Fault Control for Switched Capacitor Power Converters
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Solution Overview
Problem
Switched capacitor power converters face challenges in protecting switch elements from voltage stresses that exceed their breakdown voltages, leading to potential damage and faulty operation, especially during transient or fault conditions, due to the limitations of low-voltage transistor switches used in high-voltage conversion applications.
Innovation Solution
The implementation of fault control circuitry that measures internal voltages and currents associated with switching elements and phase nodes, allowing for the detection of deviations from predetermined ranges, and altering the converter's operation by disconnecting or limiting current flow through high-voltage switches to prevent damage, including over-voltage and under-voltage protection mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-voltage transistor switches are used in high-voltage conversion applications, then device cost and switching power loss are reduced, but the switches become vulnerable to voltage stresses exceeding their breakdown voltages during transient or fault conditions
Solution Approach 1:
The patent introduces a fault control circuit as an intermediary system that includes voltage measurement circuitry and current measurement circuitry. These circuits monitor the voltage across and current through each switch element, and when abnormal conditions are detected (voltage or current exceeding predetermined thresholds), the fault control circuit activates high-voltage switch elements to disconnect or limit current flow, thereby protecting the low-voltage switches from damage while allowing the low-voltage switches to continue operating efficiently during normal conditions
2Reliability
If fault control circuitry with measurement and protection mechanisms is added, then switch element protection is improved, but device complexity increases
Solution Approach 1:
The fault control circuit is segmented into distinct functional modules: voltage measurement circuitry for monitoring voltage across switch elements, current measurement circuitry for monitoring current through switch elements, and control logic that processes measurements and activates protection. This segmentation allows each module to perform its specific function independently, making the overall protection system more manageable and easier to integrate without excessively increasing complexity
Solution Approach 2:
The measurement circuitry continuously monitors voltage and current parameters, and the control logic automatically compares these measurements against predetermined thresholds and activates protection mechanisms when needed. This self-service approach allows the system to protect itself without requiring external intervention or complex external control systems
Data Source
AI summary
Transient or fault conditions for a switched capacitor power converter are detected by measuring one or more of internal voltages and/or currents associated with switching elements (e.g., transistors) or phase nodes, or voltages or currents at terminals of the converter, and based on these measurements detect that a condition has occurred when the measurements deviate from a predetermined range. Upon detection of the condition fault control circuitry alters operation of the converter, for example, by using a high voltage switch to electrically disconnect at least some of the switching elements from one or more terminals of the converter, or by altering timing characteristics of the phase signals.