Current Limit Protection Trimming Circuit
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Solution Overview
Problem
Existing short-circuit protection mechanisms for electronic devices exhibit substantial variations in maximum permissible output current due to manufacturing imperfections, leading to potential damage from current spikes during short-circuits.
Innovation Solution
A current limiting circuit with a trimming circuit portion that adjusts resistance based on temperature and input voltage, using a resistive part and a condition-tracking transistor to configure the maximum output current, thereby reducing deviations caused by variations in operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior implementations of short-circuit protection are used to limit output current, then current limiting function is provided, but substantial variation in maximum permissible output current occurs due to manufacturing imperfections
Solution Approach 1:
The patent applies preliminary action by performing trimming during the manufacturing process to pre-configured the current limiting circuit with compensation values for expected parameter variations. This allows the circuit to automatically compensate for manufacturing imperfections and operating condition variations without requiring real-time adjustment, thereby improving both reliability and precision.
Solution Approach 2:
The patent implements feedback mechanisms where the circuit monitors its own operating parameters and adjusts the current limiting threshold accordingly. By using feedback from temperature sensors and voltage monitors, the circuit dynamically compensates for variations caused by manufacturing tolerances and environmental conditions, ensuring consistent current limiting performance.
2Manufacturing precision
If trimming is performed to reduce parameter variations, then manufacturing precision is improved, but device complexity increases due to additional trimming circuitry
Solution Approach 1:
The patent merges the trimming functionality with the existing current limiting circuit by integrating compensation components directly into the current limiting path. Rather than adding separate trimming circuits, the design combines multiple functions into unified circuit blocks, reducing overall complexity while maintaining precision.
Solution Approach 2:
The patent utilizes parameter changes in existing components (such as adjusting resistor values or transistor bias points) to achieve trimming effects without adding significant circuitry. By changing parameters of already-present components, the patent achieves precision improvement with minimal increase in device complexity.
3Ease of operation
If maximum output current is set to a fixed value, then ease of operation is improved, but the circuit cannot account for variations in temperature and input voltage
Solution Approach 1:
The patent applies dynamics by making the current limiting threshold adaptive rather than fixed. The circuit automatically adjusts its operating parameters in response to changes in temperature, input voltage, and other environmental conditions. This dynamic behavior maintains ease of operation (no manual reconfiguration needed) while achieving adaptability to varying operating conditions.
Solution Approach 2:
The patent implements self-service through automatic compensation mechanisms that monitor and adjust the current limiting threshold without external intervention. The circuit uses internal sensors and control logic to detect operating conditions and self-adjust parameters, eliminating the need for manual reconfiguration while maintaining adaptability to environmental variations.
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 solution effectively limits output current to a desired maximum, providing robust short-circuit protection across a wide range of operating conditions by accounting for temperature and voltage variations, thereby reducing the risk of damage to the device.
Implementation Method 1
a condition-tracking part connected in series with the resistive part and comprising a condition-tracking transistor, the condition-tracking part providing a second resistance that is dependent on temperature and said input voltage
Data Source
AI summary
A current limiting circuit portion for limiting an output current of an electronic device includes an input voltage line for receiving an input voltage and a trimming circuit portion. The trimming circuit portion includes a resistive part providing a first resistance that is configurable based on one or more resistance control signals applied thereto, and a condition-tracking part connected in series with the resistive part that includes a condition-tracking transistor, the condition-tracking part providing a second resistance that is dependent on temperature and the input voltage.