Illumination drive circuit, vehicle-mounted illumination control system, and illumination control method

Abstract

The invention provides a lighting driving circuit, a vehicle-mounted lighting control system and a lighting control method.The lighting driving circuit comprises a driving controller, a single-end primary inductance converter and at least one load control circuit, and the input end of the single-end primary inductance converter is connected with a preset power source; the output end of the single-end primary inductance converter is used for being connected with a first lighting unit, the driving controller is connected with at least one load control circuit, and the at least one load control circuit is connected with at least one second lighting unit connected with the first lighting unit in series. The second lighting unit and the first lighting unit are different types of lighting units, and the driving controller is further connected with the control end of the single-end primary inductance converter. Therefore, one path of single-end primary inductance converter is adopted to load different types of lighting units, the hardware utilization rate is improved, and the brightness adjustment of the lighting units is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit control, in particular to a lighting driving circuit, a vehicle-mounted lighting control system and a lighting control method. BACKGROUND

[0002] In some use scenarios, the lighting driving module needs to realize miniaturization and low cost under the premise of ensuring functions, and therefore a single ended primary inductor converter (SEPIC) topology structure is often used.

[0003] In the related art, in order to realize miniaturization and low cost, one type of lighting unit is usually carried by one SPEIC, for example, only a low beam (LB) is carried, however, this carrying mode results in low hardware utilization. SUMMARY

[0004] Therefore, the embodiments of the present application provide a lighting driving circuit, a vehicle-mounted lighting control system and a lighting control method to solve the problem of low hardware utilization caused by carrying one type of lighting unit by one SPEIC.

[0005] In a first aspect, the embodiments of the present application provide a lighting driving circuit, comprising: a lighting driving circuit, comprising: a driving controller, a single ended primary inductor converter, and at least one load control circuit. An input end of the single ended primary inductor converter is connected to a preset power supply, an output end of the single ended primary inductor converter is used to connect a first lighting unit, the driving controller is connected to the at least one load control circuit, the at least one load control circuit is respectively connected to at least one second lighting unit connected in series with the first lighting unit, wherein the second lighting unit and the first lighting unit are different types of lighting units. The driving controller is further connected to a control end of the single ended primary inductor converter.

[0006] In an optional implementation, the at least one load control circuit comprises: a first control circuit and a second control circuit, and the at least one second lighting unit comprises a first sub-lighting unit and a second sub-lighting unit, wherein the first sub-lighting unit and the second sub-lighting unit are different types of lighting units.

[0007] In an optional implementation, the at least one load control circuit comprises: a second control circuit, and the at least one second lighting unit comprises one type of lighting unit.

[0008] In an optional embodiment, the first control circuit comprises: a first switch tube, a voltage dividing circuit, a second switch tube, the first output end of the drive controller is connected to the control end of the first switch tube, the output end of the first switch tube is grounded, the input end of the first switch tube is connected to the input end of the voltage dividing circuit, the output end of the voltage dividing circuit is connected to the control end of the second switch tube, the output end of the second switch tube is connected to the positive power supply end of the first sub-illumination unit, and the input end of the second switch tube is connected to the negative power supply end of the first sub-illumination unit.

[0009] In an optional embodiment, the second control circuit comprises: a third switch tube, the second output end of the drive controller is connected to the control end of the third switch tube, the output end of the third switch tube is grounded, and the input end of the third switch tube is connected to the positive power supply end of the corresponding illumination unit, and the negative power supply end of the corresponding illumination unit is grounded.

[0010] In an optional embodiment, the second control circuit comprises: an integrated control chip, the second output end of the drive controller is connected to the input end of the integrated control chip, the output end of the integrated control chip is connected to the positive power supply end of the second sub-illumination unit, and the negative power supply end of the second sub-illumination unit is grounded.

[0011] In an optional embodiment, the illumination drive circuit further comprises: a switch control unit, the drive controller is connected to the first input end of the switch control unit, and the output end of the switch control unit is connected to the control end of the switch unit in the single-ended primary inductance converter.

[0012] In an optional embodiment, the illumination drive circuit further comprises: a feedback resistor, the feedback resistor is arranged between the output end of the single-ended primary inductance converter and the first illumination unit to collect a feedback voltage signal and a feedback current signal. The feedback resistor is also connected to the second input end of the switch control unit, so that the switch control unit generates the control signal of the switch unit based on the feedback voltage signal, the feedback current signal, and the voltage control signal and the current control signal output by the drive controller.

[0013] In a second aspect, the embodiments of the present application further provide a vehicle-mounted illumination control system, comprising: a first illumination unit, at least one second illumination unit, and the illumination drive circuit of any one of the first aspect. In a third aspect, the embodiments of the present application further provide an illumination control method applied to the drive controller in the illumination drive circuit of any one of the first aspect, and the method comprises: In response to a power-on signal for the lighting drive circuit, an enable signal, a current control signal, a voltage control signal, and a drive control signal are generated. The enable signal, the current control signal, and the voltage control signal are respectively sent to a single-ended primary inductor converter, and the drive control signal is sent to at least one load control circuit. The rising edge of the enable signal is later than the rising edges of the current control signal, the voltage control signal, and the drive control signal. In response to a power-down signal for the lighting drive circuit, the enable signal, the current control signal, the voltage control signal, and the drive control signal are adjusted such that the falling edge of the enable signal precedes the rising edge of the current control signal, the voltage control signal, and the drive control signal.

