US 7,872,322 B2Granted

Magnetic field sensor with a hall element

AssigneeMelexis Tessenderlo NV

InventorsChristian Schott, Radivoje Popovic, Pierre-Andre Besse, Enrico Schurig

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Abstract

A symmetrical vertical Hall element comprises a well of a first conductivity type that is embedded in a substrate of a second conductivity type and which is contacted by four contacts serving as current and voltage contacts. From the electrical point of view, such a Hall element with four contacts can be regarded as a resistance bridge formed by four resistors R1 to R4 of the Hall element. From the electrical point of view, the Hall element is then regarded as ideal when the four resistors R1 to R4 have the same value. The invention suggests a series of measures in order to electrically balance the resistance bridge. A first measure exists in providing at least one additional resistor. A second measure exists in locally increasing or reducing the electrical conductivity of the well. A third measure exists in providing two Hall elements that are electrically connected in parallel in such a way that their Hall voltages are equidirectional and their offset voltages are largely compensated.

Claims14

Dependent claims

A magnetic field sensor comprising a Hall element comprising a first contact, a second contact, a third contact and a fourth contact arranged in this sequence along a straight line on a surface of a first well of a first conductivity type that is embedded in a substrate of a second conductivity type, said four contacts being two inner contacts and two outer contacts, a first of said two outer contacts and a first of said two inner contacts for supply and discharge of a current flowing through the first Hall element, wherein the first of said two outer contacts and the first of said two inner contacts are not adjacent contacts, and a second of said two outer contacts and a second of said two inner contacts for tapping a first Hall voltage, wherein the two inner contacts are the same width and wherein the two outer contacts are the same width, wherein a distance between the first contact and the second contact is equal to a distance between the third contact and the fourth contact, wherein a distance between the second contact and the third contact is selected such that approximately R1=R2=R3 wherein R1 denotes a resistance prevailing between the first contact and the second contact R2 denotes a resistance prevailing between the second contact and the third contact and R3 denotes a resistance prevailing between the third contact and the fourth contact, and wherein the two outer contacts are connected via an additionally resistor having a resistance R5 that is selected such that approximately R1=R2=R3=R4||R5 wherein R4 denotes a resistance prevailing between the first contact and the fourth contact.

A magnetic field sensor comprising a first Hall element comprising a first contact, a second contact, a third contact and a fourth contact arranged in this sequence along a first straight line on a surface of a first well of a first conductivity type that is embedded in a substrate of a second conductivity type, said four contacts being two inner contacts and two outer contact, a first of said two outer contacts and a first of said two inner contacts for supply and discharged of a current flowing through the first Hall element, wherein the first of said two outer contacts and the first of said two inner contacts are not adjacent contacts, and a second of said two outer contacts and a second of said two inner contacts for tapping a first Hall voltage, wherein the two inner contacts are the same width and wherein the two outer contacts are the same width, wherein a distance between the first contact and the second contact is equal to a distance between the third contact and the fourth contact,

a second Hall element comprising a first contact, a second contact, a third contact and a fourth contact arranged in this sequence along a second straight line on a surface of a second well of the first conductivity type that is embedded in the substrate, said four contacts being two inner contacts and two outer contacts, a first of said two outer contacts and a first of said two inner contacts for supply and discharge of a current flowing through the second Hall element, wherein the first of said two outer contacts and the first of said two inner contacts are not adjacent contacts, and a second of said two outer contacts and a second of said two inner contacts for tapping a second Hall voltage, wherein the two inner contacts are the same width and wherein the two outer contacts are the same width, wherein a distance between the first contact and the second contact is equal to a distance between the third contact and the fourth contact,
wherein the first and second straight line run in parallel, an
wherein either the first contact of the first Hall element is connected with the fourth contact of the second Hall element, the second contact of the first Hall element is connected with the first contact of the second Hall element, the third contact of the first Hall element is connected with the second contact of the second Hall element and the fourth contact of the first Hall element is connected with the third contact of the second Hall element or the first contact of the first Hall element is connected with the second contact of the second Hall element, the second contact of the first Hall element is connected with the third contact of the second Hall element, the third contact of the first Hall element is connected with the fourth contact of the second Hall element and the fourth contact of the first Hall element is connected with the first contact of the second Hall element.

Dependencies are inferred from the claim text.