Driving device and driving method of light-emitting element

Abstract

The invention provides a driving device and a driving method of a light-emitting element. The driving device comprises a driving circuit, a slow start circuit and a capacitor. The output end of the slow start circuit is coupled to the capacitor and the driving circuit so as to provide dimming voltage. A driving signal output by the driving circuit drives the light-emitting element circuit. The driving circuit is enabled or disabled based on the enabling signal. Based on the relation between the dimming voltage and the current information of the light-emitting element circuit, the driving circuit dynamically adjusts the working period of the driving signal. In response to an enable signal to disable the drive circuit, the slow start circuit pulls down the original adjustment voltage to generate a pulled-down voltage as a dimming voltage. The drive circuit is enabled in response to the enable signal, and the slow start circuit pulls up the dimming voltage.

Description

Technical Field

[0001] The present invention relates to a driving electronic circuit, and in particular to a driving device and a driving method for a light-emitting element. Background Art

[0002] The light source of the projector has developed from a single light source to a multi-color light source (such as red, green, and blue). The projector uses pulse width modulation (PWM) dimming technology to adjust the current of the light source, thereby adjusting the brightness and color. Therefore, for the start-up of the light source, current stability is very important. Overshoot current often occurs when the light source is started quickly. The overshoot current often exceeds the rated current value. In addition to being reflected in the instability of the brightness / color of the light source, the overshoot current that exceeds the design value may also burn out the light source components. Summary of the invention

[0003] The invention provides a driving device and a driving method of a light emitting element, so as to reduce overshoot current when starting the light emitting element.

[0004] Based on the above-mentioned purpose, the present invention proposes a driving device for a light-emitting element, which includes: a driving circuit, which is used to output a driving signal to drive the light-emitting element circuit, wherein the driving circuit is enabled or disabled based on an enable signal, and the driving circuit dynamically adjusts the working cycle of the driving signal based on the relationship between the dimming voltage and the current information of the light-emitting element circuit; a slow start circuit, which has an output end coupled to the driving circuit to provide the dimming voltage, wherein the slow start circuit disables the driving circuit in response to the enable signal and pulls down the original adjustment voltage to generate a pulled-down voltage as the dimming voltage, and the slow start circuit enables the driving circuit in response to the enable signal and pulls up from the pulled-down voltage to serve as the dimming voltage; and a first capacitor, which is coupled to the output end of the slow start circuit.

[0005] In a preferred embodiment, the slow start circuit includes: a first resistor having a first end for receiving the original adjustment voltage, wherein the second end of the first resistor is coupled to the output end of the slow start circuit; and a variable resistor circuit coupled between the second end of the first resistor and a first reference voltage, wherein the variable resistor circuit reduces the resistance of the variable resistor circuit in response to the enable signal disabling the drive circuit, and the variable resistor circuit increases the resistance of the variable resistor circuit in response to the enable signal enabling the drive circuit.

[0006] In a preferred embodiment, the variable resistor circuit includes: a second resistor having a first end coupled to the second end of the first resistor, wherein the second end of the second resistor is coupled to the first reference voltage; and a shunt circuit coupled to the second end of the first resistor, wherein the shunt circuit provides a shunt path to the second end of the first resistor in response to the enable signal disabling the drive circuit, and the shunt circuit enables the drive circuit in response to the enable signal to cut off the shunt path.

[0007] In a preferred embodiment, the shunt circuit includes: a third resistor having a first end coupled to the second end of the first resistor; and a switching circuit coupled between the second end of the third resistor and the first reference voltage, wherein the switching circuit is turned on in response to the enable signal to disable the drive circuit, and the switching circuit is turned off in response to the enable signal to enable the drive circuit.

[0008] In a preferred embodiment, the switching circuit includes: a first switch having a first end coupled to the second end of the third resistor, wherein the second end of the first switch is coupled to the first reference voltage; and a control circuit coupled to the control end of the first switch, wherein the control circuit turns on the first switch in response to the enable signal to disable the drive circuit, and the control circuit turns off the first switch in response to the enable signal to enable the drive circuit.

