Where are charge pumps generally used?

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Where are charge pumps generally used? [Copy link]

 

 

My questions:

1. Where are charge pumps generally used?

2. What are the advantages, disadvantages and precautions of using a charge pump?

For example, from the perspectives of cost, EMI, PCB, ripple, X efficiency, and load capacity

How does it compare to LDO and switching power supplies?

3. Can a charge pump be used to supply negative voltage to the op amp?

bigbat

Charge pumps are widely used, mainly for the generation of positive and negative sources, high voltage signals, etc. The power supply of charge pumps is characterized by small ripple, and is often used in measurement and standard signal source circuits. The disadvantage of charge pumps is that the current is small.

maychang

[Can a charge pump be used to supply negative voltage to an op amp? ]

If a low-power op amp needs a negative power supply, it can be powered by a charge pump chip, but this is limited to situations where the maximum output current is a few mA.

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bigbat published on 2022-11-15 13:31 Charge pumps are widely used, mainly for the generation of positive and negative sources, the generation of high-voltage signals, etc. The power supply of charge pumps is characterized by small ripple, and is often used in measurement and standard signal...

This is very similar to LDO.

LDO also has low current and small ripple.

Is there any difference between charge pump and LDO in application?

bigbat

The current of the charge pump is smaller than that of the LDO, and the charge pump usually cannot be used to power common circuits such as MCU.

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bigbat posted on 2022-11-15 13:41 The charge pump has a smaller current than the LDO, and the charge pump is usually not used to power common MCU circuits.

So the application of charge pump is very narrow, right? It seems that the most common application of charge pump is level conversion chip such as max3232, and other application scenarios are not clear. From the video, it seems that the current of charge pump is generally tens of mA.

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I just checked on LiteOn, and the price of charge pumps doesn't seem to have any advantage over LDOs.

bigbat

Placatu posted on 2022-11-15 13:51 I just checked on LiChuang, and the price of charge pumps doesn’t seem to have any advantage over LDOs.

There are many op amp power supplies in the measurement circuit

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bigbat posted on 2022-11-15 14:44 There are many op amp power supplies in the measurement circuit

OK, thanks.

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maychang published on 2022-11-15 13:34 [Can a charge pump be used for negative voltage power supply of an op amp? ] If a low-power op amp requires a negative power supply, a charge pump chip can be used for power supply. But it is limited to the maximum output...

I feel that the charge pump cannot carry a large load, so LDO is generally used more often.

maychang

Placardo posted on 2022-11-15 15:53 I feel that the charge pump cannot carry a large load, so LDO is generally used more often

The charge pump can't carry a large load, but the charge pump can obtain a negative voltage from a positive power supply, or boost the power supply, which are impossible for a linear regulator.

秦天qintian0303

What I actually use is a negative voltage generator, and its power supply capacity is similar to that of an ordinary LDO.