Digital Current Sensing Circuit for RF Power Amplifiers
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Solution Overview
Problem
Existing RF power amplifier circuits in mobile communication devices face inefficiencies in measuring battery currents, particularly in charge pump circuits, which hinders performance optimization and debugging, and current measuring resistors introduce significant losses.
Innovation Solution
A digital current sensing circuit that estimates battery currents based on voltage, eliminating the need for current measuring resistors by generating an analog sense current proportional to the battery current and digitally processing it to produce a binary word representing the estimated current, thereby improving efficiency and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measuring resistors are used to measure battery current, then measurement capability is provided, but significant power losses are introduced
Solution Approach 1:
The patent introduces a voltage sensing circuit as an intermediary to indirectly measure battery current. Instead of directly measuring current through a resistor (which causes power loss), the system senses the voltage across a known reference resistor and uses this voltage information to calculate the battery current, thereby eliminating the need for direct current measurement and associated power losses
Solution Approach 2:
The patent replaces the traditional resistive current measurement method with a voltage-based sensing approach. By substituting direct current measurement with voltage sensing and subsequent current calculation through a microcontroller, the system eliminates the power loss inherent in resistive measurement while maintaining measurement capability
2Measurement precision
If multiple current measuring resistors are added to measure battery currents in multiple charge pump circuits, then measurement capability is improved, but device complexity and power losses increase
Solution Approach 1:
The patent implements a universal voltage sensing and processing system that can measure battery currents in multiple charge pump circuits using a single integrated approach. The same voltage sensing circuitry and microcontroller-based processing system are used across all circuits, eliminating the need for separate measuring resistors in each circuit and reducing overall device complexity
Solution Approach 2:
The patent merges the current measurement function into a centralized voltage sensing and processing system. Instead of having separate current measuring resistors distributed across multiple charge pump circuits, the system combines all measurements into a unified architecture where a single voltage sensing circuit and shared microcontroller handle all current measurement tasks
3Measurement precision
If current measuring resistors are used, then battery current can be measured, but the measurement accuracy is compromised due to the resistors introducing measurement errors and power losses
Solution Approach 1:
The patent uses a voltage sensing circuit as an intermediary that provides accurate current measurement without the measurement errors introduced by resistors. By sensing voltage across a known reference and calculating current through the microcontroller, the system achieves higher measurement accuracy while eliminating the power losses and errors associated with direct resistive measurement
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
Enables accurate estimation of battery currents without adding resistors, enhancing the efficiency and performance of RF power amplifier circuits by allowing for improved debugging and optimization of mobile communication devices.
Implementation Method 1
analog current sensing circuit configured to generate an analog sense current proportional to the battery current based on the voltage
Data Source
AI summary
A digital current sensing circuit and related apparatus is provided. In one aspect, a digital current sensing circuit can be configured to estimate a battery current in a coupled circuit based on a voltage corresponding to the battery current. More specifically, the digital current sensing circuit generates an analog sense current proportional to the battery current based on the voltage and digitally processes the analog sense current to generate a battery current indication signal indicative of an estimation of the battery current. In another aspect, a number of digital current sensing circuits can be provided in an apparatus to concurrently estimate a number of battery currents in a number of circuits (e.g., charge pump circuits). As a result, it may be possible to test, debug, and/or fine-tune the apparatus based on the estimated battery currents for improved performance.