Light source control circuit and system

Abstract

The utility model discloses a light source control circuit and system. The light source control circuit comprises a first filtering module, an under-voltage protection module, a current adjusting module, a ripple supplementing module and a second filtering module. The first filtering module, the under-voltage protection module, the ripple supplementing module and the second filtering module are connected with the current adjusting module; the first filtering module, the under-voltage protection module and the current adjusting module are further connected with the main control module, and the ripple supplementing module and the second filtering module are further connected with the LED element. According to the light source control circuit provided by the embodiment of the utility model, by arranging the first filtering module, the under-voltage protection module, the current adjusting module, the ripple supplementing module and the second filtering module, the output current of the circuit can be ensured to be stable, so that the LED element obtains constant brightness output.

Description

Technical Field

[0001] The utility model relates to the technical field of LED lighting, and in particular to a light source control circuit and system. Background Art

[0002] Light Emitting Diode (LED) light sources have the advantages of energy saving, environmental protection, and low power consumption, and have been widely used in home lighting, automotive lighting and other fields. In order to meet the lighting needs of users, LED drive circuits often need to have dimming functions. Pulse Width Modulation (PWM) dimming technology uses the change of duty cycle to change the average value of LED load current, thereby adjusting the LED brightness. It is currently the most widely used PWM dimming technology.

[0003] However, the existing light source control circuit using PWM dimming technology cannot ensure the stability of the output current of the circuit. Utility Model Content

[0004] The utility model provides a light source control circuit, which can ensure the output current of the circuit is stable by arranging a first filtering module, an undervoltage protection module, a current regulating module, a ripple supplementing module and a second filtering module, so that the LED element can obtain a constant brightness output.

[0005] In a first aspect, an embodiment of the utility model provides a light source control circuit, including: a first filtering module, an undervoltage protection module, a current regulating module, a ripple supplementing module and a second filtering module;

[0006] The first filtering module, the undervoltage protection module, the ripple supplement module and the second filtering module are all connected to the current regulating module;

[0007] The first filtering module, the undervoltage protection module and the current regulating module are also connected to the main control module, and the ripple supplement module and the second filtering module are also connected to the LED element.

[0008] Optionally, the main control module includes a control voltage signal output terminal, an enable signal output terminal and a power signal output terminal;

[0009] The first filter module is connected to the main control module via the control voltage signal output terminal;

[0010] The undervoltage protection module is connected to the main control module via the enable signal output terminal;

[0011] The current regulating module is connected to the main control module via the power signal output terminal.

[0012] Optionally, the current regulation module includes: a voltage control chip, a current sampling resistor and a switch tube;

[0013] The voltage control chip includes an LM3409 chip;

[0014] The LM3409 chip includes a first current detection terminal, a second current detection terminal and a driving terminal;

[0015] One end of the current sampling resistor is connected to the first current detection end and the power signal output end, and the other end of the current sampling resistor is connected to the second current detection end;

[0016] The gate of the switch tube is connected to the driving end, the source of the switch tube is connected to the second current detection end, and the drain of the switch tube is connected to the second filtering module.

[0017] Optionally, the first filtering module includes: a first resistor;

[0018] The LM3409 chip also includes an analog dimming terminal;

[0019] One end of the first resistor is connected to the control voltage signal output end, and the other end of the first resistor is connected to the analog dimming end.

[0020] Optionally, the first filtering module further includes: a second resistor and a first capacitor;

[0021] One end of the second resistor is connected to the analog dimming end, and the other end of the second resistor is grounded;

[0022] One end of the first capacitor is connected to the analog dimming end, and the other end of the first capacitor is grounded.

[0023] Optionally, the undervoltage protection module includes: a third resistor and a fourth resistor;

[0024] The LM3409 chip also includes an undervoltage lockout terminal;

[0025] One end of the third resistor is connected to the enable signal output terminal, and the other end of the third resistor is connected to the undervoltage lockout terminal;

[0026] One end of the fourth resistor is connected to the undervoltage lockout end, and the other end of the fourth resistor is grounded.

