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Mechanical Aspects in Electronics Systems Design

Scientific Study 2013 31 Pages

Engineering - Mechanical Engineering

Excerpt

Inhaltsverzeichnis

Abstract

List of Tables

List of Figures

CHAPTER 1
1. Opto-electronics packaging and Failure Analysis Methodologies
1.1 Recommendations for Opto-electronics packaging design
1.2 Recommendations for Failure Analysis Technique
1.3 Merits and Demerits of Packaging design and failure analysis techniques
1.4 Essential modifications for the improvement and realization of the product
3.5 Conclusion

CHAPTER 2
2. Datasheet development and testing of an electronic product
2.1 Development of data sheet for Linear Power Supply
2.1.1 Product Design Specifications
2.1.2 Brief Introduction to the DC power supply
2.1.3 Packaging Details
2.1.4 Dimensions of the system
2.1.5 Min/Max current, voltage and power ratings
2.2 Schematic Development
2.3 Interfaces Available
2.4 Components details with Cost and Availability
2.5 Test set up and results
2.8 Conclusion

CHAPTER 3
3. Thermal Analysis and Vibration testing of the DC power supply
3.1 Thermal variation of critical components and spacing between the critical components
3.2 Design of casing for power supply and its geometrical parameters
3.3 Design, Modeling and Simulation of mechanical casing for power supply using ICEPACK
3.4 Optimized solution for mechanical casing design to meet the thermal variations
3.5 Experimental set up to carry out vibration analysis for the power supply
3.6 Conclusion
3.6 Module Learning Outcomes
3.7 Summary

REFERENCES

List of Tables

Table 2. 1 General Description

Table 2. 2 DC Power supply specifications

Table 2. 3 Component specifications

Table 2. 4 DC power supply

Table 2. 5 Packaging Details

Table 2. 6 PCB and Components Dimensions

Table 2. 7 Power ratings of the Power supply

Table 2. 8 Components Details and Cost

Table 2. 9 Test Results

Table 3. 1 Material and total power (W)

Table 3. 2 Temperature simulation results

List of Figures

Figure 2. 1 DC power Supply Schematic

Figure 2. 2 Design Rule Check (DRC)

Figure 2. 3 Power Supply Interfaces

Figure 2. 4 Switch Interface

Figure 2. 5 5V output and current testing

Figure 2. 6 12 V output and current testing

Figure 3. 1 Identification of critical components

Figure 3. 2 Moniter Points

Figure 3. 3 Assigning material properties and total power

Figure 3. 4 Temperature variation of the critical components

Figure 3. 5 Casing of the Power Supply

Figure 3. 6 Goemetrical Dimensions of Power supply

Figure 3. 7 Design of the Power supply casing without openings

Figure 3. 8 Checking the Designed Model

Figure 3. 9 Simulation of the casing with a opening

Figure 3. 10 Cabinet with fins and fans

Figure 3. 11 Power supply model with forced convention using a fan

Figure 3. 12 Power supply setup for vibration testing

Figure 3. 13 Complete setup for vibration testing of the power supply

Figure 3. 14 Natural Frequency at equilibrium state of the system

Figure 3. 15 External influence on the system using impact hammer

List of Symbols and Acronyms

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Abstract

The demand for opto-electronics is increasing as we are nearing the future due to the need for high data rate, high bandwidth, lossless transmission and low electromagnetic interference sensitivity. In chapter 1, the present research carried on the mature laser technology i.e. GaAs, in order to improve its efficiency. The packaging principle used for receivers can be applied for the packaging of the laser driver circuit and the laser source in a single module. The concept of FRACAS (Failure Reporting, Analysis and Corrective Action System) has been described and failure analysis technique for Electrical overstress (EOS) is described. An industrial approach to calculating the reliability of a system with some known data is described. Some challenges with respect to packaging has been discussed in detail and some methods to overcome challenges such as lattice mismatch has been described.

Every electronic components or electronic systems have certain specifications based on which it is developed and all components have datasheets of their own. The datasheets consists complete details related to the product such as product design specifications, packaging type, power ratings, dimensions etc. Any components can be selected for a particular application by referring their datasheets. In chapter 2, a datasheet for a DC power supply has been developed covering most of the important details that may be needed for designing and modeling using software tools. The schematic of the power supply is developed and practical tests are performed on the power supply, which has been described in details with the test results. The power supply has four interfaces and the functionality and usability of these interfaces has been shown and described in detail.