[0014] In an optional implementation, the method further includes: In response to a duty cycle adjustment signal for the drive control signal, the enable signal is adjusted from a high level to a low level, and the duty cycle of the drive control signal is adjusted. The adjusted drive control signal is sent to the at least one load control circuit, and the enable signal is restored to a high level after a preset time.

[0015] This application provides a lighting drive circuit, an on-board lighting control system, and a lighting control method. The circuit includes a drive controller, a single-ended primary inductor converter, and at least one load control circuit. The input terminal of the single-ended primary inductor converter is connected to a preset power supply, and the output terminal of the single-ended primary inductor converter is connected to a first lighting unit. The drive controller is connected to at least one load control circuit, and the at least one load control circuit is connected in series with at least one second lighting unit, wherein the second lighting unit and the first lighting unit are different types of lighting units. The drive controller is also connected to the control terminal of the single-ended primary inductor converter. Therefore, a single-ended primary inductor converter is used to drive different types of lighting units, improving hardware utilization and satisfying the brightness adjustment of the lighting units. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Schematic diagram of the lighting driving circuit provided in the embodiments of this application Figure One ; Figure 2 A circuit schematic diagram of a single-ended primary inductance converter provided for an embodiment of the present application; Figure 3 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Two ; Figure 4 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Three ; Figure 5 A circuit schematic diagram of a first control circuit provided for an embodiment of the present application; Figure 6 A circuit schematic diagram of a second control circuit provided for an embodiment of the present application Figure One ; Figure 7 A circuit schematic diagram of a second control circuit provided for an embodiment of the present application Figure Two ; Figure 8 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Four ; Figure 9 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Five ; Figure 10 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Six ; Figure 11 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Seven ; Figure 12 A schematic diagram of a lighting driving circuit provided for an embodiment of the present application Figure Eight ; Figure 13 A flowchart of a lighting control method provided for an embodiment of the present application Figure One ; Figure 14 A flowchart of a lighting control method provided for an embodiment of the present application Figure Two ; Figure 15 A lighting control timing diagram provided for an embodiment of the present application Figure One ; Figure 16 A lighting control timing diagram provided for an embodiment of the present application Figure Two ; Figure 17 A lighting control timing diagram provided for an embodiment of the present application Figure Three . DETAILED DESCRIPTION

[0018] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0019] In order to solve the problem that the hardware utilization rate is not high due to the use of one type of lighting unit with one SEPIC load, the present application provides a lighting driving circuit which uses one single-ended primary inductor converter (SEPIC) to load different types of lighting units, thereby improving the hardware utilization rate.

[0020] Figure 1 The schematic diagram of the lighting driving circuit provided by the embodiments of the present application Figure One As shown in Figure 1 The lighting driving circuit comprises a driving controller 10, a single-ended primary inductor converter 20, and at least one load control circuit 30.

[0021] The input end of the single-ended primary inductor converter 20 is connected to a preset power supply 40, and the output end of the single-ended primary inductor converter 20 is used to connect a first lighting unit 50. The driving controller 10 is connected to the at least one load control circuit 30, and the at least one load control circuit 30 is respectively connected to at least one second lighting unit 60 connected in series with the first lighting unit 50. The second lighting unit 60 and the first lighting unit 50 are different types of lighting units.

[0022] The driving controller 10 is further connected to the control end of the single-ended primary inductor converter 20.

[0023] The driving controller 10 can be a microcontroller unit (MCU). The first lighting unit 50 and the at least one second lighting unit 60 are LED loads. The first lighting unit 50 can be a low beam (LB), and the at least one second lighting unit 60 can include a high beam (HB) and a corner light (CL).

[0024] The preset power supply 40 is configured to provide an input power for the single-ended primary inductance converter 20, and an output end of the single-ended primary inductance converter 20 is connected to the first lighting unit 50, and the first lighting unit 50 and the at least one second lighting unit 60 are connected in series, so that the current flowing through the path where the first lighting unit 50 and the at least one second lighting unit 60 are located is controlled by the output of the single-ended primary inductance converter 20, that is, the brightness of the first lighting unit 50 and the at least one second lighting unit 60 is controlled.

[0025] The driving controller 10 is connected to the at least one load control circuit 30 to output a corresponding driving control signal to control the brightness of each second lighting unit 60, that is, the bright-dark condition, through each load control circuit 30, wherein one load control circuit 30 controls one second lighting unit 60.

[0026] The control end of the single-ended primary inductance converter 20 can be the control end of the switching unit in the single-ended primary inductance converter 20, and the driving controller 10 can control the output voltage of the single-ended primary inductance converter 20 by controlling the duty cycle of the switching unit.

[0027] Figure 2 The circuit schematic diagram of the single-ended primary inductance converter provided in the embodiment of the present application is shown in Figure 2 The single-ended primary inductance converter 20 includes an inductor L1, an inductor L2, a switching unit S, a diode D1, a coupling capacitor C1, and an output capacitor C2.

