30V adjustable current LED driver
What you normally do is configure the LED driver to output the current that corresponds to maximum brightness and use PWM dimming from the microcontroller when you need a lower brightness, without changing the driver's current. It is easier to implement and avoids the issue that the color of a LED changes at very low currents, eg. a nice warm white LED could look greenish. With PWM dimming the current and therefore color is always the same, you only change the duty cycle.

So what you need ideally is a 0.7 A boost LED driver (current-regulated) with a PWM dimming input. Are you looking for a ready-to-use module or a chip that you'll integrate into your own circuit?

You could use a voltage-regulated boost converter followed by a step-down current regulator/LED driver, but in this case the losses will add up, eg. if your regulators are 85% efficient each you will have an overall efficiency of 72% only.