Switched Capacitor Converter Fault Detection for Switch Overvoltage
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Solution Overview
Problem
Switched capacitor power converters face challenges in protecting switch elements from voltage stresses exceeding their breakdown voltages, leading to potential damage and faulty operation, especially during high-voltage conversions where low-voltage transistors are used.
Innovation Solution
Incorporating fault control circuitry that measures internal voltages and currents to detect deviations from predetermined ranges, allowing for the alteration of switch operations, such as disconnection or timing modifications, to prevent over-voltage and under-voltage conditions, and implementing over-voltage and under-voltage protection mechanisms for capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-voltage transistors are used to reduce cost and improve efficiency, then device cost and power loss are reduced, but the transistors become vulnerable to voltage stresses exceeding their breakdown voltages during transient or fault conditions
Solution Approach 1:
The patent implements preliminary protective action by detecting fault conditions (over-voltage, under-voltage, over-current) before they can damage the low-voltage transistors. The control circuit continuously monitors voltage and current levels and takes preventive measures by altering switch operations or disconnecting protected switches when fault thresholds are approached, thereby protecting the transistors before voltage stresses exceed their breakdown ratings.
Solution Approach 2:
The patent introduces a control circuit as an intermediary between the high-voltage power conversion process and the low-voltage transistors. This control circuit acts as a mediator that detects fault conditions and intervenes by modifying switch operations or disconnecting protected switches, thereby shielding the low-voltage transistors from harmful voltage stresses while allowing them to operate efficiently during normal conditions.
2Power
If the number of capacitors is increased to achieve higher voltage conversion ratios, then voltage conversion capability is improved, but circuit complexity and the number of required switch elements increase
Solution Approach 1:
The patent implements multi-functionality by using a single control circuit to manage and protect multiple switch elements across different stages of the charge pump. The control circuit performs multiple functions including detecting fault conditions, altering switch operations to prevent over-voltage/under-voltage, and disconnecting protected switches. This universal control approach simplifies the overall system by consolidating protection logic rather than requiring separate protection circuits for each switch-capacitor stage.
Solution Approach 2:
The patent dynamically changes operational parameters by adjusting switch timing characteristics and disconnecting switches based on detected fault conditions. The control circuit monitors voltage and current parameters in real-time and modifies the operation of switch elements (changing their on/off timing or disconnecting them entirely) to prevent damage while maintaining voltage conversion functionality. This parameter-based control allows the system to adapt to different operating conditions without requiring physical reconfiguration of the capacitor network.
3Reliability
If switch elements are operated at higher voltage ratings to ensure protection, then reliability is improved, but transistor area and capacitances increase leading to higher die cost and switching power loss
Solution Approach 1:
The patent applies preliminary protective action by detecting and responding to fault conditions before they can damage low-voltage transistors. The control circuit continuously monitors voltage and current levels and takes preventive measures by altering switch operations or disconnecting protected switches when fault thresholds are approached, allowing the use of smaller, more efficient low-voltage transistors without sacrificing reliability.
Solution Approach 2:
The patent implements feedback control by continuously monitoring voltage and current parameters and using this information to adjust switch operations in real-time. The control circuit receives feedback from voltage sensors and current sensors, processes this information to detect fault conditions, and responds by modifying switch timing or disconnecting switches, thereby enabling the use of optimized low-voltage transistors that minimize switching losses while maintaining protection.
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.