Slew-Rate-Controlled Charging Circuit for EMI-Stable Load Driving
Solution Overview
Problem
Conventional inverter circuits lack control over the slew rate, leading to abnormal charging/discharging and electromagnetic interference due to uncontrolled output signal timing, affecting the normal operation of circuit systems.
Innovation Solution
A charging/discharging control circuit comprising a first and second inverter circuit with control transistors and a driving circuit, where the control transistors are connected in diode form, allowing for the generation of control voltages that adjust the slew rate by varying the threshold voltage, enabling controlled charging and discharging of a load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional inverter circuit is used as an output circuit, then the structure is simple, but the slew rate cannot be controlled causing abnormal charging/discharging and electromagnetic interference
Solution Approach 1:
The patent divides the output circuit into multiple inverter stages (first inverter circuit, second inverter circuit, third inverter circuit) with distinct functions. Each inverter stage processes the signal sequentially, allowing control over the slew rate at each stage while maintaining overall circuit functionality. This segmentation enables controlled charging/discharging without requiring a completely different circuit architecture.
Solution Approach 2:
The patent introduces dynamic control mechanisms by adding control transistors (first control transistor, second control transistor, third control transistor) that can dynamically adjust the slew rate of each inverter stage. These control transistors modify the circuit's behavior in real-time based on operating conditions, enabling adaptive control of signal transition rates while maintaining circuit simplicity.
2Speed
If the inverter circuit outputs signal too fast, then the circuit operation speed is high, but electromagnetic interference and abnormal charging/discharging occur
Solution Approach 1:
The patent implements periodic control of the signal transition through control signals that regulate the slew rate of each inverter stage. By periodically adjusting the charging/discharging rates of the control nodes, the circuit can maintain high-speed operation while preventing electromagnetic interference through controlled signal transitions. The multi-stage inverter structure with control transistors enables this periodic modulation of signal speed.
3Reliability
If control transistors are added to control slew rate, then the charging/discharging operation becomes stable, but the circuit complexity increases
Solution Approach 1:
The patent merges the control function into the existing inverter structure by integrating control transistors directly within each inverter stage. Rather than adding separate control circuits, the control transistors are combined with the switch elements and load elements of each inverter, sharing common nodes and signals. This merging approach enables slew rate control while minimizing additional circuit complexity.
Data Source
AI summary
A charging/discharging control circuit, comprising a first inverter circuit, a second inverter circuit and a driving circuit. The first inverter circuit is configured to generate a first control voltage on a first control node according to a threshold voltage of a first control transistor. The second inverter circuit is configured to generate a second control voltage on a second control node according to a threshold voltage of a second control transistor. The driving circuit is coupled to the first inverter circuit, the second inverter circuit and a load, and is configured to selectively charge or discharge the load according to the first control voltage or the second control voltage.