A current controller for controlling an input current carried by a primary conductor. The current controller has a gapped core of magnetic material magnetically coupled to the primary conductor, as for example by the primary conductor being wound around the core. A secondary conductor is magnetically coupled to the core of magnetic material in an opposite manner to the primary conductor such that current flowing in the secondary conductor generates a second magnetic field in the core opposed to the first magnetic field. A Hall effect latch is located in the air gap and has output voltage corresponding to a hysteresis function of the difference in the first and second magnetic fields.

Using hall device for controlling current in a switchmode circuit

Circuit and method for biasing a plate-shaped sensor element ( 2 ) made of doped semiconductor material and having a first resp. second excitation contact (C, A) connected to a first resp. second excitation node (Cn, An), and a first resp. second sense contact (B, D) connected to a first resp. second sense node (Bn, Dn). The plate-shaped sensor element is electrically isolated from a substrate or well ( 5 ) by means of a first PN-junction. The method comprises: a) applying to the first excitation node (Cn) a predefined first current (I ex ) generated by a first current source ( 11 ); b) applying to the second excitation node (An) a second current (I′ ex ) generated by a controllable second source ( 12 ); c) controlling the second source ( 12 ) by means of a negative feedback loop based on a comparison between a value representative for a common mode voltage (V cm ) of the voltages (VB, VD) of the sense nodes (Bn, Dn) and a predefined reference voltage (V ref ), such that the common mode voltage (V cm ) is substantially equal to the reference voltage (V ref ).

Circuit and method for biasing a plate-shaped sensor element of semiconductor material

A Hall-effect amplifying device comprising a Hall generator and an electronic amplifier is provided with a feedback resistor circuit which connects the amplifier output directly with one of the two Hall-voltage electrodes of the Hall generator. The amplifier in this device is an electronic direct-current amplifier of high-ohmic input resistance and high no-load gain. The resistance of the feedback connection is two or more orders of magnitude higher than the internal resistance between the Hall-voltage electrodes of the Hall generator.

Hall-effect amplifying device with temperature compensated characteristic

An isolator circuit of the type designed to accept an input current and to generate a corresponding output current which is isolated from the input. The isolator circuit is formed with a core developing a flux in response to the input current and having a feedback winding for carrying the isolated output current. A magneto-sensitive element, such as a Hall effect element, responds to flux in the core, and an amplifier receives the output of the magneto-sensitive element and supplies a current to the feedback winding so as to cancel the flux produced in the core due to the input current. Improved frequency response is attained by means of a compensation winding disposed to respond to the difference between the flux produced by the input current and the flux produced by the output current. The compensation winding is connected in the isolator circuit with the voltage developed across the compensation winding being superposed on the output of the magneto-sensitive element and supplied to the input of the amplifier. The voltage developed across the compensation winding leads the voltage across the magneto-sensitive element and compensates for phase lags arising in the current, thereby extending accurate frequency response of the circuit.

Isolator circuit with improved frequency response

Integrated circuit and method for biasing a Hall plate (2) having a first resp. second excitation contact (C, A) connected to a first resp. second excitation node (Cn, An), and a first resp. second sense contact (B, D) connected to a first resp. second sense node (Bn, Dn). The Hall plate is electrically isolated by means of a first PN-junction. The method comprises: a) applying to the first excitation node (Cn) a predefined first current (lex) generated by a first current source (11); b) applying to the second excitation node (An) a second current (l'ex) generated by a controllable second source (12); c) controlling the second source (12) by means of a negative feedback loop based on a difference between a common mode voltage (Vcm) of the voltages (VB, VD) of the sense nodes (Bn, Dn) and a predefined reference voltage (Vref), such that the common mode voltage (Vcm) is substantially equal to the reference voltage (Vref).

Bizet Pierre

Papers

Driftless direct current amplifier