Level shifting in HV CMOS processes
Most technologies are limited to VGS &lt; 10 V, or 5 V in more modern ones, and need circuits like this. High voltage level shifters are needed in high voltage DC/DC converters and similar circuits. 

The general approach is to create a rail that is ~ 5 V below the HV supply and use this to limit the VGS of the high side FETs. You also don't drive the 10 pF load directly -- buffers (also powered from the HV-5 supply) minimize the load on the level shifter portion itself. 

Care needs to one taken in these circuits to ensure that the HV devices don't get damaged; that the outputs are controlled when the supplies are starting up, and that speed is maintained.