[0009] In a preferred embodiment, the control circuit includes: a fourth resistor having a first end coupled to a power supply voltage, wherein a second end of the fourth resistor is coupled to the control end of the first switch; and a second switch having a first end coupled to the control end of the first switch, wherein a second end of the second switch is coupled to a second reference voltage, the second switch is turned off in response to the enable signal disabling the drive circuit, and the second switch is turned on in response to the enable signal enabling the drive circuit.

[0010] In a preferred embodiment, the control circuit also includes: a fifth resistor having a first end coupled to the second end of the fourth resistor, wherein the second end of the fifth resistor is coupled to the third reference voltage; a sixth resistor having a first end for receiving the enable signal, wherein the second end of the sixth resistor is coupled to the control end of the second switch; and a seventh resistor having a first end coupled to the second end of the sixth resistor, wherein the second end of the seventh resistor is coupled to the fourth reference voltage.

[0011] In a preferred embodiment, the soft start circuit enables the driving circuit in response to the enable signal, and pulls up the pulled-down voltage to the original adjustment voltage to serve as the dimming voltage.

[0012] Based on the above-mentioned purpose, the present invention also proposes a driving method for a light-emitting element, which includes: enabling or disabling the driving circuit by an enable signal; dynamically adjusting the duty cycle of the driving signal by the driving circuit based on the relationship between the dimming voltage and the current information of the light-emitting element circuit, wherein the output end of the slow start circuit is coupled to the driving circuit to provide the dimming voltage; the driving circuit outputs the driving signal to drive the light-emitting element circuit; the slow start circuit disables the driving circuit in response to the enable signal and pulls down the original adjustment voltage to generate a pulled-down voltage as the dimming voltage; and the slow start circuit enables the driving circuit in response to the enable signal and pulls up the pulled-down voltage to serve as the dimming voltage, wherein the first capacitor is coupled to the output end of the slow start circuit.

[0013] In a preferred embodiment, it also includes: the variable resistance circuit of the slow start circuit responds to the enable signal to disable the driving circuit and reduce the resistance of the variable resistance circuit, wherein the first end of the first resistor of the slow start circuit receives the original adjustment voltage, the second end of the first resistor is coupled to the driving circuit to provide the dimming voltage, and the variable resistance circuit is coupled between the second end of the first resistor and the reference voltage; and the variable resistance circuit responds to the enable signal to enable the driving circuit and increase the resistance of the variable resistance circuit.

[0014] Based on the above scheme, when the enable signal disables the driving circuit, the slow start circuit generates a pulled-down voltage lower than the original adjustment voltage, and uses the pulled-down voltage as the dimming voltage provided to the driving circuit. When the enable signal enables the driving circuit, the slow start circuit slowly pulls up the dimming voltage from the pulled-down voltage level to approximately the original adjustment voltage level. After the enable signal enables the driving circuit, the driving circuit can dynamically adjust the duty cycle of the driving signal based on the relationship between the dimming voltage and the current information of the light-emitting element circuit, thereby dynamically adjusting the current of the light-emitting element. In the process of the driving circuit being enabled / started, because the dimming voltage is slowly pulled up to approximately the original adjustment voltage level, the overshoot current of the light-emitting element when starting the light-emitting element can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. 1 is a schematic diagram of a circuit block of a driving device for a light emitting element according to an embodiment.

[0016] Figure 2 FIG. 1 is a schematic diagram illustrating a situation in which an overshoot current occurs when a light emitting device circuit is started up quickly according to an embodiment.

[0017] Figure 3 It is a circuit block diagram of a driving device of a light emitting element according to an embodiment of the present invention.

[0018] Figure 4 It is a flowchart of a driving method of a light emitting element according to an embodiment of the present invention.

[0019] Figure 5 FIG. 1 is a schematic diagram of signal waveforms during a slow-start driving circuit according to an embodiment of the present invention.

