Patent ID: 7671637
Filing Date: 2010-03-02
Classification: G11C,H03K

Abstract:
1. A current switch comprising: two differential pairs of two transistors each, these pairs being arranged in cascade form, the second pair having complementary current outputs, one of which supplies current while the other is blocked and vice versa depending on the state of a differential signal applied between the bases of the two transistors of the first pair, the first pair being connected to a ground through a constant current source supplying a current of value Io, this source comprising a transistor, the base of which is held at a bias voltage Vbias, wherein the second differential pair is connected to ground directly through a resistance, and the first differential pair is supplied by a voltage equal to N·Vbe+Vbias, where N is a whole number, and Vbe is the base-emitter voltage of the transistor of the current source supplying the current Io, and wherein the first differential pair has voltage supplied by a supply transistor placed in series between a main supply voltage source Vcc and the differential pair, the supply transistor having its base controlled by a junction node between a low-voltage-drop current source connected to the supply voltage Vcc and a series-connected group, connected to ground, of a plurality of transistors mounted as diodes and a resistance, the voltage Vbias being taken at the base of one of the transistors mounted as a diode.