Dynamic Comparator Charge Recycling to Cut Reset Current
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Solution Overview
Problem
Conventional dynamic comparators waste stored charge in the charge storage capacitor when switching from the comparison state to the reset state, leading to inefficiencies in power consumption and increased charge-discharge current.
Innovation Solution
A dynamic comparator design that includes a switching charge storage unit with multiple switching transistors and a charge storage capacitor, allowing the voltage on the capacitor terminals to be recycled from half of the system voltage to the full system voltage during state transitions, thereby preventing charge loss and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge storage capacitor is pre-charged to system voltage in reset state, then the comparator can operate in comparison state, but the stored charge is wasted when switching back to reset state
Solution Approach 1:
The patent recovers the charge that would otherwise be discarded from the charge storage capacitor by adding a charge recycling circuit. This circuit captures the charge from the capacitor's first terminal when switching from comparison state to reset state and redirects it to the second terminal, thereby recovering the energy that would have been wasted and enabling continuous operation without charge loss.
2Reliability
If the charge storage capacitor is pre-charged to system voltage, then the comparator can function properly, but larger charge-discharge current is required
Solution Approach 1:
By recovering and recycling the charge from the charge storage capacitor instead of discharging it to ground, the patent significantly reduces the charge-discharge current requirement. The recycling circuit redirects the charge to maintain the capacitor's voltage, eliminating the need for large discharge currents and reducing overall power consumption while maintaining proper comparator functionality.
Data Source
AI summary
A dynamic comparator includes a differential amplifier stage, a switching unit and a switching charge storage unit. The switching charge storage unit includes a plurality of switching transistors, and a charge storage capacitor electrically connected to the plurality of switching transistors. When an operational mode of the dynamic comparator is switched from a comparison state to a reset state, a voltage on one of a first terminal and a second terminal of the charge storage capacitor is increased from a half of the system voltage to a system voltage, so as to implement a charge recycle effect. The dynamic comparator of the present invention can have lower power consumption and lower charge-discharge current.