± 150 V pulses are referenced to ground, actually they are ±xxx mA pulses where xxx ranges from 10 to 300 mA. The output needs to be controlled constant current because the load can vary up to 1000 ohms.
First there will be a (up to) 300 uS + pulse and then a small (200uS) gap and then a (up to) 300 uS - pulse, and then a long (10mS to 20mS) gap before it all repeats again. Pulses are current controlled. this requirement is what the power supply is for.
If I can generate the +ve voltage, is there an easy way to generate the -ve voltage or do I need a second SMPS?
PI Switcher looks interesting, I will check it out.