"One week's solution to analog electricity" - power circuit

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One 、 Power circuit

The following figure is the simulation diagram of the power circuit ：

The alternating current passes through a transformer 、 Rectifier diode and step-down chip can get the required DC signal .
Device selection ：
1、 The reverse voltage that the rectifier diode can withstand Be greater than Peak value of input voltage ;

2、 The voltage withstand value of the capacitor It should be greater than the loading voltage at both ends of the capacitor

3、 Transformer voltage It shall be greater than the input voltage required by the voltage stabilizing module , electric current The output current required is greater than that required .

4、C1 As bypass capacitor , Filter the input interference signal to prevent self excitation ;C3 and C4 As coupling capacitance , Filter out signal interference and self excitation at the output end , Energy storage function .

Two 、 Adjustable power supply design

use LM317 and LM337 Two types of linear voltage stabilized source for circuit design , The following figure shows the contents of the linear stabilized voltage source data manual .

LM337 Pin 2 and 3 There is a minimum limit on the current between , As shown in the figure below

We assume that the pins 2 and 3 Current between 6mA, The available resistance is set to 200R, Change the resistance R2 The output voltage of the linear regulator can be adjusted by the size of .
LM317 The adjustment mode of is the same as that of LM337, The circuit design is as follows ：

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Two 、 Diffusers and diffusers

The principle diagram of the companding circuit is as follows ：

The simulation diagram of the companding circuit is ： Join in 3V Zener diode , The output voltage becomes 8V.

The principle of the current expansion circuit is as follows ：

Iom It is the output current of the voltage stabilizing chip when the triode is turned on , The simulation diagram is as follows

3、 ... and 、 Switching Mode Power Supply

The tube consumption of linear regulator is very large , The power efficiency is the original （40%-60%）, The switching power supply is more efficient .
I wrote a blog to introduce the basic principle and topology of switching power supply , here Do not go into .