A package structure for improving electrostatic discharge resistance of a low-power LED element

Abstract

This utility model discloses a packaging structure for improving the electrostatic discharge (ESD) tolerance of low-power LED components. The structure includes a housing, within which a PCB circuit board is mounted. The PCB circuit board houses an LED component, a capacitor, and a resistor. The capacitor and resistor are connected in parallel with the LED component. The low-power LED component has a power rating of 0.06W–0.5W, the capacitor's capacitance ranges from 22nF to 100nF, and the resistor's resistance ranges from 2.2KΩ to 33KΩ. This packaging structure can improve the ESD sensitivity level of low-power LED components to level 3 or even higher, reducing the risk of ESD damage.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor device technology, and specifically to a packaging structure that improves the electrostatic discharge tolerance of low-power LED components. Background Technology

[0002] Low-power LED components are sensitive to electrostatic discharge (ESD) and are defined as Class 1 ESD-sensitive components in the GJB1649-93 standard. In the Human Body Model, the ESD tolerance of low-power LED components is typically far below 2KV, posing a significant risk of ESD damage in practical applications.

[0003] To improve the electrostatic discharge (ESD) tolerance of LED components, a parallel Zener diode or transient voltage suppressor (TVS) is used. The nonlinear characteristics of the Zener diode or TVS are used to clamp the voltage or shunt the current, thereby increasing the ESD tolerance of the LED component to over 2KV. However, this approach has obvious limitations.

[0004] First, both Zener diodes or TVS diodes and LEDs are nonlinear components. The voltage clamping or current shunting efficiency of Zener diodes or TVS diodes is limited, making it difficult to improve the electrostatic discharge voltage withstand capability of LEDs to levels far exceeding 2KV, let alone reaching the relatively safe 8KV or above under natural conditions, which is the Class 3 standard for electrostatic sensitive components. Second, there is a mismatch between the clamping voltage tolerance of Zener diodes or TVS diodes and the forward voltage tolerance of the LED components themselves. When high-clamping-voltage components like Zener diodes or transient voltage suppressor diodes are used in combination with LEDs with low forward voltage values, the consistency of the electrostatic discharge voltage withstand capability of the LED components deteriorates, and the clamping protection function may even fail. Furthermore, although the reverse characteristics of Zener diodes or TVS diodes are better than their forward characteristics, the polarity of electrostatic discharge acting on LED components is random. Insufficient forward characteristics limit the overall performance of the solution to electrostatic sensitivity level 1 or 2, making it difficult to meet higher electrostatic protection requirements. Utility Model Content

[0005] The purpose of this invention is to provide a packaging structure that improves the electrostatic discharge tolerance of low-power LED components. This packaging structure can improve the electrostatic discharge sensitivity level of low-power LED components to level 3 or even higher, reducing the risk of electrostatic damage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A packaging structure for improving the electrostatic discharge tolerance of low-power LED components includes a packaging housing, a PCB circuit board disposed within the packaging housing, an LED component, a capacitor, and a resistor disposed on the PCB circuit board, wherein the capacitor is connected in parallel with the LED component, the resistor is connected in parallel with the LED component, the power of the low-power LED component is 0.06W-0.5W, the capacitance value ranges from 22nF to 100nF, and the resistance value ranges from 2.2KΩ to 33KΩ.

[0008] Preferably, the capacitor is an MLCC X5R capacitor packaged using a standard 01005 surface mount device.

[0009] Preferably, the resistor is a thin-film resistor packaged using a standard 01005 surface mount device.