[0028] The one end of the inductor L1 is connected to the positive power supply end of the preset power supply 40, the negative power supply end of the preset power supply 40 is grounded, the other end of the inductor L1 is respectively connected to the one end of the coupling capacitor C1 and the one end of the switching unit S, the other end of the switching unit S is grounded, the other end of the coupling capacitor C1 is grounded through the inductor L2, and the other end of the coupling capacitor C1 is also connected to the one end of the output capacitor C2 through the diode D1, and the other end of the output capacitor C2 is grounded.

[0029] The working process of the single-ended primary inductance converter 20 includes two stages: switching-on stage and switching-off stage, wherein in the switching-on stage, the switching unit S is turned on, the input voltage of the preset power supply 40 is applied to the inductor L1, the inductor L1 starts to store energy, and at the same time, the coupling capacitor C1 discharges the inductor L2 through the switching unit S, at this time, the diode D1 is cut off due to reverse bias, and the output voltage of the output capacitor C2 is used to supply power to the load alone.

[0030] During the switch-off phase, inductors L1 and L2 generate a reverse electromotive force to maintain the current. This reverse electromotive force causes diode D1 to be forward biased and conduct. That is, the energy stored in inductors L1 and L2 charges the output capacitor C2 through diode D1 and supplies power to the load. If the stored energy is released, the current stops, and the output voltage will gradually drop to 0V, thus failing to supply power to the load.

[0031] In this process, by controlling the on and off times of the switching unit S, i.e. the duty cycle of the pulse width modulation (PWM) signal, the output voltage of the single-ended primary inductor converter 20 can be adjusted, thereby providing a stable output voltage for the load.

[0032] In the lighting drive circuit provided in this embodiment, a single-ended primary inductor converter is used to drive different types of lighting units, which improves hardware utilization and meets the requirements for brightness adjustment of the lighting units.

[0033] Figure 3 Schematic diagram of the lighting driving circuit provided in the embodiments of this application Figure Two ,like Figure 3 As shown, in an optional embodiment, at least one load control circuit 30 includes a first control circuit 301 and a second control circuit 302, and at least one second lighting unit 60 includes a first sub-lighting unit 601 and a second sub-lighting unit 602, wherein the first sub-lighting unit 601 and the second sub-lighting unit 602 are lighting units of different types.

[0034] The first sub-lighting unit 601 can be HB, the second sub-lighting unit can be CL, the first control circuit 301 can be a high-side switching (HSS) circuit and a high-side control circuit, used to control the brightness of the first sub-lighting unit 601, and the second control circuit 302 can be a low-side switching (LSS) circuit and a low-side control circuit, used to control the brightness of the second sub-lighting unit 602.

[0035] Figure 4 Schematic diagram of the lighting driving circuit provided in the embodiments of this application Figure Three ,like Figure 4 As shown, in an optional embodiment, at least one load control circuit 30 includes a second control circuit 302, and at least one second lighting unit 60 includes a type of lighting unit 603.

[0036] In one type, the lighting unit 603 can be CL or HB, and the first control circuit 302 can be a low-side control circuit.

[0037] In the lighting driving circuit provided in the embodiment, one single-end primary inductor converter is used to drive two or three different types of lighting units, thereby improving hardware utilization and meeting the brightness adjustment of the lighting units through different load control circuits.

[0038] Figure 5 The circuit schematic diagram of the first control circuit provided in the embodiment is shown in Figure 5 The first control circuit 301 includes a first switch tube (such as an NMOS) Q2, a voltage dividing circuit 3011, a second switch tube (such as a PMOS) Q1, the first output end of the drive controller 10 is connected to the control end of the first switch tube Q2, the output end of the first switch tube Q2 is grounded, the input end of the first switch tube Q2 is connected to the input end of the voltage dividing circuit 3011, the output end of the voltage dividing circuit 3011 is connected to the control end of the second switch tube Q1, the output end (HB_A) of the second switch tube Q1 is connected to the positive power supply end of the first sub-lighting unit, and the input end (HB_C) of the second switch tube Q1 is connected to the negative power supply end of the first sub-lighting unit.

[0039] The control end of the first switch tube Q2 is a gate (G), the input end of the first switch tube Q2 is a drain (D), the output end of the first switch tube Q2 is a source (S), the control end of the second switch tube Q1 is a gate (G), the input end of the second switch tube Q1 is a source (S), and the output end of the second switch tube Q1 is a drain (D).

[0040] The input end and the output end of the first switch tube Q2 can also be connected to a voltage stabilizing tube D2, so as to protect the first switch tube Q2 from high voltage and ensure the stability and reliability of the circuit.

[0041] In some embodiments, the first control circuit 301 further includes a voltage stabilizing tube D3, a first capacitor C3, a second capacitor C4, a third capacitor C5, a fourth capacitor C6, a first resistor R1, and a second resistor R2, the voltage stabilizing tube D3 and the first capacitor C3 are connected in parallel and arranged between the control end and the output end of the second switch tube Q1, one end of the second capacitor C4 is connected to the output end of the second switch tube Q1, the other end of the second capacitor C4 is grounded, one end of the third capacitor C5 is connected to the input end of the second switch tube Q1, the other end of the third capacitor C5 is grounded, one end of the fourth capacitor C6 is connected to the control end of the first switch tube Q2, the other end of the fourth capacitor C6 is grounded, one end of the first resistor R1 is connected to the first output end of the drive controller 10, the other end of the first resistor R1 is respectively connected to one end of the fourth capacitor C6 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded.

