TDC Voltage-Controlled Oscillator Gate Stabilization
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Solution Overview
Problem
The variation in power-supply voltage caused by current flow during startup of voltage-controlled oscillators in time-to-digital converters leads to unstable operation and reduced accuracy in distance measurement devices.
Innovation Solution
Incorporating a supply circuit that supplies a current to the gate of the control transistor of the voltage-controlled oscillator to stabilize the control voltage and reduce crosstalk between TDCs, using a capacitive element and switch elements to manage charge injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage-controlled oscillator is used to generate multiphase clocks in TDCs, then the clock frequency can be increased and measurement precision can be improved, but power-supply voltage variation occurs during startup causing unstable operation
Solution Approach 1:
The supply circuit pre-charges the gate capacitance of the control transistor before the oscillator starts oscillating. This preliminary action ensures that the control voltage is already stable when the oscillator begins to operate, preventing voltage variations during startup and ensuring stable operation of the TDC.
Solution Approach 2:
The supply circuit acts as an intermediary between the power supply and the control transistor gate. It includes a capacitor connected in parallel with the gate to provide a stable voltage reference, and a switch that controls the charging path of the capacitor. This intermediary structure isolates the oscillator from power supply fluctuations and ensures operational stability.
2Productivity
If multiple TDCs are operated simultaneously with increased clock frequency, then productivity is improved, but crosstalk between TDCs increases due to power-supply voltage variation
Solution Approach 1:
Each TDC is equipped with its own dedicated supply circuit that independently charges the gate capacitance of its control transistor. This segmentation ensures that power supply variations in one TDC do not affect other TDCs, eliminating crosstalk even when multiple TDCs operate simultaneously at high frequencies.
Solution Approach 2:
The supply circuit with the capacitor and switch acts as an intermediary that isolates each TDC from common power supply fluctuations. The capacitor stores charge locally at the gate, providing a stable voltage reference that prevents crosstalk between adjacent TDCs during high-speed operation.
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
Stabilizes the operation of time-to-digital converters, reducing crosstalk and improving distance measurement accuracy by suppressing voltage variations.
Implementation Method 1
using a capacitive element and switch elements to manage charge injection
Data Source
AI summary
An electronic circuit is provided. The electronic circuit includes a plurality of time-to-digital converters. Each of the plurality of time-to-digital converters includes a voltage-controlled oscillator configured to generate a multiphase clock. Each voltage-controlled oscillator includes a control transistor which is arranged between a first power supply line and a second power supply line and includes a gate to which a control voltage is input, and each voltage-controlled oscillator further includes a supply circuit configured to supply a current to the gate.