Before the large scale manufacturing and production of any product, it is necessary to conduct two basic tests i.e. Thermal analysis and vibration tests for any given product. These tests help us to get an insight to the reliability of the product. In chapter 3, the power supply is modeled using the software tool ICEPACK v13, using which thermal analysis is performed on the critical components and the temperature variation curves along with the simulation results has been discussed. The method of casing used for the power supply for modeling and the types of conventions i.e. natural and forced convention systems has been compared and discussed. An experimental set up used for performing vibration testing on the power supply has been demonstrated and described in detail.

CHAPTER 1

1. Opto-electronics packaging and Failure Analysis Methodologies

1.1 Recommendations for Opto-electronics packaging design

Packaging is nothing but a sequence of process steps involving connecting, protecting and manufacturing of the devices. The widespread commercial utilization of semiconductor lasers have now included the opportunities to make use array of diode lasers as monolithic components on the Silicon Integrated Circuits (IC’s). Presently the laser manufactures are optimizing the design and process to maximize the laser performance for InGaAsP wafers producing around 10,000 lasers per square inch of the wafer for a compact opto-electronics module packaging. Receivers have been developed which consists of an array of photodiodes along with pre-amplifiers in one module mounted on Silicon substrate in one single package, where one side of the photodiode’s receive photons and convert it into the desired current or voltage, while on the other side it has electrical contacts in order to trigger the desired component or IC, therefore the same packaging principle can be applied for the array of transmitting lasers that improves manufacturability reducing cost, which has been demonstrated in [Mino F. Dautartas 2002 IEEE]. Another important aspect of Opto-electronic packaging is the wire bonding. Many Opto-electronics packaging is designed as “butterfly” shape which deals with both electrical and optical signals. The Electrical interconnections are from the cantilevel leads to the pads of the die mounted inside the package, where the height difference between the cantilevel leads and the die pads are large, therefore it requires the wirebonds to have the capability of deeper access and typically wire bonding in opto-electronic packaging has the first bond on the cantilevel leads and the second bond on the die pads due to the bond pads on the cantilevel leads being very close to the package walls, therefore to avoid interference of the wedge with the package walls the first bond is normally placed on the leads, and there are three wirebond technologies that are used for opto-electronics packaging i.e. thermo-compression bonding, thermo-sonic bonding and ultrasonic bonding as illustrated in [jianbio pan 2004]. The ability to faithfully reproduce designed features on a wafer is important to the success of optical devices. Critical Dimension (CD) control and smooth device surfaces are two of the most important parameters that must be controlled during processing. Resolving CDs of approximately 350 nm is hardly a challenge for modem optical lithography processes, whose minimum features have already been demonstrated below 45 nm. Resolution, however, is not the only concern when designing planar optical circuits. The need for better resolution demands flat surfaces on which to pattern features. This requirement comes about as a result of the usable Depth of Focus (DOF) at the image plane of standard projection optics lithography equipment; 90 nm process technology has a usable DOF < 300 nm. As a result, wafer topography must be kept below the DOF value to successfully resolve minimum feature sizes.

1.2 Recommendations for Failure Analysis Technique

Every product or a system has modes of failure. It is important and necessary to understand why a failure has occurred or why a component has failed in order to rectify the failure and this process is known as FRACAS (Failure Reporting, Analysis and Corrective Action System) [Walter Willing, Jonathan 2012].A common failure fault that is encountered during electrical testing is the components damage in a system that is caused due to electrical overstress. Electrical Over-Stress (EOS) is a term used to describe the thermal damage that may occur when an electronic device is subjected to a current or voltage that is beyond the specification limits of the device. During the testing the Voltage v/s Current (VI) characteristics curve is drawn or traced for the input to each components present in the system in order to identify if there’s any electrical input overstress have occurred. The identified failed parts VI characteristics can be compared to the VI characteristics of the good part and if there’s any deviation from the desired response, then the test results are noted and recorded for later examination of that failed part in order to rectify the fault. In industries, all systems that are developed have to undergo environmental tests, mechanical tests and electrical tests in order to detect faults, analyze and rectify them, these test procedures have been illustrated in [MIL-STD-883F 1996]. Another common technique apart from weibull distribution and exponential distribution model is the reliability prediction of a system, where the failure rate of the components and the reliability of the system is calculated. Let’s Assume that 600 parts where stressed at 150°C ambient for 3000 hours with one failure at 2000 hours for a photo resist flaw (0.7eV) and one failure at 3000 hours for an oxide defect (0.3eV); the internal temperature rise (Tj) of the part is 20°C and the product was tested at 1000, 2000 and 3000 hours. Then to find the FIT rate for the process with M=6.3 (chi factor distribution for DOF = 2r+2 for r=2) at 55°C, it is necessary to calculate the Acceleration factors AF1 and AF2 due to the faults and then the Total Device Hours is calculated followed by the calculation of systems Failure rate in FIT and then the life time of the product or system as illustrated in detail [William J. Vigrass 1997]. These predictions are used to evaluate design feasibility, compare design alternatives, identify potential failure areas, trade-off system design factors, and track reliability improvement.

