Power Tutorials

How rechargeable batteries, charging, and discharging cycles work The battery stores electrical energy in form of chemical energy and the chemical energy again able to convert into electrical energy. The conversion of chemical energy to electrical energy is called discharging. The chemical reaction during discharge makes electrons flow through the external load connected at the…

Lithium-ion batteries are another popular type of batteries that are used in the Uninterruptible Power Supply (UPS) designs. These batteries are commonly used in portable electronic devices. These are low maintenance batteries having high energy density, small size and light weight which makes them suitable for use in most of the portable devices. But, due to high energy density in comparison to the weight and volume of the Li-ion Battery, there are also some safety concerns while charging the Li-ion batteries. Before designing a charger circuit for these batteries, let us first understand charging methods and topologies involved in charging Li-ion batteries. Also, precautions required in handling, storing and disposing of these batteries are must to know.

The main source of power is usually the AC Mains. The Mains Supply is used to charge a battery through the charger circuit. The battery provides the power backup when the mains supply is cut off. A battery stores electrical energy in the form of DC current.  The power backup is provided by connecting the load circuit to the inverter. The inverter draws the power from the charged battery on power failure, converts back the DC power to AC power and provides power backup to the load. This is how any basic UPS works.

In the previous tutorial, Online UPS was assembled from its basic building blocks like Lead Acid battery Charger, Square Wave Inverter and Modified Sine Wave Inverter. Now in this tutorial, offline UPS will be designed. The Offline UPS is one of the topologies of UPS (Uninterruptible Power Supply). In UPS system, the term topology refers to the switching mechanism of the UPS system.  Contrary to online UPS, in offline UPS, the load circuit is initially directly powered by the AC mains. On the failure of power supply, the power failure is detected by a switching circuit and the power is provided to the load through the battery and inverter after the power failure has already occurred. So, in the offline UPS, the load experiences the power cutoff once before it receives the power backup from the UPS.

In this era of battery-operated devices, a DC-DC converter is needed to meet the divergent power requirements of the electronic circuitry. A battery is a type of DC Supply whose output voltage varies with its use. This means it cannot maintain a constant voltage at the output due to its discharging characteristics. For this reason,…

In many applications, there’s a need for a constant voltage source. However, there are more constant current source applications than constant voltage sources. Most power supplies are voltage sources, including batteries and bench power.  A constant current source can be used anywhere a fixed current is required. A resistor can also be used, but the…

Everyone must be familiar with the term – Switched Mode Power Supply or SMPS. Yes, they are used in every personal computer. In fact, the Switched Mode Power Supply is widely used with many other devices. Once it is understood that what SMPS actually is, its countless applications can be easily imagined.  

In the previous tutorial, square wave inverter was designed. Square wave inverter was simple to design but had certain drawbacks. The AC appliances are actually designed to operate on sine wave and square wave though being AC signal does not match to an ideal sine wave.Due to this, when an appliance is powered by a square wave inverter, it may have noise or humming sound during its operation. So, designing of a modified sine wave inverter will be discussed in this tutorial.

In the previous tutorial, basic operation of a modified sine wave inverter was discussed. It was mentioned in the previous tutorial that the H-bridge MOSFET circuit of the quasi sine wave inverter cannot be directly interfaced with the microcontroller circuit. There is a need of a Gate driver circuit as an intermediate circuit between the microcontroller and the H-bridge MOSFET circuit. The H-bridge MOSFET circuit generates a modified sine wave by switching the MOSFETs in a sequential manner with predetermined delay. This sequential switching of the MOSFETs in the previous tutorial was explained with the help of a truth table and circuit diagrams.

In the previous tutorial, a half wave bridge circuit with IR-2110 gate driver circuit was designed. The working principle of a modified sine wave inverter has been already discussed. Now it’s time to complete the circuit of Modified Sine Wave Inverter. The complete sine wave inverter can be designed using full bridge circuit and a step up transformer.The aim of this project is design an inverter which can output a quasi sine waveform having a frequency of 50 Hz and 220 V peak voltage. So all the building blocks will be combined in this tutorial to make the final circuit of the sine wave inverter. 

In the previous tutorial, a square wave generator was designed having a symmetric output waveform having 50 Hz frequency and 12 V peak to peak voltage. The square wave generator designed using 555 timer IC was meant to provide input square wave in the inverter circuit.  Now, it is time to complete the square wave inverter circuit by adding a switching mechanism and step up transformer in the previous designed circuitry. The square wave generated from the 555 IC based circuit has peak to peak voltage of 12 V. This voltage needs to be stepped up using a step up transformer. So a step up transformer of 12V-0-12V rating is used for this purpose. But not only the voltage need to be simply stepped up, there is also a need for switching mechanism which allows drawing power from the inverter on power failure.

