Design method for linear constant-current driving of LED automobile lamp

Abstract

The invention discloses a design method for linear constant-current driving of an LED automobile lamp, and the method comprises the following steps: 1, selecting an ESOP-packaged linear constant-current driving IC, and designing an aluminum nitride ceramic switching substrate corresponding to the ESOP-packaged linear constant-current driving IC; step 2, mounting an ESOP packaged linear constant current driving IC on the aluminum nitride ceramic switching substrate to form a ceramic substrate IC assembly; according to the method, thermoelectric separation can be achieved, reliability is guaranteed, the cost performance is high, the method is suitable for application occasions where small LED automobile lamps have wide working voltage range requirements and high power requirements, the reliability can be guaranteed, and high and low temperature cycle tests required by the LED automobile lamps can be smoothly passed.

Description

Technical Field

[0001] The invention relates to the technical field of lamps, in particular to the technical field of a design method for a linear constant current drive of an LED automobile lamp. Background Art

[0002] Linear constant current drive is increasingly used in the field of LED automotive lights due to its advantages such as simple circuit, reliability, high cost performance, and easy to pass EMC test.

[0003] There are three main known packaging methods for LED automotive light linear driver ICs: 1. ESOP plastic packaging process; 2. DFN bracket + silicone filling process; 3. Ceramic substrate + silicone filling process.

[0004] The advantages of the ESOP plastic packaging process are simplicity, reliability, mature technology, and lowest cost. The disadvantage is that it cannot achieve thermal and electrical separation, so the driving power is low and it cannot be used in small LED car lights or applications with wide operating voltage range requirements and high power requirements. The IC using this process can pass the high and low temperature cycle test (PTC test) required by LED car lights and has high reliability.

[0005] The cost of the DFN bracket + silicone filling process is medium. The advantage is that it can achieve thermal and electrical separation, which is suitable for small LED car lights or applications with wide operating voltage range requirements and high power requirements. The disadvantage is that the silicone filling process cannot guarantee reliability and life. The thermal expansion and contraction of the filled silicone during operation due to hot and cold shocks will cause the gold wire of the chip welding to break or the solder joint to peel off, causing IC failure. The IC using this process cannot pass the high and low temperature cycle test (PTC test) required by LED car lights, and there is a high risk of early failure.

[0006] The ceramic substrate + silicone filling process has the highest cost. Its advantage is that it can achieve thermal and electrical separation, and is suitable for small LED car lights or applications with wide operating voltage range requirements and high power requirements. Its disadvantage is that the silicone filling process cannot guarantee reliability and life. The thermal expansion and contraction of the filled silicone during operation due to hot and cold shocks may cause the gold wire of the chip welding to break or the solder joint to peel off, causing IC failure. The IC using this process cannot pass the high and low temperature cycle test (PTC test) required by LED car lights, and there is a high risk of early failure. Summary of the invention

[0007] The purpose of the present invention is to solve the problems in the prior art and propose a design method for linear constant current drive of LED automobile lights, which can simultaneously achieve thermal and electrical separation and ensure reliability, has high cost performance, is suitable for applications where small LED automobile lights have wide operating voltage range requirements and high power requirements, can ensure reliability, and can successfully pass the high and low temperature cycle tests required for LED automobile lights.

[0008] To achieve the above object, the present invention proposes a design method for a linear constant current drive of an LED automotive lamp, comprising the following steps: Step 1, select a linear constant current driver IC of ESOP package, and design an aluminum nitride ceramic transfer substrate corresponding to the linear constant current driver IC of ESOP package; Step 2: Mount the ESOP packaged linear constant current driver IC on the aluminum nitride ceramic transfer substrate to form a ceramic substrate IC assembly; Step three, mounting the ceramic substrate IC assembly on the LED light source board.

[0009] Preferably, the left side of the ESOP packaged linear constant current driver IC is provided with a VIN pin, a GND pin, a CS pin and an S pin in sequence from top to bottom, and the right side of the ESOP packaged linear constant current driver IC is provided with a SEL / NC pin, a SGND / NC pin, a HLT / NC pin and a DR pin in sequence from top to bottom.

[0010] Preferably, the CS pin and S pin of the ESOP packaged linear constant current driver IC are connected in parallel, the SEL / NC pin and SGND / NC pin of the ESOP packaged linear constant current driver IC are connected in parallel, a DR element is arranged in the ESOP packaged linear constant current driver IC, and the DR pin and the DR element are connected.

