Help post, please tell me how to convert 7.2V power supply to 5V or 3V low power chip

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Help post, please tell me how to convert 7.2V power supply to 5V or 3V low power chip [Copy link]

 

Please share the low-power chip or circuit construction of 7.2V power supply to 3V or 5V, thank you all

qwqwqw2088

Only consider low power consumption, not power size.

chunyang

The required current parameters must be given, and high conversion efficiency rather than low power consumption should be required here.

qwqwqw2088

You can consider TP2085. The commonly used output voltages are 3.3V, 4.4V and 5V. The input voltage can be as high as 18V. The static voltage is only 3uA. It is often used in RTC.

qwqwqw2088

There are many switching power supply chips.

You can go to the TI official website and enter the parameters to choose by yourself

qwqwqw2088

For example, TPS63900
can start at no load, and the efficiency can reach 90% at a current of more than 10uA.

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qwqwqw2088 Published on 2020-11-5 16:41 You can consider TP2085. The commonly used output voltages are 3.3V, 4.4V and 5V. The input voltage can be as high as 18V. The static voltage is only 3uA, which is often used in RTC.

Thanks for sharing

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chunyang posted on 2020-11-5 16:39 The required current parameters must be given. High conversion efficiency rather than low power consumption should be required here.

I'm a novice, I didn't explain it clearly.

chunyang

Meng Meng Meng Meng Zhe posted on 2020-11-5 16:52 I am a novice and did not express myself clearly

That doesn’t matter, you’ll understand once you learn it.

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chunyang posted on 2020-11-5 16:55 It doesn't matter, you will understand after learning.

Our product itself is powered by 3.6V, but now it needs to be changed to 7.2V. The product itself requires low power consumption, so we are currently selecting power supply chips.

chunyang

You must first figure out the current parameters you need, which determines the device selection. For example, if you need a current of 1mA or 100A, the difference is huge.

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chunyang posted on 2020-11-5 16:58 The OP must first figure out the required current parameters, which determines the device selection. For example, if you need a current of 1mA and a current of 100A, the difference is too huge...

The current of the current circuit is about 30mA. I have no experience in selecting power chips before, and I don't have any way to find out. Does anyone have any recommended chips?

chunyang

Meng Meng Meng Meng Zhe published on 2020-11-5 16:57 Our product itself uses 3.6V power supply, but now it needs to be changed to 7.2V power supply. The product itself requires low power consumption. We are currently selecting the power chip...

First, find out whether the product is powered directly by 3.6V or through a power converter. If it is the latter, then examine its input voltage range and conversion efficiency. For power-sensitive devices, power conversion should be done in one step as much as possible, while making an appropriate trade-off between pursuing the highest possible conversion efficiency and price.

chunyang

Meng Meng Meng Meng Zhe published on 2020-11-5 17:03 The current of the current circuit is about 30mA. I have no experience in selecting power chips before, and I don’t have any channels. Does the big brother have any recommended chips?

30mA current is not very small, so linear regulators can be excluded and only switching power supplies can be considered. Specifically, first examine the previous post, and then narrow the scope based on your other needs, such as whether soft switching is required, ripple parameters, etc. In particular, you need to determine the cost budget. Under the same current and input range, high-efficiency chips are usually more expensive.

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chunyang published on 2020-11-5 17:04 Then first figure out whether the product is powered directly by 3.6V or through a power converter. If it is the latter, it is necessary to examine its input voltage range and conversion efficiency...

I've learned a lesson. Thanks, sir.

明和研翔科技

Meng Meng Meng Meng Zhe published on 2020-11-5 16:57 Our product itself uses 3.6V power supply, but now it needs to be changed to 7.2V power supply. The product itself requires low power consumption. We are currently selecting the power chip...

It is originally powered by 3.6V, but now it needs to be changed to 7.2V as the product requires low power consumption.

Is your power supply battery-powered? Change from one battery to two in series, and require low static power consumption.

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Minghe Yanxiang Technology published on 2020-11-6 17:07 It is powered by 3.6V, but now it needs to be changed to 7.2V. The product requires low power consumption. Is your power supply battery powered? It is powered by a...

Yes

电源芯片韩生

I have it. Please add me on QQ: 3174515692 and I will send you the information.

明和研翔科技

chunyang posted on 2020-11-5 17:09 The current of 30mA is not very small, so the linear regulator can be excluded and only the switching power supply can be considered. First examine the previous post, and then according to your other...

I don't agree with your point of view. It depends on what the load is. Is there any requirement for ripple? If the load is just to power the MCU.

Linear regulators are sufficient. If you want to be safer, you can also use SOT89 packaging. Low power consumption and low cost. Only switching power supply IC can be used.

7.2V - 3V = 4.2V * 0.03A current = 0.126W heat dissipation power. (If the lithium battery is fully charged at 8.4V, 8.4V-3V = 5.4V*0.03A = 0.162W)

The SOT23 package is 0.2~0.25W. If it is greater than 0.126W or 0.162W, it can be used.

SOT89 package is 0.5W

chunyang

Minghe Yanxiang Technology published on 2021-5-5 16:09 I don't agree with your point of view. It depends on what the load is? Is there any requirement for ripple? If the load is just to power the MCU. The linear regulator is...

Don't forget that the original poster emphasized that low power consumption should be maintained after the 3.6V to 7.2V power supply is changed. This is not just about the power dissipation of the power conversion device. If a linear regulator is used, the battery life will be reduced. "Usable" and "best choice" are sometimes completely different things. What you said is only true when there is no power consumption requirement.