Voltage regulators

All electronic devices are designated to run at predetermined power ratings, i.e. voltage and current. While current consumption is dynamic and depends on the device load, the voltage supply is fixed and ideally constant for the proper functioning of the device. A voltage regulator is responsible to maintain this ideal voltage needed for the device. Your laptop, wall charger, and coffee maker all have voltage regulators. A voltage regulator is a circuit that creates and maintains a fixed output voltage, irrespective of changes to the input voltage or load conditions. It may use a simple feed-forward design or may include negative feedback. Their primary purpose is to stabilize the voltage within a specified range to ensure the proper functioning of electronic systems. Voltage regulators are employed in a wide range of applications, from small electronic devices to large power systems. Voltage regulators (VRs) keep the voltages from a power supply within a range that is compatible with the other electrical components. While voltage regulators are most commonly used for DC/DC power conversion, some can perform AC/AC or AC/DC power conversion as well.

1. Purpose:

   • Voltage regulators are used to ensure a stable and reliable power supply for electronic devices and systems. They prevent voltage fluctuations, which can be detrimental to the performance and lifespan of electronic components.

2. Types of Voltage Regulators:

   • Linear Voltage Regulators: These regulators operate by dissipating excess energy as heat to maintain a constant output voltage. They are simple and provide low-noise output but may not be as efficient as other types.
   • Switching Voltage Regulators (Switching Regulators): These regulators use switching components (transistors, inductors, and capacitors) to control the output voltage. They are more energy-efficient but may introduce more noise.

3. Linear Voltage Regulators:

   • Linear voltage regulators are commonly used for applications where low noise and simplicity are essential. They consist of a series pass transistor, a reference voltage source, and feedback control. A linear voltage regulator utilizes an active pass device (such as a BJT or MOSFET), which is controlled by a high-gain operational amplifier. To maintain a constant output voltage, the linear regulator adjusts the pass device resistance by comparing the internal voltage reference to the sampled output voltage, and then driving the error to zero. Common linear regulator ICs include the 78xx series (positive voltage regulators) and the 79xx series (negative voltage regulators).

4. Switching Voltage Regulators:

   • Switching regulators are more complex but offer higher efficiency by varying the duty cycle of a switching transistor. A switching regulator circuit is generally more complicated to design than a linear regulator, and requires selecting external component values, tuning control loops for stability, and careful layout design. They include buck regulators (step-down), boost regulators (step-up), and buck-boost regulators (step-up and step-down).

5. Integrated Circuits (ICs):

   • Voltage regulators are often available in the form of integrated circuits (ICs) that include all the necessary components for regulation. These ICs simplify the design process and are widely used in various electronic applications.

6. Adjustable vs. Fixed Voltage Regulators:

   • Some voltage regulators have a fixed output voltage, while others are adjustable. Adjustable regulators allow users to set the output voltage to a specific value within a predefined range.

7. Voltage Regulator Modules:

   • Voltage regulators are often available as modules or components that can be easily integrated into electronic circuits. These modules may include additional features such as overvoltage protection, overcurrent protection, and thermal shutdown.

8. Three-Terminal and Two-Terminal Regulators:

   • Linear voltage regulators are commonly available as three-terminal devices, where the input, ground, and output terminals are defined. Two-terminal voltage regulators, such as Zener diodes, are also used for simple voltage regulation.

9. Voltage Regulator Stability:

   • The stability of a voltage regulator refers to its ability to maintain a constant output voltage despite variations in input voltage and load conditions. Stability is a critical factor in ensuring the reliable operation of electronic systems.