[0011] Preferably, the front side of the aluminum nitride ceramic transfer substrate corresponds to the mounting surface of the linear constant current driver IC of the ESOP package, the front side of the aluminum nitride ceramic transfer substrate is provided with a front transfer circuit, the front transfer circuit is provided with conductive vias at the pin positions corresponding to the linear constant current driver IC of the ESOP package, the back side of the aluminum nitride ceramic transfer substrate is provided with electrical pins connected to the front transfer circuit through conductive vias, the back side of the aluminum nitride ceramic transfer substrate is provided with a large-area heat sink pad, and the large-area heat sink pad has no electrical connection.

[0012] Preferably, a small-area heat sink pad is provided on the front side of the aluminum nitride ceramic transfer substrate corresponding to the mounting surface of the linear constant current driver IC of the ESOP package, and the small-area heat sink pad has no electrical connection.

[0013] Preferably, the large-area heat sink pad and the small-area heat sink pad contact each other for thermal conduction.

[0014] Preferably, conductive layers are provided on both the front and back surfaces of the aluminum nitride ceramic transfer substrate, the conductive layer on the front surface of the aluminum nitride ceramic transfer substrate is provided with a positive wiring circuit, and the conductive layer on the back surface of the aluminum nitride ceramic transfer substrate is provided with a reverse wiring circuit, and the positive wiring circuit and the reverse wiring circuit are connected through conductive vias.

[0015] Preferably, the front side of the LED light source board corresponds to the mounting surface of the aluminum nitride ceramic adapter substrate, and a base surface heat sink pad is provided on the front side of the LED light source board. The base surface heat sink pad and the large area heat sink pad correspond to contact heat conduction.

[0016] Preferably, the base surface heat sink pad is directly arranged on the copper body of the LED light source board by using a copper base plate boss process.

[0017] Preferably, the LED light source board is provided with D1 element, D2 element, R1 element, LED lamp panel and U1 element, the U1 element is a ceramic substrate IC assembly, the U1 element is respectively connected to the D1 element, D2 element and LED lamp panel one by one, and the LED lamp panel is respectively connected to the D1 element and D2 element.

[0018] Beneficial effects of the present invention: The present invention can realize the transformation of non-thermoelectric separation IC into thermoelectric separation application, and can simultaneously ensure the thermoelectric performance and reliability of linear IC. Its cost is between DFN bracket + silicone filling process and ceramic substrate + silicone filling process, and has high cost performance and application space, and can simultaneously take into account the realization of thermoelectric separation and the guarantee of reliability. The LED car lamp constant current driver using this design method is suitable for application in small LED car lamps or applications with wide operating voltage range requirements and high power requirements, and can ensure reliability, can smoothly pass the high and low temperature cycle test (PTC test) required by LED car lamps, can solve the existing core problems of LED car lamp linear constant current drive technology, and contribute to the wide application of LED car lamp linear constant current drive technology.

[0019] The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the design structure of the linear constant current drive of the LED automobile lamp of the present invention; Figure 2 It is a schematic diagram of the structure of a linear constant current driver IC of an ESOP package according to the design method of the linear constant current driver of an LED automobile lamp of the present invention; Figure 3 It is a schematic diagram of the wiring structure of the linear constant current driver IC of the ESOP package of the design method of the linear constant current driver of the LED automobile lamp of the present invention; Figure 4 It is a schematic diagram of the front structure of the ESOP packaged aluminum nitride ceramic transfer substrate of the design method of the linear constant current drive of the LED automobile lamp of the present invention; Figure 5 It is a schematic diagram of the reverse structure of the ESOP packaged aluminum nitride ceramic transfer substrate of the design method of the linear constant current drive of the LED automobile lamp of the present invention; Figure 6 It is a schematic diagram of the structure of the ceramic substrate IC assembly of the ESOP package of the design method of the linear constant current drive of the LED automobile lamp of the present invention; Figure 7 It is a front structural schematic diagram of an ESOP-packaged LED light source board of the design method of the linear constant current drive of an LED automobile lamp of the present invention; Figure 8 It is a schematic diagram of the reverse structure of an ESOP-packaged LED light source board according to the design method of the linear constant current drive of an LED automobile lamp of the present invention.