[0027] Optionally, the ripple supplement module includes: a fifth resistor and a second capacitor;

[0028] The LM3409 chip also includes an output control terminal and a ground terminal;

[0029] One end of the fifth resistor is connected to the output control end, and the other end of the fifth resistor is connected to the LED element;

[0030] One end of the second capacitor is connected to the output control end, and the other end of the second capacitor is grounded;

[0031] The ground terminal is grounded.

[0032] Optionally, the second filtering module includes: a first diode and a first inductor;

[0033] The cathode of the first diode is connected to the drain of the switch tube, and the anode of the first diode is grounded;

[0034] One end of the first inductor is connected to the drain of the switch tube, and the other end of the first inductor is connected to the LED element.

[0035] Optionally, the second filtering module further includes: a third capacitor and a fourth capacitor;

[0036] One end of the third capacitor is connected to the LED element, and the other end of the third capacitor is grounded;

[0037] One end of the fourth capacitor is connected to the LED element, and the other end of the fourth capacitor is grounded.

[0038] In a second aspect, an embodiment of the utility model further provides a light source control system, comprising the light source control circuit, the main control module and the LED element as described in the first aspect;

[0039] The main control module is connected to the light source control circuit, and the light source control circuit is also connected to the LED element.

[0040] The utility model provides a light source control circuit and system, the light source control circuit includes: a first filter module, an undervoltage protection module, a current regulation module, a ripple supplement module and a second filter module; the first filter module, the undervoltage protection module, the ripple supplement module and the second filter module are all connected to the current regulation module; the first filter module, the undervoltage protection module and the current regulation module are also connected to the main control module, and the ripple supplement module and the second filter module are also connected to the LED element. The light source control circuit provided by the embodiment of the utility model can ensure the output current of the circuit is stable by setting the first filter module, the undervoltage protection module, the current regulation module, the ripple supplement module and the second filter module, so that the LED element can obtain a constant brightness output.

[0041] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A schematic diagram of the structure of a light source control circuit provided by an embodiment of the utility model;

[0044] Figure 2 A circuit diagram of a light source control circuit provided by an embodiment of the utility model;

[0045] Figure 3 A structural schematic diagram of a light source control system provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] Figure 1A schematic diagram of a light source control circuit provided by an embodiment of the utility model, referring to Figure 1 The light source control circuit includes: a first filtering module 110 , an undervoltage protection module 120 , a current regulating module 130 , a ripple supplementing module 140 and a second filtering module 150 .

[0049] Continue to refer Figure 1 The first filter module 110, the undervoltage protection module 120, the ripple supplement module 140 and the second filter module 150 are all connected to the current regulation module 130. The first filter module 110, the undervoltage protection module 120 and the current regulation module 130 are also connected to the main control module 200, and the ripple supplement module 140 and the second filter module 150 are also connected to the LED element 300.

[0050] It is understandable that after the control voltage output by the main control module 200 is filtered by the first filter module 110 , adjusted by the current regulation module 130 , and filtered by the second filter module 150 , the output current of the circuit can be guaranteed to be stable.

[0051] The light source control circuit provided in the embodiment of the utility model can ensure the output current stability of the circuit by setting the first filter module 110, the undervoltage protection module 120, the current regulation module 130, the ripple compensation module 140 and the second filter module 150, so that the LED element 300 can obtain a constant brightness output.

[0052] Optionally, based on the above embodiment, continue to refer to Figure 1 The main control module 200 includes a control voltage signal output terminal PWM, an enable signal output terminal LEDCS1, and a power signal output terminal D12V. The first filter module 110 is connected to the main control module 200 through the control voltage signal output terminal PWM. The undervoltage protection module 120 is connected to the main control module 200 through the enable signal output terminal LEDCS1. The current regulation module 130 is connected to the main control module 200 through the power signal output terminal D12V.

