Patent ID: 7532953

Claim:
A processor-readable medium storing code representing instructions to cause a processor to perform a process, the code comprising code to: receive a parameter signal associated with a selected pressure level of a vacuum pump coupled to a wound dressing including a porous substrate and a cover membrane; receive a pressure signal from a sensor coupled to the wound dressing, the pressure signal associated with a pressure in the wound dressing; and output a control signal to a pulse width modulating circuit, the control signal operative to change the vacuum pump from a first mode to a second mode, the first mode being associated with a negative pressure in the wound dressing, the second mode being associated with a negative pressure in the wound dressing lower than the pressure associated with the first mode, the control signal being based on the parameter signal and the pressure signal, the pulse width modulating circuit configured to output a pulse width modulated signal having a duty cycle associated with a flow rate of the vacuum pump.