An inertial vibration scavenging micro-generator is described which is suitable for biomedical applications. MEMS fabrication techniques have been used to construct a variable capacitor having one moving plate on which a proof mass is attached. Energy is extracted when the plates separate at constant charge. This device is non-resonant, so can operate over a wide range of excitation frequencies and amplitudes. The energy extracted per cycle, 120 nJ, is well above previous reports. The fabrication techniques employed are described, and test data are given and compared to modeling results, showing good agreement.