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[Boost Converter] How can i make a internal POWER MOSFET

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Y.C Park

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Hi expert!!!

I have a some questions.
Normal Boost converter chip has no VOUT Pin. (schottky type)
for example
INPUT 3.7V
OUTPUT 25V
Mosfet gate driving voltage 25V
How can i make a gate driver power supply?
Boost converter chip has no information about VOUT.
Is it possible HIGH Voltage MOSFET dirve low voltage?

I am very confusing.
Please Help me !!!
 

Hi,PARK
As I Know,There are many DC/DC IC's to Drive the MOSFET gate,such as Maxim,ST etc.
And I hope the attachment can help you a little.
 

Some foundry provide LV and HV devices in the same process. But driving capability of HV devices will be very low, because of
1) oxide is much thicker (up to 10 times then LV)
2) they will be driven by LV
You will get very large MOSFET layout area and as a result get high price of your IC.
To enhance efficiency modern power MOSFET are manufactured with specific process (double diffusion or trench vertical transistor) different from conventional logic process. Both of them use substrate as a drain of MOSFET and it makes them incompatible with any analog or logic process.
 

Most HV tolerant processes (even ones designed specifically for power) can only handle 5V on the gate (even though the drain can handle upwards of 70V). Therefore, it is easy to drive the power NMOS of a boost converter because you can drive it with the input voltage level (in your case 3.7V). You should check the process documentation from your fab to see what your devices are capable of.
 

There are some ways to improve device to HV,
also u can try to change the device structure to do it.
 

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