1.3 Merits and Demerits of Packaging design and failure analysis techniques

In photonics, one of the limitations is the lack of monolithic long lived laser on silicon, therefore from several years the main effort has been focused on the growth GaAs on silicon, with associated problems related 4% lattice mismatch the two materials i.e. GaAs and Silicon. GaAs or InP compounds exhibit a larger lattice constant than that of Si. The only exception is GaP, which has an indirect bandgap and is not suitable as a laser material. Therefore one of the major roadlocks for further development of optoelectronics with respect to materials is the lattice mismatch between two materials or between the films and the available substrates. Mismatched lattice leads to a high defect density (in the 108 - 1O10 level). In spite of the intense efforts made to address this problem, it may not be feasible to reduce the defect density by several orders of magnitude in the conventional approach, until lattice matched substrates are available. Another issue that can be encountered during packaging for optoelectronics is due to the growing density of functionalities and complexity of interfacing interdisciplinary functions that needs to be integrated in a single system i.e. mechanical, electronics and optics. Proper packaging considering thermal issues, vibrations and shock analysis will lead to a mechanical structure for opto-electronics that is highly reliable and whose survival rate will be longer, thus making the system more reliable. Integration problems related to chemical contamination are likely to pose practical problems due to physical limitations caused due to issues like corrosion. Most conflicts can be addressed by incorporating extra de-contamination steps or adding dedicated tools for the problematic operations, but these solutions can lead to increase in cost. Problems due to chemical contamination have been brought under control in standard silicon processing, but would need to be checked on if the process demands the inclusion of elements and compounds not used in standard processing, but even after its introduction over four years ago, the semiconductor industry is still trying to rectify issues associated with copper (Cu) contamination. There are still no universally acceptable levels of Cu contamination, and many questions still remain about how far beyond the fabrication tools and chambers one must de-contaminate, therefore similar logistical problems may be waiting for the monolithic integration of optical devices with electronics and its packaging.

1.4 Essential modifications for the improvement and realization of the product

The system design can be improved by making an effort to overcome the problem of lattice mismatch between the GaAs and the Silicon substrate by making use of the available alloys. Optimization of electronic or optical devices require the capability of forming alloys and heterogeneous structures that can provide improvement in lattice matching. Therefore alloys were developed and examined by making use of Nitride compounds such as GaAIN, GaInN. The combination of a mature technology such as GaAs along with GaN to form GaAsN will allow to produce light emitting alloys with a wider and better range of lattice constant[J. Salzman and I. Samid 1996]. Thermal budget limits are critical when integrating different devices into the same process. Failing to account for thermal budgets could result in the interdiffision of dopant species, weakening of metal layers, and the introduction of stress due to differing coefficients of thermal expansion. Thermal budgets for both aluminum and copper back-end processes with oxide-based dielectrics are limited by the metal and Interlayer Dielectric (ILD). Although some low-k dielectrics (k < 3.9) are being used (e.g. Carbon-Doped Oxide (CDO)), the thermal stresses and the weaker mechanical properties of CDO will not be able to tolerate temperatures in excess of 450°C; low-k solutions such as Spin-on- Dielectrics will drive the thermal budgets even lower. In the case of electro-optical (EO) polymers, the thermal budget can decrease dramatically, since typical glass transition temperatures are in the range of 150°C - 250°C. For all practical purposes, these polymers can only be integrated as the last steps of the process. The 12 channel 3.125 Gb/s VCSEL laser driver IC has been designed using SiGe BICMOS process technology. This miniature laser driver IC can be used for development of opto-electronic systems. The driver IC is integrated in a module with an array of 12 VCSEL laser sources. This driver IC’s results has been measured and evaluated[ Allan Armstrong, Scott killmeyer IEEE 2001].