[0042] The voltage stabilizing tube D3 can be a high-power transient voltage suppression diode, denoted as AK, the first capacitor C3 is a charge-discharge capacitor, arranged between the control end and the output end of the second switch tube Q1, used to control the switching speed of the second switch tube Q1, reduce switching noise, and protect the output end from overvoltage damage.

[0043] The second capacitor C4 is a filter capacitor, used to filter the signal output by the output end of the second switch tube Q1, the third capacitor C5 is a filter capacitor, used to filter the signal input to the input end of the second switch tube Q1, and the fourth capacitor C6 is a filter capacitor, used to filter the signal input to the control end of the first switch tube Q2.

[0044] The first resistor R1 and the second resistor R5 are voltage dividing resistors, used to divide the high-side control signal (HB_control) output by the driving controller 10 to protect the control end of the first switch tube Q2 from overvoltage damage. The driving control signal includes the high-side control signal.

[0045] In some embodiments, the voltage dividing circuit 3011 includes a third resistor R3 and a fourth resistor R4, one end of the third resistor R3 serving as an input end of the voltage dividing circuit 3011, the other end of the third resistor R3 and one end of the fourth resistor R4 being connected, the other end of the third resistor R3 serving as an output end of the voltage dividing circuit 3011, and the other end of the fourth resistor R4 being connected to the output end of the second switch tube Q1.

[0046] The voltage across the third resistor R3 is input to the control end of the second switch tube Q1 to control the second switch tube Q1 to close or open, thereby protecting the control end of the second switch tube Q1 from overvoltage damage.

[0047] In the specific implementation process, the load control circuit 30 outputs a high-side control signal, which is divided by the first resistor R1 and the second resistor R5, and then input to the control end of the first switch tube Q2 to control the first switch tube Q2 to close. The voltage after voltage division is input to the control end of the second switch tube Q1 through the third resistor R3 in the voltage dividing circuit 3011 to control the second switch tube Q1 to open, thereby inputting the voltage after passing through the fourth resistor R4 in the voltage dividing circuit 3011 to the positive power supply end of the first sub-illumination unit 601, and the negative power supply end of the first sub-illumination unit 601 is grounded. Therefore, when the voltage difference between the positive and negative power supply ends of the first sub-illumination unit 601 exceeds the preset forward voltage drop, the first sub-illumination unit 601 is turned on and emits light.

[0048] It should be noted that if the second switch tube Q1 is closed, the second switch tube Q1 is turned on, and the voltage difference between the positive and negative power supply terminals of the first sub-illumination unit 601 is less than the preset forward voltage drop, so that the first sub-illumination unit 601 is extinguished. Wherein the brightness of the first sub-illumination unit 601 is proportional to the average current passing through it. The high-side control signal output by the drive controller 10 is a PWM signal, and the PWM signal controls the average current passing through the first sub-illumination unit 601 by changing the time ratio of high level and low level (i.e. duty cycle), thereby adjusting the brightness. For example, the MCU can output a 200Hz PWM signal to adjust the brightness of HB.

[0049] Wherein, when the duty cycle is close to 100%, the first sub-illumination unit 601 is in a high level state most of the time, and the average current passing through it is large, so the first sub-illumination unit 601 will be very bright, when the duty cycle is close to 0%, the first sub-illumination unit 601 is in a low level state most of the time, and the average current passing through it is small, so the first sub-illumination unit 601 will be very dark or almost not bright, when the duty cycle is between 0% and 100%, the brightness of the first sub-illumination unit 601 will change according to the size of the duty cycle, realizing different brightness levels.

[0050] Figure 6 Circuit schematic of the second control circuit provided for the embodiments of the present application Figure One As Figure 6 shown, in an optional embodiment, the second control circuit 302 includes a third switch tube (such as NMOS) Q3, the second output end of the drive controller 10 is connected to the control end of the third switch tube Q3, the output end of the third switch tube Q3 is grounded, and the input end (HB_C) of the third switch tube Q3 is connected to the positive power supply end of the corresponding illumination unit. The negative power supply end of the corresponding illumination unit is grounded.

[0051] Wherein, if at least one load control circuit 30 includes the first control circuit 301 and the second control circuit 302, the input end (HB_C) of the third switch tube Q3 is connected to the positive power supply end of the second sub-illumination unit 601, and the negative power supply end of the second sub-illumination unit 602 is grounded.

[0052] If at least one load control circuit 30 includes the second control circuit 302, the input end (HB_C) of the third switch tube Q3 is connected to the positive power supply end of a type of illumination unit, and the negative power supply end of a type of illumination unit is grounded.

[0053] In some embodiments, the second control circuit 302 further comprises a filter circuit 3021 and a fifth capacitor C7, the second output end of the drive controller 10 is connected to the control end of the third switch tube Q3 through the filter circuit 3021, one end of the fifth capacitor C7 is connected to the input end of the third switch tube Q3, and the other end of the fifth capacitor C7 is grounded.

[0054] The filter circuit 3021 is configured to filter the low-side control signal input from the drive controller 10 to the second control circuit 301 and then input to the control end of the third switch tube Q3. The drive control signal includes the low-side control signal.

[0055] The filter circuit 3021 includes a fifth resistor R5 and a sixth capacitor C8, one end of the fifth resistor R5 is connected to the second output end of the drive controller 10, the other end of the fifth resistor R5 is connected to the control end of the third switch tube Q3 through the sixth capacitor C8, and the other end of the fifth resistor R5 is grounded.