[0020] Figure 6 FIG. 4 is a circuit block diagram of a slow start circuit according to an embodiment of the present invention.

[0021] Figure 7 FIG. 1 is a circuit block diagram of a variable resistor circuit according to an embodiment of the present invention.

[0022] Figure 8 FIG. 4 is a circuit block diagram of a shunt circuit according to an embodiment of the present invention.

[0023] Fig. 9 FIG. 4 is a circuit block diagram of a switch circuit according to an embodiment of the present invention.

[0024] Fig.10 FIG. 4 is a circuit diagram of a control circuit according to another embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to provide a further understanding of the purpose, structure, features, and functions of the present invention, the following detailed description is given in conjunction with the embodiments.

[0026] Figure 1 FIG. 1 is a schematic diagram of a circuit block of a driving device 100 for a light emitting element according to an embodiment. The system (pre-circuit of the driving device 100, not shown) can output an enable signal LED_EN to enable or disable the driving device 100. Figure 1 The driving device 100 shown includes a driving circuit 110. The system can output an enable signal LED_EN to an enable pin EN of the driving circuit 110 to enable or disable the driving circuit 110. When the enable signal LED_EN disables the driving circuit 110, the drive signal PWM1 output by the driving circuit 110 can turn off the light-emitting element circuit LU1. The drive signal PWM1 can be a pulse width modulation (PWM) signal or other signals. When the enable signal LED_EN enables / starts the driving circuit 110, the drive signal PWM1 output by the driving circuit 110 can light up the light-emitting element circuit LU1. Based on actual design, the light-emitting element circuit LU1 may include one or more light-emitting elements, such as a light-emitting diode (LED) or other light-emitting elements.

[0027] The system can output the original adjustment voltage LED_Iadj to the dimming pin ADIM of the driving circuit 110 to control the driving circuit 110 to dim the light emitting element circuit LU1. The light emitting element circuit LU1 can provide current information (a signal representing the light emitting element current I_LED) to the feedback pin FB of the driving circuit 110. The driving circuit 110 can compare the original adjustment voltage LED_Iadj with the current information (light emitting element current I_LED) of the light emitting element circuit LU1. Based on the relationship between the original adjustment voltage LED_Iadj and the light emitting element current I_LED of the light emitting element circuit LU1, the driving circuit 110 can dynamically adjust the duty cycle of the driving signal PWM1. That is, the driving circuit 110 can adjust the brightness of the light emitting element circuit LU1 based on the original adjustment voltage LED_Iadj. The dynamic adjustment of the duty cycle of the driving signal PWM1 includes but is not limited to adjusting the duty cycle, frequency and amplitude of the driving signal PWM1.

[0028] Figure 2 FIG. 1 is a schematic diagram illustrating a situation in which an overshoot current occurs when a light emitting device circuit is quickly started according to an embodiment. Figure 2 Draws in Figure 1 The waveform diagram of the enable signal LED_EN, the original adjustment voltage LED_Iadj and the light emitting element current I_LED, wherein the vertical axis represents voltage or current, and the horizontal axis represents time. Generally speaking, after the user completes the brightness adjustment of the light emitting element circuit LU1, the original adjustment voltage LED_Iadj will maintain a certain fixed level to keep the brightness of the light emitting element circuit LU1 stable.

[0029] When the enable signal LED_EN is at a low logic level, the driving circuit 110 is disabled. At this time, the driving signal PWM1 output by the driving circuit 110 can turn off the light-emitting element circuit LU1 (the light-emitting element current I_LED approaches zero). When the enable signal LED_EN changes to a high logic level, the enable signal LED_EN can quickly start the driving circuit 110. At this time, the driving signal PWM1 output by the driving circuit 110 can turn on the light-emitting element circuit LU1. The driving circuit 110 does not have a soft start control pin and cannot solve the overshoot current problem. When the light-emitting element circuit LU1 is quickly started, the light-emitting element current I_LED often has an overshoot current. When the overshoot current exceeds the rated current value, in addition to the user being easily aware of the instability of the brightness / color of the light source, there is also the possibility of burning the light-emitting element.

