DC/DC Boost Converter using UC3843


0

DC/DC converters are very popular among electronics enthusiasts and are widely used in industry. There are three main types of non-isolated DC/DC converters: buck, boosters, and buck boosters. In this article/video, I used key components such as the popular UC3843 chip, a power Schottky diode, and an N-channel MOSFET to design a compact DC/DC boost converter. The input voltage can be as low as 9V, making it suitable for a variety of applications, such as converting 12-18V to power a laptop using a single 12V battery. I used the Altium Designer 21 and SamacSys component libraries to design the schematic and PCB. PCBs manufactured by PCBWay in green solder mask. Also, I checked the circuit noise number with a Siglent SDS2102X Plus/SDS1104X-E oscilloscope and Siglent SDM3045X multimeter. Let’s get started! Specifications Input voltage: 9-16V Output voltage: 28V max (can be increased, see text) Output current: 4A max Output noise (no load): 5mA Output noise (2-A load): 27 Millivolt ampere analysis circuit Figure 1 shows the schematic diagram of a DC/DC boost converter. As can be seen, the heart of the circuit is the UC3843 chip. 1 Figure 1: A schematic diagram of the UC3843 DC/DC boost converter C1 and C2 was used to reduce the input noise. L1, D1, and Q1 create an enhanced switching network. L1 is an 8-A to 10-A 100-µH inductor. D1 is the MBR20100CT2 Schottky diode (two parallel diode in one package). Q1 is an IRFZ44 N-channel MOSFET.3 The impedance (RDS(on)) MOSFET is about 28 mA and can handle up to 50 amps at 25°C. These characteristics make these components well suited for this project. IC1 is the boost converter circuit control unit. According to the UC3943 datasheet: “UC3842 / UC3843 / UC3844 / UC3845 are constant frequency current mode PWM controllers. They are specifically designed for offline and DC-to-DC converter applications with minimal external components. These integrated circuits feature a trimmed oscillator. For precise duty cycle control, a temperature-compensated reference, a high-gain and error amplifier, a current-sensing comparator, and a high-current totem pole output to drive a power MOSFET.” C3, C4, C5, C6, and C7 are used to reduce the noise generated. The output of a boost converter is usually noisier than a buck converter, especially using discrete components. Single-chip buck/boost controller less noise; However, the output voltage and current of these controllers are limited. R1 is a 10k multicycle potentiometer that you can set to adjust the output voltage. You can increase the output voltage level by decreasing the value of R5. The output voltage is determined using this formula: VOUT = 2.5 (1 + R1 / R5) So as is evident when R5 is 1K, the maximum output voltage is somewhere between 27 V and 28 V if we reduce the value of R5 to 820R or 680R , the maximum output voltage will be around 32V to 33V or 39V to 40V. (50 volts), which, of course, may be less than 50 volts in practice (due to manufacturing tolerances). R2 and R3 are placed in parallel, building up an initial load to help stabilize the output voltage. PCB Layout Figure 2 shows the PCB layout of the design. It is a two-layer PCB board with a combination of SMD and through-hole components. A view of the top layer, bottom layer, silk screen, and solder mask (top layer) is included in Figure 2. Figure 2: PCB layout of a DC/DC boost converter As I mentioned in the abstract, I used Altium Designer 4 software to design the schematic and the PCB . I didn’t have the schematic code, PCB footprint, and 3D model for many of the components in this project. So instead of wasting my time designing component libraries from scratch and increasing the risk of errors and mismatches, I used the free, IPC-branded SamacSys component libraries and imported them directly into an Altium PCB project using the SamacSys Altium plugin. Plug-ins provided for the majority of CAD electronic design software, 6 not just for Altium Designer. Figure 3 shows the CAD software for the supported electronic design. Figure 3: Electronic CAD design software (plugins) supported by SamacSys Specifically, I used SamacSys libraries for IC1,7 Q1,8 and D1,9 which you can find in references. Another option is to download component libraries from ComponentSearchEngine.com and import them manually. Figure 4 shows the components identified in the