Photodetection circuit and distance measuring device
AssigneeSony Semiconductor Solutions Corporation
InventorYasunori Tsukuda
Life of this patent
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Abstract
There is provided a photodetection circuit and a distance measuring device. The photodetection circuit includes an avalanche photodiode, a charging circuit that supplies a voltage to the avalanche photodiode, and an input amplifier including a comparison circuit in which a voltage level of an output terminal changes according to a comparison result between a voltage of an input terminal connected to the avalanche photodiode and a reference voltage, and a voltage control circuit that changes a potential of the reference voltage. The photodetection circuit additionally includes a state detecting circuit that sets timing for causing the voltage control circuit to change the potential of the reference voltage on the basis of a detection result of the voltage level.
Claims13
A photodetection circuit, comprising:
- an avalanche photodiode;
- a charging circuit configured to supply a voltage to the avalanche photodiode;
- an input amplifier including:
- a comparison circuit configured to change a voltage level of an output terminal of the input amplifier based on a comparison result between a voltage of an input terminal of the input amplifier and a reference voltage, and
- a voltage control circuit configured to change a potential of the reference voltage, wherein
- the input terminal of the input amplifier is connected to the avalanche photodiode,
- the comparison circuit includes an inverter circuit, and
- the voltage control circuit includes:
- a switching element connected to the inverter circuit, and
- one of a resistive element or a current source connected in parallel with the switching element;
- and
- a state detecting circuit configured to set, based on a detection result of the voltage level, a timing for the voltage control circuit, wherein
- the change of the potential of the reference voltage is based on the set timing, and
- the switching element is configured to execute a switching operation based on an output voltage of the state detecting circuit.
A distance measuring device, comprising:
- a photodetection circuit that includes:
- an avalanche photodiode;
- a charging circuit configured to supply a voltage to the avalanche photodiode;
- an input amplifier including:
- a comparison circuit configured to change a voltage level of an output terminal of the input amplifier based on a comparison result between a voltage of an input terminal of the input amplifier and a reference voltage, and
- a voltage control circuit configured to change a potential of the reference voltage, wherein
- the input terminal of the input amplifier is connected to the avalanche photodiode,
- the comparison circuit includes an inverter circuit, and
- the voltage control circuit includes:
- a switching element connected to the inverter circuit, and
- one of a resistive element or a current source connected in parallel with the switching element;
- and
- a state detecting circuit configured to set, based on a detection result of the voltage level, a timing for the voltage control circuit, wherein
- the change of the potential of the reference voltage is based on the set timing, and
- the switching element is configured to execute a switching operation based on an output voltage of the state detecting circuit;
- and
- a signal processing circuit configured to process an output signal of the photodetection circuit.
A photodetection circuit, comprising:
- an avalanche photodiode;
- a charging circuit configured to supply a voltage to the avalanche photodiode;
- an input amplifier including:
- a comparison circuit configured to change a voltage level of an output terminal of the input amplifier based on a comparison result between a voltage of an input terminal of the input amplifier and a reference voltage, wherein the input terminal of the input amplifier is connected to the avalanche photodiode, and
- a voltage control circuit configured to change a potential of the reference voltage;
- and
- a state detecting circuit configured to set, based on a detection result of the voltage level, a timing for the voltage control circuit, wherein
- the change of the potential of the reference voltage is based on the set timing, and
- the input amplifier includes:
- a first input amplifier configured to output the comparison result to a signal processing circuit, and
- a second input amplifier configured to output the comparison result to the state detecting circuit.
Dependencies are inferred from the claim text.