Abstract: The present invention relates to a drive system wherein a typically chain power transmission system is replaced by an electric motor and where the electric motor is powered by a generator, and where the generator is connected to a dynamic naturally powered source through a transmission mechanism, the dynamic naturally powered source being, such as, but not limited to, a biologically driven source like the pedals of a bike operated by a human being. This may be directly linked or there may be energy storage means in-between. The present invention introduces such a vehicle where the generator is capable of adding a controllable counter torque, or more generally a counter force, to the operation of the transmission mechanism and where the energy generation in the generator is related to the counter torque.

Abstract: The invention relates to a current limiting method, e. g. for Class D amplifiers comprising a unique detection- and control method. The current detection circuit can be implemented as a voltage measurement where the measured voltage corresponds to the current flowing through the power-switching device. The device can be switched OFF when a set limit is reached. By forcing certain OFF time, the associated control system behaves as a self-oscillating current limiting circuit. This can be implemented locally close to the switching device and be independent of other local or global control systems.

Abstract: The present invention relates to a method for correcting for a source of non-linearity and noise introduced in a switching power amplification stage during power amplification of a pulse-modulated reference signal from a pulse modulator, where the method comprises the following steps: —providing an output stage embedded in an analogue self-oscillating control loop able to receive a pulse-referenced input signal; —generating a feedback signal from the switching power amplification stage or after a demodulation filter; —deriving an error signal by comparing the feedback signal with the reference signal; —filtering the error signal by a low pass filter for reducing the higher harmonics of the carrier; —adding a compensator for generating high loop gain in the audio band; —feeding the compensator output to a zero cross detector or comparator, thus providing a carrier for re-modulation or re-timing by feeding the filtered signal to a zero cross detector or comparator, which controls the output stage.

Abstract: The present invention relates to the application of a free-tunning clock signal in a pulse-width modulator (PWM) Specifically there is disclosed an integrated circuit comprising a pulse-width modulator (2) for converting an input signal (6) into a pulse-width-modulated signal (8), the pulse-width modulator (2) being clocked by a clock signal (4) generated by a clock generator (3) which generates a free-running clock signal In a preferred embodiment of the invention, the clock generator (3) is provided in the same integrated circuit (1), such as a chip, as the digital pulse-width modulator (2).

Abstract: The present invention relates to a method for correcting for a source of non-linearity and noise introduced in a switching power amplification stage during power amplification of a pulse-modulated reference signal from a pulse modulator, where the method comprises the following steps: —providing an output stage embedded in an analogue self-oscillating control loop able to receive a pulse-referenced input signal; —generating a feedback signal from the switching power amplification stage or after a demodulation filter; —deriving an error signal by comparing the feedback signal with the reference signal; —filtering the error signal by a low pass filter for reducing the higher harmonics of the carrier; —adding a compensator for generating high loop gain in the audio band; —feeding the compensator output to a zero cross detector or comparator, thus providing a carrier for re-modulation or re-timing by feeding the filtered signal to a zero cross detector or comparator, which controls the output stage.

Abstract: The invention relates to a current limiting method, e. g. for Class D amplifiers comprising a unique detection- and control method. The current detection circuit can be implemented as a voltage measurement where the measured voltage corresponds to the current flowing through the power-switching device. The device can be switched OFF when a set limit is reached. By forcing certain OFF time, the associated control system behaves as a self-oscillating current limiting circuit. This can be implemented locally close to the switching device and be independent of other local or global control systems.

Abstract: A pulse width modulator (10) for converting a digital signal into a PWM signal, comprising a plurality of integrators (11) with integrator gains (12) arranged in series, a comparator (17) for comparing the output of the last integrator (11?) with a reference, and thereby creating the PWM signal. The modulator further has means (13) for realizing self-oscillation at a desired switching frequency, and a feedback path (14) connected to a point down stream said comparator and leading to a plurality of summing points, each preceding one of said integrators, wherein the PWM signal is quantized in time by the clock frequency of the modulator, and wherein the integrator gains (12) are adapted to reduce any quantization noise.

Abstract: A half-bridge driver includes first and second power switches, connected with their respective current paths in series, a pulse generator for generating a voltage pulse waveform, arranged to drive the first power switch, a first current generator for generating a current pulse for each negative flank of the voltage pulse waveform, a second current generator for generating a current pulse for each positive flank of said voltage pulse waveform, and a differential current receiver circuit. The differential current receiver circuit is connected to the first and second current generators, and is arranged to generate an output signal equal to the difference of the currents flowing through the current generators. The output signal is arranged to drive the second power switch.