SEMICONDUCTOR DEVICE
First Claim
1. A semiconductor device comprising:
- a first trans-impedance amplifier that converts a first current signal generated by a first photodiode, into which an optical signal is input, into a first voltage signal;
a second trans-impedance amplifier that converts a second current signal generated by a second photodiode, to which an optical signal is blocked, into a second voltage signal;
a peak hold circuit that holds the peak value of the first voltage signal;
a comparator that outputs a pulse on the basis of the first and second voltage signals; and
a threshold current setting circuit that draws out a threshold current, which is proportional to a reference current generated on the basis of a voltage difference between a peak voltage output by the peak hold circuit and a reference voltage at the output node of the second photodiode, from the connection between the second photodiode and the second trans-impedance amplifier.
2 Assignments
0 Petitions
Accused Products
Abstract
A semiconductor device that includes: a first trans-impedance amplifier that converts a first current signal generated by a first photodiode, into which an optical signal is input, into a first voltage signal; a second trans-impedance amplifier that converts a second current signal generated by a second photodiode, to which an optical signal is blocked, into a second voltage signal; a peak hold circuit that holds the peak value of the first voltage signal; a comparator that outputs a pulse on the basis of the first and second voltage signals; and a threshold current setting circuit that draws out a threshold current, which is proportional to a reference current generated on the basis of a voltage difference between a peak voltage output by the peak hold circuit and a reference voltage at the output node of the second photodiode, from the connection between the second photodiode and the second trans-impedance amplifier.
11 Citations
7 Claims
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1. A semiconductor device comprising:
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a first trans-impedance amplifier that converts a first current signal generated by a first photodiode, into which an optical signal is input, into a first voltage signal; a second trans-impedance amplifier that converts a second current signal generated by a second photodiode, to which an optical signal is blocked, into a second voltage signal; a peak hold circuit that holds the peak value of the first voltage signal; a comparator that outputs a pulse on the basis of the first and second voltage signals; and a threshold current setting circuit that draws out a threshold current, which is proportional to a reference current generated on the basis of a voltage difference between a peak voltage output by the peak hold circuit and a reference voltage at the output node of the second photodiode, from the connection between the second photodiode and the second trans-impedance amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification