What is a linear regulated power supply
Here the linear regulator power supply, refers to the adjustment tube work in a linear state of the DC power supply. Adjust the tube to work in a linear state, so to understand: RW (see the following analysis) is continuously variable, that is linear. And in the switching power supply is not the same, switch (in the switching power supply, we generally call the tube called switch) is working in the open and close the two states: open - resistance is very small; off - resistance is Big. The pipe in the switch state is clearly not a linear state.
Linear regulated power supply is a relatively early class of DC regulated power supplies. Linearly regulated DC power supply is characterized by: the output voltage is lower than the input voltage; fast response speed, low output ripple; low noise generated by the operation; low efficiency (now often see the LDO is to solve the problem of efficiency problems) ; Large heat (especially high-power power), indirectly to the system to increase thermal noise
According to the adjustment of the working state of the tube, we often put the power supply is divided into two categories: linear power supply and switching power supply. In addition, there is a small power supply using a regulator.
Linear power supply adjustment tube work in the amplification state, and thus a large amount of heat, low efficiency (35%), need to add a large volume of heat sink, but also need to also large volume of power transformer, when the production of multiple sets of voltage output When the transformer will be more large. Switching power supply regulator tube in the saturation and cut-off state, and thus heat a small, high efficiency (75%) and save a large volume of the transformer. But the switching power supply output of the DC above will be superimposed on the larger ripple (50mV at 5V output typical), in the output and then connected to the Zener diode can be improved, and the other because the switch is to produce a large spike interference, but also need In the circuit, the magnetic beads are improved. Relatively speaking, the linear power supply is not the above defects, its ripple can be done very small (5mV below). For the power efficiency and installation volume requirements of the place with switching power supply is better for electromagnetic interference and power purity requirements of the place (such as capacitance leakage detection) multi-use linear power supply. In addition, when the circuit needs to be isolated when most of the current DC-DC to do the isolation part of the power supply (DC-DC from its working principle is the switching power supply). Also, the switching power supply used in the high-frequency transformer may be more trouble around the system.
