DC-DC power supply device
By introducing RC circuits and anti-reverse connection modules into the DC-DC power supply device, the circuit instability problem caused by the combination of constant current chips and inductors is solved, and the absorption and suppression of voltage peaks and spikes is achieved, and the EMC conduction effect is improved. Reduced costs.
Patent Information
- Application Number
- CN202420854469.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2025-01-10
- Estimated Expiration
- 2034-04-23
AI Technical Summary
The coordination between the constant current chip and the inductor in existing LED power supplies causes unstable circuits, resulting in voltage peaks or spikes, affecting EMI conduction, and the filtering solution of DC-DC power supplies on the market is relatively expensive.
Design a DC-DC power supply device, including a first filter module, an LED constant current driving module and a second filter module, by setting the RC circuit to absorb the voltage peak or peak of the inductor element in the second filter module, and preventing reverse connection The module uses diodes for protection to ensure circuit stability.
Effectively suppress EMI conduction, improve circuit stability, meet national EMC certification standards, reduce the impact of inductive energy storage instability, and improve the EMC conduction effect.
Smart Images
Figure CN222339263U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of LED power supplies, and in particular relates to a DC-DC power supply device. Background Art
[0002] The constant current chip used in the LED power supply in the prior art needs to be used with an inductor. Since the inductor itself has parasitic capacitance and inductance, resonance will occur, which may cause circuit instability, voltage peaks or spikes, or voltage reversal in overload, transient or AC lines. In order to avoid these effects, a resistor is usually connected in parallel to the I-shaped inductor. According to the inductance formula △u=L*(△I / △T), a sudden current will be generated when the MOS tube inside the constant current chip is turned on and off, resulting in a transient voltage spike. This spike will affect the operation of the entire circuit, and then cause EMI conduction to be interfered by the spike.
[0003] Currently, most DC-DC power supplies on the market use common mode and plug-in I-shaped inductors for filtering to improve EMI conduction. This technology incurs relatively large costs in terms of process and cost. Utility Model Content
[0004] In order to overcome the above technical defects, the utility model provides a DC-DC power supply device, which can suppress EMI conduction.
[0005] The utility model is realized by the following scheme:
[0006] A DC-DC power supply device, comprising:
[0007] A first filtering module, an input end of which is connected to a power supply;
[0008] An LED constant current driving module, whose input end is connected to the output end of the first filtering module;
[0009] A second filter module, whose input end is connected to the output end of the LED constant current drive module, and whose output end is connected to the LED load;
[0010] The second filtering module includes: an RC circuit connected to the output end of the LED constant current driving module.
[0011] As a further improvement of the utility model, the utility model further includes: an anti-reverse connection module connected between the power supply and the first filtering module.
[0012] As a further improvement of the utility model, the first filtering module includes: a first capacitor, a second capacitor, a first polarity capacitor, a second polarity capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor and a first inductor;
[0013] The positive electrode of the power supply is connected to the input end of the LED constant current driving module through the first resistor, and the second resistor and the first inductor are both arranged in parallel with the first resistor;
[0014] The negative electrode of the power supply is grounded through the third resistor and the fourth resistor;
[0015] The positive electrode of the power supply is connected to the negative electrode of the power supply through the first capacitor;
[0016] The positive electrode of the power supply is connected to the negative electrode of the power supply through the first inductor, the first polarity capacitor, the third resistor, and the fourth resistor;
[0017] The second polarity capacitor is arranged in parallel with the first polarity capacitor;
[0018] The second capacitor is arranged in parallel with the first polarity capacitor.
[0019] As a further improvement of the present invention, the second filtering module further includes:
[0020] A third capacitor connected to the output end of the LED constant current driving module.