[0056] The fifth capacitor C7 is a filter capacitor configured to filter the signal output from the output end of the third switch tube Q3.

[0057] In the implementation process, the load control circuit 30 outputs a low-side control signal (HB_control), which is input to the control end of the third switch tube Q3 after being filtered by the filter circuit 3021, so as to control the third switch tube Q3 to be turned off, thereby making the voltage at the positive power supply end of the second sub-illumination unit 602 equal to the voltage at the negative power supply end of the first sub-illumination unit 601, and the negative power supply end of the second sub-illumination unit 602 is grounded. Therefore, when the voltage difference between the positive and negative power supply ends of the second sub-illumination unit 602 exceeds the preset forward voltage drop, the second sub-illumination unit 602 is turned on and emits light.

[0058] It should be noted that if the third switch tube Q3 is closed, the voltage difference between the positive and negative power supply ends of the second sub-illumination unit 602 is less than the preset forward voltage drop, so that the second sub-illumination unit 602 is turned off. The brightness of the second sub-illumination unit 602 is proportional to the average current passing through it. The low-side control signal output by the drive controller 10 is a PWM signal, which controls the average current passing through the second sub-illumination unit 602 by changing the time ratio of high level and low level (i.e. duty ratio), thereby adjusting the brightness. The MCU can output a 200Hz PWM signal to adjust the brightness of the CL.

[0059] When the duty cycle is close to 100%, the second sub-illumination unit 602 is in a high level state most of the time, the average current passing through is large, and therefore the second sub-illumination unit 602 is very bright; when the duty cycle is close to 0%, the second sub-illumination unit 602 is in a low level state most of the time, the average current passing through is small, and therefore the second sub-illumination unit 602 is very dark or almost not bright; when the duty cycle is between 0% and 100%, the brightness of the second sub-illumination unit 602 changes according to the size of the duty cycle, realizing different brightness levels.

[0060] Figure 7 Circuit schematic of the second control circuit provided for the embodiments of the present application Figure Two As shown in Figure 7 In an optional embodiment, the second control circuit 302 includes an integrated control chip 3022, the second output end of the drive controller 10 is connected to the input end of the integrated control chip 3022, and the output end (HB_C) of the integrated control chip 3022 is connected to the positive power supply end of the second sub-illumination unit 602, and the negative power supply end of the second sub-illumination unit 602 is grounded.

[0061] The integrated control chip 3022 is an integrated circuit (IC).

[0062] In some embodiments, the second control circuit 302 further includes a fifth resistor R5, a seventh capacitor C9, and an eighth capacitor C10, the fifth resistor R5 and the seventh capacitor C9 constitute an RC filter circuit, one end of the fifth resistor R5 is connected to the second output end of the drive controller 10, the other end of the fifth resistor R5 is connected to the input end of the integrated control chip 3022, the other end of the fifth resistor R5 is also grounded through the seventh capacitor C9, the output end of the integrated control chip 3022 is grounded through the eighth capacitor C10, and the eighth capacitor C10 is a filter capacitor.

[0063] Figure 8 Schematic of the illumination driving circuit provided for the embodiments of the present application Figure Four As shown in Figure 8 In an optional embodiment, the illumination driving circuit further includes a switch control unit 70, the drive controller 10 is connected to the first input end of the switch control unit 70, and the output end of the switch control unit 70 is connected to the control end of the switch unit S in the single-ended primary inductance converter 20.

[0064] The illumination driving circuit further includes a feedback resistor Ris, which is arranged between the output end of the single-ended primary inductance converter 20 and the first illumination unit 50 to collect feedback voltage signals and feedback current signals.

[0065] The feedback resistor 80 is also connected to a second input of the switch control unit 70, so that the switch control unit 70 generates the control signal of the switch unit S based on the feedback voltage signal, the feedback current signal, and the voltage control signal and the current control signal output by the driving controller 10.

[0066] Wherein, the voltage signal and the current signal of the output end of the single-ended primary inductance converter 20 are collected as the feedback voltage signal and the feedback current signal through the feedback resistor Ris, the driving controller 10 is configured to send the enable signal, the voltage control signal and the current control signal to the switch control unit 70, and the switch control unit 70 generates the control signal of the switch unit S based on the feedback voltage signal, the feedback current signal, and the voltage control signal and the current control signal when the enable signal is high, so as to control the on and off time of the switch unit S, so that the feedback voltage signal and the feedback current signal are respectively the voltage control signal and the current control signal. Thus, a stable output voltage is provided for the load.

[0067] In some embodiments, the two ends of the feedback resistor 80 are connected to the current feedback input of the switch control unit 70 through the differential current feedback line, and the end of the feedback resistor 80 close to the first lighting unit 50 is connected to the voltage feedback input of the switch control unit 70 through the voltage feedback line, and the second input of the switch control unit 70 includes the current feedback input and the voltage feedback input.

[0068] Taking the first lighting unit as LB, and taking the at least one second lighting unit as HB and CL for example, the current flow direction is indicated by the thick line, Figure 9 Schematic diagram of the lighting driving circuit provided by the embodiment of the present application Figure Five , Figure 10 Schematic diagram of the lighting driving circuit provided by the embodiment of the present application Figure Six , Figure 11 Schematic diagram of the lighting driving circuit provided by the embodiment of the present application Figure Seven , Figure 12 Schematic diagram of the lighting driving circuit provided by the embodiment of the present application Figure Eight .

