, since the switch control circuit can control the LED branch circuit to be in a disabled state, it can prevent the leakage caused by the capacitor continuing to discharge to the LED branch circuit when the input voltage is disconnected; it can also control the LED branch circuit to be disabled when the LED branch circuit is short-circuited to solve the short-circuit problem of the LED branch circuit.

[0073] Optionally, the switch control circuit may be a circuit of a type such as a multi-way selection circuit, and its specific circuit type is not limited here.

[0074] For example, if the switch control circuit is a multi-way selection circuit, the output ports of the multi-way selection circuit are respectively connected to the enable ends of the LED branch circuits, the input ends of the multi-way selection circuit are used to receive enable signals, and the control end of the multi-way selection circuit is connected to the data signal control circuit to determine which output ends output the enable signals through the control signal output by the data signal control circuit.

[0075] In one implementation, the LED driver chip further includes a constant current PWM control current circuit. An enable terminal of the constant current PWM control current circuit is connected to the data signal control circuit, each output terminal of the constant current PWM control current circuit is configured to be connected to an LED branch circuit, and the constant current PWM control current circuit is used to control the current size of each LED branch circuit under the control of the data signal control circuit.

[0076] The current size of each LED branch circuit is controlled by a constant current PWM control current circuit, so that each LED branch circuit can be dimmed more finely.

[0077] The constant current PWM control current circuit may be any type of power supply constant current circuit based on PWM current feedback, and its specific circuit structure is not limited here.

[0078] Optionally, the LED branch circuit may be grounded via the constant current PWM control current circuit.

[0079] Alternatively, if each LED branch circuit includes a first switch, a third resistor and multiple LEDs connected in series, each output end of the constant current PWM control current circuit is configured to be connected to an enable end of a first switch, and the voltage acquisition interface of the constant current PWM control current circuit is configured to be connected to the third resistor. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor, so as to control the current size of each LED branch circuit.

[0080] The constant current PWM control current circuit can determine the current of the LED branch circuit by detecting the voltage of the third resistor, and then adjust the current of the LED branch circuit by adjusting the conduction degree of the first switch. In this way, the current of the LED branch circuit will not directly flow through the constant current PWM control current circuit, so even if the current in the LED branch circuit is large, it will not cause the constant current PWM control current circuit to overheat.

[0081] Optionally, the implementation of the first switch, the third resistor and the plurality of LEDs connected in series may be: a plurality of LEDs connected in series in sequence, and a first switch connected to the cathode of the last-stage LED, and the other end of the first switch is grounded through the third resistor. In this case, each output end of the constant current PWM control current circuit is respectively used to be connected to an enable end of a first switch, and the voltage acquisition interface of the constant current PWM control current circuit is used to be connected to an end of the third resistor away from the ground.

[0082] Alternatively, the third resistor may not be directly grounded. In this case, the voltage acquisition interface of the constant current PWM control current circuit includes a first voltage acquisition interface and a second voltage acquisition interface. The first voltage acquisition interface and the second voltage acquisition interface are respectively connected to the two ends of the third resistor to detect the voltage value of the third resistor.

[0083] In one implementation mode, the LED driver chip may further include a switch control circuit and a constant current PWM control current circuit, such as Figure 4 shown.

[0084] The enable end of the switch control circuit is connected to the data signal control circuit, each output end of the switch control circuit is configured to be connected to the enable end of an LED branch circuit, and the switch control circuit is used to send an enable signal to each LED branch circuit under the control of the data signal control circuit. The enable end of the constant current PWM control current circuit is connected to the data signal control circuit, each output end of the constant current PWM control current circuit is configured to be connected to an LED branch circuit, and the constant current PWM control current circuit is used to control the current size of each LED branch circuit under the control of the data signal control circuit.

[0085] The specific implementation method and principle of the switch control circuit and the constant current PWM control current circuit have been clearly described in the previous text. For the sake of brief description, they will not be repeated here.

[0086] Based on the same technical concept, the present application also provides an LED control circuit, such as Figure 5 As shown, the LED control circuit includes an LED branch circuit, an H-bridge circuit and an LED driving chip.

