Time-Delay VTVA Circuit With Non-Overlapping Phase Amplification
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Solution Overview
Problem
Conventional voltage-to-time-to-voltage amplifiers (VTVA) face challenges such as non-linearity, reduced speed, noise, and sensitivity to process, voltage, and temperature (PVT) variations, which hinder the performance of pipelined analog-to-digital converters (ADCs).
Innovation Solution
The proposed VTVA design includes a first input capacitive element, a first amplifier, a first current source, and a first output capacitive element, where the first current source sources or sinks current during non-overlapping phases to both the input and output capacitive elements, allowing for efficient voltage-to-time-to-voltage amplification without delay lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional voltage-to-time-to-voltage amplifiers are used, then the circuit structure is simple, but the linearity is poor and sensitivity to PVT variations is high
Solution Approach 1:
The amplifier operation is segmented into distinct non-overlapping phases (first phase for input capacitive element, second phase for output capacitive element). This temporal segmentation allows the same current source to be used sequentially for both elements without interference, improving linearity while avoiding the need for completely separate current sources that would increase complexity.
Solution Approach 2:
The amplifier employs periodic non-overlapping phases to alternately charge/discharge the input and output capacitive elements. This periodic action with clear phase separation ensures that each element receives dedicated current sourcing/sinking time, reducing PVT sensitivity and improving linearity through consistent, repeatable operation cycles.
2Speed
If conventional amplifiers are used, then the circuit is easier to implement, but the amplification speed is reduced
Solution Approach 1:
The input capacitive element is charged or discharged during the first phase before the output phase begins. This preliminary action on the input element prepares the signal for amplification, and the non-overlapping timing ensures that the output phase can proceed immediately afterward without waiting for input phase completion, thereby increasing amplification speed.
Solution Approach 2:
The amplifier uses dynamic switching between two operational phases controlled by non-overlapping clock signals. This dynamic phase switching allows the circuit to rapidly transition between processing the input capacitive element and the output capacitive element, achieving faster overall amplification speed compared to static or sequentially slower conventional designs.
3Object-affected harmful factors
If conventional amplifiers are used, then the circuit structure is simpler, but noise performance is degraded
Solution Approach 1:
By segmenting the current sourcing/sinking operation into non-overlapping phases for the input and output capacitive elements, the circuit reduces simultaneous switching noise and current noise. Each element is processed during its dedicated phase, preventing noise interference between input and output stages while maintaining a relatively simple circuit structure.
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
This design achieves faster amplification times, increased linearity, and reduced sensitivity to PVT and common-mode variations compared to conventional amplifiers, thereby enhancing the performance of pipelined ADCs.
Implementation Method 1
a first input capacitive element selectively coupled to a first input node of the VTVA
Implementation Method 2
comparing, via a first amplifier, a voltage on the first input capacitive element to a threshold voltage
Implementation Method 3
a first output capacitive element coupled to a first output node of the VTVA
Data Source
AI summary
Certain aspects of the present disclosure generally relate to a voltage-to-time-to-voltage amplifier (VTVA). The VTVA may include: a first input capacitive element selectively coupled to a first input node of the VTVA; a first amplifier having an input coupled to the first input capacitive element; a first current source configured to sink a first discharge current from the first input capacitive element during a first phase through a first switch; and a first output capacitive element coupled to a first output node of the VTVA. In some aspects, the first current source is further configured to sink a second discharge current from the first output capacitive element during a second phase through a second switch, the second switch comprising a control input coupled to an output of the first amplifier; and the first phase is non-overlapping with the second phase.