[0030] Figure 31 is a circuit block diagram of a driving device 300 for a light emitting element according to an embodiment of the present invention. The system (pre-circuit of the driving device 300, not shown) can output an enable signal LED_EN to enable or disable the driving device 300. In addition, the system can output an original adjustment voltage LED_Iadj to control the driving device 300 to dim the light emitting element circuit LU3. Figure 3 The enable signal LED_EN, the original adjustment voltage LED_Iadj and the light emitting element circuit LU3 can refer to Figure 1 The related descriptions of the enable signal LED_EN, the original adjustment voltage LED_Iadj and the light emitting element circuit LU1 are shown, so they are not repeated here.

[0031] Figure 3 The driving device 300 shown includes a soft start circuit 310, a capacitor C11 and a driving circuit 320. The enable terminal EN of the driving circuit 320 receives the enable signal LED_EN. The driving circuit 320 is used to output a driving signal PWM3 to drive the light emitting element circuit LU3. The driving signal PWM3 can be a PWM signal or other signals. When the enable signal LED_EN disables the driving circuit 320, the driving signal PWM3 of the driving circuit 320 can turn off the light emitting element circuit LU3. Based on the actual design, in some embodiments, Figure 3 The driving circuit 320 shown can refer to Figure 1 Alternatively, the driving circuit 320 may include a well-known light source element driving circuit or other drivers.

[0032] The input end of the slow start circuit 310 receives the original adjustment voltage LED_Iadj. The detection end of the slow start circuit 310 receives the enable signal LED_EN. The output end of the slow start circuit 310 is coupled to the capacitor C11 and the driving circuit 320 to provide a dimming voltage V_DIM. When the enable signal LED_EN enables / starts the driving circuit 320, the driving signal PWM3 output by the driving circuit 320 can light up the light emitting element circuit LU3. The driving circuit 320 can compare the dimming voltage V_DIM with the current information of the light emitting element circuit LU3 (a signal for representing the light emitting element current I_LED). Based on the relationship between the dimming voltage V_DIM and the light emitting element current I_LED of the light emitting element circuit LU3, the driving circuit 320 can dynamically adjust the duty cycle of the driving signal PWM3.

[0033] Figure 4 FIG. 1 is a flow chart of a method for driving a light emitting element according to an embodiment of the present invention. Figure 3 and Figure 4In step S410, the driving device 300 receives an enable signal LED_EN. The enable signal LED_EN can enable or disable the driving circuit 320 (step S420). In response to the enable signal LED_EN disabling the driving circuit 320 (the determination result of step S420 is "No"), the slow start circuit 310 can pull down the original adjustment voltage LED_Iadj to generate a pulled-down voltage as the dimming voltage V_DIM (step S430).

[0034] Figure 5 FIG. 1 is a schematic diagram of signal waveforms during a slow-start driving circuit according to an embodiment of the present invention. Figure 5 Draws in Figure 3 The waveform diagram of the enable signal LED_EN, the original adjustment voltage LED_Iadj, the dimming voltage V_DIM and the light emitting element current I_LED is shown in FIG. 1 , wherein the vertical axis represents the voltage or current, and the horizontal axis represents the time. Generally speaking, after the user completes the brightness adjustment of the light emitting element circuit LU3, the original adjustment voltage LED_Iadj will maintain a certain fixed level to keep the brightness of the light emitting element circuit LU3 stable.

[0035] Please refer to Figure 3 , Figure 4 and Figure 5 When the enable signal LED_EN is at a low logic level, the driving circuit 320 is disabled. In response to the enable signal LED_EN disabling the driving circuit 320 (the determination result of step S420 is "No"), the slow start circuit 310 can pull down the original adjustment voltage LED_Iadj to generate a pulled-down voltage VL as the dimming voltage V_DIM (step S430). At this time, the driving signal PWM3 output by the driving circuit 320 can turn off the light emitting element circuit LU3 (the light emitting element current I_LED approaches zero).

