Abstract: The invention relates to a method of fabricating a microneedle array in a substrate, a drug delivery device comprising one or more microneedles extending upwards from the front surface of the substrate, the microneedles having a generally conical-shaped body defined by a plurality of surfaces sloping upwards from a relatively broad base to a tip, and one or more substances coating the microneedles, the one or more substances being operable to be administered to a patient, wherein the tips of the one or more microneedles are sufficiently sharp to penetrate an outer layer of the skin of the patient, and a method of administering one or more substances to a patient using the device.

Abstract: A resonant switching power system operates with two resonant frequencies. A first frequency depends on the secondary leakage inductance of an output transformer and capacitor. The first frequency varies with changes in the load because load changes alter the leakage inductance. A second resonant frequency depends on the gate source capacitance of two MOSFET power devices in the circuit and the leakage inductance of the circuit's driving transformer. Power is thereby supplied that is always in phase with the load so that switching in the power supply occurs when current is near zero. High thermal efficiency is thereby achieved.

Abstract: Apparatus and methods for reducing radio frequency interference produced by switching amplifiers, includes a variable-order noise shaper in a system that includes an AM tuner. An alternative implementation involves determining the tuned frequency of a radio signal. A first sampling rate is provided at which the radio signal is to be sampled. The first sampling rate is associated with a plurality of first harmonic frequencies. A second sampling rate is also provided and is associated with a plurality of second harmonic frequencies different than the first harmonic frequencies. The method involves selectively sampling the radio signal at one of the first and second sampling rates, wherein the first sampling rate is selected when the first harmonic frequencies do not coincide with the tuned frequency, and the second sampling rate is selected when the second harmonic frequencies do not coincide with the tuned frequency.

Abstract: A bridged amplifier output stage capable of sharing a common conductor between independent loads. Multi-Channel pulse width modulated output signals are time division multiplexed to reduce the number of required conductors. The output stages are driven such that the non-common conductor time multiplexed off-channel(s) receives a copy of the shared common signal. The differential signal on the off-channel(s) is thereby cancelled even though the common conductor is carrying a signal for use by the on-channel.

Abstract: A system and method for reducing distortion in a pulse width modulated digital system by selectively implementing linearization. The linearization is implemented computationally efficient, using no division operations. A frequency detector is implemented which causes signals to bypass the linearization algorithm at frequencies where the new modes of distortion become significant as a result of the linearization when used in combination with an interpolation filter.

Abstract: An all digital switching amplifier wherein linearization of the power switch is accomplished solely by using three states. A small, fixed width, bi-state compensating carrier waveform is added to the leading or training edges of an oversampled main input pulse producing a compensated composite waveform. This compensating carrier linearizes output from a power switch by effecting common mode cancellation of switch time errors. Output pulse width combinations for the compensating carrier are obtained from a look-up table stored in memory. A correction mechanism is implemented to correct for harmonic distortion that is dependent on the modulation level or index and results from the compensating carrier modulation. The correction mechanism applies the inverse of the modulation induced distortion to the oversampled compensated composite input signal to null distortion products resulting from the modulation scheme used to apply the small carrier to linearize the performance of the tri-state power switch.

Abstract: A switching amplifier system which in one embodiment includes switching circuitry responsive to a tri-state command signal for providing a power output from a power supply which has amplitude levels, time durations, and polarities corresponding to the tri-state command signal for supply to a load via a suitable filter. A further embodiment includes a linear amplifier, the switching circuitry responding to a fourth state command signal for actuating the linear amplifier to respond directly to an input signal when the amplitude of the input signal is below a selected level.