Resonant Driver Circuit for BPSK Phase Shifts Without Capacitor Loss

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Solution Overview

Problem

Binary Phase Shift Keying (BPSK) modulation in antenna circuits results in low power and operational efficiencies due to capacitance, leading to energy wastage and decreased signal quality, especially with high Q-factors requiring enhanced cooling mechanisms.

Innovation Solution

A driver circuit with a predriver and pulse generator that adjusts the duty cycle and resonance frequency of the RLC tank circuit by adding and removing capacitance, allowing phase shifts without capacitor charging and discharging, thus minimizing energy dissipation and improving power efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If BPSK modulation is used in antenna circuits, then data rate and authentication speed are improved, but power efficiency and operational efficiency deteriorate due to capacitor charging and discharging

Engineering Contradiction:
Improvedata rateVSAvoidpower efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The circuit performs preliminary action by pre-charging the capacitor to the carrier voltage level before the phase shift occurs. This ensures that when the phase shift happens, the capacitor is already charged and does not need to be discharged and recharged, thereby avoiding energy loss while enabling fast phase transitions for BPSK modulation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the voltage parameter of the capacitor dynamically. During non-modulation periods, the capacitor voltage is maintained at the carrier voltage level. During phase shift, the voltage is adjusted appropriately. This parameter change allows phase shifts without the traditional charge-discharge cycle, improving power efficiency while maintaining high data rate capability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high Q-factor capacitance is used in the antenna circuit, then signal quality is improved, but the width of the valley increases causing slower phase settling and reduced power efficiency

Engineering Contradiction:
Improvesignal qualityVSAvoidphase settling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The capacitor is pre-charged to the appropriate voltage level before the phase shift occurs. This preliminary charging action ensures that when the phase shift is commanded, the capacitor is already in the correct state, eliminating the need for a long charging period after the phase shift and thus reducing the valley width and phase settling time while maintaining high Q-factor for signal quality

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If traditional capacitor-based phase shifting is used, then phase modulation is achieved, but energy is wasted due to repeated charging and discharging of capacitors

Engineering Contradiction:
Improvephase modulation capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The capacitor is pre-charged to the carrier voltage level before phase modulation occurs. This preliminary charging eliminates the need for repeated charging and discharging cycles during BPSK modulation, thereby maintaining full phase modulation capability while dramatically reducing energy consumption associated with capacitor charge-discharge operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention dynamically changes the capacitor voltage parameter to match the carrier signal level during non-modulation periods. This parameter adjustment allows the capacitor to be in a ready state for phase shifts without requiring energy-intensive charging operations, thus enabling efficient phase modulation with minimal energy consumption

Inventive Principle:
Principle #35Parameter changes

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 solution enhances power efficiency and signal quality by eliminating the need for capacitor charging and discharging, resulting in a clean spectrum and efficient phase shifts without additional spurs, improving the overall performance of BPSK modulation in antenna circuits.

Implementation Method 1

The carrier wave is used to cause resonance in the RLC tank circuit

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3121963B1Efficient driver circuit
Publication Date: 2021.08.04 NXP BV
  • EP3121963B1 patent drawingFigure 1
  • EP3121963B1 patent drawingFigure 2
  • EP3121963B1 patent drawingFigure 3

AI summary

A driver circuit (100) for driving a resonance circuit (156) is disclosed. The driver circuit (100) includes an input to receive an input signal, an amplifier (150) to amplify the input signal, a pulse generator (158) to generate a pulse train (160) based on a modulation signal, a switch (162) coupled to the pulse generator (158), a capacitor (C2) coupled to the switch in parallel such that when the switch is on, the capacitor is bypassed and a Resistor-Inductor-Capacitor (RLC) tank circuit coupled to the switch (162) and the capacitor (C2) such that the capacitor (C2) is connected in series to capacitance of the RLC tank circuit.