It's a load based darlington shunt with a mosfet stage for greater efficiency. The zener values will need adjusting so that the stages sync.
The source is low impedance; it will drop significantly under load. Normally the darlington stage won't be used but when it needs to shunt some of the power it is load based, rather than a straight zener clamp.
Am I missing anything?
PS) transistor on right is also darlington.
The source is low impedance; it will drop significantly under load. Normally the darlington stage won't be used but when it needs to shunt some of the power it is load based, rather than a straight zener clamp.
Am I missing anything?
PS) transistor on right is also darlington.