[0021] As a further improvement of the utility model, the second filtering mode further includes: a fifth resistor, a fourth capacitor, and a fifth capacitor;
[0022] The output end of the LED constant current driving module is connected to the positive electrode of the LED load through the fourth capacitor and the fifth resistor;
[0023] Two ends of the fourth capacitor are connected to the positive electrode of the LED load and the negative electrode of the LED load respectively;
[0024] One end of the third capacitor is connected to the fifth capacitor, the negative electrode of the LED load, and the output end of the LED constant current driving module, and the other end is grounded.
[0025] As a further improvement of the present utility model, the RC circuit includes: a sixth capacitor and a sixth resistor;
[0026] The output end of the LED constant current driving module is grounded through the sixth capacitor and the sixth resistor.
[0027] As a further improvement of the utility model, the utility model further comprises: a safety resistor connected between the anti-reverse connection module and the first filter module.
[0028] As a further improvement of the utility model, the anti-reverse connection module includes: a first diode, a second diode, a third diode, and a fourth diode;
[0029] The positive electrode of the power supply is connected to the first filter module through the first forward-conducting diode, and is connected to the first filter module through the third reverse-conducting diode;
[0030] The negative electrode of the power supply is connected to the first filter module through the second forward-conducting diode, and is connected to the first filter module through the fourth reverse-conducting diode.
[0031] Compared with the prior art, the beneficial effects of the utility model are as follows: by setting an RC circuit in the second filter module, the voltage peak or spike of the inductor element in the LED constant current drive module is absorbed, the voltage peak or spike generated in the inductor is improved, and the national EMC certification standard is met, thereby greatly improving the good effect of EMC conduction, avoiding the influence of the unstable circuit caused by the long-term energy storage of the inductor, and greatly improving the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings, wherein:
[0033] Figure 1 The figure is a schematic diagram of the overall structure of the DC-DC power supply device of the utility model.
[0034] Figure numerals: 1. first filter module; 2. LED constant current drive module; 3. second filter module; 31. RC circuit; 4. anti-reverse connection module. DETAILED DESCRIPTION
[0035] It should be clear that the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present application.
[0036] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.
[0037] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.
[0038] The utility model provides a DC-DC power supply device, such as Figure 1 As shown, it includes: a first filter module 1, an LED constant current driving module 2, and a second filter module 3; the input end of the first filter module 1 is connected to the power supply; the input end of the LED constant current driving module 2 is connected to the output end of the first filter module 1; the input end of the second filter module 3 is connected to the output end of the LED constant current driving module 2, and the output end is connected to the LED load; the second filter module 3 includes: an RC circuit 31 connected to the output end of the LED constant current driving module 2.
[0039] In order to improve the safety performance of the entire power supply device, the utility model further comprises: an anti-reverse connection module 4 connected between the power supply and the first filter module 1 .
[0040] The first filtering module 1 includes: a first capacitor C1, a second capacitor C2, a first polarity capacitor EC1, a second polarity capacitor EC2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a first inductor L1; the positive electrode of the power supply is connected to the input end of the LED constant current driving module 2 through the first resistor R1, and the second resistor R2 and the first inductor L1 are both arranged in parallel with the first resistor R1; the negative electrode of the power supply is grounded through the third resistor R3 and the fourth resistor R4; the positive electrode of the power supply is connected to the negative electrode of the power supply through the first capacitor C1; the positive electrode of the power supply is connected to the negative electrode of the power supply through the first inductor L1, the first polarity capacitor EC1, the third resistor R3, and the fourth resistor R4; the second polarity capacitor EC2 is arranged in parallel with the first polarity capacitor EC1; the second capacitor C2 is arranged in parallel with the first polarity capacitor EC1.
[0041] The second filtering module 3 further includes: a third capacitor C3 connected to the output end of the LED constant current driving module 2 .
[0042] The second filtering module also includes: a fifth resistor R5, a fourth capacitor C4, and a fifth capacitor C5; the output end of the LED constant current driving module 2 is connected to the positive electrode of the LED load through the fourth capacitor C4 and the fifth resistor R5; the two ends of the fourth capacitor C4 are respectively connected to the positive electrode of the LED load and the negative electrode of the LED load; one end of the third capacitor C3 is connected to the fifth capacitor C5, the negative electrode of the LED load, and the output end of the LED constant current driving module 2, and the other end is grounded.