[0036] When the enable signal LED_EN changes to a high logic level, the enable signal LED_EN can quickly start the driving circuit 320. At this time, the driving signal PWM3 output by the driving circuit 320 can turn on the light-emitting element circuit LU3. In response to the enable signal LED_EN enabling the driving circuit 320 (the judgment result of step S420 is "yes"), the slow start circuit 310 can slowly pull up the dimming voltage V_DIM from the pulled-down voltage VL to a level approximately equal to the original adjustment voltage LED_Iadj (step S440). Based on the buffering of the capacitor C11, the pull-up of the dimming voltage V_DIM is gradual (such as Figure 5As shown in FIG. 4 ). Based on the relationship between the dimming voltage V_DIM and the current information of the light emitting device circuit LU3, the driving circuit 320 can dynamically adjust the duty cycle of the driving signal PWM3 (step S450). The driving circuit 320 outputs the driving signal PWM3 to drive the light emitting device circuit LU3 (step S460). Due to the gradual increase of the dimming voltage V_DIM, the light emitting device current I_LED of the light emitting device circuit LU3 can be slowly increased to the target current level, thereby effectively reducing the overshoot current.

[0037] In summary, when the enable signal LED_EN disables the driving circuit 320, the slow start circuit 310 generates a pulled-down voltage VL lower than the original adjustment voltage LED_Iadj, and uses the pulled-down voltage VL as the dimming voltage V_DIM provided to the driving circuit 320. When the enable signal LED_EN enables the driving circuit 320, the slow start circuit 310 slowly pulls up the dimming voltage V_DIM from the pulled-down voltage level VL to a level approximately equal to the original adjustment voltage LED_Iadj. After the enable signal LED_EN enables the driving circuit, the driving circuit 320 can dynamically adjust the duty cycle of the driving signal PWM3 based on the relationship between the dimming voltage V_DIM and the current information of the light emitting device circuit LU3 (a signal representing the light emitting device current I_LED), thereby dynamically adjusting the light emitting device current I_LED. During the process of enabling / starting the driving circuit 320, because the dimming voltage V_DIM is slowly pulled up to a level approximately equal to the original adjustment voltage LED_Iadj, the overshoot current of the light emitting element can be effectively reduced when starting the light emitting element. When the light emitting element current I_LED has an overshoot current, the slow start circuit 310 can control the overshoot current within the design range that meets the device specifications.

[0038] Figure 6 FIG. 4 is a circuit block diagram of a soft start circuit 310 according to an embodiment of the present invention. Figure 6 The slow start circuit 310 can be used as Figure 3 The slow start circuit 310 is one of many implementation examples. Figure 6In the illustrated embodiment, the slow start circuit 310 includes a resistor R1 and a variable resistor circuit 311. The first end of the resistor R1 is used to receive the original adjustment voltage LED_Iadj. The second end of the resistor R1 is coupled to the output end of the slow start circuit 310 to provide the dimming voltage V_DIM to the driving circuit 320. The variable resistor circuit 311 is coupled between the second end of the resistor R1 and a reference voltage (e.g., a ground voltage or other fixed voltage). In response to the enable signal LED_EN disabling the driving circuit 320, the variable resistor circuit 311 can reduce the resistance of the variable resistor circuit 311. At this time, the variable resistor circuit 311 can pull down the original adjustment voltage LED_Iadj to generate a pulled-down voltage VL as the dimming voltage V_DIM. In response to the enable signal LED_EN enabling the driving circuit 320, the variable resistor circuit 311 can increase the resistance of the variable resistor circuit 311. At this time, based on the buffering of the capacitor C11, the variable resistor circuit 311 can slowly pull up the dimming voltage V_DIM from the pulled-down voltage level VL to a level that is approximately equal to the original adjustment voltage LED_Iadj.

