Rotational speed device with magneto-electric elements
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHiroshi Shimamura, Shinjiro Ueda
Life of this patent
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Abstract
A rotational speed-detecting device of the present invention drives a sensor means 11, which includes a detecting unit that connects magneto-electric elements in series. A comparison voltage generator connects comparison voltage resistors in series, and is connected in parallel with the detecting unit, with a constant voltage by a constant-voltage control means 13, to which constant voltage is supplied by a constant-voltage generating means 14. The constant voltage means 14 controls a constant current of the constant-current means 15 with an on-and-off output from a comparison means 12 so as to superpose and flow a rectangular wave current in a power supply line between Vcc and VR.
Claims9
A rotational speed-detecting device comprising:
- sensor means including a detecting unit which includes magneto-electric elements of positional detection type coupled in series, and a comparison voltage generating unit which includes comparison voltage resistors coupled in series, said comparison voltage generating unit is coupled in parallel with said detecting unit;
- comparison means coupled to said detecting unit of said sensor means and to said comparison voltage generating unit;
- a power supply line having a supply terminal and a return terminal;
- constant-voltage control means coupled to said supply terminal of said power supply line and said sensor means, said constant-voltage control means for supplying constant voltage to said sensor means;
- constant-current means coupled to said supply terminal and said return terminal of said power supply line, said constant-current means for determining a constant current flow between said supply terminal and said return terminal;
- and
- constant-voltage generating means coupled to said supply terminal and said return terminal of said power supply line, said constant-voltage generating means for supplying constant voltage to said constant-voltage control means and said constant-current means,
- wherein a rectangular wave current is superimposed on the current flow in said power supply line by controlling a constant current of said constant-current means with an on-and-off output signal from said comparison means, so that a rectangular wave voltage is detectable across a load coupled between said return terminal of said power supply line and a ground.
A rotational speed detecting device comprising:
- sensor means including i) a detecting unit including magneto-electric elements coupled in series and ii) a comparison voltage generating unit including resistors coupled in series, said comparison voltage generating unit being coupled in parallel with said detecting unit;
- comparison means adapted for receiving a midpoint voltage of said detecting unit and a midpoint voltage of said comparison voltage generating unit, and outputting a two level voltage output signal based on a detecting voltage of said magneto-electric elements;
- a supply terminal;
- a return terminal;
- constant-voltage control means connected to said supply terminal and said sensor means, and for supplying constant voltage to said sensor means;
- constant-current means for determining a constant current between said supply terminal and said return terminal based on the output signal from said comparison means;
- and
- constant-voltage generating means connected to said supply terminal, said return terminal, said constant-voltage control means and said constant-current means, and for supplying a constant voltage to said constant-voltage control means and said constant-current means.
Dependencies are inferred from the claim text.