510results about How to "Current is limited" patented technology

An apparatus basically uses a simple and compact multi-axis magnetic lens to focus each of a plurality of charged particle beams on sample surface at the same time. In each sub-lens module of the multi-axis magnetic lens, two magnetic rings are respectively inserted into upper and lower holes with non-magnetic radial gap. Each gap size is small enough to keep a sufficient magnetic coupling and large enough to get a sufficient axial symmetry of magnetic scale potential distribution in the space near to its optical axis. This method eliminates the non-axisymmetric transverse field in each sub-lens and the round lens field difference among all sub-lenses at the same time; both exist inherently in a conventional multi-axis magnetic lens. In the apparatus, some additional magnetic shielding measures such as magnetic shielding tubes, plates and house are used to eliminate the non-axisymmetric transverse field on the charged particle path from each charged particle source to the entrance of each sub-lens and from the exit of each sub-lens to the sample surface.

A startup control method of a BLDC motor is disclosed. The method can control the BLDC motor to prevent the generation of a transient current such that the vibration of the BLDC motor can be reduced at the startup stage and perform a stable conversion into a sensorless operation mode such that the startup failure rate of the BLDC motor can be reduced. The startup control method includes commutating a current applied to stator windings according to a rotor position. The method of operating the BLDC motor includes a rotor position that is forcibly aligned and so that phase commutation is performed, a back-electromotive force (back-emf) is detected from a lead voltage of a phase of a voltage which is not applied thereto after performing phase commutation and a determination is performed as to whether the detected back-emf is in a rising interval. The lead voltage of the phase of the voltage which is not applied thereto is integrated, such that if the back-emf is in a rising interval and if an instance that the integration result is greater than a predetermined value a phase commutation time point is set and conversion into a sensorless operation mode is performed if the back-emf detected from the lead voltage is in a stable interval, based on a frequency of the voltage applied to the stator winding.

This invention describes a method for improving antenna isolation in an electronic communication device using grounded RF microwave elements and patterns (structures). According to embodiments of the present invention, the RF microwave element can be implemented as a short-circuited section of a quarter-wavelength long transmission line (such as a stripline), or the RF microwave element can contain a metallic coupler and two thin striplines with different lengths, or the RF microwave element can be implemented using a balun concept.