[0039] Figure 7 FIG. 4 is a circuit block diagram of a variable resistor circuit 311 according to an embodiment of the present invention. Figure 7 The variable resistor circuit 311 can be used as Figure 6 One of many implementation examples of the variable resistor circuit 311 is shown. Figure 7 In the illustrated embodiment, the variable resistor circuit 311 includes a resistor R2 and a shunt circuit 312. The first end of the resistor R2 is coupled to the second end of the resistor R1 to receive the dimming voltage V_DIM. The second end of the resistor R2 is coupled to a reference voltage (e.g., a ground voltage or other fixed voltage). The shunt circuit 312 is coupled to the second end of the resistor R1 to receive the dimming voltage V_DIM. In response to the enable signal LED_EN disabling the driving circuit 320, the shunt circuit 312 can provide a shunt path to the second end of the resistor R1. In response to the enable signal LED_EN enabling the driving circuit 320, the shunt circuit 312 can cut off the shunt path.

[0040] Figure 8 FIG. 4 is a circuit block diagram of the shunt circuit 312 according to an embodiment of the present invention. Figure 8 The shunt circuit 312 shown can be used as Figure 7 The shunt circuit 312 is one of many implementation examples. Figure 8In the illustrated embodiment, the shunt circuit 312 includes a resistor R3 and a switch circuit 313. The first end of the resistor R3 is coupled to the second end of the resistor R1 to receive the dimming voltage V_DIM. The switch circuit 313 is coupled between the second end of the resistor R3 and a reference voltage (e.g., a ground voltage or other fixed voltage). In response to the enable signal LED_EN disabling the driving circuit 320, the switch circuit 313 is turned on. Therefore, the shunt circuit 312 can provide a shunt path to the second end of the resistor R1. In response to the enable signal LED_EN enabling the driving circuit 320, the switch circuit 313 is turned off. Therefore, the shunt circuit 312 can cut off the shunt path.

[0041] Fig. 9 FIG. 4 is a circuit block diagram of the switch circuit 313 according to an embodiment of the present invention. Fig. 9 The switch circuit 313 shown can be used as Figure 8 One of many implementation examples of the switch circuit 313 shown. Fig. 9 In the illustrated embodiment, the switch circuit 313 includes a switch QR3 and a control circuit 314. A first terminal (e.g., a collector of a transistor) of the switch QR3 is coupled to a second terminal of the resistor R3. A second terminal (e.g., an emitter of the transistor) of the switch QR3 is coupled to a reference voltage (e.g., a ground voltage or other fixed voltage). The control circuit 314 is coupled to a control terminal (e.g., a base of the transistor) of the switch QR3. In response to the enable signal LED_EN disabling the driving circuit 320, the control circuit 314 turns on the switch QR3. In response to the enable signal LED_EN enabling the driving circuit 320, the control circuit 314 turns off the switch QR3.

[0042] exist Fig. 9 In the illustrated embodiment, the control circuit 314 includes a resistor R4 and a switch QR4. A first end of the resistor R4 is coupled to a power supply voltage Vcc. A second end of the resistor R4 is coupled to a control end of the switch QR3. A first end of the switch QR4 (e.g., a collector of a transistor) is coupled to the control end of the switch QR3. A second end of the switch QR4 (e.g., an emitter of a transistor) is coupled to a reference voltage (e.g., a ground voltage or other fixed voltage). A control end of the switch QR4 (e.g., a base of a transistor) receives an enable signal LED_EN. In response to the enable signal LED_EN disabling the driving circuit 320, the switch QR4 is turned off. In response to the enable signal LED_EN enabling the driving circuit 320, the switch QR4 is turned on.