[0069] As shown in Figure 9 , if LB, HB and CL need to be lighted, the single-ended primary inductance converter 20 has an output voltage, LB is lighted, PMOS Q1 in the first control circuit 301 is disconnected, CL is lighted, NMOS Q3 in the second control circuit is disconnected, and HB is lighted.

[0070] As shown in Figure 10 , if LB needs to be lighted, the single-ended primary inductance converter 20 has an output voltage, LB is lighted, PMOS Q1 in the first control circuit 301 is closed, CL is extinguished, NMOS Q3 in the second control circuit 302 is closed, and HB is extinguished.

[0071] As shown in Figure 11 , if LB and HB need to be lighted up, the single-ended primary inductance converter 20 exists output voltage, then LB is lighted up, PMOS Q1 in the first control circuit 301 is closed, then CL is turned off, NMOS Q3 in the second control circuit is closed, then HB is turned off.

[0072] As shown in Figure 12 , if LB and CL need to be lighted up, the single-ended primary inductance converter 20 exists output voltage, then LB is lighted up, PMOS Q1 in the first control circuit 301 is opened, then CL is lighted up, NMOS Q3 in the second control circuit 302 is closed, then HB is turned off.

[0073] The embodiment of the present application also provides a vehicle-mounted lighting control system, comprising: a first lighting unit 50, at least one second lighting unit 60 and the lighting drive circuit.

[0074] In some cases, due to the slow response of the topology of the single-ended primary inductance converter SEPIC, it is also more sensitive to the change of the load, when the load current suddenly changes, such as switching from light load to full load, the slow response SEPIC cannot quickly adjust the duty cycle, resulting in instantaneous drop (Undershoot) or overshoot (Overshoot) of the output voltage, and the lighting unit flickers, brightens and darkens alternately.

[0075] Based on this, the present application also provides a lighting control method, which solves the problem that when the load suddenly changes or the load changes frequently, the timing of the lighting drive circuit needs to be adjusted to realize the normal output of the lighting drive circuit under the condition of using SEPIC.

[0076] Figure 13 The flowchart of the lighting control method provided by the embodiment of the present application Figure One The execution subject of the embodiment can be the drive controller in the lighting drive circuit.

[0077] As shown in Figure 13 , the method can comprise: S101, in response to a power-on signal for the lighting drive circuit, generating an enable signal, a current control signal, a voltage control signal and a drive control signal, and sending the enable signal, the current control signal and the voltage control signal to the single-ended primary inductance converter respectively, and sending the drive control signal to at least one load control circuit.

[0078] The power-on signal for the lighting drive circuit can be a lighting trigger signal, and the user can trigger the drive controller to generate the power-on signal by pressing the lighting start button.

[0079] In response to a power-on signal for the lighting driving circuit, a enable signal, a current control signal, a voltage control signal and a driving control signal are generated, wherein the driving control signal comprises at least one control signal, the enable signal, the current control signal and the voltage control signal are respectively sent to the single-ended primary inductance converter, and the at least one control signal is respectively sent to at least one load control circuit, one load control circuit corresponding to one control signal.

[0080] The rising edge of the enable signal is later than the rising edges of the current control signal, the voltage control signal and the driving control signal.

[0081] When the enable signal is at a high level, the switch unit in the single-ended primary inductance converter is closed, and the single-ended primary inductance converter normally supplies power to the load; when the enable signal is at a low level, the switch unit in the single-ended primary inductance converter is opened, and the single-ended primary inductance converter cannot supply power to the load.

[0082] That is, when the lighting driving circuit is powered on, the single-ended primary inductance converter needs to be output after other signals are sent, so as to avoid that when the enable signal is at a high level, the current control signal, the voltage control signal and the driving control signal are set to high level, so that the single-ended primary inductance converter detects sudden change of the load, resulting in that the output voltage of the single-ended primary inductance converter instantaneously drops or overshoots, and the lighting unit flickers, brightens and darkens alternately.

[0083] In some embodiments, the driving control signal comprises a high-side control signal and a low-side control signal, the high-side control signal is sent to the first control circuit to control the brightness of the first lighting unit, and the low-side control signal is sent to the second control circuit to control the brightness of the second lighting unit.

[0084] In some embodiments, the enable signal, the current control signal and the voltage control signal are sent to the switch control unit to control the on and off time of the switch unit in the single-ended primary inductance converter based on the current control signal, the voltage control signal, a feedback current signal and a feedback voltage signal, so as to provide stable output voltage for the load.

[0085] S102, in response to a power-off signal for the lighting driving circuit, the enable signal, the current control signal, the voltage control signal and the driving control signal are adjusted, so that the falling edge of the enable signal is earlier than the rising edges of the current control signal, the voltage control signal and the driving control signal.

[0086] The power-off signal for the lighting driving circuit can be a light-off trigger signal, and the user can trigger the driving controller to generate the power-off signal by pressing the lighting off button.

