dhenry:
Remember an LED cannot by itself control the current flowing through it, it's not like a incandescent lamp that has a fixed resistance which controls the current at a given voltage per ohm's law.
That's not true. Most (all?) of the led drivers actually control the voltage on applied on the led string based on a feedback voltage sensed on the current going through the led string. So they are actually controlling the voltage.
Well I disagree with your statement, The driver manipulates its output voltage in an attempt to control the current. But perhaps I'm just disagreeing with your use of the term 'control' rather then your understanding of the feedback control loop being used.
I would equate it to the terms used in classic PID control theory, where the 'setpoint' is the desired 700ma current flow value, the current is the measured 'process control variable', and the 'output' is the voltage used to adjust any error term until process variable equals the setpoint. So in classic control theory it would be called a 'current controller' never a voltage controller.
Lefty