Electricity: power supply or regulation systems – Self-regulating – Using a three or more terminal semiconductive device as the...
Reexamination Certificate
2000-08-30
2002-03-12
Sterrett, Jeffrey (Department: 2838)
Electricity: power supply or regulation systems
Self-regulating
Using a three or more terminal semiconductive device as the...
C323S313000
Reexamination Certificate
active
06356065
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a current-voltage converter for converting a current signal to a voltage pulse, particularly to a current-voltage converter in which a threshold value during generation of a voltage pulse can change to indicate a constant ratio in accordance with a peak value of an input current.
2. Related Background Art
In a conventional art, when a current signal is converted to a voltage pulse, a main method comprises once converting the current signal to a voltage signal, and subsequently using a desired threshold voltage to convert the voltage signal to the voltage pulse.
For example, when a threshold value during generation of the voltage pulse is changed to indicate a constant ratio in accordance with a peak value of an input current, a circuit shown in
FIG. 1
is used. In
FIG. 1
, R
1
denotes a resistance for converting an input signal current i
in
to a voltage,
41
,
42
denote operational amplifiers, the operational amplifiers
41
,
42
together with a diode D
1
and a capacity C
1
disposed therebetween constitute a voltage mode peak hold circuit, and the voltage mode peak hold circuit holds a peak value Vs(peak) of an input signal Vs after the voltage conversion. Characters R
2
, R
3
denote resistances, and form a voltage Vref by dividing Vs(peak) to R
3
/(R
2
+R
3
). A voltage comparator
43
uses Vs as one input and reference voltage Vref as another input. According to
FIG. 1
, since the reference voltage Vref of the voltage comparator indicates a value obtained by multiplying the input signal peak value by R
3
(R
2
+R
3
), a current-voltage converter can be constituted in which the threshold value during the generation of the voltage pulse changes to indicate the constant ratio in accordance with the peak value of the input current.
However, since the converter shown in the circuit of
FIG. 1
is constituted of a plurality of operational amplifiers, voltage comparator, resistance, diode, capacitor, and the like, a circuit scale tends to be enlarged.
As described above, according to a shown technique, in the constitution of the current-voltage converter in which the threshold value during the generation of the voltage pulse changes to indicate the constant ratio in accordance with the peak value of the input current, there is a problem that the circuit scale is enlarged. This raises problems such as increase of occupied area, and increase of power consumption, and there is a room for improvement.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a current-voltage converter which can change a threshold value during generation of a voltage pulse to indicate a constant ratio in accordance with a peak value of an input current with a smaller circuit scale.
Further object of the present invention is to provide a current-voltage converter which can select the ratio.
Another object of the present invention is to provide a current-voltage converter comprising: current transmission means for outputting a plurality of currents proportional to an inputted current; current mode peak hold means for inputting the current outputted from the current transmission means, and outputting the current proportional to a peak value of the inputted current; and current comparison means for comparing the current outputted from the current transmission means with the current outputted from the current mode peak hold means, inputting the current for conversion to a voltage pulse, and outputting a voltage.
Still another object of the present invention is to provide a current-voltage converter comprising: current transmission means for outputting a plurality of currents proportional to an inputted current; current mode peak hold means for inputting the current outputted from the current transmission means, and outputting the current proportional to a peak value of the inputted current; subtraction means for obtaining a difference between the current outputted from the current transmission means and the current outputted from the current mode peak hold means; and current-voltage conversion means for inputting the current outputted from the subtraction means and outputting a pulse voltage depending upon whether the input current is positive or negative.
REFERENCES:
patent: 4086624 (1978-04-01), Fraley
patent: 4642551 (1987-02-01), Miller
patent: 4877953 (1989-10-01), Yamamuro
patent: 5123732 (1992-06-01), Gross et al.
patent: 5237493 (1993-08-01), Durig et al.
patent: 5266887 (1993-11-01), Smith
patent: 5563502 (1996-10-01), Akioka et al.
patent: 5841310 (1998-11-01), Kalthoff et al.
patent: 5952885 (1999-09-01), Wu et al.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Sterrett Jeffrey
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