[0087] In response to the power-down signal for the lighting driving circuit, the enable signal, the current control signal, the voltage control signal and the driving control signal are adjusted so that the falling edge of the enable signal is earlier than the rising edges of the current control signal, the voltage control signal and the driving control signal, that is, the single-ended primary inductance converter is directly disconnected first and then the other signals are reset, thereby avoiding the sudden setting of the current control signal, the voltage control signal and the driving control signal to low level when the enable signal is high, so that the sudden change of the load causes the output voltage of the single-ended primary inductance converter to drop or overshoot, and the lighting unit flickers or becomes bright and dark alternately.

[0088] Figure 14 Flowchart of the lighting control method provided by the embodiment Figure Two As shown in Figure 14 In an optional embodiment, the method can further include: S201, in response to the duty cycle adjustment signal for the driving control signal, the enable signal is adjusted from high level to low level, and the duty cycle of the driving control signal is adjusted.

[0089] The duty cycle adjustment signal for the driving control signal can be generated by the user by pressing the brightness adjustment button.

[0090] When the single-ended primary inductance converter normally outputs, in response to the duty cycle adjustment signal, the enable signal is adjusted from high level to low level, and the duty cycle of the driving control signal is adjusted to obtain the adjusted driving control signal.

[0091] S202, the adjusted driving control signal is sent to at least one load control circuit, and the enable signal is restored to high level after a preset time length.

[0092] Each load control circuit is used to control the corresponding lighting unit, and the adjusted driving control signal is sent to at least one load control circuit, so that each load control circuit controls the corresponding lighting unit, which is similar to the load output by the single-ended primary inductance converter changing from light load to heavy load and from heavy load to light load, if the enable signal is high, the overcurrent protection of the switch control unit will be triggered, and then the switch control unit will be reset, which will cause the phenomenon that the lighting unit flickers and can be seen by naked eye. Therefore, in the case that the enable signal is low, the adjusted driving control signal is used to control the lighting unit, and the enable signal is restored to high level after a preset time length, so that the single-ended primary inductance converter has a short non-working time, and then normally outputs after controlling the lighting unit. In this way, no matter how many duty cycles of output are required, the phenomenon of lighting flicker will not occur, and the brightness requirements of different lighting units are met.

[0093] In the lighting control method provided in the embodiment, after the timing scheme is implemented, the brightness of the at least one second lighting unit can be controlled by the driving control signal, and the overcurrent protection is not triggered, so that the human eye cannot obviously see the flicker of the lighting unit.

[0094] It should be noted that if there is no timing requirement, the HB_Control and the CL_Control are 200Hz PWM signals, and at this time, it is found that all the lamps (LB, HB and CL) will flicker, which is incorrect. The reason is that the SEPIC is a 4th order topology structure, and the response time is slow. Due to the slow response time, when the duty cycle output of HB and CL is output, the situation is similar to that the load of the SEPIC output is suddenly changed from light load to heavy load, and from heavy load to light load. At this time, the overcurrent protection of the switch control unit is triggered, and the switch control unit is reset, and the phenomenon is that the human eye can see the flicker of the lamp. Based on this, the lighting control method provided in the embodiment can be used to set the timing of each signal, and the LB, HB and CL are taken as examples, Figure 15 The lighting control timing diagram provided in the embodiment of the application Figure One As shown in Figure 15 , the LB&HB&CL lighting trigger signal (Signal Detection) is high (ON), that is, the power-on signal, and the low level (OFF) is the power-off signal. The power-on signal needs to be lighted, the EN is the enable signal of the SEPIC, the signal is high, the SEPIC outputs, and the I, V, HB_Control and CL_Control are current control signals, voltage control signals, high-side control signals and low-side control signals, respectively.

[0095] When powered on, the EN of the SEPIC needs to be pulled high to output after the action of other signals is completed (the time is ensured to be within 30mS). When powered off, the EN of the SEPIC needs to be pulled low to stop output before the other signals are reset (the time is ensured to be within 30mS).

[0096] Taking the HB_Control as an example, Figure 16 The lighting control timing diagram provided in the embodiment of the application Figure Two As shown in Figure 16 , the HB_Control is a high-side control signal with a 200Hz PWM duty cycle of 70%, the HB detection signal (Signal Detection) is a signal that needs to output HB, that is, a 200Hz 70% duty cycle, and the HB output signal (OUTPUT) indicates the actual output of the HB, that is, a 200Hz 70% duty cycle and the HB detection signal are consistent.

[0097] It can be seen that the HB_Control is just opposite to the HB OUTPUT, when the MCU gives to the HB_Control, the EN is low, that is to say, when the HB_Control jumps (whether it is rising or falling), at this time, it needs to ensure that the SEPIC does not output (the EN is low), and the action time is ensured within 90uS.

[0098] In addition, when only the LB, HB and LB, CL are lit and there is a duty cycle, the HB and CL can be realized according to the timing of Figure 16 , which can control the brightness of the HB and CL, and will not appear, for example, the flicker of the naked eye.

[0099] If the HB and CL need a duty cycle at the same time, because the duty cycles of the HB and CL are inconsistent, the specific timing is shown in Figure 17 , Figure 17 The lighting control timing diagram provided by the embodiment of the present application is shown in Figure Three , as shown in Figure 17 , when the MCU controls the HSS and LSS, it only pulls down the EN at the rising edge (low to high change) of the signal, and does not care about the falling edge (flicker condition is also acceptable), and synchronizes the rising edge of the HB_Control and the CL_Control.

