EVO2 with recess into switching power supplies

In the last lesson, we disassembled a transformer or linear power supply; if you look at its block diagram, you can clearly trace its linearity, all the blocks follow each other and do not have an inconsistent connection. These power supplies are currently used only in audio equipment, since, unlike switching power supplies, they do not produce noise or interference (you may have heard the unpleasant squeak of a switching power supply, which is the norm for many). Comparison of transformers of the same power pulsed and linear power supplies The transformer power supply has one significant drawback - its size. It was the dimensions that served as the impetus for the development of switching power supplies, but to better understand how this happened, let's look at an example. Transformer output current shape Now on the market you can find a roomy SUV with a 1.2 or 1.4 liter engine, which was unthinkable just a few decades ago, where 2.5-3 liters were considered the norm. The secret is in the turbine - most of these small displacement (size) engines have a special air turbine, which forces air into the combustion chamber and increases power to the limiting values. What if we try to perform the same operation in electricity - the developers of power supplies thought. But how do you make electricity spin like a turbine? Frequency It was the frequency that became the key to the creation of small-sized power supplies with very good output characteristics. As we know, in a transformer there is a primary winding and a secondary winding, for example, if a voltage of 220 volts is applied to the primary winding, where 100 turns are wound, then we will remove 22 volts from the secondary winding with 10 turns, but voltage is only one of the characteristics of the current, so What is important is its strength, the smaller the transformer (smaller turns and wire diameter), the less strength it has. In a socket, the current frequency is 50 hertz, but if we somehow increase this frequency at least twice, then we can use a transformer 2 times smaller and get almost the same power, because we get a turbine effect. Working principle of TNY264 The turbine of a switching power supply is a PWM controller, in our case with EVO2 it is TNY264, let's look at the device and operating principle of this chip in a little more detail. Running TNY264 on a development board In the last lesson, you asked for more typical faults and specific repairs, but we decided not to give fish, but to continue to give a fishing rod, since we believe that knowledge of the principles is more important than typical faults, since having the first, you can always come to the second with experience, while At the same time, without knowing the basics and principles, any non-standard repair will be baffling, and this lesson is dedicated not to EVO2 modules, which are very rare and will soon disappear completely, but to switching power supplies, which are found in all control modules of any equipment, not only washing machines cars Changes in TNY264 pulses from feedback Now that we know why we are delving into the theory, let's power our microcircuit using an external power supply. In this way, you can check almost any PWM controllers in any power supply; the voltage and pinout of the microcircuit can always be viewed in the datasheet. Diagnostics of a switching power supply Block diagram of a switching power supply First: what you need to check before connecting the switching power supply to the network is the absence of a short circuit in the input circuit and in the load; if you stand with a multimeter at the points where there should be 5 and 12 volts, there should never be low resistance, i.e. The multimeter should not beep in the "dialing" mode. Second: after applying a voltage of 220 volts to the input of the power supply, always through the light bulb, it may blink a little and go out, which means everything is more or less suitable, look at the voltage at the Output, if there is no voltage, look at the integrity of the PWM, the voltage at
Включение лампочки на макетной плате.jpg
Включение лампочки на макетной плате.jpg
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