Control-Integrated circuit for SMPS SG : Pulse frequency modulation and pulse width modulation are two types of techniques used in control integrated circuits for switch-mode power supplies.
In Pulse frequency modulation technique on time of pulse remains constant but the frequency increases with the increase in load. But the Pulse frequency modulation technique causes some issues in switch-mode power supplies. The width of the pulse or on time increase with the increase in load. Pulse width modulation also resolves the issues which occur in Pulse frequency modulation.
Therefore, Pulse width modulation is a preferred technique for control circuits of switch-mode power supplies. I will discuss these things in detail later in this article.
There are two types of PWM controller integrated circuits:. The voltage control method used a feedback voltage by comparing it with a reference value to set a duty cycle of PWM.
In return to control the output voltage of SMPS. While the current control method uses Output current from output inductor to compare it with the reference value and to set the duty cycle of PWM.
I have used a voltage mode PWM controller in pure sine wave inverter. This is a pin configuration diagram and the functionality of each pin is provided in the next section. By adjusting the values of CT capacitor, RT resistor, and discharge resistor. Circuit diagrams of example below show the circuit diagram of sg which generates two inverted PWM signals.
Users can adjust the width of PWM using a variable resistor shown in the feedback circuit. You can change the variable resistor value to adjust the resolution of PWM. Two Mosfets and ferrite core transformer are used in push-pull configuration mode. This example circuit provides power regulated voltage output with the help of the feedback circuit.
Variables resistor R10 provide voltage regulation feature. How to synchronize the two SG Give me a tip please I intend to use one at high frequency 24KHz and the other at low Hz. If anyone can help me, I will be very grateful. Thank you. Dear sir please i would like to know how to get 5ohz oscillation from the ic I calculated the circuit above from the formula and didnt get 50hz. Please help me out, Thank you.
Notify me of follow-up comments by email.Tools: 1. Soldering iron 2. Some solder 3. Small needle nose plier 4. A wire striper For the matrix: 1. Some single core wire 7.
Perfboard 8. Arduino optional - 9. This is one of the most important part of this project, because it based on LEDs it's very critical to choose the right ones.
I recommend using 5mm diffused LEDs because they give a good amount of light and make a clear image the color of the LEDs is your Choice only. You can use a 3mm LEDs too but it would make soldering really hard and you would get a small display. Another tip is to buy the LEDs from Ebay because you can get a really good price and sometimes get free resistors as well like in my case. Do not buy exactly 80 LEDs because one or more of the LEDs can be damaged, my advice to buy 10 or 20 more, and if some will be left over you can always use them in future project.
You should first get some specs on your LEDs, you should know their forward voltage and forward current, you can get this info from the seller. The Arduino gives an output of 5V so your Source voltage is 5V.
So what is multiplexing: It is basically a way to split information in to little peaces and send it one by one. In our case we split the image that we want to display to 10 peaces 10 rowsWe want to scan the rows of the matrix light up one row at a time and send info from the Arduino to the columns. All the columns are positives of the LEDs and the rows are negatives so if the first row is connected to ground and we send information to the columns we will only light the first row.
To get a good display we need to scan the rows very fast, so fast the the human eye thinks that all of the rows are connected at the same time. This IC basically scans the rows of the matrix lights up one row at a time. In our case we want to connect the rows to ground but the doesn't build to sink current, so to solve this little problem we need to use a transistor with a resistor.
The has 10 output pins so we need 10 resistors and 10 transistors, we connect the 1K resistors to the outputs of the and the base of the transistor to the other end of the resistor. Then we connect the collectors of the transistor to the rows and the emitter to the ground. By connecting more IC's you can increase the number of outputs with losing more micro-controller pins.
Soldering the LED matrix is a very tricky thing ,there are a lot of ways to do it and I will give you just two. The first one is the one I used and this way takes a lot of time and effort but the end result is very nice and pretty.
You need to connect all the positive leads of the LEDs in columns and the negative lead in rows. Now you do this by taking the positive lead of the first LED and bend it down to the other LEDs, solder the pins which touch each other, from here take the last lead that you soldered and bend it again down and repeat till you have all the positive leads connected in the column. Now the tricky part is connecting the negative pins in a row because you can't bend them and solder like you did with the positive leads.
Now I used little jumpers from solid core wire and connect them like you can see in the picture below this takes lots of time and work. The second way is to start the same way as in the first way but the only difference is in connecting the negative pins.
This method saves lots of time and is a lot simpler. The trick is to put some tape or another thing on the columns connections to isolate them from the negative pins and if you do that you can bend the negative leads too and connect them like you did with the positive ones. Without the shift register: Via a resistor you connect each column to the arduino pins The reset pin of the goes to pin 8 on the arduino and the clock pin goes to pin 9 on the arduino. I have written a little program to make scrolling text and added all the letters and number lots of workI used ports for my program because it saves space and easier to handle.It is made of silicon material and specially designed for low voltage, low to medium current and low power amplifier applications.
It means it has a high collector therefore it is mostly used in that circuits where low to medium current is required. It works on high transition frequency value MHz with delay time 10ns, rise time 25ms, storage time ms and fall time 60ms. It is friendly to use and easily available online market in a TO package. These pins are used in the circuit for turning on or off the transistor. Its pin configuration diagram is shown here according to datasheet:.
Similarly in the amplification application, it can be connected in three configurations such as common emitter, common collector and common base. Current, voltage and power can be easily amplified by using these configuration modes. In this section, we will discuss some examples using this NPN transistor.
First, we will see an example of a simple LED controlling example with a switch. After that, we will see an example of controlling a dc motor with Arduino Uno. In this example circuit, we attach a push-button with a base terminal.
In this example, a 2N NPN transistor is used in common emitter configuration mode. This circuit controls a dc motor through a transistor that is used as a switch. We can use Arduino Uno or any microcontroller to control this circuit.
The working of this circuit is exactly the same as you have seen in the last section except dc motor is used. A 2D diagram helps while designing a PCB diagram and during electronics components assembly. You can download the datasheet for a dimension diagram of other packages. Notify me of follow-up comments by email. Notify me of new posts by email.
Table of Contents. The collector pin is an output pin and it is used for providing transistor current to the output load.We come across LCD displays everywhere around us. Computers, calculators, television sets, mobile phones, digital watches use some kind of display to display the time. An LCD is an electronic display module which uses liquid crystal to produce a visible image.
Contrast adjustment; the best way is to use a variable resistor such as a potentiometer.
The output of the potentiometer is connected to this pin. Rotate the potentiometer knob forward and backwards to adjust the LCD contrast. A 16X2 LCD has two registers, namely, command and data.
The register select is used to switch from one register to other. A command is an instruction given to LCD to do a predefined task. Examples like initializing it, clearing its screen, setting the cursor position, controlling display etc. Processing for commands happens in the command register. When we send data to LCD it goes to the data register and is processed there. Generating custom characters on LCD is not very hard. CG-RAM is the main component in making custom characters.
It stores the custom characters once declared in the code. CG-RAM size is 64 byte providing the option of creating eight characters at a time. Each character is eight byte in size. We can generate custom characters at these addresses. Once we generate our characters at these addresses, now we can print them on the LCD at any time by just sending simple commands to the LCD. Character addresses and printing commands are below.
In the table above you can see starting addresses for each character with their printing commands. The first character is generated at address 0x40 to 0x47 and is printed on LCD by just sending simple command 0 to the LCD.
The second character is generated at address 0x48 to 0x55 and is printed by sending 1 to LCD. How to power tge LCD? This is useful to read lcd text even in darkness. Hex adresses should end at 7f not You started at the right hex address but counted in decimal. Sign in Join. Sign in. Log into your account.
Multiplexing With Arduino and the 74HC595
Sign up. Password recovery. Saturday, July 18, Advertise Contact About Magazine. Forgot your password? Get help. Create an account. Electronics For You.In this project, we will build few simple LED Circuits. Nowadays, people are investing more in LEDs due to their energy efficiency.
Home lighting, office lighting, Automobile lighting, Street lighting etc. Students, hobbyists and makers often work with LEDs in different types of projects. LEDs are very sensitive components with respect to voltage and current and they must be provided with rated current and voltage values.
Wrong voltage or current to LED will burn them off. But as the complexity of the circuit increases, choosing the right resistor with right wattage is important.
The circuit diagram for this circuit is shown below. The following image shows the setup of single LED connected to a 12V Supply and a current limiting series resistor. The important component other than the LED of course is the Resistor. So, selecting the right resistor with the right wattage is very important.
First, we will calculate the resistance.HOW TO MAKE SCROLLING TEXT LED DISPLAY -- 48X8 LED MATRIX -- Huge LED Matrix BY MANMOHAN PAL
The value of the series resistor can be calculated using the following formula. Substituting these values in the above equation, we can calculate the value of Series Resistance as. Now that we have calculated the resistance of the series resistor, the next step is to calculate the power rating of this resistor.
Power Rating of a Resistor specifies the value of power that a resistor can safely dissipate. The Power Rating of a Resistor can be calculated using the following formula. Here, V RES is the voltage drop across the resistor and.