[0010] In the above technical solution, by connecting both capacitors and resistors in parallel with the low-power LED components, the low-power LED components are not damaged under applied electrostatic discharge voltages of 8KV or even 12KV. This raises the electrostatic discharge sensitivity level of the low-power LED components to level 3 or even higher, reducing the electrostatic protection requirements for LED component production sites, transportation logistics, usage sites, and related personnel, thereby lowering the electrostatic control costs of LED component-related processes. The capacitor's capacitance ranges from 22nF to 100nF. During electrostatic discharge impacts, the capacitor can quickly absorb and disperse the electrostatic discharge voltage, preventing damage to the LED components. Simultaneously, the resistor's resistance ranges from 2.2KΩ to 33KΩ, limiting the maximum impedance across the LED components, preventing charge accumulation in the capacitor, and simultaneously discharging the charge when the capacitor absorbs external electrostatic discharge. Attached Figure Description

[0011] Figure 1 This is a packaging diagram of the present invention;

[0012] Figure 2 This is the circuit diagram of this utility model;

[0013] Figure 3 This is the equivalent circuit diagram of the LED element with parallel capacitor C1 and resistor R1 for electrostatic discharge of the human body according to this utility model.

[0014] In the diagram, 1 is the package; 2 is the LED component; C1 is the capacitor; and R1 is the resistor. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings:

[0016] like Figure 1 and Figure 2As shown, a packaging structure for improving the electrostatic discharge tolerance of low-power LED components includes a package 1. Within the package 1 are an LED component 2, a capacitor C1, and a resistor R1. The power of the low-power LED component is 0.06W-0.5W. Both capacitor C1 and resistor R1 are connected in parallel with the LED component 2. Through the synergistic effect of capacitor C1 and resistor R1, the electrostatic discharge tolerance of the LED component 2 is improved.

[0017] When an electrostatic discharge (ESD) pulse is applied to this package structure, capacitor C1 acts as an ESD spike absorption element. At the rising edge of the ESD pulse, capacitor C1 exhibits extremely low impedance, enabling it to quickly shunt the high-frequency spike current generated by the ESD pulse. The high-frequency components in the ESD pulse are largely absorbed by the capacitor, thus preventing these high-frequency spikes from directly affecting LED element 2 and reducing the risk of damage to LED element 2 due to excessive instantaneous overvoltage.

[0018] Resistor R1 acts as the bleeder resistor for capacitor C1. After an electrostatic discharge pulse, capacitor C1 may have stored some charge. Resistor R1 provides a discharge path for capacitor C1, slowly releasing the stored charge and preventing charge accumulation that could lead to malfunctions in subsequent circuits. Simultaneously, resistor R1 also plays a current-limiting role in the circuit, working in conjunction with capacitor C1 to limit the current flowing through LED element 2, further protecting it from damage.

[0019] In this application, capacitor C1 is a standard 01005 surface mount MLCC X5R capacitor with dimensions of 15.8×8×8mil (approximately 0.4×0.2×0.2mm). The capacitance range of capacitor C1 is 22nF-100nF. This avoids the problem that an excessively large capacitance would result in a long charging time, which would slow down the response time to suppress high-frequency components in the electrostatic discharge pulse, causing the LED element 2 to require time to withstand residual high voltage charging. Conversely, an excessively small capacitance would fail to absorb sufficient electrostatic discharge charge, resulting in a still high transient voltage and ineffective protection of the LED element 2. Therefore, the configuration of capacitor C1 achieves a balance between charge absorption capacity and high-frequency response characteristics, ensuring that the LED element 2 is protected from electrostatic discharge failure while meeting the requirements of a compact layout.

[0020] The resistors are standard 01005 surface mount thin-film resistors with dimensions of 15.8×8×8mil (approximately 0.4×0.2×0.2mm). The resistance value of resistor R1 ranges from 2.2KΩ to 33KΩ. This effectively attenuates the high-frequency components in the electrostatic discharge pulse, preventing damage to LED element 2 from the high-frequency part and preventing capacitor C1 from overheating or even breaking down due to high current surges. It also ensures that capacitor C1 can absorb the energy generated by electrostatic discharge in time, preventing excessive residual high voltage across LED element 2. Thus, it protects LED element 2 from electrostatic discharge damage in a compact layout.

