What are the advantages and disadvantages of common voltage regulators?
A voltage regulator is a device that stabilizes the output voltage. The voltage stabilizer is composed of a voltage regulating circuit, a control circuit, and a servo motor. When the input voltage or load changes, the control circuit samples, compares, and amplifies, and then drives the servo motor to rotate to change the position of the carbon brush of the voltage regulator. By automatically adjusting the coil turns ratio, the output voltage is kept stable. In this article, the editor will give an introduction to power regulators, switching regulators and linear regulators, hoping to be of great reference value to readers.
The power supply voltage stabilizer is a power supply circuit or power supply equipment that can automatically adjust the output voltage. Its function is to stabilize the power supply voltage that fluctuates greatly and does not meet the requirements of electrical equipment within its set value range to make each circuit or electrical equipment It can work normally under the rated working voltage. The voltage stabilizer can be widely used in: industrial and mining enterprises, oil fields, railways, construction sites, schools, hospitals, post and telecommunications, hotels, scientific research and other departments of electronic computers, precision machine tools, computer tomography (CT), precision instrument test equipment, elevators Lighting, imported equipment and production lines and other places that require a stable voltage of the power supply. It is also suitable for users at the end of the low-voltage distribution network where the power supply voltage is too low or too high, and the fluctuation range is large, and the electrical equipment with large load changes. It is especially suitable for all places that require high power grid waveforms. The high-power compensating power regulator can be connected to firepower, hydraulic power and small generators.
A switching regulator is a type of voltage regulator that uses an output stage, which repeatedly toggles the "on" and "off" states, together with energy storage elements (capacitors and inductors) to generate an output voltage. Its voltage regulation is to adjust the switching according to the feedback of the output voltage. In a fixed frequency regulator, by adjusting the pulse width of the switching voltage - this is called PWM control. In a controlled oscillator or pulse-mode regulator, the width and frequency of the switching pulses are kept constant, however, the "on" or "off" of the output switch is controlled by feedback.
Depending on the arrangement of the switches and energy storage components, the resulting output voltage can be greater or less than the input voltage, and multiple output voltages can be generated with a single regulator. In most cases, under the same input voltage and output voltage requirements, Buck switching regulators are more efficient than linear regulators in converting power.
Pros: High efficiency (less power required for heat dissipation) Ability to handle higher power density topologies, results can be used to deliver single or multiple output voltages, and can be greater or less than the input voltage.
Disadvantages: high output continuous wave voltage, electromagnetic interference (EMI), short transient recovery time.
A linear regulator uses a closed feedback loop to bias the pass element to maintain a constant voltage at its output terminals. The op-amp drives the base of Q1 to ensure that the voltage at its inverting input is equal to the reference voltage at its non-inverting input
The op amp in this circuit has a small load, base current and minimal capacitive load so it responds very quickly to load changes.
Linear regulators are usually highly integrated, including pass elements and feedback loops. Some linear regulators are adjustable when used with an external resistor divider. The important parameters related to the linear regulator mainly include 4, which are as follows
1. Maximum Input Voltage: This is the maximum voltage that can be applied across the input terminals without damaging or damaging the device.
2. Input voltage-output voltage difference: Some adjustable linear regulators have a maximum input-output voltage difference rating.
3. Rated current: the maximum current that the linear regulator can provide. It depends on other factors such as input-output voltage difference, ambient temperature and heat dissipation. The power rating of a package indicates how much power the package can dissipate, which may depend on thermal and layout requirements.
4. Voltage drop: This is the minimum input-output voltage difference that the device can accept and produce a stable voltage.