Icepower A/s

Eskil Jørgensen

Kennet Skov Andersen

The invention relates to a compensator device for compensating signal dependent delay variations, including dead time and reverse recovery time, causing un-linearity in a Class-D amplifier where the compensator device comprises: a first input terminal for receiving an input pulse width modulated input PWM signal comprising pulses with falling flanks corresponding to a falling level transition and rising flanks corresponding to a rising level transition; and a second input terminal configured to receive the signal provided at an output switching node of a Class-D amplifier; an output terminal for providing a compensated output signal; and controllable delay means configured to receive and delay the pulse modulated input signal, thereby providing a delayed version of the input signal to said output terminal of the compensator device. The compensator device further comprises time measuring means configured for measuring the time between a transition of the signal provided at the output terminal of the compensator device and the corresponding transition of the signal at the output switching node of a Class-D amplifier and based on these measurements providing a control signal to the controllable delay means. An advantageous effect of the present invention is that the rising and falling level transition delays will be substantially similar thus substantially removing non-linearity and obtaining substantially correct pulse widths. The invention further relates to a corresponding method, a driver device and a Class-D amplifier.

Dead time compensation

A switching power conversion system and a method for start-up pop minimization in an audio amplifier assembly are disclosed. The switching power conversion system comprises a forward path including a compensator, a switching power stage and a demodulation filter. The system further comprises a DC-servo and a pre-charging circuit and a sequence control unit configured for providing a start-up sequence where the compensator and DC-servo are correctly biased and a bootstrap capacitor within the switching power stage is charged before the switching power stage is started. Hereby, it is e.g. possible to minimize the audible start-up pop in audio amplifier assemblies.

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Vaerløse, Denmark

Eskil Jørgensen