Power adapter for laptop in car. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Power Supplies
Comments on the article
A laptop is certainly a handy thing, but the problem is that its battery charge usually lasts for two or three hours of work. It is not enough. It is quite reasonable, when moving by car, to power and charge the laptop from the car's on-board network. But, for reasons unknown to me, the supply voltage of most laptops is 19 V. To be honest, this is a very strange figure.
There can be only one way out - to make a DC-DC converter that increases the voltage of a car battery to 19 V. Now there are many DC-DC converter circuits, by changing the ratio of measuring voltage divider resistors of which you can get a variety of output voltages, from units of volts to 30 ...
The converter can be powered by voltage from 10 to 15 V, at the output 19 V at a maximum current of 2,5 A. There is a protection circuit against lowering the input voltage below 10 V and against overload at the output.
(click to enlarge)
The duty cycle pulse controller is made on a specialized UC3843 (A2) microcircuit. The scheme is almost typical. The output pulses are fed to the gate of a powerful key field effect transistor VT1. The conversion takes place at a frequency of about 50 kHz. The voltage pumping occurs on the inductance L1. The rectifier is made on the Schottky diode VD5. Ripple smoothes first C10. This is followed by a filter of two inductors L2 and L3 and two capacitors C9 and C8.
The output voltage is set by resistors R11-R12. They form a voltage divider, the ratio of the shoulders of which should be such that, with the required output voltage, there is a voltage of 2 V at pin 2 A2,5. With the values \u11b\u12bof the resistances R18,75 and R11 indicated in the diagram, the output voltage will be stably maintained at 12 V. resistors, additional resistances of a much larger value. On the printed circuit board, tracks are provided for them. By turning on the resistance in parallel with R19, we reduce the output voltage, and in parallel with R11, we increase the output voltage.
Diode VD1 helps to blow fuse FS1 in case of incorrect input voltage supply.
A protection circuit is made on the dual operational amplifier A1. On the OU A1.1 - a circuit for measuring and controlling the input voltage. As long as the input voltage is above 10V, the voltage at the inverse input A1.1 is greater than at the direct one.
The output is zero, the H1 LED is off, and the generator blocking voltage is not supplied to terminal 3 A2.
If the input voltage decreases, the voltage at the direct input A1.1 becomes greater than at the inverse one. - the output voltage is one, LED H1 is on, and generator A2 is blocked. If you need to change the blocking threshold, you can choose the resistance of the resistor R3 or R4.
The second OU A1.2 measures the output current.
The measuring resistance is the windings of the coils L2 and L3. In case of overload, the voltage at the direct input A1.2 will be greater than the voltage at the inverted input. At the output of A1.2, a unit voltage appears. LED H2 lights up and through it, a blocking voltage is supplied to pin 3 A2.
The protection threshold is highly dependent on the active resistance of the coils L2 and L3. The threshold during the adjustment process is set by selecting the resistance of the resistor R13. When it decreases, the trip current decreases, and when it increases, it increases.
The coils are wound on ferrite rings. Coil L1 is wound on a ferrite ring with an outer diameter of 23 mm. It contains 60 turns of PEV 0,61 wire. Coils L2 and L3 are wound on ferrite rings with an outer diameter of 16 mm. They contain 120 turns of PEV 0,43 wire.
Everything is assembled on one printed circuit board.
The board is compact, so the parts must be miniature. The board is one-sided, it has several jumpers made with a mounting wire.
Coils L1-L3 are installed vertically. Initially, they are held on their own pins, and after the adjustment is completed, they are glued to the board with epoxy glue.
All capacitors must be rated for at least 25 V.
Diode 1N4007 can be replaced with KD209 or excluded from the circuit altogether, but in this case, if the polarity of the input voltage connection is incorrect, the circuit may fail before the FS1 fuse.
Diodes 1N4148 can be replaced with KD522.
Author: Karavkin V.
See other articles Section Power Supplies.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
Artificial leather for touch emulation
15.04.2024
In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>
Petgugu Global cat litter
15.04.2024
Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>
The attractiveness of caring men
14.04.2024
The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>
| Random news from the Archive Improvement of clean methanol fuel cells
12.12.2020
Due to the many environmental problems caused by the use of fossil fuels, many scientists around the world are focused on finding effective alternatives. While there are high hopes for hydrogen fuel cells, the reality is that transporting, storing, and using pure hydrogen comes with huge additional costs, making it difficult for today's technologies. In contrast, methanol (CH3O3), a type of alcohol, does not require refrigeration, has a higher energy density, and is easier and safer to transport. Thus, a transition to a methanol-based economy is a more realistic goal.
However, generating electricity from methanol at room temperature requires a direct methanol fuel cell (DMFC), a device that has so far offered poor performance. One of the major problems with DMFCs is the undesired "methanol oxidation" reaction that occurs during the transition of methanol, "that is, as it passes from the anode to the cathode. This reaction results in the destruction of the platinum (Pt) catalyst, which is essential to the operation of the cell. While certain strategies have been proposed to mitigate this problem, none have been good enough so far due to cost or stability issues.
A group of scientists from Korea came up with a creative and effective solution. They made - using a relatively simple procedure - a catalyst consisting of Pt nanoparticles enclosed in a carbon shell. This shell forms an almost impermeable carbon network with small holes caused by nitrogen defects. Although oxygen, one of the main reactants in DMFC, can reach the Pt catalyst through these "holes", the methanol molecules are too large to pass through.
"The carbon shell acts like a molecular sieve and provides selectivity for the desired reactants that can actually reach the sites of the catalyst. This prevents unwanted reaction of the Pt nuclei," explains Prof. Oh Jung Kwon from Incheon National University (Korea), who led the study.
The scientists conducted various experiments to characterize the general structure and composition of the prepared catalyst, and proved that oxygen can pass through the carbon shell, but methanol cannot. They also found an easy way to control the number of defects in the casing by simply changing the temperature during the heat treatment step. In subsequent experimental comparisons, their new purified catalyst outperformed commercial Pt catalysts and also showed much higher stability.
|
Other interesting news:
▪ Home Air Purifier Xiaomi Mi Air Purifier Max
▪ Data is transmitted at the time of the handshake
▪ Mobile phone Apple iPhone 3G S
▪ Gravity and earthquake
▪ Approved a single standard chargers for all gadgets
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Consumer Electronics. Selection of articles
▪ article Seriously and for a long time. Popular expression
▪ article What is the largest flying bird? Detailed answer
▪ Article Unloader Truck Driver. Standard instruction on labor protection
▪ article Instead of a refrigerator relay. Encyclopedia of radio electronics and electrical engineering
▪ article Artificial honey from sugar. Chemical experience
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese