A 200-V high-voltage amplifier using a parasitic field-oxide transistor for voltage feedback

A 200-V high-voltage amplifier with a 50-kHz bandwidth is built in a 10-V trench-isolated CMOS process with complementary high-voltage transistors. The high-voltage amplifier uses parasitic field-oxide transistors to dc stabilize the input-output voltage transfer characteristic. Use of parasitic field-oxide transistors for output voltage sensing provides only a small capacitive output load and eliminates the need for high-voltage resistor feedback networks. By removing resistor feedback networks, compact and low-power high-voltage amplifiers may be realized for a certain class of applications.