A method of converting an analog signal (V 1) being provided by an analog input signal source to a high-accuracy digital signal (Dout), the method comprising: providing a first reference signal (V L); providing a second reference signal (V H), the analog signal (V I) having a magnitude V I greater than or equal to a magnitude V L of the first reference signal (V L) and less than or equal to a magnitude V H of the second reference signal (V H); using a low accuracy analog-to-digital converter that samples the analog signal (V I), the first reference signal (V L) and the second reference signal (V H) to provide a low accuracy digital signal based on the sampling; and controlling a high accuracy analog-to-digital converter by a switching sequence based on the low accuracy digital signal, the switching sequence being a sequence that controls a sampling by the high accuracy analog-to-digital converter of the analog signal (V I), the first reference signal (V L) and the second reference signal (V H), and that controls an analog-to-digital conversion by the high accuracy analog-to-digital converter of the analog signal (V I), thereby producing the high accuracy digital signal (Dout), wherein the high accuracy analog-to-digital converter performs N successive sampling operations of the analog input signal (V I) with a sampling device so as to draw substantially zero average current from the analog input signal source by performing the following steps: the sampling device performs N 1 sampling operations on the analog input signal (V I) and the first reference signal (V L), N 1 being a subset of N, and the sampling device performs N 0 sampling operations on the analog signal (V I) and the second reference signal (V H), N 0 being equal to N - N 1, N and N 1 being obtained from the low accuracy digital signal provided by the low accuracy analog-to-digital converter, wherein N 1 is equal to N x (V I - V L) / (V H - V L). providing a first reference signal (V L); providing a second reference signal (V H), the analog signal (V I) having a magnitude V I greater than or equal to a magnitude V L of the first reference signal (V L) and less than or equal to a magnitude V H of the second reference signal (V H); using a low accuracy analog-to-digital converter that samples the analog signal (V I), the first reference signal (V L) and the second reference signal (V H) to provide a low accuracy digital signal based on the sampling; and controlling a high accuracy analog-to-digital converter by a switching sequence based on the low accuracy digital signal, the switching sequence being a sequence that controls a sampling by the high accuracy analog-to-digital converter of the analog signal (V I), the first reference signal (V L) and the second reference signal (V H), and that controls an analog-to-digital conversion by the high accuracy analog-to-digital converter of the analog signal (V I), thereby producing the high accuracy digital signal (Dout), wherein the high accuracy analog-to-digital converter performs N successive sampling operations of the analog input signal (V I) with a sampling device so as to draw substantially zero average current from the analog input signal source by performing the following steps: the sampling device performs N 1 sampling operations on the analog input signal (V I) and the first reference signal (V L), N 1 being a subset of N, and the sampling device performs N 0 sampling operations on the analog signal (V I) and the second reference signal (V H), N 0 being equal to N - N 1, N and N 1 being obtained from the low accuracy digital signal provided by the low accuracy analog-to-digital converter, wherein N 1 is equal to N x (V I - V L) / (V H - V L). the sampling device performs N 1 sampling operations on the analog input signal (V I) and the first reference signal (V L), N 1 being a subset of N, and the sampling device performs N 0 sampling operations on the analog signal (V I) and the second reference signal (V H), N 0 being equal to N - N 1, N and N 1 being obtained from the low accuracy digital signal provided by the low accuracy analog-to-digital converter, wherein N 1 is equal to N x (V I - V L) / (V H - V L).