Patent ID: 8253279

Claim:
An active medical device, comprising: a battery ( 10 ) providing an input voltage (V i ); a user circuit powered at a nominal voltage (Vref); a switching power supply ( 14 ) comprising: (1) an input ( 12 ) receiving the input voltage (V i ); (2) an output ( 16 ) supplying the user circuit with an output voltage (V O ); (3) an inductor having an inductance value (L); (4) a buffer capacitor (C O ); (5) a switching network (S 1 . . . S 5 , D 1 . . . D 4 ), providing between the input, the output, the inductor and the buffer capacitor during successive cycles and according to a predefined topology of the switching power supply, at least two alternative configurations, including: (a) a charging phase configuration of energy storage, wherein the inductor is charged by a current delivered by the battery, the current having an increasing intensity up to a peak current (I K ), and (b) a discharge phase configuration of energy release, wherein the energy accumulated in the inductor during the charging phase is transferred to the buffer capacitor and from the buffer capacitor to the user circuit, and (6) means ( 18 , 20 , 22 ) for controlling the switching network at the end of the charging phase and the discharging phase so as to regulate the output voltage as a function of the input voltage from the nominal voltage, wherein said means for controlling the switching network comprises: (a) no means for measuring the current through the inductor; (b) an analog to digital converter ( 20 ) delivering a digital value representative of the input voltage (V I ); and (c) a predictor means for calculating a priori a duration of the charging phase and a duration of the discharging phase, each duration being calculated according to a plurality of parameters comprising: the input voltage (V I ), the output voltage (V O ), the nominal voltage (V ref ), the inductance value (L), and the peak current (I K ).