op amp controlling a mosfet

Imagine you have a vehicle that receives up to ten amps from a
generator, and with the generator off you need a blocking rectifier to
keep the 12 volt battery from discharging into the generator windings,
so you decide to use the body diode of mosfet as the blocking
rectifier; during charging you can have the mosfet turned on to reduce
dissipation. The blocking has to occur in the positive rail because
ground consists of the vehicle chassis.
What is the best way? I was thinking about something along these
lines:

generator
|
,------------+
| |
| _ _|D
'--|-\ | STP80PF55
LF412| >-+-|| p-channel
,--|+/ | |_ mosfet
| | |S
| 100K |
| | |
| | |
'-------+----+
|
|
battery

Somebody told me the LF412 works with common mode inputs at the
positive rail, but if I should be looking at some other op-amp let me
know.
http://www.national.com/ds/LF/LF412.pdf

.

Relevant Pages

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  • Re: op amp controlling a mosfet
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