3.5 Conclusion

The laser manufactures are doing optimizations for the laser technology and its performance. Principle packaging for receivers can be applied for packaging of laser driver circuit with laser sources. An important aspect of optoelectronics packaging is wire bond. A basic methodology for failure analysis is the FRACAS. An industrial approach for calculating the reliability of the system is done using the formulas of acceleration factor, failure rate and concept of MTTF. EOS can be detected by plotting VI curve for the input of each component and comparing it to a good known reference curves. An important limitation of the laser source packaging for optoelectronics as the lattice mismatch constant for which alloys are developed using nitrate compounds for better lattice matching of the materials. A laser driver IC is integrated with array of 12 VSCEL laser sources using the BiCMOS process technology which can be packaged into one single miniature module that can be used for the development of optoelectronic system.

CHAPTER 2

2. Datasheet development and testing of an electronic product

2.1 Development of data sheet for Linear Power Supply

The datasheet was developed for the DC linear power supply available in the hardware lab of MSRSAS. Some general details regarding the power supply has been described in the table

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Table 2. 1 General Description

2.1.1 Product Design Specifications

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Table 2. 2 DC Power supply specifications

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Table 2. 3 Component specifications

2.1.2 Brief Introduction to the DC power supply

The Linear DC power supply has output voltages of 5 Volts and 12 Volts, which are regulated by using the highly reliable voltage regulators i.e. IC L7805 and IC L7812, thus generating a highly regulated DC power and additional LC filters are used for generating a smoothened DC power output. It consists of a removable a removable top lid or cover allowing for better heat dissipation.

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Figure 2. DC power supply

Additional heat sinks have been used by the regulators as shown in the Figure 2, which provides overload protection preventing the device from thermal damage. This power supply is most appropriate in use by low voltage or power applications. It is safe and has Low EMI, thus approved to domestic regulatory standards. It has three terminals i.e. ground, 5 Volts and 12 Volts outputs. Apart from these, the power supply is small and of light weight, hence it is easily portable and the power supply is designed such that its simplicity allows for easy accessibility to the on board Power supply components for maintenance and servicing.

2.1.3 Packaging Details

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Table 2. 5 Packaging Details

2.1.4 Dimensions of the system

Length x Breadth x Height (LxBxH)

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Table 2. 6 PCB and Components Dimensions

2.1.5 Min/Max current, voltage and power ratings

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Table 2. 7 Power ratings of the Power supply

2.2 Schematic Development

The Figure 2.1, shows the schematic of the DC power supply. This schematic was developed using the software tool Design Entry by Cadence v16. The main components present in the schematic are transformer, two voltage regulators, H-Bridge using diodes and filters. The output voltage regulators are IC 7805 and IC LM7812. The transformer used is of 230V/60Hz and an LC filter has been used to filter the output of LM 7805.

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Figure 2. 1 DC power Supply Schematic

The Transformer (T1) primary windings is connected to the 230V,60Hz AC main and the secondary windings are connected to the Diode H-Bridge. The transformer steps down the AC 230 Volts to AC 15 Volts (V) which is rectified by the Full Bridge Rectifier (H-Bridge) i.e. conduction during both –ve and +ve half cycles), therefore a Pulsating DC is generated. These Filter capacitors C1, C2 and C4 are used to ground AC components, blocking only the DC components to pass thus reducing ripples. Due to some voltage drops across these capacitors, the input (Vin) to the regulator IC LM7812 will be approximately 13.5V, this 13.5 V is regulated to 12Volts output (Vout) by the LM7812. Similarly the IC LM7805 is used to regulate the voltage to a +5 V output. An LC filter circuit has been used for further filter of the AC components in order to obtain a smoothened DC output Voltage, the inductor is used to block any incoming AC components, while allowing only the DC components to pass. The values of the capacitors and inductors were designed for an input of 230 Volts and output voltages of 12V and 5V.

DRC with no errors

Design Rule Check (DRC)

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Figure 2. 2 Design Rule Check (DRC)

Once the Schematic is developed, it is necessary to check and know if the developed schematic is correct, therefore a Design Rule Check (DRC) is performed on the schematic. The DRC icon is clicked to run the process as shown in Figure 2.2 A, and the Figure 2.2 B, shows the completion of the DRC of the schematic with no errors, hence schematic can be used for further designing and for development of PCB for the power supply.

