Power Stage Current Monitoring Using Virtual Current Signals
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Solution Overview
Problem
Existing smart power stage modules require additional electronic components for current monitoring, leading to increased costs.
Innovation Solution
A power stage circuit with a switch circuit, driving circuit, and current monitoring circuit that includes a current sensing circuit, virtual current signal generation circuit, and signal combination circuit, which generates a virtual current signal to monitor current without additional components, using a digital adjustment method to correct the virtual current signal for stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional electronic components are added to the power stage module for current monitoring, then current monitoring capability is improved, but manufacturing cost increases dramatically
Solution Approach 1:
The low-side switch serves dual functions: switching operation and current monitoring. The existing low-side switch is enhanced with a current sensing function by adding a sensing resistor and ADC circuit, allowing it to perform both its original switching role and new current measurement role, thereby eliminating the need for separate current monitoring components
Solution Approach 2:
The power stage module monitors its own current using internally integrated sensing circuits and processing logic. The low-side switch circuit includes built-in current sensing capability that automatically detects and reports current status to the control unit, enabling the module to self-monitor without external assistance
2Measurement precision
If virtual current signal generation circuit is added to generate accurate current monitoring signal, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The control unit continuously compares the virtual current signal with the actual current status and adjusts the PWM duty cycle accordingly. This feedback mechanism ensures accurate current monitoring and control while using simple digital signal processing rather than complex analog circuits
Solution Approach 2:
The patent replaces complex analog current sensing and signal conditioning circuits with a digital approach using ADC conversion and virtual signal generation. The current status is converted to digital signals processed by the control unit, substituting mechanical/analog systems with electronic/digital systems that are easier to integrate and control
Data Source
AI summary
A power stage circuit includes a switch circuit, a driving circuit and a current monitoring circuit. The driving circuit drives the switch circuit according to a control signal to generate an output current signal. The current monitoring circuit includes a current sensing circuit, a virtual current signal generation circuit and a signal combination circuit. The current sensing circuit senses the output current signal to generate a low-side current signal. The virtual current signal generation circuit generates a low-side voltage signal according to the low-side current signal, generates and adjusts a digital signal according to a comparison result of the low-side voltage signal and a virtual voltage signal, adjusts the virtual voltage signal according to the digital signal, and generates a virtual current signal according to the virtual voltage signal. The signal combination circuit generates a current monitoring signal according to the low-side current signal and the virtual current signal.