Switching regulators require a means to vary their output voltage in response to input and output voltage changes. How does a switching regulator control its output? Typically, the switching regulator can drive higher current loads than a linear regulator. However, the noise output from a linear regulator is much lower than a switching regulator with the same output voltage and current requirements. Using the optimum components, a switching regulator can achieve efficiencies in the 90% range. The linear regulator’s power dissipation is directly proportional to its output current for a given input and output voltage, so typical efficiencies can be 50% or even lower. What are the usual applications for linear and switching regulators? Losses are also due to the energy needed to charge and discharge the capacitance of the MOSFET gate between the threshold voltage and gate voltage. Also, MOSFET power losses occur because it takes a finite time to switch to/from the conduction to nonconduction states. Losses occur as a result of the power needed to turn the MOSFET on and off, which are associated with the MOSFET’s gate driver. What losses occur with the switching regulator? It also means higher switching losses and greater noise in the circuit. Higher switching frequencies mean the voltage regulator can use smaller inductors and capacitors. How does switching frequency impact regulator designs? Other topologies include the flyback, SEPIC, Cuk, push-pull, forward, full-bridge, and half-bridge topologies. There are three common topologies: buck (step-down), boost (step-up) and buck-boost(step-up/stepdown). What are some of the switching regulator topologies? The filtered power switch output voltage is fed back to a circuit that controls the power switch on and off times so that the output voltage remains constant regardless of input voltage or load current changes. It compares the output voltage with a precise reference voltage and adjusts the pass device to maintain a constant output voltage.Ī switching regulator converts the dc input voltage to a switched voltage applied to a power MOSFET or BJT switch. There are two types of voltage regulators: linear and switching.Ī linear regulator employs an active (BJT or MOSFET) pass device (series or shunt) controlled by a high gain differential amplifier. Understanding How a Voltage Regulator WorksĪ voltage regulator generates a fixed output voltage of a preset magnitude that remains constant regardless of changes to its input voltage or load conditions.
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