2.3 Interfaces Available

The interfaces developed for the power supply helps the user to connect low power devices to the power supply in order to supply power to that electronic device i.e. Used to power up electronic devices. The Figure 2.3, shows the power supply unit with its interfaces and hardware. The power supply has a total of five interfaces i.e. three terminals (GND, 12 Vout and 5 Vout), a Double pole- Double throw (DPDT) switch and an plug to connect to the AC mains to draw 230 V input.

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Figure 2. 3 Power Supply Interfaces

Input to transformer from AC

The Figure 2.3, shows the power supply with three terminals among which the black connector is the Ground (GND), yellow connector is the 12 Vout from IC L7812 and the red connector is the 5 Vouts from IC L7805. The wires connected to these three terminals are used for interfacing to devices or circuits to supply to power to the devices.

Power switch

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Figure 2. 4 Switch Interface

The Figure 2.4, shows the bottom and the top part of the DPDT switch. In the bottom Part, two terminals are connected to the two pin plug that is used to interface or plug to the AC mains and the other two terminals are connected to the primary windings of the transformer. The top part of the switch is the user interface for user to control the switching ON or OFF of the power supply.

2.4 Components details with Cost and Availability

The Table 2.8, shows the cost and the specifications of the different components being used in this design of the DC power supply. The cost of the components slightly varies from place to place depending on the quantity of each component being purchased. Thus the price range is showed in the table, for those components whose price per unit is not mentioned.

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Table 2. 8 Components Details and Cost

The components mentioned in the Table 2.8, are all available at electronic shops in Bangalore. Some common known shops that sell all these components are; Leed Electronics Industry Inc, JP nagar-560078 and NSK Electronics, opposite to Vishal electronics, SP road-560002. All these components are readily available or can be per-ordered in these respective shops.

2.5 Test set up and results

Tests are performed on the DC power supply available in the MSRSAS, hardware lab in order to check and analyse the response of the system or power supply. The test analysis was mainly based on checking the output voltages and load currents using a 12 Volts DC motor. The Figure 2.5 A, shows the testing of the output voltage from the 5 Volts connector that is displayed on the multimeter i.e. 5.51 Volts.

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Figure 2. 5 5V output and current testing

Iout – 0.02A for 12 V

The Figure 2.5 B, shows that a 12 Volts DC motor is interfaced to the 5 Volts output terminal of the power supply and an Ammeter (Multimeter) is connected in series to the DC motor to measure the current flowing through the DC motor (load) that is being displayed as 0.01A on the multimeter while the motor rotates at lower speeds.

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Figure 2. 6 12 V output and current testing

Once the testing of the current and voltage of the the 5 Volts output is completed, then the multimeter is interfaced with the 12 V output of the supply and the multimeter displays a result of 12.96 Volt (V) as shown in the Figure 2.6 A. The Figure 2.6 B, shows that an ammeter (multimeter) is connected in series to the DC motor which is interfaced to the 12 V output of the supply, thus the multimeter displays a higher value of current of 0.02A that is flowing through the DC motor, thus making the motor rotate much faster due to the supply voltage being much higher than 5 V i.e. 12Volts.

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Table 2. 9 Test Results

The Table 2.9, shows the test results of the power supply in which the voltages and currents flowing across a load using a 12 Volts DC motor has been described along with the practical variation has been determined in terms of accuracy.

2.8 Conclusion

The datasheet with the product design specification and other details for the DC power supply is developed that uses a 230V, 6VA Transformer giving a dual output of 5V and 12 V using the Voltage regulator IC’s L7805 and L7812. The schematic for the design is developed using Design Entry and the Design rule check (DRC) was performed with no errors, therefore further designing and development of the PCB board can be carried out using this schematic. There are generally four interfaces for this power supple i.e. three terminal connectors such as GND, 5V output and 12 V output, it has a plug that is connected to the 230 V AC mains while a switch is provide over the power supply to control the switching on and off of the power supply. All the components needed for developing this power supply are available in India, banglore which has been specified along with its details. The power supply’s output current and voltages were tested by using a multimeter and a 12 V DC motor to test the current flow. For 5 V output, the tested output voltage was 5.51 V with an accuracy of +.5%, with a current flowing through the load of 10mA, while the test output voltage for 12 V output was 12.96 V, with an accuracy of +1%, with a current of 20mA flowing across the load from the 12 Volts output of the DC power supply.

