Battery Protection IC Clamp Circuit Series Voltage
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Solution Overview
Problem
Existing battery protection ICs require high breakdown voltage when multiple batteries are connected in series, as the total battery voltage is applied to the transistors, making them inefficient and potentially damaging.
Innovation Solution
Incorporating a clamp circuit in the charge control signal input terminal of the battery protection IC to prevent the output driver from being applied with a voltage equal to or higher than the breakdown voltage, allowing the IC to manage charging and discharging effectively without the need for high breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple batteries are connected in series to increase power supply voltage, then the power supply voltage is improved, but the breakdown voltage requirement of the battery protection IC increases
Solution Approach 1:
The battery system is segmented into multiple independent protection ICs, each managing a subset of batteries. For example, in an 8-battery system, two protection ICs each manage 4 batteries, so each IC only needs to withstand 4-battery voltage rather than 8-battery voltage. This segmentation allows the system to achieve high power supply voltage while keeping individual IC breakdown voltage requirements manageable.
Solution Approach 2:
A clamp circuit is introduced as an intermediary component between the batteries and the output driver transistor. The clamp circuit actively limits the voltage applied to the transistor to a safe level (e.g., 6V) regardless of the total battery voltage, preventing breakdown while allowing the system to operate at higher voltages. This mediator protects the sensitive component from the harsh electrical environment.
2Adaptability or versatility
If the breakdown voltage of the battery protection IC is increased to handle more batteries in series, then the adaptability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
Instead of manufacturing ICs with progressively higher breakdown voltages for different battery configurations, the system segments the battery groups and uses identical or standardized protection ICs for each segment. This standardization simplifies manufacturing while maintaining adaptability to different total battery counts through configurable series/parallel connections of the segments.
Solution Approach 2:
The clamp circuit is designed as a universal protection mechanism that can be integrated into protection ICs of various battery configurations. The same basic IC design with the clamp circuit can protect different numbers of batteries by adjusting the segmentation scheme, eliminating the need to manufacture multiple specialized IC variants with different voltage ratings.
3Ease of operation
If the total battery voltage is applied to the output driver transistor, then the direct control is simplified, but the transistor breakdown risk increases
Solution Approach 1:
The clamp circuit serves as an intermediary between the high-voltage battery system and the low-voltage output driver transistor. It automatically activates when the transistor voltage approaches the breakdown threshold, providing a simple yet effective protection mechanism that requires no complex control logic while eliminating the breakdown risk.
Solution Approach 2:
The clamp circuit is pre-configured with a clamping voltage slightly above the transistor's maximum safe operating voltage. This beforehand cushioning ensures that even during transient conditions or voltage spikes, the transistor is protected from exceeding its breakdown voltage, providing a safety margin without affecting normal operation.
Data Source
AI summary
Provided are a battery protection IC adaptable to any number of batteries connected in series without increasing a breakdown voltage thereof, and a battery device including the battery protection IC mounted thereon. A charge control signal input terminal and a discharge control signal input terminal of one battery protection IC are provided with a clamp circuit (121), and hence an output driver (112) of another battery protection IC connected to those terminals is not applied with a voltage equal to or higher than a breakdown voltage. Accordingly, the breakdown voltage of the battery protection IC is not required to be high.