What is the difference between a linear regulated power supply and a switching power supply?
A linear regulated power supply changes and controls its output voltage and current by varying the degree of conduction of a transistor, which in a linear regulated power supply is equivalent to a variable resistor, connected in series in the supply circuit. Since the variable resistor flows the same current as the load, it consumes a lot of energy and leads to warming and low voltage conversion efficiency. Linear voltage regulator power supply has a common feature is that its power device regulator works in the linear region, relying on the voltage drop between the regulator pole to stabilise the output. Due to the large static loss of the adjustment tube, it is necessary to install a large heat sink to dissipate heat. Because the transformer of the linear power supply works on the industrial frequency (50Hz), so the mass is larger.
Linear regulated power supplies are commonly used in low voltage applications, like LDOs need to meet a certain voltage difference. The output voltage adjustment rate and ripple are better, the efficiency is lower, and fewer peripheral components are required, which is low cost. The circuit is relatively simple.
Linear regulated power supply has the advantage of high stability, small ripple, high reliability, easy to make multi-output continuously adjustable power supply. The disadvantage is that the volume is large, bulky, relatively low efficiency. This type of regulated power supply and there are many kinds of output from the nature of the regulated power supply can be divided into regulated power supply, regulated current power supply and set of regulated voltage, regulated current in a regulated voltage regulated current (dual regulated) power supply. From the output value can be divided into fixed output power supply, band switch adjustable and potentiometer continuously adjustable type. From the output indication, it can be divided into pointer indication type and digital display type.
Switching power supply is applicable to the full voltage range, does not require differential voltage, can use different circuit topology to achieve different output requirements. The adjustment rate and output ripple are not as good as linear power supply, and the efficiency is high. It requires many peripheral components and has high cost. The circuit is relatively complex. Switching DC regulated power supply its circuit type mainly has single-ended flyback, single-ended forward, half-bridge, push-pull and full-bridge. It and the fundamental difference between linear regulated power supply is the circuit of the transformer does not work at the frequency but work in tens of kilohertz to several megahertz. Power tube is not working in the linear region, but saturation and cut-off region, that is, working in the switching state; switching DC regulated power supply is also named.
The biggest difference between linear regulated power supply and switching power supply is that the tubes (either bipolar or MOSFET) in linear regulated power supply work in linear state, while the tubes in switching power supply work in switching state. Linear regulated power supplies and switching power supplies are named accordingly.