[0053] The control voltage signal output terminal PWM is used to output the control voltage, the enable signal output terminal LEDCS1 is used to output the enable signal, and the power signal output terminal D12V is used to output the power signal.

[0054] Figure 2 A circuit diagram of a light source control circuit provided in an embodiment of the utility model. Optionally, based on the above embodiment, refer to Figure 2 The current regulation module 130 includes: a voltage control chip U1, a current sampling resistor Rs and a switch tube Q1.

[0055] Continue to refer Figure 2, the voltage control chip includes an LM3409 chip. The LM3409 chip includes a first current detection terminal CSP, a second current detection terminal CSN, and a driving terminal PGATE. One end of the current sampling resistor Rs is connected to the first current detection terminal CSP and the power signal output terminal D12V, and the other end of the current sampling resistor Rs is connected to the second current detection terminal CSN. The gate of the switch tube Q1 is connected to the driving terminal PGATE, the source of the switch tube Q1 is connected to the second current detection terminal CSN, and the drain of the switch tube Q1 is connected to the second filter module 150.

[0056] The voltage control chip of the embodiment of the utility model includes an LM3409 chip, which can provide a wide input voltage range, an adjustable low reference voltage differential current detection function and a fast output enable / disable control function. Among them, one end of the current sampling resistor Rs is connected to the first current detection terminal CSP and the power signal output terminal D12V, the other end of the current sampling resistor Rs is connected to the second current detection terminal CSN to detect the current output from the power signal output terminal D12V, and the driving terminal PGATE is connected to the gate of the switch tube Q1 to control the conduction or shutdown of the switch tube Q1.

[0057] Optionally, based on the above embodiment, the current regulating module 130 further includes a fifth capacitor C5, the light source control circuit of the embodiment of the utility model further includes a sixth capacitor C6, and the LM3409 chip further includes a power input terminal VIN and a voltage input terminal VCC. One end of the fifth capacitor C5 is connected to the power input terminal VIN, the other end of the fifth capacitor C5 is connected to the voltage input terminal VCC, one end of the sixth capacitor C6 is connected to the power signal output terminal D12V, the other end of the sixth capacitor C6 is grounded, and the power input terminal VIN is also connected to the power signal output terminal D12V.

[0058] In the embodiment of the utility model, the fifth capacitor C5 and the sixth capacitor C6 are provided to better protect the circuit and ensure the stability and efficiency of the circuit.

[0059] Optionally, based on the above embodiment, continue to refer to Figure 2 The first filter module 110 includes: a first resistor R1. The LM3409 chip also includes an analog dimming terminal IADJ. One end of the first resistor R1 is connected to the control voltage signal output terminal PWM, and the other end of the first resistor R1 is connected to the analog dimming terminal IADJ.

[0060] In an embodiment of the utility model, one end of the first resistor R1 is connected to the control voltage signal output terminal PWM, and the other end of the first resistor R1 is connected to the analog dimming terminal IADJ, which can filter out the noise of the voltage signal input from the control voltage signal output terminal PWM to the analog dimming terminal IADJ, thereby stabilizing the current output by the light source control circuit of the embodiment of the utility model.

[0061] Optionally, based on the above embodiment, continue to refer to Figure 2 The first filter module 110 further includes: a second resistor R2 and a first capacitor C1. One end of the second resistor R2 is connected to the analog dimming terminal IADJ, and the other end of the second resistor R2 is grounded. One end of the first capacitor C1 is connected to the analog dimming terminal IADJ, and the other end of the first capacitor C1 is grounded.

[0062] In the embodiment of the utility model, one end of the second resistor R2 is connected to the analog dimming terminal IADJ, and the other end of the second resistor R2 is grounded. One end of the first capacitor C1 is connected to the analog dimming terminal IADJ, and the other end of the first capacitor C1 is grounded, which can further filter out the noise of the voltage signal input from the control voltage signal output terminal PWM to the analog dimming terminal IADJ, thereby making the current output by the light source control circuit of the embodiment of the utility model more stable.

