Q:

Convert a PWM to analogue with double the voltage range?

I have a PWM output (0-5v) that I need to convert to an analogue voltage. Simple = RC filter. However, the voltage range from that analogue voltage needs to be twice that of the input voltage, and I'm just not sure of the best approach.
Basically: 5v PWM to 10v analogue
A colleague suggested to use a voltage doubler (such as 7660) to power an op-amp, configured with a gain of 2.
Any other suggestions would be greatly appreciated.
Thanks

A:

A voltage doubler won't be effective especially if the PWM duty cycle 30% or less - the 7660 needs at least 1.5V to power it and that is the first problem. The second problem would be finding an op-amp with perfect rail-to-rail outputs. Again a problem made worse at low voltages.
Apart from anything else the 7660 converts its input to a negative voltage and that is of little use here.
The only solution I can think of is to provide a 10.5V supply to a rail-to-rail op-amp with a gain of +2.

A:

Filter the PWM with a suitable LPF. Use a DC-DC converter to get +12V or + 15V from the 5V rail. Use a gain of two single-supply amplifier powered from the 12V rail to double the voltage input. Done. 

simulate this circuit – Schematic created using CircuitLab