[0043] Fig.10 FIG. 1 is a circuit diagram of a control circuit 314 according to another embodiment of the present invention. Fig.10 In the illustrated embodiment, the control circuit 314 includes a resistor R4 , a switch QR4 , a resistor R5 , a resistor R6 , and a resistor R7 . Fig.10 The resistor R4 and switch QR4 shown can be referred to Fig. 9 The relevant description of the resistor R4 and the switch QR4 is not repeated here. Fig.10 In the illustrated embodiment, a first end of the resistor R5 is coupled to a second end of the resistor R4. A second end of the resistor R5 is coupled to a reference voltage (e.g., a ground voltage or other fixed voltage). A first end of the resistor R6 is used to receive an enable signal LED_EN. A second end of the resistor R6 is coupled to a control end of the switch QR4 (e.g., a base of a transistor). A first end of the resistor R7 is coupled to a second end of the resistor R6. A second end of the resistor R7 is coupled to a reference voltage (e.g., a ground voltage or other fixed voltage).

[0044] When the enable signal LED_EN is at a low logic level, the switch QR4 is not turned on, causing the power voltage Vcc to turn on the switch QR3. At this time, the original adjustment voltage LED_Iadj is divided by the resistors R1, R2 and R3 to generate a dimming voltage V_DIM that is less than the original adjustment voltage LED_Iadj. The lowered dimming voltage V_DIM is LED_Iadj*(R3 / / R2) / [R1+(R3 / / R2)]=(LED_Iadj*R2*R3) / (R1*R2+R1*R3+R2*R3)=VL. When the enable signal LED_EN is at a high logic level, the switch QR4 is turned on, causing the switch QR3 to be turned off. At this time, the original adjustment voltage LED_Iadj is divided by the resistors R1 and R2 to pull up the dimming voltage V_DIM. The pulled-up dimming voltage V_DIM is (LED_Iadj*R2) / (R1+R2). When the switch QR3 is not turned on, the original adjustment voltage LED_Iadj can charge the capacitor C11 through the resistor R1 to slowly pull the dimming voltage V_DIM from the pulled-down voltage level VL to a level approximately equal to the original adjustment voltage LED_Iadj (e.g. Figure 5 shown).

[0045] In summary, the present invention provides a driving device and a driving method for a light-emitting element. When an enable signal disables a driving circuit, the slow start circuit generates a pulled-down voltage lower than an original adjustment voltage, and uses the pulled-down voltage as a dimming voltage provided to the driving circuit. When the enable signal enables the driving circuit, the slow start circuit slowly pulls up the dimming voltage from the pulled-down voltage level to approximately the original adjustment voltage level. After the enable signal enables the driving circuit, the driving circuit can dynamically adjust the duty cycle of the driving signal based on the relationship between the dimming voltage and the current information of the light-emitting element circuit, thereby dynamically adjusting the current of the light-emitting element. In the process of enabling / starting the driving circuit, because the dimming voltage is slowly pulled up to approximately the original adjustment voltage level, the overshoot current of the light-emitting element can be effectively reduced when starting the light-emitting element.

[0046] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention are all within the scope of patent protection of the present invention.

Claims

1. A driving device for a light emitting element, characterized in that: include: A driving circuit for outputting a driving signal to drive a light-emitting device circuit, wherein the driving circuit is enabled or disabled based on an enabling signal, and the driving circuit dynamically adjusts a duty cycle of the driving signal based on a relationship between a dimming voltage and current information of the light-emitting device circuit; A slow start circuit having an output terminal coupled to the driving circuit to provide the dimming voltage, wherein the slow start circuit disables the driving circuit in response to the enable signal and pulls down the original adjustment voltage to generate a pulled-down voltage as the dimming voltage, and the slow start circuit enables the driving circuit in response to the enable signal and pulls up the pulled-down voltage to serve as the dimming voltage; as well as The first capacitor is coupled to the output terminal of the slow start circuit.

