Patent ID: 9570906
Date: 2017-02-14
CPC Classifications: H01L,H02H

Claim:
1. A voltage supply for providing a clamped voltage to a circuit element to be protected against electrical overstress (EOS), comprising: a reference voltage module including a first active element having a first control terminal and first current carrying terminals, the first current carrying terminals being connected in series between a reference current source that provides a reference current and a first impedance across a power supply, and the first control terminal being connected to one of the first current carrying terminals and to the reference current source to provide a reference voltage defined by the reference current flowing in the first impedance; and a voltage clamp module including a second active element having second current carrying terminals and a second control terminal connected to receive the reference voltage; wherein the second active element is a transistor, and one of the second current carrying terminals is a source terminal of the transistor that is connected to provide to the protected circuit element the clamped voltage whose variation is limited by the reference voltage, and wherein the reference current source comprises a band-gap voltage source and a voltage-to-current converter for providing the reference current, wherein the first impedance comprises a first resistor and the voltage-to-current converter applies the voltage from the band-gap voltage source to a second resistor of similar type to the first resistor, and wherein the voltage-to-current converter provides the reference current to the first resistor by mirroring a current flowing through the second resistor with a current mirror.