Hello, everyone, if you use LDO to convert from 24V to 5V, the voltage drop of 19V will cause a lot of power consumption. (The issue of not recommending using LDO is not discussed here)
I have such an idea. I don't know whether this circuit is practical or not, and what are the disadvantages, I don't hesitate to enlighten me.
As shown in the figure, use a Zener diode to step down, down to 8V, and then input to the LDO input. The LDO outputs 5V, and the maximum load current is about 2A. Does such a large load current affect the Zener diode?
Fredrick postato su November 20, 2020
Since LZ has said that it is appropriate not to consider the LDO, then leave it alone,
2A current, have you considered the power consumption of resistors and Zener?
The voltage regulator tube is connected in parallel with the LDO. When the load at the output of the LDO is not so large, the voltage regulator tube with such a large current must be eaten up.
Linnea postato su November 20, 2020
Is the landlord sure that the regulator tube can be brought up?
Freyja postato su November 20, 2020
As the landlord said, it must be realized by LDO, then add a series of voltage regulator before LDO (regulator IC or discrete parts can be), output about 15V, and then give LDO as input. In this way, the reason The power borne by an LDO is transferred to the secondary level, but if the maximum current of the 5V load is 2A, the power borne by each level will reach: 2A*(24-5) V=38W, and the power drawn by each level is still 19W. This power is completely used for heating, how much heat sink is needed to achieve it?
