Voltage Converter Input Current Extraction via Slope Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage converters require external sense resistors to monitor input current, which occupy space on the circuit board and necessitate dedicated pins, complicating the design and increasing board real estate requirements.
Innovation Solution
A voltage converter design that utilizes a slope detector circuit and inductor current sense circuit to generate signals indicative of the inductor current, allowing for the estimation of input current without direct measurement, thereby eliminating the need for external sense resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external sense resistor is used to monitor input current, then current monitoring capability is achieved, but board space is occupied and dedicated pins are required
Solution Approach 1:
The patent merges the current sensing function with existing inductor current measurement circuitry. The slope detector circuit that was previously used only for current mode control now also provides input current monitoring information by detecting the rising edge slope of the inductor current, eliminating the need for separate sense resistors and pins.
Solution Approach 2:
The patent makes the slope detector circuit multi-functional. It serves dual purposes: maintaining current mode control functionality while simultaneously providing input current monitoring capability. This universal approach allows one circuit to perform multiple functions, reducing overall component count and board space requirements.
2Measurement precision
If an external sense resistor is used to monitor input current, then current monitoring capability is achieved, but device complexity increases due to dedicated pins
Solution Approach 1:
The patent combines the input current monitoring function with the existing slope detector circuit and microcontroller. By processing the slope detector output signal to identify the rising edge portion of the inductor current waveform, the system achieves current monitoring without requiring additional dedicated pins or external components.
Solution Approach 2:
The patent enables the voltage converter's existing control circuitry to serve the additional function of input current monitoring. The slope detector circuit and microcontroller process their normal control signals to simultaneously extract input current information, making the system self-sufficient without external monitoring components.
Data Source
AI summary
A voltage converter includes a high side power transistor coupled to an input voltage node and a low side power transistor coupled to the high side power transistor at a switch node. The switch node is configured to be coupled to an inductor. A slope detector circuit is configured to receive a signal indicative of a current through the inductor. The inductor current is a triangular waveform comprising a ramp-up phase and a ramp-down phase. The slope detector circuit also is configured to generate an output signal encoding when the inductor current is ramping up and when the inductor current is ramping down.