Abstract: An actuator subsystem for use in a scanning probe microscope (SPM) system having a probe for measuring a sample comprises and actuator and an actuator driving circuit. The actuator operates in the SPM system to generate relative motion between the probe and the sample while the SPM system collects data indicative of a property of the sample. The relative motion includes a range of motion of at least 1 micron. The actuator driving circuit applies a drive signal to the actuator to cause the relative motion, and has a small signal bandwidth of at least 200 kHz with a phase lag of not more than 100 degrees within the small signal bandwidth.

Abstract: An RF matching network includes a switching element that quickly switching between a first matching sub-network and a second matching sub-network, such that the impedance of neither sub-network is coupled to the other when selected by the switch. In one embodiment, the switching element includes a bipolar transistor, a TRIAC device and a PIN diode. The PIN diode conducts or attenuates the RF signal depending on its bias voltage. The bipolar transistor controls the bias voltage on the PIN diode. The TRIAC device protects the bipolar transistor damage that can be caused from high voltages generated at the PIN diode when the PIN diode is not conducting the RF signal.

Abstract: A regulating control circuit for a single-ended switching power supply includes means for controlling the switching duty cycle during start-up, normal operation and current limiting modes. Normal operation utilizes a duty cycle of less than about 50%, but low input voltage operation can occur for limited times at duty cycles up to 70%-80%. A time base generator defines the maximum permissible switch conduction time, as well as the switching rate. During start-up, input current is restricted to reduce dissipation within the control circuit, the start-up duty cycle also being maintained at a low value by extending the switch non-conduction time. In the current limiting mode, the duty cycle is reduced as a function of current demand to achieve constant current operation over a given range of output voltages, and to achieve current foldback below such range. In current foldback, the switch non-conduction period is extended to obtain unusually low duty cycles in near shorted output conditions.