J
James A
I want to use a buck converter to set-down a 4.8V battery to 3.5V
- Using the PIC pwm pin to drive the gate of the mosfet.
I've performed all the necessary calculation (L, C, Frequency, Duty
Cycle ect).
I was just looking into mosfets to use as the switch when i realised
that I am not going to be able to do it.
THe mosfet I found was a zemtech ZXm61N02F, the threshold voltage Vgs
= 0.7 V
So in other words if i want to be able to switch the MOSFET on/off I
will need to be able to Supply (4.8 + 0.7) = 5.5V to the gate in order
to do so. Since the PIC is powered at 5V this is not possible.
I was wondering if there is some way I can connect up the mosfet
switch so that i can perform this operation whilst maintaing the high
effeciency of the buck converter.
I have googled around without success.
I'm sure this is a fairly common application so I must be overlooking
something.
Thankyou for your time.
James A
- Using the PIC pwm pin to drive the gate of the mosfet.
I've performed all the necessary calculation (L, C, Frequency, Duty
Cycle ect).
I was just looking into mosfets to use as the switch when i realised
that I am not going to be able to do it.
THe mosfet I found was a zemtech ZXm61N02F, the threshold voltage Vgs
= 0.7 V
So in other words if i want to be able to switch the MOSFET on/off I
will need to be able to Supply (4.8 + 0.7) = 5.5V to the gate in order
to do so. Since the PIC is powered at 5V this is not possible.
I was wondering if there is some way I can connect up the mosfet
switch so that i can perform this operation whilst maintaing the high
effeciency of the buck converter.
I have googled around without success.
I'm sure this is a fairly common application so I must be overlooking
something.
Thankyou for your time.
James A