Avalanche Photodiode Bias Cutoff to Prevent Standby Flow-Through Current
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Solution Overview
Problem
Existing photoelectric conversion devices do not adequately address the phenomenon that occurs when the switch for controlling the voltage of an avalanche photodiode (APD) is turned off, leading to inefficiencies and increased power consumption.
Innovation Solution
A photoelectric conversion device is designed with a switch that controls the resistance value between a power supply and the APD, including a cut-off unit to cut off the electrical path between power supplies, preventing flow-through currents during non-exposure periods and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the switch for controlling the voltage of the APD is turned off, then the device enters standby state, but flow-through currents occur between power supplies causing increased power consumption
Solution Approach 1:
The patent extracts and removes the harmful flow-through current from the circuit by introducing a cut-off unit that specifically targets and eliminates this parasitic current path between power supplies when the APD is in standby state, without affecting the main signal detection function
Solution Approach 2:
The cut-off unit acts as an intermediary component inserted between the power supplies and the APD circuit. It mediates the power delivery by selectively blocking the flow-through current while allowing legitimate power delivery during active operation, thus resolving the energy loss problem without compromising device functionality
2Reliability
If the switch controls resistance value between power supply and APD, then voltage control is achieved, but electrical path remains connected causing continuous power consumption during non-exposure periods
Solution Approach 1:
The patent segments the power delivery path into two distinct controllable sections: the main switch that controls voltage to the APD for reliable operation, and the cut-off unit that separately controls the parasitic power consumption path. This segmentation allows independent optimization of voltage control reliability and power consumption reduction
3Loss of energy
If the cut-off unit cuts off electrical path between power supplies, then power consumption is reduced, but voltage control of APD must be carefully managed
Solution Approach 1:
The patent implements preliminary action by having the cut-off unit activate before the main switch transitions to standby state. This timing sequence ensures that the electrical path is already blocked when voltage control is reduced, preventing any potential flow-through current while maintaining the ability to quickly restore full voltage control when needed
Solution Approach 2:
The system employs periodic action through coordinated switching where the cut-off unit and main switch operate in a defined sequence during exposure and non-exposure periods. This periodic coordination ensures that power consumption is minimized during standby while voltage control reliability is maintained during active photon detection phases
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages the APD's voltage control, reducing power consumption and maintaining efficient photon detection operations by preventing flow-through currents during non-exposure periods.
Implementation Method 1
Each pixel can detect light in a single photon level using a phenomenon in which photocharge generated due to incidence of a photon on the APD causes avalanche multiplication
Implementation Method 2
a switch configured to switch a resistance value between the first power supply and the first terminal
Data Source
AI summary
A photoelectric conversion device includes an avalanche photodiode including a first terminal and a second terminal, a first power supply connected to the first terminal, a second power supply connected to the second terminal, and a switch for switching a resistance value between the first power supply and the first terminal. The first terminal of the avalanche photodiode is connected to each of a gate of a first p-channel metal-oxide semiconductor (PMOS) transistor and a gate of a first n-channel MOS (NMOS) transistor, the first PMOS transistor and the first NMOS transistor being connected in series between a third and a fourth power supplies. The photoelectric conversion device further includes a first cut-off unit for cutting off an electrical path between the third power supply and the fourth power supply, and if the switch is controlled to a standby state, the first cut-off unit cuts off the electrical path.