Hearing instrument with switchable power supply voltage

A hearing instrument comprising:

• a microphone comprising a microphone transducer element mounted in a microphone housing, wherein the microphone transducer element is configured to provide a transducer signal in response to receipt of sound;
• a microphone amplification circuit configured to generate an amplified microphone signal based on the transducer signal;
• a control and processing circuit coupled to the microphone amplification circuit for receipt and processing of the amplified microphone signal according to a hearing loss of a user;
• and
• a level detector configured to detect a level of the amplified microphone signal;
• wherein the microphone amplification circuit is coupled to a switchable power supply, and wherein the switchable power supply is configured to selectively connect a first power supply voltage, having a first DC voltage level, or a second power supply voltage, having a second DC voltage level, to the microphone amplification circuit based on the detected level of the amplified microphone signal, the second DC voltage level being higher than the first DC voltage level.