Asynchronous Digital Shunt Regulation for Wireless Power Receivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless power receivers experience over-voltage during start-up and load switching due to delays in clock initialization, requiring high-voltage devices that increase cost and die area, and are not effectively regulated by series regulators.
Innovation Solution
Implementing an asynchronous digital shunt regulation system that uses a current steering DAC and comparator to bypass excess voltage to ground, allowing regulation without a system clock, thus preventing over-voltage and eliminating the need for high-voltage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series regulator is used to regulate voltage in a wireless power receiver, then voltage regulation is provided during normal operation, but over-voltage occurs during start-up and load switching due to clock initialization delays
Solution Approach 1:
The patent inverts the regulation approach from series regulation to shunt regulation. Instead of regulating voltage in series with the load, a shunt regulator is placed in parallel with the load to actively sink excess current and maintain voltage during start-up and load switching, thereby preventing over-voltage conditions that occur with series regulation.
Solution Approach 2:
The shunt regulator is activated before the main system clock starts pulsing, during the clock-start-up delay period. This preliminary action ensures voltage regulation is already in place before the digital circuitry becomes operational, preventing over-voltage from occurring during this critical transition period.
2Reliability
If high-voltage devices are used to prevent over-voltage damage, then device protection is improved, but die area and cost increase
Solution Approach 1:
The patent uses standard-voltage transistors in the shunt regulator that are less expensive and occupy smaller die area compared to high-voltage transistors. The shunt regulator actively manages voltage to prevent over-voltage conditions, allowing the use of lower-voltage-rated, smaller, and cheaper transistors throughout the circuit.
3Ease of manufacture
If standard CMOS process steps are used, then manufacturing cost is reduced, but high-voltage device construction is not possible
Solution Approach 1:
The patent changes the operating voltage parameters through the shunt regulator control mechanism, maintaining voltages within standard CMOS ranges even during transient conditions. This allows the use of standard CMOS fabrication processes without requiring specialized high-voltage process steps, reducing manufacturing complexity and cost.
4Reliability
If a clocked digital regulator is used, then regulation control is improved, but start-up delay increases due to clock initialization
Solution Approach 1:
The shunt regulator uses an asynchronous control mechanism that does not depend on the system clock. The regulator monitors voltage conditions and adjusts shunt current independently, allowing it to provide immediate regulation during start-up without waiting for clock initialization, thus eliminating the start-up delay inherent in clocked digital regulators.
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 asynchronous digital shunt regulation system effectively maintains target voltage levels during start-up and load switching without initial clock delays, reducing the need for high-voltage devices and minimizing die area, thereby lowering costs and improving performance.
Implementation Method 1
The power is transferred wirelessly by electromagnetic induction
Implementation Method 2
The wireless signal received on receiver antenna 128 is rectified by rectifier 102
Data Source
AI summary
A receiver is energized by wireless power from a coil antenna. A matching network tunes the receiver to a resonant frequency and a bridge and capacitor generate an output voltage. The output voltage is divided and compared to a reference voltage. An asynchronous digital controller increases a digital count when the compare result is true, but decreases the digital count when the compare result is false. A current-steering Digital-to-Analog Converter (DAC) shunts a current from the output that is a function of the digital count. The asynchronous digital controller, comparator, and DAC do not use a system clock, so the digital feedback to the shunt current operates when the target output voltage is reached, preventing over-voltage when waiting for the system clock to begin pulsing. The digital count is compared to a digital threshold to recover transmitted Amplitude-Shifted-Keyed (ASK) data.