Power Switch Current Mirror Bias Control for Fast Overcurrent Limiting
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Solution Overview
Problem
Existing power switch circuits face challenges in achieving fast response speed and overcurrent protection while maintaining low static power consumption, as they require a balance between bias current and aspect ratio of transistors, leading to inefficiencies and increased static current when trying to increase the limited electrical current.
Innovation Solution
A control circuit with a current mirror configuration using an output voltage tracker, main switch bias generator, and reference current device, which generates tracking voltages and control voltages to manage output current and prevent overcurrent, implemented with transistors forming a current mirror circuit to stabilize voltage and current supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If bias current is increased to achieve fast response speed and overcurrent protection, then response speed and protection capability are improved, but static power consumption increases
Solution Approach 1:
The patent applies dynamics by making the bias current adjustable rather than fixed. The bias current can be dynamically increased during overcurrent protection events to achieve fast response, and reduced during normal operation to minimize static power consumption. This is implemented through the control circuit that adjusts the bias current based on operational conditions.
Solution Approach 2:
The patent changes the parameter of bias current from a fixed value to a variable parameter that can be adjusted based on operational needs. By changing the bias current parameter dynamically, the system achieves fast response speed when needed while maintaining low static power consumption during normal operation.
2Quantity of substance
If aspect ratio of transistors is adjusted to increase limited electrical current, then current capability is improved, but static current increases
Solution Approach 1:
The patent makes the limited electrical current capability dynamic by using control circuits that can adjust the effective current limit based on operational conditions. Rather than relying solely on fixed transistor aspect ratios, the system dynamically controls the current limiting behavior to provide high current capability when needed while maintaining low static current.
Solution Approach 2:
The patent segments the current control function into multiple independent control circuits that can operate independently. This allows the system to provide high current capability through coordinated control of multiple circuits while each circuit maintains efficient static characteristics, avoiding the need for large aspect ratios in single transistors.
3Reliability
If conventional power switch circuits are used to achieve overcurrent protection, then protection function is provided, but response speed is slow and static power consumption is high
Solution Approach 1:
The patent applies preliminary action by pre-configuring the control circuits and bias generators to be ready for immediate overcurrent detection and response. The circuit maintains standby control mechanisms that can activate instantly upon detecting overcurrent conditions, achieving fast response speed while keeping static power consumption low during normal operation.
Solution Approach 2:
The patent implements feedback mechanisms where the control circuits continuously monitor operational parameters and provide real-time feedback to adjust the switching behavior. This feedback system enables fast detection and response to overcurrent conditions while allowing the circuit to operate efficiently during normal conditions, reducing static power consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The control circuit achieves faster response speed, reduced static current, and lower static power consumption, effectively preventing overcurrent damage and improving circuit reliability with enhanced power management.
Implementation Method 1
The main switch and the duplicating switching element form a current mirror configuration circuit. The current mirror configuration circuit uses the main control end as a current mirror input end, uses the main output end as a current mirror output end.
Data Source
AI summary
A control circuit for a main switch is provided. The control circuit includes an output voltage tracker, a main switch bias generator, and a reference current device. The output voltage tracker is coupled to the main output end and generates a first tracking voltage positively correlated to an output voltage. The main switch bias generator, in response to the first tracking voltage, generates a second tracking voltage substantially equal to the output voltage. The reference current device is coupled to the main switch bias generator and is used to generate a control voltage on a main control end. The reference current device is used to limit the maximum value of the output current. The main switch and a duplicating switching element of the main switch bias generator form a current mirror configuration circuit. The consuming current of the output voltage tracker is positively correlated to the output current.