[0087] The output end of the boost circuit of the driving chip is connected to the input end of the H-bridge circuit, the output end of the H-bridge circuit is connected to the first end of the LED branch circuit, and the second end of the LED branch circuit is grounded; the output end of the H-bridge circuit is grounded through the first capacitor.

[0088] Optionally, the LED branch circuit may include one or more LEDs. Where multiple LEDs are included, the multiple LEDs may be connected in series or in parallel. Alternatively, multiple LED branches may be connected in parallel, where each LED branch includes one or more LEDs connected in series.

[0089] The gates of the four transistors of the H-bridge circuit may receive an H-bridge circuit control signal transmitted from the outside, or may receive an H-bridge circuit control signal sent by a data signal control circuit in the LED driver chip.

[0090] In one implementation manner, if an H-bridge control circuit is present in the LED driver chip, the output end of the H-bridge circuit may be configured to pass through a first resistor ( Figure 6 The R1 shown in the figure is connected to the first end of the LED branch circuit, and the enable end of the H-bridge circuit (i.e. Figure 3 The gates of the four transistors shown in the figure are connected to the control end of the H-bridge control circuit; the output end of the H-bridge circuit is grounded through the first capacitor ( Figure 6 For ease of understanding, see Figure 6 .

[0091] The first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driving chip are respectively connected to the two ends of the first resistor. The data signal control circuit is also used to control the H-bridge control circuit to adjust the topology of the H-bridge circuit according to the voltage across the first resistor so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

[0092] By monitoring the voltage across the first resistor, the current of the LED branch circuit can be determined. By controlling the H-bridge circuit through the H-bridge control circuit, the topology of the H-bridge circuit can be changed, and the H-bridge circuit can also achieve constant voltage output or constant current output, so that the solution can be applied to more scenarios and the applicability of the solution is improved.

[0093] Optionally, if an H-bridge control circuit exists in the LED driver chip, the enable end of the H-bridge circuit may be connected to the control end of the H-bridge control circuit, and the second end of the LED branch circuit may be connected to the control end of the H-bridge control circuit through a second resistor ( Figure 7 R2 shown in the figure is grounded; the output end of the H-bridge circuit is connected to the first capacitor ( Figure 7 C1 is shown as grounded. For ease of understanding, refer to Figure 7 .

[0094] The first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driving chip are respectively connected to the two ends of the first resistor. The data signal control circuit is also used to control the H-bridge control circuit to adjust the topology of the H-bridge circuit according to the voltage across the first resistor so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

[0095] By monitoring the voltage across the second resistor, the current of the LED branch circuit can be determined. By controlling the H-bridge circuit through the H-bridge control circuit, the topology of the H-bridge circuit can be changed, and the H-bridge circuit can also achieve constant voltage output or constant current output, so that the solution can be applied to more scenarios and improve the applicability of the solution.

[0096] In one implementation, the LED driver chip is an LED driver chip that at least includes a switch control circuit, and the LED branch circuits include multiple LEDs. Each output terminal of the switch control circuit is connected to the enable terminal of each LED branch circuit, and the switch control circuit is used to enable the target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit. In this way, multiple LED branch circuits can be controlled. For ease of understanding, please refer to Figure 8 .

[0097] In this implementation, each LED branch circuit has a second switch (such as Figure 8M5, M6, M7 shown).

[0098] Optionally, the second switch in each LED branch circuit may be arranged at any position in the LED branch circuit, as long as it can achieve that when the second switch is turned off, the LED branch circuit is disabled; when the second switch is turned on, the LED branch circuit is turned on.

[0099] In one implementation, the LED driver chip is an LED driver chip including a constant current PWM control current circuit.

[0100] Each input end of the constant current PWM control current circuit is connected to an LED branch circuit. The constant current PWM control current circuit is used to control the current size of each LED branch circuit under the control of the data signal control circuit.

[0101] The current size of each LED branch circuit is controlled by a constant current PWM control current circuit, so that each LED branch circuit can be dimmed more finely.