[0021] In the figure: 1-ceramic substrate IC assembly, 2-LED light source board, 11-aluminum nitride ceramic transfer substrate, 12-ESOP packaged linear constant current driver IC. DETAILED DESCRIPTION

[0022] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The design method of the linear constant current drive of the LED automobile lamp of the present invention comprises the following steps: Step 1, select a linear constant current driver IC 12 of an ESOP package, and design an aluminum nitride ceramic transfer substrate 11 corresponding to the linear constant current driver IC 12 of the ESOP package; Step 2: Mount the ESOP packaged linear constant current driver IC 12 on the aluminum nitride ceramic transfer substrate 11 to form a ceramic substrate IC assembly 1; Step three: mount the ceramic substrate IC assembly 1 on the LED light source board 2 .

[0023] Embodiment 1

[0024] The left side of the ESOP packaged linear constant current driver IC12 is provided with a VIN pin, a GND pin, a CS pin and an S pin in sequence from top to bottom, and the right side of the ESOP packaged linear constant current driver IC12 is provided with a SEL / NC pin, a SGND / NC pin, a HLT / NC pin and a DR pin in sequence from top to bottom. The CS pin and the S pin of the ESOP packaged linear constant current driver IC12 are connected in parallel, and the SEL / NC pin and the SGND / NC pin of the ESOP packaged linear constant current driver IC12 are connected in parallel. A DR element is provided in the ESOP packaged linear constant current driver IC12, and the DR pin and the DR element are connected.

[0025] Embodiment 2

[0026] The difference between this embodiment and the first embodiment is that the front side of the aluminum nitride ceramic transfer substrate 11 corresponds to the mounting surface of the linear constant current driver IC 12 of the ESOP package, the front side of the aluminum nitride ceramic transfer substrate 11 is provided with a front transfer circuit, the front transfer circuit is provided with a conductive via at the pin position corresponding to the linear constant current driver IC 12 of the ESOP package, the back side of the aluminum nitride ceramic transfer substrate 11 is provided with an electrical pin connected to the front transfer circuit through a conductive via, the back side of the aluminum nitride ceramic transfer substrate 11 is provided with a large-area heat sink pad, and the large-area heat sink pad has no electrical connection. The front side of the aluminum nitride ceramic transfer substrate 11 is provided with a small-area heat sink pad corresponding to the mounting surface of the linear constant current driver IC 12 of the ESOP package, and the small-area heat sink pad has no electrical connection, and the large-area heat sink pad and the small-area heat sink pad are in contact with each other for thermal conduction, and the front side of the LED light source board 2 corresponds to the mounting surface of the aluminum nitride ceramic transfer substrate 11, and the front side of the LED light source board 2 is provided with a base surface heat sink pad, and the base surface heat sink pad and the large-area heat sink pad are in contact with each other for thermal conduction, and the base surface heat sink pad is directly arranged on the copper body of the LED light source board 2 using a copper substrate boss process.

[0027] Embodiment 3

[0028] The difference between this embodiment and the first embodiment is that the aluminum nitride ceramic transfer substrate 11 is provided with a conductive layer on both the front and back sides, the conductive layer on the front side of the aluminum nitride ceramic transfer substrate 11 is provided with a positive wiring circuit, and the conductive layer on the back side of the aluminum nitride ceramic transfer substrate 11 is provided with a reverse wiring circuit, the positive wiring circuit and the reverse wiring circuit are connected through conductive vias, the LED light source board 2 is provided with a D1 element, a D2 element, an R1 element, an LED lamp panel and a U1 element, the U1 element is a ceramic substrate IC assembly 1, the U1 element is respectively connected to the D1 element, the D2 element and the LED lamp panel, and the LED lamp panel is respectively connected to the D1 element and the D2 element.

[0029] The present invention can realize the transformation of non-thermoelectric separation IC into thermoelectric separation application, and can simultaneously ensure the thermoelectric performance and reliability of linear IC. Its cost is between DFN bracket + silicone filling process and ceramic substrate + silicone filling process, and has high cost performance and application space, and can simultaneously take into account the realization of thermoelectric separation and reliability. The LED car lamp constant current driver using this design method is suitable for application in small LED car lamps or applications with wide operating voltage range requirements and high power requirements, and can ensure reliability, can smoothly pass the high and low temperature cycle test (PTC test) required by LED car lamps, can solve the existing core problems of LED car lamp linear constant current drive technology, and contribute to the wide application of LED car lamp linear constant current drive technology.

