Adjustable Slope Charging Circuit for MOS Capacitors
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Solution Overview
Problem
Conventional charging circuits for MOS transistor capacitors face issues with discontinuous charging voltages and require either reduced charging currents or increased capacitance, leading to inefficiencies and increased costs, particularly in adapting to adjustable charging slopes and periods with soft start operations.
Innovation Solution
A charging circuit utilizing a combination of current mirrors, switch transistors, and resistors to adjust conduction currents and output voltages, allowing for adaptive charging slopes and periods without reducing currents or increasing capacitance, thereby eliminating turning points and leakage current interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If charging currents are reduced to slow down charging operation, then charging slope is adjusted, but leakage current effectively influences charging operation and productivity decreases
Solution Approach 1:
The patent implements dynamic charging current control through a charging circuit that adjusts the charging current in real-time based on the capacitor's charging state. The circuit transitions from a constant current source to a dynamically adjusted current source, enabling the charging slope to be adaptively controlled without being constrained by fixed current values, thus maintaining productivity while achieving adjustable charging slopes.
Solution Approach 2:
The patent changes the charging current parameter dynamically during the charging process. By using a charging circuit that can adjust the current magnitude based on voltage thresholds and timing requirements, the system achieves variable charging slopes without reducing overall productivity. The current parameter is modified according to the charging stage, allowing optimization of both charging slope and efficiency.
2Duration of action of moving object
If capacitance of MOS transistor capacitor is increased to slow down charging operation, then charging period is adjusted, but extra areas are needed in circuit layout increasing product cost
Solution Approach 1:
Instead of increasing capacitance to extend charging period, the patent changes the charging current parameter dynamically. By controlling the current magnitude and timing through the charging circuit, the system achieves extended charging periods without requiring larger capacitance values, thereby avoiding increased circuit layout area and reduced productivity.
3Device complexity
If constant current source is used for charging operation, then simple circuit structure is maintained, but discontinuous charging voltages occur and adaptability decreases
Solution Approach 1:
The patent transitions from a static constant current source to a dynamic charging circuit that can adapt its current output based on charging requirements. The charging circuit incorporates control mechanisms that adjust the current in real-time, enabling discontinuous charging voltages to be smoothed and providing adaptability for different charging slopes without significantly increasing circuit complexity.
Solution Approach 2:
The charging circuit is designed with multi-functionality to handle various charging scenarios. It can operate in different modes (constant current, variable current, soft start) depending on the requirements, making it universally applicable to different charging situations while maintaining a relatively simple overall structure.
4Reliability
If charging current is reduced to meet soft start requirements, then soft start operation is achieved, but leakage current interference increases and productivity decreases
Solution Approach 1:
The patent implements dynamic current control to achieve soft start operations. The charging circuit gradually increases the current from a low initial value to the required operating current, providing smooth startup without sudden current spikes. This dynamic adjustment maintains reliability for soft start while avoiding the need to operate at reduced current levels, thus preserving productivity.
Data Source
AI summary
A charging circuit includes a first current mirror for receiving an input voltage, a second current mirror including a first branch circuit and a second branch circuit for receiving the input voltage, a switch transistor coupled to the first current mirror and the first branch circuit for determining a conduction condition of the switch transistor according to a switch signal, a first resistor including a first resistance and one end coupled to the switch transistor, and a second resistor including a second resistance and one end coupled the second branch circuit of the second current mirror, wherein the first current mirror and the second current mirror perform a charging operation of a loading circuit according to the first resistance and the second resistance.