Hysteretic Buck Controller With Inductor Current Estimation
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Solution Overview
Problem
Existing buck converter topologies face inefficiencies at light loads due to high quiescent current and noise from dual current sensing circuitry, which also introduces switching noise and is layout sensitive.
Innovation Solution
A power converter employing a positive slope inductor coil estimator that senses current through a low side switch, reducing the need for dual current sensing and using a transconductance network to estimate current magnitude, thereby minimizing power consumption and noise while maintaining transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual current sensing circuitry is used in hysteretic buck controller, then transient response is improved, but quiescent current increases and efficiency decreases at light loads
Solution Approach 1:
The patent extracts only the necessary current sensing function by using a single current sensing circuit instead of dual sensing circuits. The inductor coil current estimation circuit reconstructs the full current waveform from the partial sensing data, eliminating the need for redundant sensing circuits while maintaining transient response performance.
Solution Approach 2:
The patent creates a copy of the current waveform through estimation circuitry that reconstructs the complete inductor current signal from partial sensing data. This estimated current copy is then used for control decisions, replacing the need for multiple physical sensing circuits.
2Measurement precision
If dual current sensing circuitry is used in hysteretic buck controller, then current measurement accuracy is improved, but noise and switching interference increase
Solution Approach 1:
The patent removes the noisy dual sensing circuitry and keeps only one current sensing circuit. The estimation circuit reconstructs the complete current waveform mathematically, eliminating the source of switching noise and layout sensitivity while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces physical dual sensing circuits with an estimation-based computational approach. Instead of using multiple physical sensors that introduce noise, the system uses mathematical estimation to reconstruct current waveforms, substituting mechanical/electrical sensing with signal processing.
3Measurement precision
If current sensing circuitry is used in both high side and low side switches, then current control precision is improved, but device complexity and layout sensitivity increase
Solution Approach 1:
The patent extracts only the essential current sensing requirement by implementing sensing on one side only. The estimation circuit compensates for the missing sensing data, simplifying the overall sensing architecture while maintaining control precision.
Solution Approach 2:
The single current sensing circuit serves multiple functions: it provides direct current measurement during NMOS conduction and serves as the basis for estimating current during PMOS conduction through the estimation circuit, replacing what would otherwise require separate sensing circuits.
Data Source
AI summary
A circuit and method for power converter for improved current monitoring, comprising a buck converter comprising a high side switch, a current sensing circuits parallel to the buck converter configured to sense a current through a low side switch, and a positive slope inductor coil estimator sensing circuit parallel to a buck converter configured to estimate a current magnitude.