Skip to main content

What is a Low-dropout Voltage Regulator?


A low-dropout voltage regulator is such a regulator that can work at a very small input-output differential voltage, that means this voltage regulators can regulate the output voltage even when the output voltage is extremely getting ready to the input voltage. If you use a standard linear regulator(for example a 78XX), you need a minimum difference between input and output voltage of about 2V, so if you want 5V, you have to provide minimum 7V as its input. If input goes below that voltage the regulation can not work. This 2V margin is named dropout voltage, you'll realize it within the datasheet of several part. Low-dropout voltage regulators have much lower dropout voltage about 0.5V-1.5V.

So why do we need this?

As for the linear voltage regulators, the lower the difference between input and output the higher the efficiency it will have because the power dissipation of the device is usually the difference between input and output voltage increased by the current its supply, thus low-dropout regulators permits you to input a way lower voltage than that of a traditional regulator allowing a lot of higher potency, lower heat generation and of-course lower minimum in operation voltage.

What do we need?
LDOs comprise three basic functional elements – a pass element, a reference voltage, and an error amplifier. Under normal operation, the pass element behaves as a voltage controlled current source. A compensated control signal from the error amplifier drives the pass element. The error amplifier senses the output voltage and compares it with the reference voltage. LDO regulator designs use four different kinds of pass elements – PNP transistor based regulators, NPN transistor based regulators, P-channel MOSFET-based regulators and N-channel MOSFET-based regulators.
While using a specific LDO in their circuits, designers need to consider the performance of the LDO with respect to its dropout voltage, load regulation, line regulation, and the power supply rejection ratio or PSRR.
In this post i'll be writing regarding 3 completely different low-dropout voltage regulators. First one is a fixed 5V output regulator which has a 0.5V dropout and can provide 1A of current. This is ideal for many small projects that does not require much current. This integrated circuit can provide other voltage levels too but I will write about the 5V one right now.
Components needed for this:
1. Integrated Circuit : LM2940
2. Capacitor : 0.47uF at the input to suppress noise, 100uF electrolytic at the output to maintain stability, low ESR(Equivalent Series Resistance) capacitor preferred, 0.1ohm-1ohm capacitors.
3, sink and thermal interface material for LM2940 if necessary.

Labels:

Comments

Post a Comment

Popular posts from this blog

What is Solar Panels? How Does a Solar Panel Work?

Solar Panels Photovoltaic (PV) is the term identified with the change of light into power utilizing semiconducting materials that display the photovoltaic impact. A typical use of this technology is solar panels which comprise of solar cells that generate solar power. They can be installed on south-facing roofs, walls or on the ground, and can be fixed or have a solar tracker that follows the sun across the sky. The installation of solar panels is very beneficial for both private and commercial users because the solar power became electricity will be sold to the energy supplier. The feed-in tariff can reduce energy bills and price of solar panel installation. The advantage of this type of energy source is that it is clean energy, so generates no pollution and no greenhouse gas emissions. It is however dependent on direct sunlight so around 10% to 25% is lost when a tracking system is not used. How Does a Solar Panel Work? The solar cells within a solar array produce DC elect...
Post a Comment
Read more

Different types of Limit Switches

Rotary Geared Limit Switches The operating of the Limit Switch is to prevent the mechanism or drive at the intense forward/reverse positions. The Limit Switches are significantly suited to use on reversing drives like a hoist, winches, rolling mills and various other mechanisms used in steel plants such as coke ovens, feeding machinery, valve drives etc. The contacts of Limit Switches are forty amps rated ceaselessly at 500 Volts A. C. The Limit switch is often supplied with two NC contacts or four NC contacts or (2 NO + two NC) contacts as per the need. For Series Limit Switches are shields are provided. The frequency of switching of each contact is suitable for a maximum of 720 operations per hour. The speed of the driving shaft rotation shouldn't be over 60 rpm. Features:- High durable standards Optimum performance Easy to install Counter Weight Limit Switches A metal structure offers the required stability to Counter Weight Limit Switches that job on heavy c...
Post a Comment
Read more

Categories of Limit Switches

A limit switch is an electro-mechanical device that have an actuator mechanically linked to a set of contacts. When any object comes into contact with the actuator then device operates the contacts to make or break an electrical connection. Limit switches are used in a various kinds of applications and environments because of their ruggedness, simple visible operations, ease of installation and operational reliability. Limit switches are used in an assortment of applications and environments due to their ruggedness, reliability of operation and simplicity of installation. Limit switches are available in a variety of rotary arm styles, body, operation requirements, and environmental factors including moisture, contamination, temperature, shock and vibration. Other factors to consider when choosing a limit switch include operating force, reset force, over-travel, pre-travel, along with safety requirements. Limit switches are also available in four unique different categories: Glo...
Post a Comment
Read more