What is a good way to prevent DCDC power supply output backflow?

kal9623287

What is a good way to prevent DCDC power supply output backflow? [Copy link]

 

The problem I saw elsewhere is that the DCDC module output itself does not have the second tube behind it, because this power module needs to power the device, and the device also has other power supply voltages, and there is a concern that it will be backflowed, so this diode is added

Is it necessary to add this diode?

What is a good way to prevent backflow of DCDC power supply output? Are there other methods? Teachers in the forum, please give me some advice.

maychang

[Is it necessary to add this diode?]

It depends on the specific situation. If the electrical equipment is powered by multiple power supplies, and there is a possibility of current backflow from this power supply, but this power supply does not allow current backflow, then this diode is necessary.

As for whether the MP2307 chip allows current backflow, it depends on its specific internal structure.

chunyang

"Other methods" besides diodes usually use MOS tubes for control.

秦天qintian0303

If you add a diode, there will be a voltage drop. How can the 3.3V of the next stage flow back? If you are still worried, you can use an ideal diode device.

秦天qintian0303

It seems similar to MX16171D. You can learn more about this device.

kal9623287

Qintianqintian0303 posted on 2023-5-4 14:59 It seems to be similar to MX16171D. You can learn more about this device

OK

秦天qintian0303

Published on May 12, 2023-5-12 14:44 May I ask, what kind of diode is the ideal diode device?

It is not a diode, but it performs the same function as a diode, but with almost no voltage drop.

lkh747566933

Since there is a risk of backflow, the feedback resistor should not be connected after the diode.

dyjccx

The oring circuit and the control circuit can be built by yourself using transistors, or you can use a dedicated oring chip.

https://www.doc88.com/p-6886672309990.html

kal9623287

dyjccx posted on 2023-10-10 22:35 oring circuit, the control circuit can be built by yourself with triodes, or you can use oring dedicated chips. https://www.doc88.com/p-68866723 ...

Excuse me, is this the circuit you are talking about?

Where can I find this special chip for ORing?

Recommend one, look at the information

dyjccx

kal9623287 posted on 2023-10-17 09:31 Excuse me, are you talking about this kind of circuit? Where can I find this kind of oring dedicated chip? Recommend one and take a look at the information

https://www.ti.com/power-management/power-switches/ideal-diodes-oring-controllers/products.html?keyMatch=ORING#3278=ORing%20controller&

kal9623287

dyjccx posted on 2023-10-19 21:15 https://www.ti.com/power-management/power-switches/ideal-diodes-oring-controllers/products.html?ke ...

Thanks

But I didn't see any information on this in the link you recommended.

Could you please take a screenshot?

dyjccx

Analyze the specific situation. The diode has a voltage drop loss. If you can accept the voltage and loss after the diode voltage drop, of course it is OK! For large currents, MOS is generally used if the output voltage accuracy is high, at least the loss is unacceptable.

xiaoxieer

Learn how to prevent backflow

liamin0424

Come in and study

redguo

It depends on the specific situation. If the electrical equipment is powered by multiple power supplies, and there is a possibility of current backflow from this power supply, but this power supply does not allow current backflow, then this diode is necessary.

MJMXW

kal9623287 posted on 2023-10-25 10:05 Thank you, but I didn’t see any information on this in the link you recommended. Could you please take a screenshot and tell me about it?

You can use Wuxi Mingxinwei's ideal diodes, MX5050T, MX5052S, MX16171, MX74610. You can check their website for a complete range of models. There is always one that suits you.