[0100] The reason for selecting the rising edge synchronization is that when the HB_Control changes from low to high, Figure 5 , the PMOS Q1 in the PMOS is closed, at this time, the HB is actually extinguished, and there will be a momentary impact current when the heavy load becomes a light load, and similarly, when the CL_Control changes from low to high, Figure 6 , the NMOS Q3 in the NMOS is closed, at this time, the CL is actually extinguished, and there will also be a momentary impact current when the module changes from a heavy load to a light load, in this switching process, the EN is closed (pulled down), at this time, it does not work, so it will not trigger the overcurrent protection, and will not appear the flicker of the naked eye.

[0101] The embodiment of the present application also provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program is run by a load controller to execute the above-mentioned lighting control method.

[0102] It should be noted that: similar labels and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings, and in addition, the terms "first", "second", "third" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0103] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present application, and are used to illustrate the technical solutions of the present application, but not to limit the same. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that any person skilled in the art can make modifications or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some of the technical features within the technical scope disclosed by the present application. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. All should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A lighting driving circuit, characterized in that, include: Drive controller, single-ended primary inductor converter, and at least one load control circuit; The input terminal of the single-ended primary inductor converter is connected to a preset power supply, and the output terminal of the single-ended primary inductor converter is used to connect to the first lighting unit. The drive controller is connected to the at least one load control circuit, and the at least one load control circuit is respectively connected to at least one second lighting unit connected in series with the first lighting unit. The second lighting unit and the first lighting unit are different types of lighting units. The drive controller is also connected to the control terminal of the single-ended primary inductor converter.

2. The circuit according to claim 1, characterized in that, The at least one load control circuit includes a first control circuit and a second control circuit, and the at least one second lighting unit includes a first sub-lighting unit and a second sub-lighting unit, wherein the first sub-lighting unit and the second lighting unit are different types of lighting units.

3. The circuit according to claim 1, characterized in that, The at least one load control circuit includes a second control circuit, and the at least one second lighting unit includes a type of lighting unit.

4. The circuit according to claim 2, characterized in that, The first control circuit includes: a first switching transistor, a voltage divider circuit, and a second switching transistor. The first output terminal of the drive controller is connected to the control terminal of the first switching transistor. The output terminal of the first switching transistor is grounded. The input terminal of the first switching transistor is connected to the input terminal of the voltage divider circuit. The output terminal of the voltage divider circuit is connected to the control terminal of the second switching transistor. The output terminal of the second switching transistor is connected to the positive power supply terminal of the first sub-lighting unit. The input terminal of the second switching transistor is connected to the negative power supply terminal of the first sub-lighting unit.

5. The circuit according to claim 2 or 3, characterized in that, The second control circuit includes: a third switching transistor, the second output terminal of the drive controller is connected to the control terminal of the third switching transistor, the output terminal of the third switching transistor is grounded, the input terminal of the third switching transistor is connected to the positive power supply terminal of the corresponding lighting unit, and the negative power supply terminal of the corresponding lighting unit is grounded.

6. The circuit according to claim 2, characterized in that, The second control circuit includes an integrated control chip, the second output terminal of the drive controller is connected to the input terminal of the integrated control chip, the output terminal of the integrated control chip is connected to the positive power supply terminal of the second sub-lighting unit, and the negative power supply terminal of the second sub-lighting unit is grounded.

7. The circuit according to claim 1, characterized in that, The lighting drive circuit further includes a switch control unit, the drive controller being connected to the first input terminal of the switch control unit, and the output terminal of the switch control unit being connected to the control terminal of the switch unit in the single-ended primary inductor converter.

8. The circuit according to claim 7, characterized in that, The lighting driving circuit further includes a feedback resistor, which is disposed between the output terminal of the single-ended primary inductor converter and the first lighting unit to collect feedback voltage signals and feedback current signals. The feedback resistor is also connected to the second input terminal of the switch control unit, so that the switch control unit generates the control signal of the switch unit based on the feedback voltage signal, the feedback current signal, and the voltage control signal and current control signal output by the drive controller.

9. A vehicle-mounted lighting control system, characterized in that, include: The first lighting unit, at least one second lighting unit, and the lighting driving circuit according to any one of claims 1-8.

10. A lighting control method, characterized in that, The method, applied to a drive controller in a lighting drive circuit according to any one of claims 1-8, comprises: In response to a power-on signal for the lighting drive circuit, an enable signal, a current control signal, a voltage control signal, and a drive control signal are generated. The enable signal, the current control signal, and the voltage control signal are respectively sent to a single-ended primary inductor converter, and the drive control signal is sent to at least one load control circuit. The rising edge of the enable signal is later than the rising edges of the current control signal, the voltage control signal, and the drive control signal. In response to a power-down signal for the lighting drive circuit, the enable signal, the current control signal, the voltage control signal, and the drive control signal are adjusted such that the falling edge of the enable signal precedes the rising edge of the current control signal, the voltage control signal, and the drive control signal.

11. The method according to claim 10, characterized in that, The method further includes: In response to a duty cycle adjustment signal for the drive control signal, the enable signal is adjusted from a high level to a low level, and the duty cycle of the drive control signal is adjusted. The adjusted drive control signal is sent to the at least one load control circuit, and the enable signal is restored to a high level after a preset time.

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