[0102] Optionally, the second end of the LED branch circuit is grounded via a constant current PWM control current circuit. For ease of understanding, refer to Fig. 9 This method directly controls the current of the LED branch circuit through a constant current PWM control current circuit.

[0103] Optionally, the implementation method of each LED branch circuit including a first switch, a third resistor and multiple LEDs connected in series and the connection method with the constant current PWM control current circuit have been clearly described in the previous text and will not be repeated here for the sake of brief description.

[0104] Optionally, each LED branch circuit includes a plurality of LEDs connected in series, and a first switch connected to the cathode of the last stage LED ( Fig.10 M8, M9, M10 shown in the figure), the other end of the first switch is connected through a third resistor ( Fig.10 R3, R4, R5) shown are grounded.

[0105] The enable end of each first switch is connected to an output end of the constant current PWM control current circuit, and the end of the third resistor away from the ground is connected to the voltage acquisition interface of the constant current PWM control current circuit. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor to achieve the control of the current size of each LED branch circuit. For ease of understanding, please refer to Fig.10 .

[0106] The constant current PWM control current circuit determines the current of the LED branch circuit by detecting the voltage of the third resistor, and then adjusts the current of the LED branch circuit by adjusting the conduction degree of the first switch. In this way, the current of the LED branch circuit will not directly flow through the constant current PWM control current circuit, so even if the current in the LED branch circuit is large, it will not cause the constant current PWM control current circuit to overheat.

[0107] In order to facilitate understanding of the above LED control circuit, its implementation method will be described below in combination with multiple embodiments.

[0108] Embodiment 1, the structure of LED control circuit is as follows Fig.11 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, a switch control circuit, and a constant current PWM control current circuit.

[0109] The input voltage ( Fig.11 The Vin shown in FIG. 1 is boosted, and then the H-bridge circuit is boosted for a second time. The boosted voltage of the H-bridge circuit supplies energy to the LED branch circuit. The data signal control circuit determines whether the voltage or current output by the H-bridge circuit meets the use requirements by detecting the voltage across R1. If not, a signal is sent to the H-bridge control circuit to change the topology of the H-bridge circuit through the H-bridge control circuit.

[0110] The switch control circuit controls the second switch ( Fig.11 The current of the LED branch circuit flows into the constant current PWM control current circuit to control the current value of each LED branch circuit through the constant current PWM control current circuit.

[0111] Among them, the H-bridge circuit can be controlled to output a constant current through the H-bridge control circuit. In this case, the current of each LED branch circuit is always constant (the current output by the H-bridge circuit is constant), so that the LED branch circuit can have a faster response speed.

[0112] Alternatively, the H-bridge circuit can be controlled to output a constant current through an H-bridge control circuit. In this case, the voltage of each LED branch circuit is always constant (the current output by the H-bridge circuit is constant), so the current of each LED branch circuit can be fine-tuned separately through a constant current PWM control current circuit, thereby making the dimming of the LED branch circuit more precise.

[0113] Embodiment 2, the structure of the LED control circuit is as follows Fig.12As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, and a switch control circuit.

[0114] Among them, the switch control circuit can be normally open or set to PWM switch control. When the LED branch circuit needs to be turned off, it can be closed through the switch control circuit to avoid the occurrence of leakage current.

[0115] Embodiment 3, the structure of the LED control circuit is as follows Fig.13 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, and a switch control circuit.

[0116] This embodiment adopts a low-side constant current method and can effectively avoid the problem of short circuit of the LED branch circuit by collecting the voltage change of the LED cathode (the voltage change on both sides of R2).

[0117] Embodiment 4, the structure of the LED control circuit is as follows Fig.14 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, and a constant current PWM control current circuit.

[0118] In this embodiment, there may be multiple LED branch circuits. When the current in the LED branch circuit has a relatively high requirement for accuracy, such as the need to control fine brightness levels, linear dimming, DC dimming or exponential dimming, etc., the chip-integrated constant current PWM control current circuit can be directly used to achieve constant current dimming control of each LED branch circuit.

[0119] Example 5, the structure of the LED control circuit is as follows Fig.15 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, and a constant current PWM control current circuit.

