Logarithmic a/d converter, method of logarithmic a/d conversion logarithmic d/a converter, method of logarithmic d/a conversion, and system for measuring physical quantity
AssigneeSumitomo Metal Industries, Ltd.
InventorMasami Yakabe
Life of this patent
Estimating the term…
Abstract
An analog multiplier 11 raises a base reference voltage “Vref0” to the nth power so that a reference voltage “Vref1” is produced. Analog multipliers 12 and 13 sequentially raise the reference voltage “Vref1” to the nth power so that reference voltages “Vref2” and “Vref3” are produced. Switch groups 38-41 control the reference voltages “Vref0” to “Vref3”, which are then sent to an analog multiplier 14 together with an input voltage “Vin”. A comparator 14 sequentially compares a multiplication result “Vx” of the multiplier 14 with a voltage “Vout” outputted from a sensor circuit 2, so that a digital output value “Dout” is produced. The analog multiplier 14 is set as appropriate.
Claims15
A logarithmic A/D converter, comprising:
- a reference voltage generating unit that includes at least one first multiplier that raises a predetermined inputted reference voltage to an nth power;
- a comparison voltage operating unit that is connected to at least one output terminal of said reference voltage generating unit to select a reference voltage;
- and
- a comparator connected to an output terminal of the comparison voltage operating unit for receiving the selected reference voltage and to an input terminal for a voltage to be converted.
A logarithmic A/D conversion method, comprising:
- generating a plurality of reference voltages, wherein values of the reference voltages have a relation of a progression made by raising the reference voltages to an nth power from an inputted reference voltage;
- generating a plurality of comparison voltages based on at least one of the plurality of reference voltages;
- and
- determining an output digital value based on the plurality of comparison voltages, the output digital data corresponding to a voltage to be converted.
A physical quantity measuring system, comprising a logarithmic A/D converter that includes:
- a reference voltage generating unit that contains at least one first multiplier that raises a predetermined inputted reference voltage to an nth power;
- a comparison voltage generating unit that is connected to an output terminal of the reference voltage generating unit;
- and
- a comparator connected to an output terminal of the comparison voltage generating unit and to an input terminal for a voltage to be converted;
- wherein a voltage inputted to the physical quantity measuring system is connected to a base voltage input terminal of the converter, and a voltage outputted from the quantity measuring system is connected to the input terminal for a voltage to be converted.
Dependencies are inferred from the claim text.