An integrated high-voltage switching circuit includes a switch having ON and
OFF
states and having a parasitic gate capacitance. The switch consists of a pair of
DMOS transistors integrated back to back and having a shared gate terminal, the
drains of the DMOS transistors being connected to the input and output terminals
of the switch respectively. The switching circuit further includes a turn-on circuit
comprising a PMOS transistor having its drain connected to the shared gate terminal
of the switch via a first diode, having its source connected to a global switch
gate bias voltage terminal from which the PMOS transistor draws current, and having
its gate electrically coupled to a switch gate control terminal that receives a
switch gate control voltage input. The switch transitions from the OFF state to
the ON state in response to a first transition of the switch gate control voltage
input that causes the PMOS transistor to turn on, and the switch remains in the
ON state in response to a second transition of the switch gate control voltage
input that causes the PMOS transistor to turn off. The DMOS transistors turn on
in response to the shared gate being coupled to the switch gate bias voltage when
the PMOS transistor turns on.