Charge Discharge Control Circuit Terminal Reduction
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Solution Overview
Problem
Conventional charge/discharge control circuits for battery devices have a complex configuration that makes it difficult to reduce the number of terminals, thereby increasing costs.
Innovation Solution
A charge/discharge control circuit design that reduces the number of output terminals by using a single output terminal to control cell-balance discharging FETs connected in parallel to two series-connected batteries, achieved through a configuration with a power supply terminal, an input terminal, a ground terminal, and a control circuit that sends control signals to select the appropriate voltage for cell-balance control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional charge/discharge control circuit configuration is used, then cell balance control can be achieved, but the number of terminals cannot be reduced, increasing cost
Solution Approach 1:
The patent combines multiple output terminals into a single output terminal that controls both first and second cell balance circuits. The control circuit outputs a single cell balance control signal that is distributed to multiple Nch FETs (33a, 33b) through the shared output terminal, eliminating the need for separate output terminals for each battery cell while maintaining independent control capability.
Solution Approach 2:
The single output terminal serves multiple functions by controlling both the first cell balance circuit (32a, 33a) and the second cell balance circuit (32b, 33b). The control circuit 304 generates a unified cell balance control signal that can selectively activate different FETs based on which battery cell requires balancing, making the output terminal universal for multiple control purposes.
2Ease of manufacture
If the number of output terminals is reduced to one, then cost is reduced, but it becomes challenging to control multiple cell balance circuits independently
Solution Approach 1:
The patent segments the control function by providing separate control paths within the control circuit 304 for different battery cells. The control circuit includes distinct overcharge detection circuits (301a, 301b) and cell balance detection circuits (303a, 303b) for each battery cell, allowing independent detection and control decisions while using a single shared output terminal to execute the control actions.
Solution Approach 2:
The control circuit 304 acts as an intermediary that processes detection signals from multiple battery cells and generates appropriate control signals for multiple FETs through a single output terminal. The control circuit mediates between the multiple detection circuits and the multiple cell balance circuits, enabling independent control functionality to be achieved through a unified output interface.
Data Source
AI summary
A charge/discharge control circuit includes: an output terminal from which a cell-balance control signal is sent to each of the first and the second cell balance circuits; the first and the second voltage detection circuits; a control circuit configured to send the first and the second control signals in accordance with a detection signal received from at least one of the first and the second voltage detection circuits; and an output circuit configured to select one of a voltage of a power supply terminal, a voltage of an input terminal connected to each of a negative electrode of a first battery and a positive electrode of a second battery, and a voltage of a ground terminal in accordance with the first and second control signals, and send the selected voltage to the output terminal.