I would like to ask about the AMS1117 and LM2596S chips

ILAI

I would like to ask about the AMS1117 and LM2596S chips [Copy link]

I have to work on a logistics robot topic for a work training competition recently, so I am learning how to draw integrated circuit boards. The chip I use is STM32F407VET6.

Now I am very confused about the power supply. One solution is to use two AMS1117 chips, 12V input, to reduce to 5V and 3.3V. Another solution is to use LM2596 chip plus peripheral components to form a DCDC buck to get 5V and 3.3V. Of the two solutions, AMS1117 is definitely simpler, but I am not sure if it will have an impact on motors less than 10W and various small modules. Will LM2596 be better?

Please help me, thank you!

chunyang

The power conversion scheme is not just about the right voltage. Other factors such as current, power dissipation, ripple parameters, efficiency, etc. must also be considered. 1117 is a linear regulator with a variety of specifications. The maximum current of the common SOT223 package is 800mA-1A, and the maximum output power is 5W for a 5V output. If the motor is 5V 10W, it is obviously impossible to drive it. Then consider the power dissipation caused by the input and output voltage drop and the resulting heating and heat dissipation problems. 2596 is a switching power supply chip, which is of course more efficient. As for whether it is "better", it depends on other requirements.

maychang

AMS1117 is a linear voltage regulator chip, which has no peripheral components and is easy to use. However, because it is a linear voltage regulator chip, its efficiency is low (especially when the input voltage is high and the output voltage is low, such as 12V input and 3.3V output as mentioned by the original poster). LM2576 is a switching voltage regulator chip, which has many peripheral components and is more complicated to use, but it is more efficient.

maychang

maychang published on 2019-11-19 19:12 AMS1117 is a linear voltage regulator chip. It does not have any peripheral components and is easy to use. However, because it is a linear voltage regulator chip, its efficiency is relatively low (especially the input...

As for the original poster's suggestion of using AMS1117 to drive a 10W motor, that's impossible because the power loss is too great.

wudayongnb

First, we should evaluate the power consumption of the whole system. How many volts are the motor powered by? If it is powered by 5V, it is estimated that 2596 will not work. If the cost and PCB area are not strict, it is recommended to use 2596 and 1117 together, 2596 is used to convert 12V to 5V, and 1117 is used to convert 5V to 3.3V. If the power consumption of the whole system is not large, you can also use only 1117 to convert 12 to 5, and then to 3.3. If there is an AD acquisition function in the system, it is best to use a linear power supply to power the AD part.

qwqwqw2088

These two chips are commonly used, with large quantities and low cost. They are used to power the stm32 system. 2596 reduces 12V to 5V, and then uses 1117 to reduce it to 3.3V. There is no special requirement for the power supply. It is completely OK. We often do this here.

philips_lu

12V to get 5V and 3.3V, you can get 5V first and then get 3.3 or get 5V and 3.3V simultaneously. I personally recommend getting 5V first and then 3.3V through 5V. As for what chip to use, whether to use linear or switching power supply, the main considerations are cost and efficiency (mainly heat issues). Of course, there is some ambiguity in the 10W motor you mentioned. Is your motor 12V, 5V or 3.3V? Generally speaking, 1117 is enough for MCU and peripheral power supply. In most cases, 10W motors are powered by 12V. Various small modules also have power supply selection issues.