Battery Protection Circuit Calibrates Trip Point
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Solution Overview
Problem
Conventional battery protection circuits suffer from poor protection trip accuracy due to unpredictable real-world characteristics of discrete components, leading to increased power loss, cost, and size, which is becoming less tolerable with the rising power requirements in mobile devices.
Innovation Solution
A battery protection circuit with a protection integrated circuit (IC) that calibrates the protection trip point to compensate for process and temperature variations of the on-state resistance of power semiconductor switches, using a trimming technique to improve accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional discrete components are used in battery protection circuits, then the circuit can be implemented with standard components, but the protection trip accuracy deteriorates due to unpredictable real-world characteristics and process variations
Solution Approach 1:
The patent merges the power semiconductor switch and protection IC into a single integrated device. The protection IC is directly coupled to the power semiconductor switch, allowing the protection circuit to be calibrated based on the actual operational characteristics of the specific switch instance. This integration eliminates the unpredictability of discrete component variations and ensures accurate protection tripping.
Solution Approach 2:
The protection trip point is calibrated based on the actual on-resistance of the specific power semiconductor switch instance. By measuring and adjusting the protection threshold to match the real-world characteristics of the installed switch, the system compensates for process variations and ensures both high accuracy and reliability.
2Measurement precision
If discrete components are used with calibration, then protection accuracy can be improved, but the device complexity and component count increase
Solution Approach 1:
The protection IC and power semiconductor switch are integrated into a single device, reducing the number of discrete components. The calibration function is built into the protection IC, which directly interfaces with the switch, eliminating the need for external calibration circuits or additional components.
Solution Approach 2:
The protection IC performs self-calibration by measuring the actual on-resistance of the coupled power semiconductor switch and adjusting its protection trip point accordingly. This self-calibrating capability eliminates the need for external calibration equipment or complex calibration circuits, reducing overall device complexity while maintaining high accuracy.
3Device complexity
If conventional protection circuits are used, then the design is simpler, but power loss increases due to inaccurate protection tripping
Solution Approach 1:
The protection trip point is dynamically calibrated based on the actual on-resistance of the power semiconductor switch. This ensures that the protection circuit trips at the correct current threshold, preventing both premature tripping (which would cause unnecessary power loss) and failure to trip (which would allow dangerous conditions). The calibration is achieved through measuring the actual switch characteristics and adjusting the protection threshold accordingly.
4Ease of manufacture
If discrete components with tolerances are used, then manufacturing is easier, but the protection trip point varies unpredictably with temperature and process variations
Solution Approach 1:
The protection IC and power semiconductor switch are manufactured as an integrated device, ensuring that they work together as a matched pair. The calibration process measures the actual characteristics of the specific switch instance and configures the protection IC accordingly, compensating for process variations that occur during manufacturing.
Solution Approach 2:
The protection trip point is calibrated based on the actual on-resistance of the specific power semiconductor switch instance. This calibration process adjusts the protection threshold to account for process variations, ensuring consistent and accurate protection performance across different manufacturing batches and temperature conditions.
Data Source
AI summary
The present disclosure is directed to a system for battery management and protection. A battery protection circuit may include a power semiconductor switch and a control integrated circuit (IC). The battery protection circuit may be configured to regulate the charging and/or discharging of a battery and further prevent the battery from operating outside of a safe operating area based on a protection trip point (e.g. overcurrent detection point) of the protection IC. The protection IC may be configured to calibrate a protection trip point so as to compensate for process and temperature variations of on resistance (RSSon) of the power semiconductor switch.