Dual-Comparator Current-Mode Rectifier for Wireless Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless power receivers face challenges in accurately sensing AC signals and reliably turning on/off due to system noise and ringing from resonances in the receive coil, leading to inefficiencies and higher power consumption in existing integrated rectifier circuits.
Innovation Solution
A dual-comparator, current-mode rectifier with a dynamic turn-on threshold is implemented, using two comparators instead of four, with an initial low turn-on threshold that increases for additional hysteresis to prevent false triggering, and resets at the end of each cycle, allowing for true current-mode switching and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed threshold is used for comparator switching, then the circuit structure is simple, but false triggering occurs due to resonance current and noise
Solution Approach 1:
The patent applies dynamics by making the comparator threshold dynamic rather than fixed. The threshold voltage is adjusted based on the operating state: during turn-on it is set low to enable fast response, and during normal operation it is raised to prevent false triggering from resonance and noise. This dynamic adjustment resolves the contradiction between simple circuit structure and reliable switching.
Solution Approach 2:
The patent uses preliminary action by pre-setting the turn-on threshold to a low value before the switching event occurs. This allows the comparator to respond quickly to the incoming signal without being constrained by a higher normal operating threshold, thereby achieving fast turn-on while maintaining reliability during normal operation.
2Speed
If the turn-on threshold is set low for fast response, then switching speed is improved, but false triggering due to resonance current increases
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the threshold voltage based on the switching phase. During the turn-on phase, the threshold is set low to enable fast response. After turn-on, the threshold is raised to prevent false triggering from resonance current. This time-varying threshold strategy allows the system to achieve both fast switching and high reliability.
Solution Approach 2:
The patent implements periodic action by resetting the threshold to its low turn-on value at the beginning of each AC cycle and raising it after successful turn-on. This periodic reconfiguration ensures that the low threshold is only active when needed for fast response, while the high threshold protects against false triggering during the rest of the cycle.
3Reliability
If four comparators are used in traditional rectifier, then reliability is improved, but chip area and power consumption increase
Solution Approach 1:
The patent applies merging by combining the functions of multiple comparators into a single comparator with dynamic threshold control. The single comparator performs both turn-on detection and normal operation monitoring by dynamically adjusting its threshold, eliminating the need for separate comparators and reducing chip area while maintaining reliability.
Solution Approach 2:
The patent implements universality by making the single comparator multi-functional. It serves both as a turn-on detector (with low threshold) and as a normal operation monitor (with high threshold) by dynamically adjusting its threshold voltage. This multi-functionality replaces the need for multiple specialized comparators, reducing chip area and power consumption.
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 solution ensures well-defined states across operating conditions, eliminates the need for additional logic, reduces chip area and power consumption, and enhances efficiency by preventing false triggering and resonance-induced inefficiencies.
Implementation Method 1
The electromagnetic waves are transmitted over the air, and are then received and converted into usable electrical current by a wireless power receiver
Implementation Method 2
A dual-comparator, current-mode rectifier with a dynamic turn-on threshold is implemented, using two comparators instead of four
Data Source
AI summary
A dual-comparator rectifier circuit of a wireless power receiver includes a receive coil configured to generate a current in response to receiving power through electromagnetic waves from a wireless power transmitter and a bridge circuit. The bridge circuit includes four branches, and one node of each of the four branches is coupled to one of a first node or a second node of the receive coil. A first branch and a second branch of the four branches are coupled to the first node and the second node of the receive coil and include a first circuit and a second circuit, respectively. The first circuit includes a first comparator and a first switch circuit and the second circuit includes a second comparator and a second switch circuit. The first circuit and the second circuit can set a dynamic turn-on threshold for the first switch circuit and the second switch circuit, respectively.