E2v Semiconductors

Sandrine Bruel

François Bore

Marc Wingender

Francois Bore

The invention relates to high-resolution analog-digital converters using so-called folding differential amplifier structures composed of differential circuits (crossed differential pairs) and of loads (cascode transistors). The folding structure according to the invention comprises, in the case where it is desired to produce four curves folded at two periods in the useful range of voltages to be converted, four folding blocks (one per curve). The first comprises 7 differential circuits and eight loads, the end loads not being linked to the output of the block. The other blocks comprise 6 differential circuits and eight loads, the last load of each block not being linked to the output of this block. Gains are achieved in terms of bulk, consumption and operating speed, with respect to existing structures.

High-speed analog-digital converter having a signal folding structure improved by reducing the number of elementary cells

The invention relates to analog integrated electronic circuits using differential pairs. The proposal is for a method of automatic correction of offset voltage. The inputs (V, V) of the differential circuit are short circuited during a calibration phase distinct from the normal usage phase. A capacitor is charged through the difference of the output currents of the branches of the differential pair in this phase. The voltage at the terminals of the capacitor is compared with at least one threshold. During the normal usage phase following the calibration phase, the result of the comparison is kept in memory. In the normal usage phase, a correction is applied depending on the result kept in memory to a current source of a follower stage upstream of the differential pair.

Electronic circuit with compensation of intrinsic offset of differential pairs

The invention relates to integrated circuits comprising a set of identical differential pairs of two transistors each (T, T; T, T) one receiving a variable voltage (Vinp, Vinn) at its base and the other receiving a fixed reference voltage (Vrefp, Vrefn). In order to reduce the dispersion of the offset voltages of said differential pairs, it is provided that the transistor (T, T) that receives a fixed reference voltage has an emitter surface at least twice as large as the transistor (T, T) that receives a variable voltage at its base. Application to signal folding circuits and to analog-to-digital converters using differential pairs of transistors.

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Grenoble, France

Sandrine Bruel