Applications of voltage regulators

• Voltage regulators are used in numerous applications, including power supplies for electronic devices, embedded systems, communication equipment, automotive systems, and industrial automation. They play a crucial role in maintaining the integrity of electronic circuits.
• Positive and negative voltage regulators can be used together to power sensors, op-amps, and other electronic modules that need both voltages.
• Voltage regulators perform the same function in large-scale power-distribution systems as they do in motor vehicles and other machines; they minimize variations in voltage in order to protect the equipment using the electricity. In power-distribution systems the regulators are either in the substations or on the feeder lines themselves. Two types of regulators are used: step regulators, in which switches regulate the current supply, and induction regulators, in which an induction motor supplies a secondary, continually adjusted voltage to even out current variations in the feeder line.
• All common microcontroller development boards, like those from Arduino and Raspberry Pi, can be powered using the LM7805 output to the 5 V p in. Arduino boards also have an onboard low-dropout voltage regulator like On Semiconductor’s NCP1117S to regulate power input coming from the barrel jack or Vin.

Voltage regulators are one of the most important components of an electronic circuit. They are responsible for its safe and consistent functioning. Extremely high voltage regulators use power electronics circuits with high power ratings in industrial settings on heavy machinery. One of the main disadvantages for linear regulators is that they can be inefficient, as they dissipate large amounts of power in certain use cases. The voltage drop of a linear regulator is comparable to a voltage drop across a resistor. Voltage regulators are essential components in electronic design, providing a stable and regulated power supply for various applications. To select the proper voltage regulator, the designer must first understand their key parameters such as VIN, VOUT, IOUT, system priorities (e.g. efficiency, performance, cost), and any additional key features, such as power good (PG) indication or enable control. Once the designer has defined these requirements, use a parametric search table to find the best device to meet the desired requirements. The parametric search table is a valuable tool for designers, as it offers different features and packages available to meet the required parameters for your application.

Manufacturers

1. Texas Instruments (TI):

   • TI is a prominent semiconductor company known for a wide range of products, including voltage regulators. They offer linear regulators, switching regulators, and integrated modules.

2. Analog Devices (ADI):

   • Analog Devices is another major player in the semiconductor industry, providing various voltage regulators, including linear regulators and switching regulators. Their products are used in a wide range of applications.

3. STMicroelectronics:

   • STMicroelectronics is a leading semiconductor manufacturer that offers a comprehensive portfolio of voltage regulators. Their products include linear regulators, switching regulators, and voltage references.

4. ON Semiconductor:

   • ON Semiconductor provides a variety of voltage regulators suitable for different applications. Their portfolio includes linear regulators, switching regulators, and voltage references.

5. Maxim Integrated:

   • Maxim Integrated is known for its high-performance analog and mixed-signal ICs, including voltage regulators. They offer linear regulators, switching regulators, and integrated power management solutions.

6. Infineon Technologies:

   • Infineon is a global semiconductor company that produces a range of voltage regulators for automotive, industrial, and consumer applications. They offer both linear and switching regulators.

7. Microchip Technology:

   • Microchip is a well-known provider of microcontroller and analog IC solutions. They offer a variety of voltage regulators, including linear regulators, switching regulators, and voltage references.

8. Diodes Incorporated:

   • Diodes Incorporated manufactures a wide range of voltage regulators, including linear regulators, switching regulators, and LED drivers. Their products are used in consumer electronics, automotive, and industrial applications.

9. NXP Semiconductors:

   • NXP provides a range of voltage regulator ICs for automotive, industrial, and consumer applications. Their portfolio includes linear regulators, switching regulators, and power management solutions.

10. Renesas Electronics:

    • Renesas offers a variety of voltage regulators, including linear regulators, switching regulators, and integrated power management ICs. Their products cater to automotive, industrial, and consumer electronics markets.

11. Fairchild Semiconductor (now part of ON Semiconductor):

    • Fairchild Semiconductor, now part of ON Semiconductor, was known for its voltage regulator ICs before the acquisition. Their products include linear regulators, switching regulators, and voltage references.

12. Rohm Semiconductor:

    • Rohm Semiconductor produces a range of voltage regulators, including linear regulators, switching regulators, and voltage references. They are used in various applications such as automotive, industrial, and consumer electronics.

13. UTC:

    • UTC (Unisonic Technologies Co.) was established in 1990, and it is the manufacturing supplier for high-tech semiconductor devices and IC design, and its products are mainly of Power Management, and Audio Power Amplifier IC, supplemented with Motor Controller, OP, and TR.