2. The driving device according to claim 1, characterized in that: The slow start circuit includes: A first resistor having a first end for receiving the original adjustment voltage, wherein a second end of the first resistor is coupled to the output end of the slow start circuit; and A variable resistor circuit is coupled between the second end of the first resistor and a first reference voltage, wherein the variable resistor circuit reduces the resistance of the variable resistor circuit in response to the enable signal disabling the drive circuit, and the variable resistor circuit increases the resistance of the variable resistor circuit in response to the enable signal enabling the drive circuit.

3. The driving device according to claim 2, characterized in that: The variable resistor circuit comprises: A second resistor having a first end coupled to the second end of the first resistor, wherein the second end of the second resistor is coupled to the first reference voltage; and The shunt circuit is coupled to the second end of the first resistor, wherein the shunt circuit provides a shunt path to the second end of the first resistor in response to the enable signal to disable the driving circuit, and the shunt circuit enables the driving circuit in response to the enable signal to cut off the shunt path.

4. The driving device according to claim 3, characterized in that: The shunt circuit includes: A third resistor having a first end coupled to the second end of the first resistor; and The switch circuit is coupled between the second end of the third resistor and the first reference voltage, wherein the switch circuit is turned on in response to the enable signal to disable the driving circuit, and the switch circuit is turned off in response to the enable signal to enable the driving circuit.

5. The driving device according to claim 4, characterized in that: The switching circuit comprises: A first switch having a first end coupled to the second end of the third resistor, wherein a second end of the first switch is coupled to the first reference voltage; and The control circuit is coupled to the control end of the first switch, wherein the control circuit disables the driving circuit in response to the enable signal to turn on the first switch, and the control circuit enables the driving circuit in response to the enable signal to turn off the first switch.

6. The driving device according to claim 5, characterized in that: The control circuit includes: a fourth resistor having a first end coupled to a power supply voltage, wherein a second end of the fourth resistor is coupled to the control end of the first switch; and The second switch has a first end coupled to the control end of the first switch, wherein the second end of the second switch is coupled to a second reference voltage, the second switch is turned off in response to the enable signal to disable the drive circuit, and the second switch is turned on in response to the enable signal to enable the drive circuit.

7. The driving device according to claim 6, characterized in that: The control circuit also includes: a fifth resistor having a first end coupled to the second end of the fourth resistor, wherein a second end of the fifth resistor is coupled to a third reference voltage; a sixth resistor having a first end for receiving the enable signal, wherein a second end of the sixth resistor is coupled to the control end of the second switch; and The seventh resistor has a first end coupled to the second end of the sixth resistor, wherein the second end of the seventh resistor is coupled to a fourth reference voltage.

8. The driving device according to claim 1, characterized in that: The slow start circuit enables the driving circuit in response to the enable signal, and pulls up the pulled-down voltage to the original adjustment voltage to serve as the dimming voltage.

9. A method for driving a light emitting element, characterized in that: include: enabling or disabling the driving circuit by an enabling signal; The driving circuit dynamically adjusts the duty cycle of the driving signal based on the relationship between the dimming voltage and the current information of the light-emitting element circuit, wherein the output end of the slow start circuit is coupled to the driving circuit to provide the dimming voltage; The driving circuit outputs the driving signal to drive the light emitting element circuit; The soft start circuit disables the driving circuit in response to the enable signal to pull down the original adjustment voltage to generate a pulled-down voltage as the dimming voltage; as well as The slow start circuit enables the driving circuit in response to the enable signal to pull up the pulled-down voltage to serve as the dimming voltage, wherein the first capacitor is coupled to the output terminal of the slow start circuit.

10. The driving method according to claim 9, characterized in that: Also includes: The variable resistance circuit of the slow start circuit disables the driving circuit in response to the enable signal to reduce the resistance of the variable resistance circuit, wherein a first end of a first resistor of the slow start circuit receives the original adjustment voltage, a second end of the first resistor is coupled to the driving circuit to provide the dimming voltage, and the variable resistance circuit is coupled between the second end of the first resistor and a reference voltage; as well as The variable resistance circuit enables the driving circuit in response to the enabling signal to increase the resistance of the variable resistance circuit.

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