[0043] The RC circuit 31 includes: a sixth capacitor C6 and a sixth resistor R6; the output end of the LED constant current driving module 2 is grounded through the sixth capacitor C6 and the sixth resistor R6.
[0044] In addition, the utility model further comprises: a safety resistor F1 connected between the anti-reverse connection module and the first filter module 1 .
[0045] The anti-reverse connection module 4 includes: a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; the positive electrode of the power supply is connected to the first filter module 1 through the first diode D1 that is forward-conducting, and is connected to the first filter module 1 through the third diode D3 that is reverse-conducting; the negative electrode of the power supply is connected to the first filter module 1 through the second diode D2 that is forward-conducting, and is connected to the first filter module 1 through the fourth diode D4 that is reverse-conducting. Next, the utility model is further explained in conjunction with the specific implementation process, as follows:
[0046] The power supply VCC is connected to 48V DC, and the current passes through the fuse resistor F1, then through the first diode D1, and then through the first filter circuit composed of the first capacitor C1, the first inductor L1, the first polarity capacitor EC1, the second polarity capacitor EC2, and the second capacitor C2. At this time, the first filter circuit supplies power to the LED constant current driver chip U1D and the LED load in the LED constant current driver module, and the constant current driver chip U1D starts to work. When the MOS tube in the constant current driver chip U1D is turned on, the current then flows through the second inductor L2. At this time, the second inductor L2 is in a charging state. At this time, the current flows through the D pin of the constant current driver chip U1D and then flows to the CS pin, the resistor RS1, the resistor RS2, the third resistor R3, the fourth resistor R4, and then to the fourth diode D4 and finally to GND to form a power supply loop. When the MOS tube is turned off, the load is powered by the inductor L2, the current flows out from pin 1 of L2, flows to the load LED+ through the freewheeling diode D5, and finally flows to pin 2 of the load LED-inductor L2, thus forming a power supply circuit for the load when the MOS tube is turned off.
[0047] Because the inductor itself has parasitic capacitance and inductance, it will produce resonance, which may cause circuit instability, voltage peaks or spikes, or voltage reversal in overload, transient or AC lines. In order to avoid these effects, a resistor is usually connected in parallel with the I-shaped inductor. According to the inductance formula
[0048] As we know from △u=L*(△I / △T), a sudden current will be generated when the MOS tube is turned on and off, resulting in a transient voltage spike. This spike will affect the operation of the entire circuit, and thus cause EMI conduction to be interfered by the spike.
[0049] At startup, the current passes through the anti-reverse connection circuit composed of the first diode D1 to the fourth diode D4 and enters the first inductor L1 (the first inductor L1 adopts a chip inductor). At this time, the first inductor L1 will store energy. Because the first inductor L1 is DC-transmitting and AC-isolating, DC current will flow to the load. When the MOS tube is turned off, the load is powered by the second inductor L2 (the second inductor L2 adopts a chip inductor). At this time, the first inductor L1 has no discharge loop, and the energy stored in the first inductor L1 can only be consumed by itself, but this consumption process is relatively slow. When the next switching cycle comes, the energy on the first inductor L1 has not been consumed, so unstable voltage peaks and spikes are generated. Therefore, the first resistor R1 and the second resistor R2 are connected in parallel to quickly consume the energy of the first inductor L1, thereby reducing the impact of the voltage peak and spike.
[0050] According to △u=L*(△I / △T), without adding RC circuit, the voltage on the second inductor L2 will suddenly change when the MOS tube starts, forming a large spike, because △T is very small when the MOS tube starts, and then △u will become larger, which will generate a very high voltage spike, which will be brought into the circuit and finally affect EMI. At this time, when EC is added, the RC circuit will absorb part of the sudden spike or clamping that occurs when the MOS tube starts, thereby changing EMI.
