Switching Apparatus Average Current Control via Voltage Calculation
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Solution Overview
Problem
Conventional current programmed control schemes rely on peak current control, which can lead to reduced accuracy in controlling average currents through inductive elements due to switching ripple currents, necessitating detection of all currents for precise control.
Innovation Solution
A switching apparatus with a signal control circuit that calculates the turn-off time of a switch using monitoring and reference voltages to accurately control the average current flowing through an inductive element, employing an SR latch and reset signal generator to manage the switch's operation based on these voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If peak current control scheme is used, then transient response and stability are improved, but accuracy of current control loop deteriorates due to switching ripple current
Solution Approach 1:
The patent segments the current control into two independent parts: peak current control for transient response and average current control for accuracy. The controller separately manages the peak current waveform and calculates the average current independently, allowing each control objective to be optimized without interference from switching ripple effects.
Solution Approach 2:
The patent introduces an average current calculator as an intermediary component that processes the peak current control signals and switching ripple information to compute the average current. This intermediary enables accurate average current measurement without directly measuring the noisy peak current, thus improving control accuracy while maintaining the benefits of peak current control.
2Measurement precision
If all currents flowing through inductive element are detected to accurately detect average current, then accuracy of current control loop is improved, but device complexity increases
Solution Approach 1:
The patent creates a mathematical copy of the average current through calculation rather than physical measurement. The average current calculator computes the average current based on peak current control parameters and switching ripple characteristics, providing an accurate representation without requiring additional physical sensors or detection circuits.
Solution Approach 2:
The patent changes the control parameter from direct current measurement to calculated average current based on voltage and timing parameters. By measuring voltages across the inductive element and calculating average current from these voltage measurements and switching timing information, the system achieves accurate current control with simpler measurement requirements.
Data Source
AI summary
Disclosed are a switching apparatus including an internal circuit using an inductive element and a control method thereof. The switching apparatus includes a switch that regulates a current of the inductive element, and a signal control circuit that arithmetically calculates a turn-off time point of the switch by using a monitoring voltage corresponding to the current of the inductive element, a sampling voltage of the monitoring voltage, and a reference voltage corresponding to a target average current of the inductive element, and controls the switch.