Magnetic Offset Correction in Semiconductor Devices
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Summary
Problems
Magnetic switches, particularly those using Hall elements, face challenges in maintaining symmetric magnetoelectric conversion characteristics due to offset voltages and magnetic offsets, which can lead to phase and duty ratio shifts in output pulse signals, affecting the performance of brushless direct current (BLDC) motors and magnetic body detection mechanisms.
Innovation solutions
A semiconductor device with a magnetic switch configuration that includes a Hall element, a switch circuit, an amplifier, a comparator, and a latch circuit, which uses a reference voltage circuit to adjust the comparator reference voltage based on control signals, allowing for optimal adjustment of the magnetic offset and improving the symmetric property of magnetoelectric conversion characteristics.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a two-way drive spinning current method is used to eliminate offset voltages, then offset voltage elimination is improved, but symmetric property of magnetoelectric conversion characteristic deteriorates when absolute value of offset voltage differs between current drive directions
Why choose this principle:
The patent applies preliminary action by adjusting the comparator reference voltage before magnetic field detection to compensate for magnetic offsets. The reference voltage adjustment circuit pre-calculates and applies the necessary voltage adjustment based on detected magnetic offset conditions, ensuring symmetric magnetoelectric conversion characteristics are established before actual measurement begins. This prevents the asymmetry that would otherwise occur during two-way drive spinning current operation.
Principle concept:
If a two-way drive spinning current method is used to eliminate offset voltages, then offset voltage elimination is improved, but symmetric property of magnetoelectric conversion characteristic deteriorates when absolute value of offset voltage differs between current drive directions
Why choose this principle:
The patent changes the parameter of comparator reference voltage to compensate for magnetic offsets. By dynamically adjusting the reference voltage level based on the detected magnetic offset conditions, the system maintains symmetric magnetoelectric conversion characteristics even when offset voltages differ between current drive directions. This parameter change allows the system to adapt to varying offset conditions while preserving measurement symmetry.
Application Domain
Data Source
AI summary:
A semiconductor device with a magnetic switch configuration that includes a Hall element, a switch circuit, an amplifier, a comparator, and a latch circuit, which uses a reference voltage circuit to adjust the comparator reference voltage based on control signals, allowing for optimal adjustment of the magnetic offset and improving the symmetric property of magnetoelectric conversion characteristics.
Abstract
A semiconductor device includes a magnetic switch provided on a semiconductor substrate. The magnetic switch includes: a Hall element, first and second power supply terminals; a current source driving the Hall element; a switch circuit switching a differential output voltage supplied from two electrodes of the Hall element to a first or second state based on a control signal supplied from a control terminal; an amplifier amplifying a signal from the switch circuit; a reference voltage circuit generating a reference voltage based on a reference common mode voltage and a control signal; a comparator receiving an output signal of the amplifier and the reference voltage; and a latch circuit latching an output voltage of the comparator. The reference voltage of the reference voltage circuit is controlled by switching from a reference value to a voltage with a high or low adjustment value according to the output voltage of the comparator.