[0021] Example 1

[0022] Calculate the voltage drop of LED element 2 under electrostatic discharge shock after connecting capacitor C1 and resistor R1 in parallel (in this embodiment, the capacitance of capacitor C1 is selected as 100nF and the resistance is 2.2KΩ).

[0023] 1. Component parameters:

[0024] Capacitor C1: A MLCC X5R capacitor in a standard 01005 surface mount package, with a capacitance of 100nF; its typical upper limit (worst-case) equivalent series resistance is R. C1 =100mΩ (This parameter can be found in the capacitor's datasheet).

[0025] Resistor R1: A thin-film resistor using a standard 01005 surface mount device package, with a resistance value of 2.2KΩ. According to GB / T19951-2005 / ISO10605:2001 standards, the human body electrostatic discharge model is as follows: R ESD =2KΩ, C ESD =330pF; The equivalent circuit diagram of LED element 2 with parallel capacitor C1 and resistor R1 for electrostatic discharge of human body is as follows: Figure 3 As shown.

[0026] 2. Calculation process:

[0027] (1) The charging time constant of capacitor C1 is τ = R ESD C1 = 2KΩ * 100nF = 200μs.

[0028] Typically, when the signal rise / fall time is longer than 25μs, the inductive reactance caused by the equivalent series inductance of capacitor C1 is negligible. In this embodiment, τ = 200μs, indicating that the charging process of capacitor C1 is not instantaneous, and the current change rate di / dt is small. According to the inductance characteristic e = -L(di / dt), when the current change rate is small, the induced electromotive force generated by the inductor is also small, and its impact on the transient response of the circuit can be ignored.

[0029] (2) Calculation of voltage drop under electrostatic discharge impact

[0030] Based on the voltage divider principle of series circuits, U Z ≈U e ×R C1 / (R ESD +R C1 ), where U e R is the voltage of electrostatic discharge; ESD R is the resistance in the human body electrostatic discharge model. C1 This is the equivalent series resistance of capacitor C1.

[0031] When the voltage U of electrostatic discharge e At 2KV, the transient charging voltage drop U of capacitor C1 Z ≈2000V*100mΩ / (2KΩ+100mΩ)≈0.1V.

[0032] When the voltage U of electrostatic discharge e At 8KV, the transient charging voltage drop U of capacitor C1 Z ≈8000V*100mΩ / (2KΩ+100mΩ)≈0.4V.

[0033] 3. Conclusion

[0034] The calculation results show that under electrostatic discharge voltage impacts of 2KV and 8KV, the transient charging voltage drops generated by capacitor C1 are 0.1V and 0.4V, respectively. Since capacitor C1 is connected in parallel with LED element 2, the voltage drop of LED element 2 is also 0.1V and 0.4V, which is lower than the forward voltage range (1.5-3.5V) and reverse voltage range (5-30V) of LED element 2. This indicates that LED element 2 will not be damaged by electrostatic discharge impacts of 2KV or 8KV.

[0035] Example 2

[0036] Capacitor C1 and resistor R1 are connected in parallel with LED element 2 for electrostatic discharge tolerance test.

[0037] 1. Testing equipment

[0038] Capacitor C1: An MLCC X5R capacitor with a standard 01005 surface mount device package and a capacitance of 100nF.

[0039] Resistor R1: A thin-film resistor in a standard 01005 surface mount device package with a resistance of 2.2KΩ.

[0040] Electrostatic discharge tester (model: EMS61000-2A): used to simulate electrostatic discharge shock, tested according to the human body model mode of GB / T19951-2005; setting the parameters of the electrostatic discharge simulator: R ESD =2KΩ, C ESD =330pF, to simulate human body discharge.

[0041] 12V battery: Provides a stable power supply for driving LED element 2.

[0042] 180Ω current-limiting resistor: used to limit the driving current of LED element 2 to prevent overcurrent damage.

