Current generator, notably for current of the order of nano-amperes, and voltage regulator using such a generator

摘要

An ultra-low current generator and a voltage regulator using such a generator. The generator includes a first set of Q transistors connected as a current mirror and able to be linked to a supply voltage; a second set of Q-1 transistors connected as a current mirror and each connected in series to one of the transistors in the first set of transistors; a first transistor connected in series with a transistor in the second set of transistors; and a second transistor, connected as a current mirror with the first transistor, and connected in series with a transistor included in the first set of transistors. The first transistor operates in its linear zone, a value of a current generated by the current generator depends on an equivalent resistance of the first transistor, and the first and second transistors have ultra-long channels, with a very large length/width ratio.

主权项

1. A current generator using field-effect transistors, the current generator comprising:
a first plurality of Q transistors connected as a current mirror and linked to a supply voltage, each of the first plurality of transistors having a channel of a first polarity; a second plurality of Q-1 transistors connected as a current mirror, each having a channel of a second polarity that is the reverse of the first polarity, and each connected in series to a transistor included in the first plurality of transistors; a first transistor N3R having a channel of the second polarity and a gate, having an equivalent resistance Req, and connected in series with a transistor included in the second plurality of transistors; and a second transistor N4 having a gate and a drain, connected as a current mirror with the first transistor N3R, and connected in series with a transistor included in the first plurality of transistors, the gate and the drain of the transistor N4 are linked; wherein
the first transistor N3R operates in its linear zone,an amount of current generated by the current generator depends on the equivalent resistance Req of the first transistor N3R, andthe first and second transistors N3R, N4 each have an ultra-long channel, each ultra-long channel having a ratio L/W greater than several hundred, L being the length of the ultra-long channel and W its width, the values of W and of L/W being determined to obtain a stable value of current as a function of a variation of the supply voltage.