RFID Voltage Regulator Circuit Without Quiescent Current
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Solution Overview
Problem
Existing voltage regulator circuits for RFID tags consume quiescent current and have complex designs with op-amps and current references, leading to high power consumption and increased die area.
Innovation Solution
A power-efficient voltage regulator circuit for RFID tags is developed, which includes a control circuit with cross-coupled transistors, an impulse current source, and a sensing circuit. This design eliminates quiescent current branches and does not require transformers, inductors, or additional voltage or current references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LDO-based voltage regulator is used, then voltage regulation is achieved without inductor or transformer, but quiescent current consumption is high and circuit complexity increases
Solution Approach 1:
The patent employs periodic switching action through switches S1-S6 that are activated in sequence during each RF cycle. The rectifier charges capacitors during positive half-cycles and discharges during negative half-cycles, creating periodic voltage regulation without continuous quiescent current draw. This periodic operation eliminates the need for continuous LDO regulation while maintaining stable output voltage.
Solution Approach 2:
The patent extracts and eliminates the quiescent current-consuming components from traditional LDO regulators. By removing the continuous bias current paths and using only switched components that draw current only during active regulation phases, the design achieves voltage regulation without the parasitic quiescent current that plagues conventional LDO implementations.
2Use of energy by moving object
If switching regulator without inductor is used, then power consumption is reduced, but static comparator consumes quiescent current and circuit complexity remains high
Solution Approach 1:
The patent merges the voltage regulation function with the existing rectifier circuitry. The same switches and capacitors used for RF-to-DC conversion are also utilized for voltage regulation, eliminating the need for separate comparator and control circuitry. This functional merging reduces component count and simplifies the overall circuit architecture while maintaining low power operation.
Solution Approach 2:
The rectifier circuit automatically performs voltage regulation through its inherent charge-pump operation. The capacitors self-charge during RF peaks and self-discharge to maintain minimum voltage levels, requiring no external control or monitoring. The circuit regulates voltage through its natural operating cycle rather than requiring active management.
3Measurement precision
If shunt limiter is used to set output voltage, then output voltage level is controlled, but excess power is shunted to ground causing higher power consumption
Solution Approach 1:
The patent implements feedback through the sensing of capacitor voltage levels during the rectifier discharge phase. The control logic monitors when capacitor voltages reach threshold levels and adjusts switching timing accordingly, creating a feedback mechanism that maintains output voltage without dissipative shunting. This feedback control enables precise voltage regulation while minimizing power loss.
Solution Approach 2:
The patent changes the operating parameters by using variable switching durations and capacitor discharge thresholds based on load conditions. By dynamically adjusting when switches are activated and how long they remain active, the circuit adapts output voltage levels without wasting power through fixed shunt paths. The parameter changes enable efficient voltage control across varying load requirements.
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 proposed voltage regulator circuit minimizes power dissipation, maximizes the reading range of RFID tags, and reduces complexity and die area, achieving efficient voltage regulation without quiescent current consumption.
Implementation Method 1
first and second input nodes connected to outputs of a rectifier circuit which generate half wave rectified voltage signals from an electromagnetic wave signal received by the RFID circuit
Implementation Method 2
first and second transistors of cross-coupled pair formed the cross-coupled pair configuration
Implementation Method 3
a blocking diode coupled between the driving transistor and the output node to block the current from flowing back to the first input node
Data Source
AI summary
A voltage regulator circuit for RFID circuit utilizing a high efficiency circuit topology to minimize power consumption to provide only required current to regulate output voltage. The voltage regulator circuit does not consume quiescent current which minimizes power consumption. It does not contain inductor, transformer, op-amp, voltage and current reference which reduces complexity and die area. The voltage regulator circuit comprises a driving element, a control circuit and a sensing circuit. The driving element drives controlled current to output to ramp up the voltage. The sensing circuit measures voltage at the output and sends signal to the control circuit if the voltage reaches target value set by the internal parameters of the components. The control circuit stops the driving element when output voltage reaches the threshold minimizing current required to regulate voltage.