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I am designing an MPPT charge controller. I have chosen my MOSFETs to be both NMOS https://www.sparkfun.com/products/10213 (FQP30N06L) 60V, 30A. Since the gate voltage is 3 to 5V. I can drive the low side, however, how can drive the high side? since \$V_g\$ should be higher than \$V_s\$, which in this case is \$V_{in}\$ (around 37 V). A lot of people say using a half bridge driver. But also there is a problem. The output voltage is present always (battery voltage), which causes a problem for the driver.

input voltage is 5-37V and I max is 9A the shared node is Dutycycle*Vin during Ton and it is 0.7V during toff

Any suggestions?
enter image description here

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  • \$\begingroup\$ Please provide circuit diagrams / schematics \$\endgroup\$ – TheAndyEngineer Apr 12 at 7:22
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The design of the standard Nch full-H bridge uses the PWM on the Lo side to create "charge pump boost voltage ( series cap and negative diode to Vdd for the Vgs on the Hi side.)

If you use the SM72295MA chip then you get these Hi/Lo drivers for an NCh H-Bridge which are used as "Double Buck" converters for PMMT regulation with matched impedance to the PV and battery voltage regulated out both by sensing V,I and controlling the PWM current thru two inductors with 4 FETs.

It also has many other features you will need with extra FETs for reverse protection etc.

_---__--_-- ... LO side PWM ---||----(Vboost).----|<|----Vdd

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