Voltage Feedback Power Circuit for Low-Power Field Instruments
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Solution Overview
Problem
Field device systems, such as radar level gauges, face challenges in managing power efficiently due to limited power availability, especially in systems using two-wire feeding or battery power.
Innovation Solution
The implementation of a field device system with power management circuitry that includes a capacitive energy storage, a first voltage converter to charge the storage at an intermediate voltage, and a second voltage converter to provide the operating voltage. A voltage feedback circuit and control circuit are used to monitor and control the charging of the energy storage, minimizing losses and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If energy is stored in a capacitive energy storage device to boost available power during periods of increased power requirements, then the available power is improved, but the device complexity increases due to the need for additional voltage converters and control circuitry
Solution Approach 1:
The voltage feedback circuit serves multiple functions: it monitors the output voltage of the energy storage device, provides feedback signals for control, and enables the system to adaptively manage power distribution. This multi-functionality reduces the need for separate dedicated circuits, thereby managing complexity while achieving power boosting capability
Solution Approach 2:
A voltage feedback circuit is implemented to continuously monitor the output voltage of the capacitive energy storage device and provide feedback signals to the control circuit. This feedback mechanism enables automatic adjustment of charging parameters, optimizes power distribution, and ensures stable operation, allowing the system to manage complexity through intelligent control rather than additional hardware
2Speed
If the clock frequency of the processor is increased during signal processing, then the processing speed is improved, but the power consumption increases
Solution Approach 1:
The system dynamically adjusts the clock frequency of the processor based on real-time processing requirements and available power levels. During periods of high power availability, the clock frequency is increased to boost processing speed. During power-constrained periods, the frequency is reduced to conserve energy, creating a dynamic balance between speed and power consumption
Solution Approach 2:
The system implements periodic power management cycles where the processor operates at high clock frequencies during active measurement and processing intervals, then transitions to low-power standby modes between measurements. This periodic action allows high processing speed when needed while minimizing average power consumption
3Reliability
If power management circuitry is added to distribute available power between components, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The power management circuitry combines multiple functions into integrated circuits: voltage conversion, energy storage control, feedback monitoring, and processor power regulation are merged into a unified power management system. This consolidation improves reliability through coordinated control while managing complexity by reducing the number of separate discrete components
Solution Approach 2:
The power management system implements self-regulating mechanisms where the voltage feedback circuit automatically adjusts charging parameters based on energy storage voltage levels, and the processor dynamically scales its power consumption based on system conditions. This self-service capability improves reliability through automatic adaptation while minimizing the need for complex external control mechanisms
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 effectively manages power in field device systems by minimizing energy losses and optimizing energy storage, thereby extending battery life and ensuring reliable operation even with limited power availability.
Implementation Method 1
a capacitive energy storage arranged to be charged by the intermediate voltage
Implementation Method 2
a first voltage converter, having a low voltage end configured to receive a drive voltage from the power interface and a high-voltage end configured to supply an intermediate voltage higher than the operating voltage
Implementation Method 3
a second voltage converter, having an input side configured to receive an input voltage from the energy storage and an output side configured to provide the operating voltage
Data Source
AI summary
A field device system determine a process variable and includes processing circuitry connected to a sensing unit for determining a process variable; a power interface arranged to receive power from a power supply, and power management circuitry to provide power at an operating voltage to the sensing unit and the processing circuitry, the power management circuitry includes: a first voltage converter receiving a drive voltage from the power interface and supplying an intermediate voltage higher than the operating voltage; a capacitive energy storage charged by the intermediate voltage; a second voltage converter receiving an input voltage from the capacitive energy storage and to provide the operating voltage; a voltage feedback circuit configured to determine an output voltage of the capacitive energy storage; and a control circuit controlling the first voltage converter to charge the capacitive energy storage based on the output voltage of the capacitive energy storage.