Hearing device comprising an amplifier system for minimizing variation in an acoustical signal caused by variation in gain of an amplifier

A hearing device comprising an amplifier system for minimizing variation in an acoustical signal caused by variation in a supply voltage to an amplifier, wherein the amplifier system comprising;

• a battery configured to provide a supply voltage to the amplifier,
• a digital signal processor configured to provide an acoustical signal to the amplifier,
• a controller unit configured to receive an enablement signal when the supply voltage is in an offset mode, wherein the supply voltage is in the offset mode when the supply voltage short termly drops below or above a supply voltage threshold, and the controller unit is further configured to transmit a request for a measured voltage during a time period based on the enablement signal, and
• a first analog-to-digital converter configured to measure during the time period the supply voltage to the amplifier based on the request for the measured voltage transmitted by the controller unit, and
• wherein the controller unit is configured to determine another offset mode in the supply voltage based on a fitting of measured voltages of the supply voltage to the amplifier, and wherein the controller unit is configured to generate a compensating signal based on an estimation of variation in the supply voltage in the another offset mode provided by the fitting of the measured voltages, and the controller unit is configure to transmit the compensating signal to the digital signal processor, the digital signal processor is configured to minimize the variation in the acoustical signal by providing the compensating signal into the acoustical signal, wherein the compensating signal provides an amplification of the acoustical signal during another time period of the another offset mode.