Title:
METHOD AND APPROACH SENSOR FOR DETECTING MAGNETIC BODY PASSING AT SPEED TO ZERO
Document Type and Number:
Japanese Patent JP3389438
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide the approach detector for a magnetic body, which can perform the accurate operation along the passing speed in a broad range of the magnetic body to zero.
SOLUTION: In an approach detector, a Hall transistor 10 forms a signal Vsig. Two counters 17 and 27 count pulses from clocks. Counting signals to two DACs(digital/analog converters), P-DAC 20 and N-DAC 30 are generated. The output signals of these DACs track the positive pulse and the negative pulse in the signal Vsig, respectively. The output signals are compared with Vsig, and a binary output voltage Vout of the approach detector is generated. A peak voltage VDAC-P is held until VDAC-P is lowered than by a fixed amount, and an output pulse is generated. By the same way, a peak voltage VDAC-N is held until the voltage is increased from VDAC-N by the fixed amount. An output pulse, which resets the counter 27 connected to the N-DAC 30, is generated.
Inventors:
Christan el moody
Rabbi Big
J M Town
Teri El Tu
Rabbi Big
J M Town
Teri El Tu
Application Number:
JP666797A
Publication Date:
March 24, 2003
Filing Date:
January 17, 1997
Export Citation:
Assignee:
Allegro Microsystems Inc
International Classes:
G01B7/00; G01D5/14; G01D5/244; G01D5/245; G01V3/08; H03K17/95; (IPC1-7): G01D5/245; G01B7/00; G01V3/08; H03K17/95
Domestic Patent References:
| JP477671A |
Other References:
【文献】米国特許5821745(US,A)
Attorney, Agent or Firm:
Kazuo Shamoto (5 outside)
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