Light receiving circuit using avalanche photodiode with a controlled voltage divider
First Claim
1. A light-receiving circuit including a bias-controlling circuit for an avalanche photodiode, said bias-controlling circuit comprising:
- a voltage source for outputting a voltage outputa current detector for detecting a photo current generated by the avalanche photodiode;
a voltage divider including a first resistor and a second resistor connected in serial to each other to divide the voltage output with a dividing ratio for outputting a divided voltage divided by the first and second resistors; and
a controller operating to maintain the voltage output of the voltage divider equal to a reference value by adjusting the voltage output of the voltage source.
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Accused Products
Abstract
The present invention provides a light-receiving circuit that applies the avalanche photodiode (APD) and reduces the power consumption at a large optical input. The bias controlling circuit of the present invention provides a voltage source, a current detector, a voltage divided, and a controller. The current detector detects the photo current generated by the APD and output the current or voltage signal corresponding to the photo current. The voltage divider divides the output of the voltage source and the current or voltage signal from the current detector thereof may affect the dividing ratio. The controller operates to maintain the output of the divider constant by adjusting the output of the voltage source. Accordingly, the output of the voltage source decreases at the high optical input, thereby reducing the power consumption of the circuit.
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Citations
11 Claims
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1. A light-receiving circuit including a bias-controlling circuit for an avalanche photodiode, said bias-controlling circuit comprising:
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a voltage source for outputting a voltage output a current detector for detecting a photo current generated by the avalanche photodiode; a voltage divider including a first resistor and a second resistor connected in serial to each other to divide the voltage output with a dividing ratio for outputting a divided voltage divided by the first and second resistors; and a controller operating to maintain the voltage output of the voltage divider equal to a reference value by adjusting the voltage output of the voltage source. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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2. The light-receiving circuit according to clam 1,
wherein the current detector outputs a current signal corresponding to the photo current to the voltage divider to vary a current flowing in the second resistor of the voltage divider.
Specification