Microchip Technology announces a new family of Radiation-Tolerant (RT) LE50-28 isolated DC-DC 50W power converters available in nine variants with single- and triple-outputs ranging from 3.3V to 28V.   The off-the-shelf LE50-28 family of power converters is designed to meet MIL-STD-461. The power converters have a companion EMI filter and offer customers ease of design to scale and…

In the previous tutorial, it was discussed that for driving a MOSFET as high side switch, a gate driver circuit needs to be used. The IR2110 IC is one of the high speed and high voltage gate driver ICs for IGBT and power MOSFET. The IC is having independent low and high side output channel.  By using a single IC, a half bridge circuit can be operated in which one MOSFET is in high side configuration and another one is in the low side configuration. For driving the high side MOSFET, this IC uses a bootstrap circuit which otherwise could have to be designed externally. Before using this IC for driving the half or full bridge circuit, it is necessary to test the faultiness of the IC. A faulty IC can give unstable output and may blow up the MOSFET or other components in the circuit. In this tutorial, the method to test the IR2110 IC is discussed.

The Uninterruptible Power Supply (UPS) is an electronics device which supplies power to a load when main supplies or input power source fails. It not only acts as an emergency power source for the appliances, it serves to resolve common power problems too. Any UPS has a power storage element which stores energy in the form of chemical energy like the energy is stored in batteries.It is like energy is stored in the form of motion in a flywheel. That is why these devices are also called battery backup or flywheel backup. The UPS not only provides emergency power, they also help to sort out common power related issues like providing protection from input power interruptions, protection from overvoltage, output voltage regulation and stabilization.

In this tutorial, a constant voltage charger for the 12V lead acid battery will be designed. The lead-acid batteries can be charged in different ways or modes. In this tutorial, a constant voltage charger will be designed for charging the lead-acid battery. The battery is required to be supplied limited current which saturates once the peak terminal voltage is achieved in the charging process. Depending on the per cell voltage of the 12V battery, the maximum rated voltage of the battery varies from 13.5 V to 14.6 V. In this tutorial, the charger circuit is designed for charging a lead acid battery having peak terminal voltage of 14.4 V.

In the previous tutorial, the basics of Lithium ion batteries were discussed. Also, it was discussed how it is important to handle these batteries with care. as mentioned in the previous tutorial, that Lithium ion batteries need to be charged using CC-CV method, in this tutorial, a Li-ion battery charger for a single-cell Li-ion battery of nominal voltage 3.7 V will be designed.  There are charger modules available in the market which can be used to charge the Li-ion batteries. In this tutorial, a charger built using the basic electronic components including Linear Regulator will be designed from scratch. The charger circuit will be customized as per the battery specifications and the charging requirements.

In the previous tutorial, the Constant Current (CC) Source of 60 mA and Constant Voltage (CV) Source of 4.2 V were designed using LM317 voltage regulator IC. The constant current source is to be used for constant current mode of the battery charging while the constant voltage source is to be used for constant voltage mode of the battery charging. During the designing of constant current source and the constant voltage source, testing a Li-ion battery before charging it was also discussed. Check out the previous tutorial “Basics of Li-ion battery charging” for learning about the basics of Lithium ion batteries, their charging methods and topologies.

The square wave inverter is easy to design and suitable for less sensitive electronic devices. For more sensitive electronics, the supply from square wave inverter can result into noise. In this tutorial, a square wave inverter is designed which will input power from a battery and output a square AC waveform. An Inverter should generate an AC signal at the output but that signal is not necessarily an exact sine wave. A square wave can also be considered as an AC signal which can be used to drive less sensitive AC devices.

TDK Corporation announces the addition of higher power, three-phase AC input models to the TDK-Lambda DRB series of DIN rail mount power supplies. With 24V, 48V, and 72V outputs, the products are rated for continuous operation at 480W or 960W and can deliver a boost of 720W and 1440W respectively for up to seven seconds.…

TDK Corporation announces the introduction of the ZWS-C series of 10, 15, 30, and 50W-rated industrial AC-DC power supplies. The products meet EN55011/EN55032-B conducted and radiated EMI in either a Class I or Class II (double insulated) construction, without the need for external filtering or shielding. With electrolytic capacitor lifetimes of up to 15 years,…