Low DC to high AC converter K1224PN1. Reference data
Encyclopedia of radio electronics and electrical engineering / Reference materials
Comments on the article
The K1224PN1 microcircuit is designed to work in a 3 V DC to 150 V AC converter to power flat fluorescent panels. These light sources have a uniform glow over the field, small thickness - less than 1 mm, so they are convenient for illuminating liquid crystal indicators in conditions of low ambient light. The supply voltage of flat luminescent panels is at least 40 V with an oscillation shape close to sinusoidal.
The microcircuit contains all the necessary elements of the converter, except for a 5 mH inductor and two frequency-setting capacitors. The device allows you to work in two modes - converter (working) and standby, in which the microcircuit remains connected to the power source, but does not produce an output voltage and consumes a current many thousands of times less than the working one.
The K1224PN1 microcircuit is functionally close to the foreign SP4424 from SIPEX.
The device is housed in a plastic eight-pin case 2101.8-2 with hard tinned pins (Fig. 1).
The functional diagram of the converter is shown in fig. 2. When the SA1 contacts are closed, the internal current generator is turned on, feeding all the nodes of the microcircuit. Two generators start working - G1 and G2.
(click to enlarge)
The first of them generates pulses with a frequency of several kilohertz, which control the transistor VT1, which switches the current through the inductor L1. In order to provide the time necessary for the accumulation of energy in the inductor, the pulses are passed through the duty cycle shaper U1. The material of the inductor magnetic circuit must correspond to the conditions of its operation. The shape of the high voltage pulses that occur at pin 3 at the moments of closing the switching transistor is shown in fig. 3a.
Since an alternating voltage is required to power the luminescent panel, the microcircuit has a channel for distributing high-voltage pulses. It consists of a G2 generator, a DD1 trigger that generates two antiphase pulse sequences, and two-transistor-trinistor switches VT2VS1 and VT3VS2. The switches open alternately, distributing pulses between pins 4 and 5 of the microcircuit, to which the load is connected.
So, when the transistor VT2 is open, and VT3 is closed, the trinistor VS2 opens, passing the next burst of high-voltage pulses through pin 5 to the load. Pin 4 at this time is connected to a common wire through a diode VD2 and an open transistor VT2.
The luminescent panel, which is a significant capacitance - about 0,05 μF, turns bursts of short high-frequency pulses into low-frequency half-waves (Fig. 3, b and c).
The logical node on the elements DD2.1 - DD2.3 serves to transfer the microcircuit to standby mode. When the contacts of the SA1 switch are opened, the elements DD2.1-DD2.3 prohibit the passage of pulses from both generators.
Main technical characteristics*
- Consumed current, mA, no more......55
- typical value......35
- Current through terminal 7, μA, no more than ...... 10
- Current consumption in standby mode, μA, no more than ...... 5
- typical value......1
- Current switching frequency through the choke, kHz......3...6
- typical value......4
- Voltage at terminal 7 in standby mode, V ...... ± 0,2
- Voltage at terminal 7 in operating mode, V ..... Upit ± 0,2
- Output voltage frequency at terminals 4 and 5 in operating mode, Hz......150...250
- Output voltage frequency at terminals 4 and 5 in operating mode when the ambient temperature changes from -40 to +70 °С, Hz......100...400
- Output voltage range, V, not less than ...... 120
- typical value......160
*At an ambient temperature of +25 °C, a supply voltage of 3 V, a load capacitance of 0,055 μF, a choke inductance of 5 mH, and a capacitance of capacitors C1 and C2 (Fig. 2) of 220 and 1500 pF, respectively.
Limit values
- Supply voltage, V ...... 2,2 ... 5
- The highest voltage applied to the throttle, V ...... 5
- Voltage at pin 7, V,
- not less ......-0,25
- no more ...... Upit + 0,25
- Peak current through terminal 3, mA, not more than......45
Authors: M. Shapovalov, S. Mikheev, Bryansk
See other articles Section Reference materials.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
A New Way to Control and Manipulate Optical Signals
05.05.2024
The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>
Primium Seneca keyboard
05.05.2024
Keyboards are an integral part of our daily computer work. However, one of the main problems that users face is noise, especially in the case of premium models. But with the new Seneca keyboard from Norbauer & Co, that may change. Seneca is not just a keyboard, it is the result of five years of development work to create the ideal device. Every aspect of this keyboard, from acoustic properties to mechanical characteristics, has been carefully considered and balanced. One of the key features of Seneca is its silent stabilizers, which solve the noise problem common to many keyboards. In addition, the keyboard supports various key widths, making it convenient for any user. Although Seneca is not yet available for purchase, it is scheduled for release in late summer. Norbauer & Co's Seneca represents new standards in keyboard design. Her ... >>
The world's tallest astronomical observatory opened
04.05.2024
Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>
| Random news from the Archive Video cameras detect crimes
12.11.2012
Scientists from Carnegie Mellon University in Pennsylvania, USA, reported on the development of software for video surveillance systems that can detect the moment of a crime in real time. Its description was presented at the conference Semantic Technology for Intelligence, Defense and Security.
The developed solution, being used at public transport stops or at airports, is able to fix when a person leaves a bag for a suspiciously long time, one of its authors Christian Lebiere cited as an example. He added that eventually the new software will be able to predict crime - that is, to predict illegal actions that have not yet occurred. Such an ability can only be found in science fiction, notes CNet.
The solution is based on machine vision technology - the recognition of stationary and moving objects and the determination of their properties. Over the past decades, scientists have made significant progress in this area, and today this technology is used in many commercial products, including the social networking site Facebook. Machine vision is also the backbone of Google's driverless car project.
The video surveillance system with the function of automatic detection of crimes distinguishes objects by types and "knows" which types of objects are allowed to perform certain actions and how to interact with each other. In turn, the offence-prediction feature, which is still experimental and under development by a team led by scientist Kris Kitani, "knows" about people's most popular routes. When the trajectories begin to suspiciously differ from the usual ones, the system turns on the alarm. The operator can already respond to this signal.
The project is sponsored by the Defense Advanced Research Projects Agency (DARPA) under the US Department of Defense. It believes that video surveillance systems equipped with such software will eventually be able to do without operators or, in any case, reduce their number and increase the efficiency of monitoring order. Such systems will never sleep and will not require rest. They are planned to be used for both civilian and military purposes.
|
Other interesting news:
▪ Features of the Lytro Camera for Mobile Phones
▪ Walruses do not have enough space in the sea
▪ Garbage t-shirts
▪ sound bait
▪ Volvo Concept Truck Hybrid Truck
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Audio and video surveillance. Selection of articles
▪ article Where are you taking us? can't see a damn thing! - Enemies cried out with heart to Susanin. Popular expression
▪ article Where is the driest place on Earth? Detailed answer
▪ article Reed lake. Legends, cultivation, methods of application
▪ article Calibrator for the oscilloscope. Encyclopedia of radio electronics and electrical engineering
▪ article Optical model of the Talking bust. Focus Secret
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