Voltage regulator

[2] A voltage regulator (VR) is an electric component regulating voltage that creates and maintains or convert to higher/lower a fixed output voltage for another circuit, irrespective of changes to Vin or load conditions. It can either increase or

regulate: to control/maintain speed of machine to work properly

VRs keep the voltages from a power supply a range compatible to other electric components. While VR are often for DC/DC power conversion, some can do AC/AC or AC/DC power conversion.

VRs use 3 pins, the input, ground, and output.

Operations

A VR's pin 1 is the input, pin 2 the ground, and pin 3 the output.

[2.1] This 7805 VR chip outputs the 6-35 V input as a 5 V constant from Vin.

We can use a capacitor to the output to make the output voltage smoother.

Types

[2.2] Basic regulators like the linear IC types drop down inputs to a desired level and shed the rest as heat.

Some like the switching type are more efficient. Fast-swtching Vin on and off results in an average voltage output

[2.2] A linear regulator (linear VR) uses a transistor controlled by feedback from a differential amplifier and reference voltage to control output voltage. They may feature fixed or variable output. Output curent is determined by the Iin minus operation losses.

Linear VRs have a fast response time but aren't every efficient.

A linear VR's Vout is always below its Vin: Vin > Vout and drops out if Vin is too low: Vin > Vout + Vdropout

[2.2] A switching regulator (switching VR) can be very efficient but hard to design unlike linear VRs. They use switching controllers to swiftly connect and disconnect either the positive or negative component of the source voltage from the rest of the converter circuit to create desired voltage and current changes.

[2.2] A feedback loop (in red in the right schematic) form the output to the controller helps to determine the switching rate. Inductors' arrangements, capacitors, and diodes in basic switching converters determines if Vout increases/decreases.

[2.2]

Voltage regulator

Operations

Types

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