[0063] Optionally, based on the above embodiment, continue to refer to Figure 2 , the undervoltage protection module 120 includes: a third resistor R3 and a fourth resistor R4. The LM3409 chip also includes an undervoltage lockout terminal UVLO. One end of the third resistor R3 is connected to the enable signal output terminal LEDCS1, and the other end of the third resistor R3 is connected to the undervoltage lockout terminal UVLO. One end of the fourth resistor R4 is connected to the undervoltage lockout terminal UVLO, and the other end of the fourth resistor is grounded.

[0064] In the embodiment of the utility model, one end of the third resistor R3 is connected to the enable signal output terminal LEDCS1, and the other end of the third resistor R3 is connected to the undervoltage lockout terminal UVLO. One end of the fourth resistor R4 is connected to the undervoltage lockout terminal UVLO, and the other end of the fourth resistor is grounded. When the input voltage is lower than the set threshold, the undervoltage lockout terminal UVLO triggers a protection mechanism to disable the LM3409 chip to prevent potential damage to the system.

[0065] Optionally, based on the above embodiment, continue to refer to Figure 2 The ripple compensation module 140 includes: a fifth resistor R5 and a second capacitor C2. The LM3409 chip also includes an output control terminal COFF and a ground terminal GND. One end of the fifth resistor R5 is connected to the output control terminal COFF, and the other end of the fifth resistor R5 is connected to the LED element 300. One end of the second capacitor C2 is connected to the output control terminal COFF, and the other end of the second capacitor C2 is grounded. The ground terminal GND is grounded.

[0066] In the embodiment of the present utility model, one end of the fifth resistor R5 is connected to the output control terminal COFF, the other end of the fifth resistor R5 is connected to the LED element 300, one end of the second capacitor C2 is connected to the output control terminal COFF, and the other end of the second capacitor C2 is grounded. The turn-off time can be set, thereby effectively controlling the output of the light source control circuit and controlling the ripple of the output current within a certain range according to the actual application situation, so as to ensure stability and efficiency.

[0067] Optionally, on the basis of the above embodiment, the second filtering module 150 includes: a first diode D1 and a first inductor L1. The negative electrode of the first diode D1 is connected to the drain of the switching transistor Q1, and the positive electrode of the first diode D1 is grounded. One end of the first inductor L1 is connected to the drain of the switching transistor Q1, and the other end of the first inductor L1 is connected to the LED element 300.

[0068] In the embodiment of the present utility model, the negative electrode of the first diode D1 is connected to the drain of the switching transistor Q1, the positive electrode of the first diode D1 is grounded, one end of the first inductor L1 is connected to the drain of the switching transistor Q1, and the other end of the first inductor L1 is connected to the LED element 300, which can make the current output by the light source control circuit of the embodiment of the present utility model more stable.

[0069] Optionally, the second filtering module 150 further includes: a third capacitor C3 and a fourth capacitor C4. One end of the third capacitor C3 is connected to the LED element 300, the other end of the third capacitor C3 is grounded, one end of the fourth capacitor C4 is connected to the LED element 300, and the other end of the fourth capacitor C4 is grounded.

[0070] In the embodiment of the present utility model, the first inductor L1, the first diode D1, the third capacitor C3, and the fourth capacitor C4 form a filtering circuit, which can make the current output by the light source control circuit of the embodiment of the present utility model more stable.

[0071] It should be noted that the voltage of the analog dimming terminal IADJ is Viadj, and the voltage across the current sampling resistor Rs is Vrs. When Vrs > Viadj, the conduction time of the switching transistor Q1 becomes longer, the energy storage of the first inductor L1 increases, and the output current of the second filtering module 150 increases. When Vrs < Viadj, the conduction time of the switching transistor Q1 becomes shorter, the energy storage of the first inductor L1 decreases, and the output current of the second filtering module 150 decreases, so as to achieve the stability of the output current of the entire circuit controlled by the given Viadj.