[0120] In this embodiment, when the voltage of Vin input remains unchanged or the voltage after doubled voltage just meets the driving voltage of the LED branch circuit, the H-bridge circuit is not required to boost the voltage. This method has a higher power efficiency, close to 98%, and can greatly reduce losses.

[0121] Example 6, the structure of the LED control circuit is as follows Fig.16 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, a switch control circuit, and a constant current PWM control current circuit.

[0122] In this embodiment, when it is necessary to drive the array LED branch circuits, the switch control circuit can be started to achieve the driving of more LED branch circuits.

[0123] Embodiment 7, the structure of the LED control circuit is as follows Fig.17 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, and a switch control circuit.

[0124] In this embodiment, by controlling the H-bridge circuit to be in a constant current output state (the output end of the H-bridge circuit outputs a constant current), multiple LED branch circuits can be driven. And the switch control circuit can control the enabling of each LED branch circuit. This embodiment can achieve a fast response of the LED branch circuit.

[0125] Embodiment 8, the structure of the LED control circuit is as follows Fig.18 As shown, the LED driver chip is an LED driver chip including a boost circuit, a data signal control circuit, an H-bridge control circuit, a switch control circuit, and a constant current PWM control current circuit.

[0126] Considering that the LED driver chip integrates a constant current PWM control current circuit, the LED current flows to GND through the LED driver chip. If there are too many LED branch circuits or the current of the LED branch circuits is too large, it may cause the LED driver chip to consume too much power and generate too much heat.

[0127] Therefore, the first switch ( Fig.18 M8, M9, M10) and the third resistor ( Fig.18 R3, R4, and R5 as shown are placed outside the chip, and the control signal is retained in the LED driver chip, so that the current of the LED branch circuit does not need to flow into the LED driver chip, thereby avoiding the problem of high power consumption and serious heat generation of the LED driver chip due to too many LED branch circuits and excessive current in the LED branch circuits.

[0128] Based on the same technical concept, the present application also provides a backlight module, which includes an LED control circuit.

[0129] The specific implementation of the LED control circuit has been clearly described in the previous text, and will not be repeated here for the sake of brief description.

[0130] Based on the same technical concept, the present application also provides a display device, which includes a backlight module. The specific implementation of the backlight module has been clearly described in the previous text, and for the sake of brief description, it will not be repeated here.

[0131] The display device may be any type of liquid crystal display.

[0132] Based on the same technical concept, the present application also provides a light-emitting device, which includes an LED control circuit.

[0133] The specific implementation of the LED control circuit has been clearly described in the previous text, and will not be repeated here for the sake of brief description.

[0134] The light-emitting device may be any device with light-emitting capability, such as a vehicle with headlights, a flashlight, a desk lamp, an LED display screen, etc.

[0135] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An LED driver chip, characterized in that: include: Data signal control circuit, boost circuit, H-bridge control circuit; The data signal control circuit is connected to the boost circuit; The output end of the boost circuit is configured to be connected to the input end of the H-bridge circuit outside the LED driver chip; the data signal control circuit is used to select a target boost ratio of the boost circuit, so that the boost circuit performs a boost process on the voltage received by itself based on the target boost ratio, and transmits the boosted voltage to the H-bridge circuit; The enable end of the H-bridge control circuit is connected to the data signal control circuit, and the control end of the H-bridge control circuit is configured to be connected to the enable end of the H-bridge circuit; the H-bridge control circuit is used to change the topological structure of the H-bridge circuit connected to itself under the control of the data signal control circuit, so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

2. The LED driver chip according to claim 1, characterized in that: The LED driver chip also includes: a switch control circuit, wherein an enable terminal of the switch control circuit is connected to the data signal control circuit, each output terminal of the switch control circuit is configured to be connected to an enable terminal of an LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit.

3. The LED driver chip according to claim 1, characterized in that: The LED driver chip also includes: A constant current PWM control current circuit, wherein the enable end of the constant current PWM control current circuit is connected to the data signal control circuit, each output end of the constant current PWM control current circuit is configured to be connected to an LED branch circuit, and the constant current PWM control current circuit is used to control the current size of each LED branch circuit under the control of the data signal control circuit.

