The voltage regulator is the main component for PCB board design to ensure stable and constant voltage for the circuit and the device’s proper operation. It is important for PCB designs since it helps to operate sensitive devices that need a certain voltage value and can affect voltage fluctuations in supply. This tutorial will cover the details of voltage regulators used for PCB designs.
What is a voltage regulator circuit?
Voltage regulators for PCB design maintain the output voltage at a constant value, irrespective of variation at the input. The main point of connection for the voltage regulator is close to the power supply, which has variable output.
The voltage value of the regulator defines which sensitive components, such as the controller and digital devices, are connected at the output. Voltage regulators are mostly used for DC-to-DC conversion or changing voltage levels according to requirements. Some types of regulators are used for AC-to-AC conversion and AC-to-DC conversion. The two most common types of voltage regulators are switching and linear voltage regulators.
Types of Voltage Regulators for PCB Design
Linear Regulators
The amplifier is made with an FET or BJT transistor used for regulating linear regulators. Transistors work by being controlled by an amplifier circuit that provides a constant output voltage. For this purpose, the output voltage of the regulator is compared to a reference voltage. The output voltage of linear regulators is reduced, and a low dropout voltage can define low dropout voltages.
The regulators work well and are part of a power-sensitive circuit since they do not have power losses and do not use any type of switching. However, some intrinsic noise is produced that is due to switching to maintaining the voltage level.
Linear regulators also work with relatively low quiescent currents with proper design configuration. While switching regulators’ feedback systems and using more quiescent power. These regulators have high efficiency—about 90 percent when working as LDOs. There is no need for any filters for linear regulators, so they can easily operate low-cost circuits. With a linear regulator, sometimes a capacitor is connected to regulate the output voltage.
Switching Regulators
The main work of switching regulators is to transform the DC voltage at the input into a stable DC output, and for this purpose, they use a BJT switch or sometimes a MOSFET switch. The output of the regulator has some ripples that filter out with the use of a filter circuit, and it also reduces switching noise on the output.
Switching regulators come in three subtypes, which are
- buck (step-down) reduce the voltage level from the input.
- boost (step-up),  It increases the voltage level as compared to the input level.
- buck-boost (step-up or step-down). It has both features for increasing and decreasing voltage levels.
Switching regulators benefits
- They are highly efficient due to their operation in two modes, either off or on. It also offers 90 percent higher efficiency than linear regulators.
- The linear regulator only steps down voltage, but the switching regulator also has features for step-up and step-down voltage. So it is used in backlights in cameras that need high voltage for a shorter duration than low voltage.
- Switching regulators do not dissipate high heat as compared to linear regulators that need heat sinks, and switching regulators do not need heat sinks.
Different Factors for Choosing Regulators
Output voltage
It is based on circuit requirements for circuits where step-down voltage is required, then boost switching regulators can be used. For different power supply sources, a single regulator can be used for each supply. Regulators deliver a fixed value of output voltage, and some adjustable regulators can also be used.
Efficiency and Noise
As the switching regulators are more efficient thatn linear regulators but they produce more noise. The noise also has a bad effect on the circuit’s working when the regulator output is high current. So for circuits here, noiseless operation is needed and sensitive devices are connected to linear regulators used.
The regulator that has high power losses is not efficient for PCB design. Linear regulators produce less noise but are not as effective as switching regulators, so most of the power is lost in the form of heat. For high-current circuits, use a heat sink for regulators. But if your project is a space constraint, then use a switching regulator.
Transient response
If a change in output current spike exists at output, then the regulator takes some time to work at the same voltage. It is called a transient response. The transient response is based on output capacitance and load current. The high-speed transient response makes sure the regulator provides the required power. Before using the regulator, you must check the datasheet and, according to the instructions, use a bypass capacitor with the output of the regulator.
Voltage Regulator Components:
The main components of the regulator are listed here.
Input Voltage:
- These voltages are provided by the main power supply of the PCB to the regulator.
Voltage Control:
- This part of the regulator helps to set the output voltage. These components are ICs, transistors, etc.
Reference Voltage:
- Some regulators work based on a reference voltage that is produced internally, compress the output voltage, and set the output voltage according to a reference value.
Feedback Circuit:
- The main purpose of the feedback circuit is to monitor and make a comparison of the output voltage with the reference voltage. It sends feedback to the voltage control component, and the required voltage level is set at the output.
Output Voltage:
- These voltages are obtained at the output terminals of the regulator and provided to the connected circuit.
 Voltage Regulators Disadvantages
- The main drawback of linear voltage regulators is their low efficiency due to high power losses.
- So the estimated power dissipation of a linear regulator before use as a larger input regulator causes high power dissipation and can damage the board and affect the working of connected components.
- The linear voltage regulator also only steps down the voltage, but the switching regulator has both step-up and step-down features.
- Either switching regulators are efficient but also have limitations in that they are more expensive than linear regulators and larger ones have complicated designs and produce more noise if external components are not connected accurately.
- Noise is the main factor in the operation of different circuits and also affects EMI performance. So we must consider the accurate features of the board before using a linear or switching regulator.
How do I choose a voltage regulator for a PCB?
- The main parameters that must be considered before using a voltage regulator for PCB design are input voltage, output voltage input current, efficiency, cost, and power good (PG) indication or enable control.
- After setting the required parameters for PCB design, use a parametric search tool to choose the required devices according to PCB assembly.
- This tool helps to get devices with different features and packages according to the required features.
- Datasheets of devices can be used to get more details about components and also to make effective and high-performance designs.
- The datasheet details the inductance, resistance, capacitance, and other technical features of the component.
Voltage Regulator Applications
- It is used in different types of consumer electronics, such as mobile phones, games, and computers.
- It is the main part of battery charges and AC-to-DC converter circuits. It also converts AC to DC on the PCB board for different components.
- It is used for regulating voltage for sensor controllers and other digital electronic devices.
- It is also used in the automobile industry.
Read also:
- What is Voltage Regulator, Types and Working
- Difference Between Shunt and Series Voltage Regulator
- Introduction to 7805 Voltage Regulator, Pinout, Working, Applications
- Introduction to Linear Series Regulators
- Introduction to Linear Shunt Regulators
Faqs
- The voltage regulator on the PCB is considered the main component that is used for voltage stability and component protection from getting damaged by overvoltage. It also ensures the accurate working of a circuit on the board.
Why you connect a voltage regulator on a circuit board?
On the PCB board, input voltage or load features vary, and a voltage regulator produces and maintains a constant output voltage.
- Make the connection of the opposite terminal of the multimeter with the output of the regulator and a negative pin
- the ground terminal. On the power supply and check output voltage, this value must be according to the rated voltage of the regulator, which can be 5 or 12 volts.
- The voltage regulator keeps the voltage of the power source within the required range that is supported by the circuit. Voltage regulators are commonly used for DC-to-DC conversion, and some are also used for AC-to-DC power conversion.
- AVR is an automatic voltage regulator used in generators for automatically regulating voltage, so it converts fluctuating voltage values to constant voltage levels.