Advanced switching power supply in a matchbox, 220/9 volts 10 watts. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Power Supplies

 Comments on the article

The article describes a simple stabilized switching power supply (SMPS), which can be placed in a case the size of a matchbox. The device is characterized by increased power density, good repeatability and is not afraid of overcurrent.

Main technical characteristics:

• AC mains voltage, V.....220±20%;
• supply voltage frequency, Hz.....40...400;
• power consumption at no load, W, not more than ..... 0,31;
• conversion frequency, kHz.....115...140;
• rated output voltage, V.....9;
• maximum output power W.....10;
• maximum efficiency, %.....88;
• specific power W/dm3.....300;
• weight (without case), g, not more than.....28.

Descriptions of miniature SMPS have been repeatedly published on the pages of the Radio magazine. As a rule, these are devices with a small output power. One of these SMPS [1] gave power up to 0,63 W to the load, being one of the most powerful sources among those that were placed in a matchbox or in the dimensions of the Krona battery [2]. In addition, these sources had a low efficiency, usually not exceeding 35%.

The proposed flyback SMPS can also be placed in a matchbox, but its output power is 15 times, and the efficiency is 2,5 times higher than that of its counterpart [1]. It was possible to achieve such high energy performance thanks to the use of a specialized TNY255P microcircuit of the TinySwitch family from Power Integrations [3, p. 479, 480] The SMPS stabilizes the output voltage, has protection against overload and short circuit in the load by skipping pulses, and the microcircuit used contains overheating protection nodes. More detailed information about the parameters and characteristics of this TNY255P chip can be found on the website.

The SMPS scheme is shown in fig. one.

Rice. 1 (click to enlarge)

Fuse FU1 protects the elements from emergencies. The thermistor RK1 limits the pulse of the charging current of the capacitor C2 to a safe value for the diode bridge VD1, and together with the capacitor C1 forms an RC filter that serves to reduce the impulse noise penetrating from the SMPS to the network. The diode bridge VD1 rectifies the mains voltage, the capacitor C2 is a smoothing one. The voltage surges of the primary winding of the transformer T1 are reduced by the damping circuit R1C5VD2. Capacitor C4 is a power filter from which the internal elements of the DA1 microcircuit are powered, its nominal capacitance can be in the range of 0,1 ... 4,7 microfarads.

The output rectifier is assembled on a VD3 Schottky diode, the output voltage ripple is smoothed out by the C6C7L1C8 LC filter. Elements R2, R3, VD4 and U1 provide, together with the DA1 chip, the stabilization of the output voltage when the load current and mains voltage change. The power-on indication circuit is made on the HL1 LED and the current-limiting resistor R4.

Fixed resistors MLT, C2-23, P1-4, tuning resistors - 3329H-1 from Bourns or the domestic analogue of SPZ-19a, oxide capacitors - imported, C1, C3 and C5 - ceramic high-voltage CD2200Z5V, DEBB33D222KA2B, C4, C7, C8 - K10-506. NTC series thermistor (with negative. TKS) - SCK-103. Chip TNY255P is interchangeable with TNY255G, TNY256P or TNY256G. diode HER208 - on HER106, HER107, HER206, HER207, 1N4937, FR306 or BY399, diode 1N5822 - on SR360, 31DQ04, 31DQ06, 90SQ045. The KS 170A zener diode can be replaced with KS162A, KS175A zener diodes, and the PC817 optocoupler can be replaced with LTV817, PC816, LTV816. LED - any miniature, preferably blue or green glow. Fuse FU1 is constructive, it is formed on the board by a printed conductor, it can be replaced with a piece of copper winding wire, for example PEV-2, with a diameter of 0,03 mm.

For the manufacture of the transformer, an armored magnetic circuit was used. B18 (without trimmer) from ferrite 2000NM. The primary winding contains 182 turns of wire with a diameter of 0,11 mm, and the secondary consists of 20 turns of wire with a diameter of 0,6 mm. Between the windings, two layers of lavsan or varnished fabric tape should be laid, soaked with paraffin to reduce acoustic noise. between the cups of the magnetic circuit, it is necessary to make a gap of 0,16 ... 0,23 mm, for which you can use a gasket made of fluoroplastic, fiberglass or, in extreme cases, cardboard. The inductor is wound on a magnetic circuit of size K10x6x2 made of ferrite 2000NM and contains 16 turns of wire with a diameter of 0,6 mm at an output current of up to 200 ... 300 mA and 3-4 turns of wire with a diameter of 0,8 mm at a current of up to 1,1 A. Sharp edges the magnetic core must first be blunted with sandpaper and wrapped with a layer of lacquer tape. For winding the transformer and inductor, wire of the PEV-2, PETVM, PETV-1, PETV-2, PET-200-1 brands should be used.

The PCB drawing is shown in fig. 2, it is made of one-sided foil fiberglass with a thickness of 1 ... 1,5 mm. The microcircuit is installed in the panel, the cups of the magnetic circuit are squeezed together and fixed to the board with two brass screws screwed from opposite sides into a brass bushing. All resistors and diodes are mounted perpendicular to the board.

Fig. 2

The appearance of the assembled board is shown in fig. 3. After checking and adjusting, it is placed in a housing made of insulating material. Establishing an SMPS comes down to accurately setting the output voltage with a trimming resistor R3.

Fig. 3

Literature

1. Moskatov E. Pulse IP in a matchbox. - Radio, 2005, No. 6, p. 26, 27.
2. Solonin V. Network in the dimensions of the "Krona". - Radio, 1999, No. 2, p. 37, 44.
3. Microcircuits for switching power supplies and their application. 2nd edition, corrected and enlarged. - M.: Dodeka-XXI Publishing House, 2001.
4.TNV253/254/255. - .

Author: E. Moskatov, Taganrog, Rostov region

See other articles Section Power Supplies.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive Silicon Motion SM2262 controller for SSD 04.06.2017 Silicon Motion introduced the SM2262 controller for solid state drives. This product, which supports PCIe 3.0 x4 and NVMe 1.3, is scheduled to begin production in the third quarter of 2017. The controller supports five channels of NAND flash, including 3D NAND. As a cache memory, you can use DDR3, DDR3L, LPDDR3, DDR4 memory. The controller provides a transfer rate in sequential read mode up to 3200 MB / s, in sequential write mode - up to 1700 MB / s. Performance in read mode with random access blocks of 4K reaches 370 IOPS, in write mode - 000 IOPS. At the same time, the SM2263XT quad-channel controller was shown, which also supports PCIe 3.0 x4 and NVMe 1.3. It is designed for entry-level SSDs and is designed to work without DRAM cache. However, thanks to the Host Memory Buffer (HMB) feature, this controller can ask the system for exclusive access to a portion of RAM for caching, which improves overall performance. The SM2263XT controller demonstrates transfer speeds of up to 2200MB/s in sequential read mode and up to 1500MB/s in sequential write mode. Performance in read mode with random access blocks of 4K reaches 250 IOPS, in write mode - 000 IOPS.

Other interesting news:

▪ Graphene crossed with nanotubes

▪ Honda S-Dream rocket car sets speed record

▪ Marvell PA800 anti-tamper chip

▪ Up to 25% of employees are prone to workaholism

▪ Norway says goodbye to FM radio

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Microcontrollers. Article selection

▪ article Chizhik-pyzhik, where have you been? Popular expression

▪ article Why are there no numbers in IKEA product names? Detailed answer

▪ article Square peas. Legends, cultivation, methods of application

▪ article Color-musical installation with pulse-number control of trinistors. Encyclopedia of radio electronics and electrical engineering

▪ article Turning ink into water. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024