CHAPTER 3

3. Thermal Analysis and Vibration testing of the DC power supply

3.1 Thermal variation of critical components and spacing between the critical components

Once the product is developed it is necessary to perform thermal analysis on the product in order to determine if the product is meeting the deadlines providing a desired response and its reliability. The thermal analysis is performed on the product using ICEPACK V13 to determine the temperature variation of the critical components that has high heat or power dissipation.

Regulator IC’s

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Figure 3. 1 Identification of critical components

The Figure 3.1 (A), shows the DC power supply with the thermal critical components in the system i.e. Voltage regulators IC’s L7805 and L 781, 230V to 15V transformer. The lesser thermal critical components identified is the four diodes (H-Bridge), which has a low power dissipation, while the capacitors can be neglected for small system due to its negligible heat dissipation. The Components on the board are placed such that all the critical components such as the two regulators and the transformer is place at the end of the PCB for better natural cooling from the open top and boundary exposure for better convection to happen. The IC’s are mounted on the heat sinks to increase the surface area and cooling mechanism due to the fins present in the heat sinks, the same goes with the transformer where the cupper windings is framed with aluminum to increase the surface area and to provide better cooling due to the fins present at the bottom of the transformer, since it is known that, heat flux is nothing but the energy dissipated per unit are and the surface area (A) is inversely proportional to the energy or heat flux dissipated i.e. if the Area is more then the stress is less and vice-versa. The DC power supply with some important components has been modeled using Icepack v13 as shown in the Figure 3.1 B, but the thermal analysis results is mainly examined for the critical components.

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Figure 3. 2 Moniter Points

Core is Cupper and total power is 5 Watt

The Figure 3.2 shows the model of power supply in icepack with the components that have been assigned with monitor points in order to obtain the thermal variation curve of the monitored points. In the model, the components with the red dots indicate that those are the components that is to be monitored, whose thermal variation curves will be generated i.e. Transformer, IC’s L7805 and L7182, Transformer and the H-bridge diodes.

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Figure 3. 3 Assigning material properties and total power

Before generating the thermal variation curves for the critical components in the power supply, it is necessary to specify the material properties and the total power parameters of all the components on board and Note that the thermal analysis variations on the critical components are performed for an ambient temperature of 24oC which is specified. The Figure 3.3 A, shows the properties blocks for the component IC L7805, in which the solid material specified is type Silicon (Si) Typical and the total power as 2 watt (W) and Figure 3.3 B, shows the material property assigned to the transformer core i.e. Cupper (Cu) pure with a total power of 5 W. The transformer has a power factor (PF) of 0.9 and a current of 5 Amperes (A), therefore total power is PF*I i.e. 0.9*5A = 4.5 Watt (W), but for worst case we consider the total power of transformer as 5W, since it’s the most critical component that can generate high amount of heat. Similarly the material and the total power output for each component must be specified before running the solution for thermal variations of the critical components.

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Table 3. 1 Material and total power (W)

Temperature variation

The Table 3.1, shows the materials and the total power rating for each of the components present on board, which was calculated by identifying the total current and voltages of the components specified in the datasheets, while some components total power has been directly mentioned in the datasheets.

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Figure 3. 4 Temperature variation of the critical components

Once the parameters such as the total power and the materials has been specified, the file is saved and the solution for the model is initiated by dropping down the solve icon in the software and then clicking “Run Solution” to obtain the thermal variation curves. The Figure 3.4 shows the Thermal variation curves for each critical component that has been assigned to monitor points.

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Table 3. 2 Temperature simulation results

The Table 3.2, shows the thermal results of the critical components after the simulation and the maximum temperature below which each of these components can operate properly. In the table, it is seen that simulation temperature results are all normal and operating under the maximum limit temperature. In the Figure 3.4, the graph shows that, initially the temperatures of the components are at the peak or very high and as the simulation goes on, eventually the temperatures of the components decreases and becomes stable under the maximum temperature as it reaches the 20 iterations and remains stable beyond. In the thermal curves it is seen that the regulator IC’s have the highest temperatures followed by the transformer and the Diodes.

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Details

Pages
31
Year
2013
ISBN (eBook)
9783656730897
ISBN (Book)
9783656730903
File size
3.8 MB
Language
English
Catalog Number
v279301
Grade
B+
Tags
Thermal analysis Vibration testing Icepack power supply interfaces air convention

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Title: Mechanical Aspects in Electronics Systems Design