[0051] When the third capacitor C3 is not added, the freewheeling diode D5 and the second inductor L2 generate a high-frequency signal, which cannot be directly coupled to the ground after passing through the load, so this high-frequency signal will cause a large interference source and affect EMI. After the third capacitor C3 is added, the third capacitor C3 is connected to the ground, so the high-frequency signal interference source generated by the freewheeling diode D5 and the second inductor L2 is coupled to the ground through the third capacitor C3, and then flows back to the input end, reducing the impact of the high-frequency signal on the circuit, thereby improving EMI.
[0052] In summary, the utility model has the following beneficial effects:
[0053] Connecting the first resistor R1 and the second resistor R2 in parallel to the L1 chip inductor can reduce the 3-5MHH and 12-15MHz at the same time without being affected by other factors.
[0054] An RC circuit is added to the second inductor L2 to absorb the sudden voltage spike on the second inductor L2, thereby improving EMI.
[0055] A third capacitor C3 is added between the output LED- and the ground to eliminate the high-frequency signal interference source caused by the freewheeling diode D5 and the second inductor L2, thereby improving EMI.
[0056] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. A DC-DC power supply device, characterized in that: include: A first filtering module, an input end of which is connected to a power supply; An LED constant current driving module, whose input end is connected to the output end of the first filtering module; A second filter module, whose input end is connected to the output end of the LED constant current drive module, and whose output end is connected to the LED load; The second filtering module includes: an RC circuit connected to the output end of the LED constant current driving module.
2. The DC-DC power supply device according to claim 1, characterized in that: Also includes: An anti-reverse connection module is connected between the power supply and the first filtering module.
3. The DC-DC power supply device according to claim 1, characterized in that: The first filtering module includes: a first capacitor, a second capacitor, a first polarity capacitor, a second polarity capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor and a first inductor; The positive electrode of the power supply is connected to the input end of the LED constant current driving module through the first resistor, and the second resistor and the first inductor are both arranged in parallel with the first resistor; The negative electrode of the power supply is grounded through the third resistor and the fourth resistor; The positive electrode of the power supply is connected to the negative electrode of the power supply through the first capacitor; The positive electrode of the power supply is connected to the negative electrode of the power supply through the first inductor, the first polarity capacitor, the third resistor, and the fourth resistor; The second polarity capacitor is arranged in parallel with the first polarity capacitor; The second capacitor is arranged in parallel with the first polarity capacitor.
4. The DC-DC power supply device according to claim 1, characterized in that: The second filtering module also includes: A third capacitor connected to the output end of the LED constant current driving module.
5. The DC-DC power supply device according to claim 4, characterized in that: The second filtering mode further includes: a fifth resistor, a fourth capacitor, and a fifth capacitor; The output end of the LED constant current driving module is connected to the positive electrode of the LED load through the fourth capacitor and the fifth resistor; Two ends of the fourth capacitor are connected to the positive electrode of the LED load and the negative electrode of the LED load respectively; One end of the third capacitor is connected to the fifth capacitor, the negative electrode of the LED load, and the output end of the LED constant current driving module, and the other end is grounded.
6. The DC-DC power supply device according to claim 4, characterized in that: The RC circuit includes: a sixth capacitor and a sixth resistor; The output end of the LED constant current driving module is grounded through the sixth capacitor and the sixth resistor.
7. The DC-DC power supply device according to claim 2, characterized in that: Also includes: A safety resistor connected between the anti-reverse connection module and the first filtering module.
8. The DC-DC power supply device according to claim 2, characterized in that: The anti-reverse connection module includes: a first diode, a second diode, a third diode, and a fourth diode; The positive electrode of the power supply is connected to the first filter module through the first forward-conducting diode, and is connected to the first filter module through the third reverse-conducting diode; The negative electrode of the power supply is connected to the first filter module through the second forward-conducting diode, and is connected to the first filter module through the fourth reverse-conducting diode.