So, the Voltage Drop across the Series Resistor is. The current through the Resistor is same as the current through the LED as they are series. So, the current through the Series Resistor is. Substituting these values in the above formula, we get the power dissipated by the resistor.
Once the right resistor is selected, we can connect the resistor in series and give the 12V Supply to the LED. The following image shows the circuit diagram of the LEDs in Series.
Since the LEDs are connected in Series, the current through all of them will be the same i. Coming to the power rating of the resistor, it is equal to 1. Once all the components are selected, we can connect them on a breadboard and power on the circuit using a 12V Supply.They are commonly used to display digits from 0 to 9 and also few alphabets usually, A to F.
Seven segment display is the most common device used for displaying digits and alphabet. Use of LEDs in seven segment displays made it more popular. The binary information can be displayed in the form of decimal using this seven segment display.
Its wide range of applications is in microwave ovens, calculators, washing machines, radios, digital clocks etc. LED or light emitting diode is P-N junction diode which emits the energy in the form of light, differing from normal P-N junction diode which emits in the form of heat. Liquid crystal displays LCD use the properties of liquid crystal for displaying. LCD will not emit the light directly. Single seven segment or number of segments arranged in an order meets our requirements.
The seven segment display dates back to century old. In the year F.
Tutorial – Arduino and the MAX7219 LED Display Driver IC
After that in seven segment display is invented and is illuminated using incandescent bulbs. They are used in electric power plants but has gained no much reputation. Generally seven segment displays are available in 10 pin package. The pin diagram of seven segment display is shown in the above figure. Seven segment display is an electronic circuit consisting of 10 pins. Out of 10 pins 8 are LED pins and these are left freely.
Depending on either the common pin is cathode or anode seven segment displays can be either named as common cathode or common anode display respectively. These are available from different vendors. They have shape of rectangular box similar to that of IC but in large size. Forward biasing the particular segment or LED will emit the light energy thus illuminating a part of numeral.
There is another segment assigned as H, used for displaying dot. The decimal or dot point is used for representing the decimal point in a numeral. For example to display 2. Generally, in LED package either all the cathodes or all anodes of the segments are combined to form a common pin.
Bottom view of the seven segment display is shown below. The bottom view of the segment shows 10 pins of the segment. These are cathode or anode pins of the LEDs present in the seven segment. Seven segment is illuminated using these pins.
The internal structure of display is very hard. This can be divided into two parts i. The internal circuit will have LEDs arranged in the rectangular form. These two parts are surrounded by glass, ceramics and plastic in order to protect them. Seven segment display works, by glowing the required respective LEDS in the numeral.
The display is controlled using pins that are left freely. Forward biasing of these pins in a sequence will display the particular numeral or alphabet.Furthermore they can be chained together to control two or more units for even more LEDs.
At first glance you may think that it takes a lot of real estate, but it saves some as well. As mentioned earlier, the MAX can completely control 64 individual LEDs — including maintaining equal brightness, and allowing you to adjust the brightness of the LEDs either with hardware or software or both.
You can even switch the display off for power saving mode, and still send it data while it is off. And another good thing — when powered up, it keeps the LEDs off, so no wacky displays for the first seconds of operation. Here is the pinout diagram for the MAX Wiring up a matrix is very simple — if you have a common matrix with the following schematic:.
The circuit is quite straight forward, except we have a resistor between 5V and MAX pin Have a look at table eleven on page eleven of the data sheet:. Finally, the MAX serial in, load and clock pins will go to Arduino digital pins which are specified in the sketch. In the last few months there has been a proliferation of inexpensive kits that contain a MAX or equivalent, and an LED matrix.
Simple LED Circuits
These are great for experimenting with and can save you a lot of work — some examples of which are shown below:. The first pulls in the library, and the second line sets up an instance to control. The four parameters are as follows:. The second line adjusts the brightness of the LEDs in sixteen stages. For both of those functions and all others from the LedControl the first parameter is the number of the MAX connected.
These functions are demonstrated in the following sketch:. How about controlling two MAXs? Or more? You will of course still need the 5V, GND, resistor, capacitors etc. You will also need to make a few changes in your sketch. They are numbered from zero upwards, with the MAX directly connected to the Arduino as unit zero, then one etc.
To demonstrate this, we replicate the previous example but with two MAXs:. First our example sketch — it is quite long however most of this is due to defining the characters for each letter of the alphabet and so on. The pertinent parts are at the top of the sketch — the following line sets the number of MAXs in the hardware:. You can then incorporate the code into your own sketches. And a video of the example sketch in action:. Although we used the LedControl library, there are many others out there for scrolling text.