Found a very similar circuit I used.
     I remember using two IRF9640 in parallel to increase efficiency.
     C=3D220pF on MC34063. Don't remember L1 value. NPN=3DBC337.



     Mark Jordan


On 31-Jan-17 09:10, IVP wrote:
> Hi Mark,
>
>> Years ago I built a 12V in, 5V 3A out power supply using the
>> MC34063 driving an IRF9640 mosfet.
>> No buffer circuit used, just a NPN to speed up gate cut off.
>> Trying to find the circuit but no luck so far
> I've seen magazine and web circuits which use a transistor to turn the
> FET off. If you look at Google images for mc34063 pch fet you'll see
> all sorts of configurations
>
> Joe
>
>
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