[0072] Figure 3 This is a schematic structural diagram of a light source control system provided by the embodiment of the present utility model. Refer to Figure 3The light source control system includes a light source control circuit 100, a main control module 200 and an LED element 300. The main control module 200 is connected to the light source control circuit 100, and the light source control circuit 100 is also connected to the LED element 300.

[0073] The light source control system provided in the embodiment of the utility model includes all technical features of the light source control circuit of the above embodiment, and thus has the same beneficial effects. For contents not described in detail in this embodiment, reference can be made to the light source control circuit of the above embodiment.

[0074] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A light source control circuit, characterized in that: include: A first filtering module, an undervoltage protection module, a current regulating module, a ripple supplementing module and a second filtering module; The first filtering module, the undervoltage protection module, the ripple supplement module and the second filtering module are all connected to the current regulating module; The first filtering module, the undervoltage protection module and the current regulating module are also connected to the main control module, and the ripple supplement module and the second filtering module are also connected to the LED element.

2. The light source control circuit according to claim 1, characterized in that: The main control module includes a control voltage signal output terminal, an enable signal output terminal and a power signal output terminal; The first filter module is connected to the main control module via the control voltage signal output terminal; The undervoltage protection module is connected to the main control module via the enable signal output terminal; The current regulating module is connected to the main control module via the power signal output terminal.

3. The light source control circuit according to claim 2, characterized in that: The current regulation module includes: a voltage control chip, a current sampling resistor and a switch tube; The voltage control chip includes an LM3409 chip; The LM3409 chip includes a first current detection terminal, a second current detection terminal and a driving terminal; One end of the current sampling resistor is connected to the first current detection end and the power signal output end, and the other end of the current sampling resistor is connected to the second current detection end; The gate of the switch tube is connected to the driving end, the source of the switch tube is connected to the second current detection end, and the drain of the switch tube is connected to the second filtering module.

4. The light source control circuit according to claim 3, characterized in that: The first filtering module includes: a first resistor; The LM3409 chip also includes an analog dimming terminal; One end of the first resistor is connected to the control voltage signal output end, and the other end of the first resistor is connected to the analog dimming end.

5. The light source control circuit according to claim 4, characterized in that: The first filtering module further includes: a second resistor and a first capacitor; One end of the second resistor is connected to the analog dimming end, and the other end of the second resistor is grounded; One end of the first capacitor is connected to the analog dimming end, and the other end of the first capacitor is grounded.

6. The light source control circuit according to claim 3, characterized in that: The undervoltage protection module includes: a third resistor and a fourth resistor; The LM3409 chip also includes an undervoltage lockout terminal; One end of the third resistor is connected to the enable signal output terminal, and the other end of the third resistor is connected to the undervoltage lockout terminal; One end of the fourth resistor is connected to the undervoltage lockout end, and the other end of the fourth resistor is grounded.

7. The light source control circuit according to claim 3, characterized in that: The ripple supplement module includes: a fifth resistor and a second capacitor; The LM3409 chip also includes an output control terminal and a ground terminal; One end of the fifth resistor is connected to the output control end, and the other end of the fifth resistor is connected to the LED element; One end of the second capacitor is connected to the output control end, and the other end of the second capacitor is grounded; The ground terminal is grounded.

8. The light source control circuit according to claim 3, characterized in that: The second filtering module includes: a first diode and a first inductor; The cathode of the first diode is connected to the drain of the switch tube, and the anode of the first diode is grounded; One end of the first inductor is connected to the drain of the switch tube, and the other end of the first inductor is connected to the LED element.

9. The light source control circuit according to claim 8, characterized in that: The second filtering module further includes: a third capacitor and a fourth capacitor; One end of the third capacitor is connected to the LED element, and the other end of the third capacitor is grounded; One end of the fourth capacitor is connected to the LED element, and the other end of the fourth capacitor is grounded.

10. A light source control system, characterized in that: It comprises the light source control circuit, main control module and LED element according to any one of claims 1 to 9; The main control module is connected to the light source control circuit, and the light source control circuit is also connected to the LED element.

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