A constant on-time switching converter includes a switching circuit, an on-time control circuit, a comparing circuit and a logic circuit. The switching circuit has a first switch and is configured to provide an output voltage to a load. The on-time control circuit generates an on-time control signal to control the on-time of the first switch. The comparing circuit compares the output voltage of the switching circuit with a reference signal and generates a comparison signal. The logic circuit generates a control signal to control the first switch based on the on-time control signal and the comparison signal. When the switching frequency of the switching circuit approaches an audible range, the switching converter enters into a sleep mode, the on-time control signal is reduced to increase the switching frequency of the switching circuit.

Tire changing machines having force feedback and position control systems are described that may be used to control operation of one or more components of the machine during a tire change procedure. Information may be provided to a machine operator concerning detected operating conditions during the procedure. Excessive or abnormal forces or component positions can be detected and corrective action may be taken at any point in the tire change procedure. Successful component position profiles may be saved for future recall and execution by the machine.