Patent ID: 7599163

Claim:
A mass flow controller comprising: a power supply; an actuator configured to modulate a position of a flow control valve; an input line configured to receive a control signal indicative of a specific mass flow, the specific mass flow corresponding to a desired actuator position; a first current switch disposed to create a first current path between the power supply and the actuator; a second current switch disposed to create a second current path between the power supply and the actuator; and a controller coupled to the first and second current switches, wherein the controller is configured to close both the first and second current switches to simultaneously provide current to the actuator via the first and second current switches so as to provide a desired rate of increase of charge in the actuator, and the controller is configured to initially close the first current switch and open the second current switch so as to initially provide current to the actuator via the first current switch, and the controller is configured to close the second current switch in response to a rate of increase of charge in the actuator being less than the desired rate.