[0030] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. The design method of linear constant current drive of LED automobile lamp is characterized by: The following steps are involved: Step 1, selecting a linear constant current driver IC (12) in an ESOP package, and designing an aluminum nitride ceramic transfer substrate (11) corresponding to the linear constant current driver IC (12) in the ESOP package; Step 2: mounting the ESOP packaged linear constant current driver IC (12) on the aluminum nitride ceramic transfer substrate (11) to form a ceramic substrate IC assembly (1); Step three: mount the ceramic substrate IC assembly (1) on the LED light source board (2).

2. The design method of linear constant current drive of LED automotive lamp as claimed in claim 1, characterized in that: The left side of the ESOP packaged linear constant current driver IC (12) is provided with a VIN pin, a GND pin, a CS pin and an S pin in sequence from top to bottom, and the right side of the ESOP packaged linear constant current driver IC (12) is provided with a SEL / NC pin, a SGND / NC pin, a HLT / NC pin and a DR pin in sequence from top to bottom.

3. The design method of linear constant current drive of LED automobile lamp as claimed in claim 2, characterized in that: The CS pin and the S pin of the ESOP packaged linear constant current driver IC (12) are connected in parallel, the SEL / NC pin and the SGND / NC pin of the ESOP packaged linear constant current driver IC (12) are connected in parallel, a DR element is arranged in the ESOP packaged linear constant current driver IC (12), and the DR pin and the DR element are connected.

4. The design method of linear constant current drive of LED automotive lamp as claimed in claim 1, characterized in that: The front side of the aluminum nitride ceramic transfer substrate (11) corresponds to the mounting surface of the ESOP packaged linear constant current driver IC (12); the front side of the aluminum nitride ceramic transfer substrate (11) is provided with a front transfer circuit; the front transfer circuit is provided with a conductive via at a pin position corresponding to the ESOP packaged linear constant current driver IC (12); the back side of the aluminum nitride ceramic transfer substrate (11) is provided with an electrical pin connected to the front transfer circuit via the conductive via; the back side of the aluminum nitride ceramic transfer substrate (11) is provided with a large-area heat sink pad, and the large-area heat sink pad has no electrical connection.

5. The design method of linear constant current drive of LED automotive lamp as claimed in claim 1, characterized in that: A small-area heat sink pad is provided on the front side of the aluminum nitride ceramic transfer substrate (11) corresponding to the mounting surface of the ESOP-packaged linear constant current driver IC (12), and the small-area heat sink pad has no electrical connection.

6. The design method of linear constant current drive for LED automotive lamps as claimed in claims 4 and 5, characterized in that: The large-area heat sink pad and the small-area heat sink pad contact each other for heat conduction.

7. The design method of linear constant current drive of LED automotive lamp as claimed in claim 1, characterized in that: The front and back surfaces of the aluminum nitride ceramic transfer substrate (11) are both provided with conductive layers; the conductive layer on the front surface of the aluminum nitride ceramic transfer substrate (11) is provided with a positive wiring circuit; the conductive layer on the back surface of the aluminum nitride ceramic transfer substrate (11) is provided with a negative wiring circuit; the positive wiring circuit and the negative wiring circuit are connected via conductive vias.

8. The design method of linear constant current drive of LED automobile lamp as claimed in claim 4, characterized in that: The front side of the LED light source board (2) corresponds to the mounting surface of the aluminum nitride ceramic transfer substrate (11), and a base surface heat sink pad is provided on the front side of the LED light source board (2), and the base surface heat sink pad and the large area heat sink pad are in contact with each other for heat conduction.

9. The design method of linear constant current drive of LED automotive lamp as claimed in claim 8, characterized in that: The base surface heat sink pad is directly arranged on the copper material body of the LED light source board (2) by using a copper base plate boss process.

10. The design method of linear constant current drive of LED automotive lamp as claimed in claim 1, characterized in that: The LED light source board (2) is provided with a D1 element, a D2 element, an R1 element, an LED lamp panel and a U1 element, the U1 element being a ceramic substrate IC assembly (1), the U1 element being connected one by one with the D1 element, the D2 element and the LED lamp panel respectively, and the LED lamp panel being connected one by one with the D1 element and the D2 element respectively.

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