[0043] 100×100mm single-sided PCB: used for soldering the LED component under test 2 to simulate the actual circuit board environment.

[0044] 2. Test Implementation Steps (with External Drive Circuit)

[0045] (1) Circuit connection:

[0046] The package structure of LED element 2, which is connected in parallel with resistor R1 and capacitor C1, is soldered onto a 100×100mm single-sided PCB using surface mount technology (SMT). LED element 2 is connected to a 12V battery through a 180Ω current-limiting resistor to form a driving circuit. The package structure of LED element 2 is lit up under a driving current of 50mA. As the unit under test, it is ensured that the circuit connection is firm and there is no short circuit or open circuit.

[0047] (2) Electrostatic discharge impact test:

[0048] Contact discharge and air discharge tests were performed on the unit under test:

[0049] Contact discharge: The discharge head of the electrostatic discharge simulator is directly contacted with the unit under test, and an electrostatic discharge voltage of 8KV is applied. This is repeated 10 times. The unit under test is undamaged and can still be lit normally.

[0050] Air discharge: The discharge head of the electrostatic discharge simulator is brought close to but does not touch the unit under test. A 12KV electrostatic discharge voltage is applied and repeated 6 times. The unit under test is undamaged and can still be lit normally.

[0051] 3. Test 2 Implementation Steps (No External Protection Circuit)

[0052] (1) Circuit connection:

[0053] The package structure of LED element 2, which has parallel resistor R1 and capacitor C1 to be tested, is soldered onto a 100×100mm single-sided PCB using surface mount technology, without being connected to any other circuits, and serves as the unit under test.

[0054] (2) Electrostatic discharge impact test:

[0055] The unit under test was subjected to contact discharge and air discharge tests, with the same electrostatic discharge voltage and number of repetitions applied.

[0056] Contact discharge: The discharge head of the electrostatic discharge simulator is directly contacted with the unit under test, and an electrostatic discharge voltage of 8KV is applied. This is repeated 10 times. The unit under test is undamaged and can still be lit normally.

[0057] Air discharge: The discharge head of the electrostatic discharge simulator is brought close to but does not touch the unit under test. A 12KV electrostatic discharge voltage is applied and repeated 6 times. The unit under test is undamaged and can still be lit normally.

[0058] 4. Conclusion

[0059] Test results show that, regardless of whether an external driving circuit is configured, the electrostatic discharge withstand capability of LED element 2, including the parallel resistor R1 and capacitor C1, can be improved to over 8KV, reaching the safety standard of electrostatic sensitivity level 3 or even higher under natural conditions. This reduces the electrostatic protection requirements for LED element 2 production sites, transportation logistics, usage sites, and related personnel, thereby reducing the electrostatic control cost of LED element 2 related processes.

[0060] This embodiment is merely an illustration of the concept and implementation of this utility model, and is not intended to limit it. Under the concept of this utility model, the technical solution without substantial changes is still within the protection scope.

Claims

1. A packaging structure for improving the electrostatic discharge tolerance of low-power LED components, comprising a packaging housing, a PCB circuit board disposed within the packaging housing, and LED components, capacitors, and resistors disposed on the PCB circuit board, characterized in that, The capacitor is connected in parallel with the LED element, the resistor is connected in parallel with the LED element, the power of the low-power LED element is 0.06W-0.5W, the capacitance value ranges from 22nF to 100nF, and the resistance value ranges from 2.2KΩ to 33KΩ.

2. The packaging structure for improving the electrostatic discharge tolerance of low-power LED components according to claim 1, characterized in that, The capacitor is an MLCC X5R capacitor packaged using a standard 01005 surface mount device.

3. The packaging structure for improving the electrostatic discharge tolerance of low-power LED components according to claim 1, characterized in that, The resistor is a thin-film resistor packaged using a standard 01005 surface mount device.

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