4. The LED driver chip according to claim 3, characterized in that: Each of the LED branch circuits includes a first switch, a third resistor and a plurality of LEDs connected in series; Each output end of the constant current PWM control current circuit is respectively configured to be connected to an enable end of the first switch, and the voltage acquisition interface of the constant current PWM control current circuit is configured to be connected to the third resistor. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor, so as to control the current size of each LED branch circuit.

5. The LED driver chip according to claim 1, characterized in that: The LED driver chip also includes: a switch control circuit, wherein an enable terminal of the switch control circuit is connected to the data signal control circuit, each output terminal of the switch control circuit is configured to be connected to an enable terminal of an LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit; A constant current PWM control current circuit, wherein the enable end of the constant current PWM control current circuit is connected to the data signal control circuit, each output end of the constant current PWM control current circuit is configured to be connected to an LED branch circuit, and the constant current PWM control current circuit is used to control the current size of each LED branch circuit under the control of the data signal control circuit.

6. An LED control circuit, characterized in that: include: LED branch circuit, H-bridge circuit, LED driver chip according to any one of claims 1 to 5; The output end of the boost circuit of the driving chip is connected to the input end of the H-bridge circuit, the output end of the H-bridge circuit is connected to the first end of the LED branch circuit, and the second end of the LED branch circuit is grounded; the output end of the H-bridge circuit is grounded through a first capacitor; The output end of the H-bridge circuit is connected to the first end of the LED branch circuit through the first resistor, and the enable end of the H-bridge circuit is connected to the control end of the H-bridge control circuit; the output end of the H-bridge circuit is grounded through the first capacitor; the first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driving chip are respectively connected to the two ends of the first resistor, and the data signal control circuit is further used to control the H-bridge control circuit to adjust the topology of the H-bridge circuit according to the voltage across the first resistor, so that the voltage output by the H-bridge circuit meets the driving requirements of the LED; Alternatively, the enable end of the H-bridge circuit is connected to the control end of the H-bridge control circuit, and the second end of the LED branch circuit is grounded through a second resistor; the output end of the H-bridge circuit is grounded through the first capacitor; the first voltage acquisition port and the second voltage acquisition port of the data signal control circuit of the driving chip are respectively connected to the two ends of the second resistor, and the data signal control circuit is also used to control the H-bridge control circuit to adjust the topology of the H-bridge circuit according to the voltage across the second resistor, so that the voltage output by the H-bridge circuit meets the driving requirements of the LED.

7. The LED control circuit according to claim 6, characterized in that: The LED driver chip is the LED driver chip according to claim 2, and the LED branch circuit includes a plurality of; Each output terminal of the switch control circuit is connected to the enable terminal of each LED branch circuit, and the switch control circuit is used to enable a target LED branch circuit in each of the LED branch circuits under the control of the data signal control circuit.

8. The LED control circuit according to claim 6, characterized in that: The LED driver chip is the LED driver chip according to claim 3, Each input end of the constant current PWM control current circuit is connected to one of the LED branch circuits, and the constant current PWM control current circuit is used to control the current size of each of the LED branch circuits under the control of the data signal control circuit.

9. The LED control circuit according to claim 8, characterized in that: The second end of the LED branch circuit is grounded through the constant current PWM control current circuit.

10. The LED control circuit according to claim 8, characterized in that: Each of the LED branch circuits includes a first switch, a third resistor and a plurality of LEDs connected in series; The enable end of each of the first switches is respectively connected to an output end of the constant current PWM control current circuit, and the third resistor is connected to a voltage acquisition interface of the constant current PWM control current circuit. The constant current PWM control current circuit is specifically used to control the conduction degree of the first switch according to the voltage of the third resistor, so as to control the current size of each LED branch circuit.

11. A backlight module, characterized in that: include: The LED control circuit as claimed in any one of claims 6 to 10.

12. A display device, characterized in that: include: The backlight module as claimed in claim 11.

13. A light emitting device, characterized in that: include: The LED control circuit as claimed in any one of claims 6 to 10.

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