Switching Converter Load Current Measurement With Leakage Compensation
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Solution Overview
Problem
Existing switching converters face challenges in accurately measuring small load currents, which are difficult to quantify using analog methods, particularly in applications requiring high power efficiency such as mobile devices with battery power sources.
Innovation Solution
The apparatus and method involve a load current meter that generates a control pulse based on the power switch driving signal, adjusts a reference current to compensate for leakage currents, and counts clock signal cycles during the switching period to accurately measure load currents, incorporating a pulse generation circuit, reference current generation circuit, clock generation circuit, and counter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If analog measurement methods are used for load current, then measurement simplicity is maintained, but measurement precision deteriorates for small load currents
Solution Approach 1:
The patent replaces analog measurement methods with a digital measurement system. The load current meter uses a pulse generation circuit to create control pulses based on power switch driving signals, a clock generation circuit to produce clock signals, and a counter to count clock cycles during switching periods. This digital substitution enables precise measurement of small load currents that are difficult to measure with analog methods, directly resolving the contradiction between measurement precision and measurement simplicity.
2Measurement precision
If leakage current compensation is implemented in the clock generation circuit, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent implements feedback through the reference current generation circuit, which adjusts the reference current based on detected leakage currents in the clock generation circuit. The load current meter measures the leakage current and feeds this information back to the reference current generation circuit, which then compensates by adjusting the reference current accordingly. This feedback mechanism ensures accurate load current measurement despite the added circuit complexity.
3Measurement precision
If digital measurement methods are used, then measurement precision improves for small currents, but ease of operation deteriorates
Solution Approach 1:
The patent merges multiple functions into the load current meter to maintain ease of operation. The device integrates the pulse generation circuit, clock generation circuit, counter, and reference current generation circuit with leakage current compensation into a single unified measurement device. This consolidation allows the complex digital measurement system to operate automatically without requiring separate manual adjustments or operations, thus maintaining ease of operation despite the advanced functionality.
Data Source
AI summary
An apparatus configured to measure a load current provided to a load of a switching converter includes a pulse generation circuit configured to generate a control pulse based on a power switch driving signal of the switching converter, a reference current generation circuit configured to generate a reference current based on the control pulse, a clock generation circuit configured to generate a clock signal based on the control pulse and the reference current, and a clock counter configured to count the number of cycles of the clock signal during a switching period of the switching converter. The reference current generation circuit is configured to adjust the reference current to compensate for a leakage current generated in the clock generation circuit during the switching period.