SamacSys Altium plug-in. Figure 4: Components identified in the SamacSys Altium plugin assembly and testing Figure 5 shows a PCB board assembled from the top and bottom. This is the prototype of the circuit. In the last revision, I added two parallel resistors as primary load. Some components are through hole and some are SMD. You should have no problem soldering the components; However, you can order a assembled panel. Figure 5: Assembled PCB board (top and bottom view) In general, there are two important parameters in voltage regulators (power supplies): line regulation and load regulation. Line regulation is the ability of a power supply to maintain a specified output voltage on changes in the input line voltage. It is expressed as a percentage of the change in the output voltage relative to the change in the input line voltage. Load regulation is the ability of a power supply to maintain a specified output voltage taking into account changes in load. This does not mean that tolerance applies when sudden changes in pregnancy occur; This means that over the allowable load range, the regulation can change by this amount. Please check the YouTube video where I am testing this. The best way to prepare these measurements is to carry a DC current. At the time of writing this article, I have not received my DC load yet, Siglent SDL1020X-E.10, I will analyze this converter device using DC load soon in the future; For now, we can at least partially test it and check the output noise. Figure 6 shows the output noise of the boost converter in the absence of a load. I used the power analysis feature of the Siglent SDS2102X Plus oscilloscope. 11 Of course, you can use the cheaper Siglent SDS1104X-E oscilloscope as well; However, the plus sign is something beyond. It is an exemplary device. Some spurts of long induction can be seen in the waveform that is unlikely to come from the output line. So I kept Vrms as a pointer. Figure 6: Output noise of a DC/DC converter using a Siglent SDS2102X Plus oscilloscope. Figure 7 shows the output noise of a DC/DC converter under 2-A load. As noted above, I don’t think these long hikes really come from width. When I move away from the probe, these spikes noticeably disappear. I recommend using some capacitors as close as possible to your load. Figure 7: Output noise of a DC/DC converter (2-A load) BOM Figure 8 shows a circuit BOM. L1 is a 47-µH to 100-H inductor that you can build or buy. I built it myself, so I can’t provide any specific part number for that. However, make sure that your inductor can withstand currents of at least 8A to 10A. You can use 1mm copper wire and a ferrite core. The hole size used for the agitator footprint is 1.3 mm. Figure 8: Bill of Materials (excluding L1) References 1UC3843 Datasheet: https://www.ti.com/lit/ds/symlink/uc3843.pdf?HQS=ti-null-null-sf-df-pf-sep- wwe&ts = 1626017670986 & ref_url = https%253A%252F%252Fcomponentsearchengine.com%252F 2MBR20100CT Datasheet: https://www.diodes.com/assets/Datasheets/MBR20100C.pdf 3IRFZ44 Datasheet: https://componentsasearchetsearchine. com//2 IRFZ44EPBF.pdf 4Altium Designer: https://www.altium.com/altium-designer 5SamacSys Altium plug-in: https://www.samacsys.com/altium-designer-library-instructions 6 SamacSys supported plugins: https://www. samacsys.com/pcb-part-libraries 7UC3843 Schematic symbol, PCB fingerprint, 3D model: https://componentsearchengine.com/part-view/UC3843D8TR/Texas%20Instruments 8IRFZ44 Schematic symbol, PCB fingerprint, 3D model: https: // Components earEngine.com/part-view/IRFZ44EPBF/Infineon 9MBR20100 Schematic symbol, PCB fingerprint, 3D model: https://componentsearchengine.com/part-view/MBR20100CT-E1/Diodes%20Inc 10Siglent SDL1020X-E DC load: http://siglentna.com/dc-electronic-load/sdl1000x/ 11 Siglent SDS2102X Plus oscilloscope: https://siglentna.com/digital-oscilloscopes/sds2000xp/ 12 Siglent SDS1104X-E Oscilloscope: https:// siglentna.com/digital-oscilloscopes/sds1000x-e-series-super-phosphor-oscilloscopes/Article: https://www.pcbway.com/blog/technology/DC_to_DC_Boost_Converter_using_UC3843.html.


Like it? Share with your friends!

0

What's Your Reaction?

hate hate
0
hate
confused confused
0
confused
fail fail
0
fail
fun fun
0
fun
geeky geeky
0
geeky
love love
0
love
lol lol
0
lol
omg omg
0
omg
win win
0
win
Joseph

0 Comments

Your email address will not be published. Required fields are marked *