Patent ID: 6713993
Filing Date: 2004-03-30
Classification: G05F

Abstract:
A high-voltage regulator circuit for delivering at least a first regulated output voltage (VREG1, VREG2) from a high input voltage (VHV), this regulator circuit including an external regulation device including an input terminal to which said high input voltage is applied, an output terminal at which said first regulated output voltage is delivered, and a control terminal connected to a control circuit of said external regulation device, this control circuit including:a voltage divider circuit connected between said output terminal and a reference potential (VSS) or ground, and delivering at one output a first divided voltage proportional, in a determined ratio, to said first regulated output voltage (VREG1); a reference cell delivering at one output a determined reference voltage (VREF); and a differential amplifier including first and second inputs to which are respectively applied said first divided voltage delivered by the voltage divider circuit and said reference voltage (VREF) delivered by the reference cell, the output of this differential amplifier controlling the conduction state of said external regulation device, wherein said control circuit further includes a first high-voltage MOSFET transistor including drain, source and gate terminals respectively connected to the control terminal of the external regulation device, to ground (VSS), and to the output of said differential amplifier, said high-voltage MOSFET transistor being an n-channel MOSFET transistor including a gate oxide having a greater thickness on the drain side than on the source side and a buffer zone on the drain side formed by an n-well.