Dual-Battery Charging Circuit With Switchable Series and Single-Cell Modes
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Solution Overview
Problem
Conventional portable devices face challenges in increasing battery capacity without enlarging the device size, and fast charging methods often require expensive buck-boost switching chargers, leading to increased cost and power consumption.
Innovation Solution
A portable device with switch control circuitry that allows batteries to operate in various modes, including one-battery and two-battery charging modes, using a simple buck charger instead of a buck-boost charger, and balancing currents between batteries to optimize charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two battery cells are coupled in series to increase battery capacity, then the device size can be smaller and circuit arrangement is more flexible, but the charging speed becomes slower and the cost increases due to requiring a buck-boost switching charger
Solution Approach 1:
The patent applies dynamics by making the battery configuration changeable through switch control circuitry. The system can dynamically switch between series and parallel battery configurations based on charging conditions. During fast charging, batteries are connected in parallel to accept higher current; during normal charging, they are connected in series. This dynamic reconfiguration resolves the contradiction by allowing fast charging capability without permanently requiring expensive buck-boost converter hardware.
Solution Approach 2:
The patent changes the electrical connection parameters (series/parallel configuration) of the battery cells based on charging requirements. By changing the connection topology parameter, the system can optimize charging speed for different power adapter outputs. This parameter change allows the same hardware to support both fast charging with high-power adapters and standard charging with typical adapters, resolving the contradiction between charging speed and cost.
2Adaptability or versatility
If a buck-boost switching charger is used to enable fast charging with typical 5V adapters, then charging compatibility is improved, but the cost and power consumption increase
Solution Approach 1:
The patent implements universality by designing a charging system that can handle multiple adapter types (5V typical adapters and higher-voltage fast-charging adapters) without requiring a dedicated buck-boost converter. The switch control circuitry enables the same simple buck charger hardware to serve multiple functions: it can charge from 5V adapters by connecting batteries in series, and can accept fast charging from higher-voltage adapters by connecting batteries in parallel. This multi-functionality resolves the contradiction by eliminating the need for expensive specialized hardware.
Solution Approach 2:
The patent extracts the complex buck-boost switching charger component from the system and replaces it with simpler components: a basic buck charger and switch control circuitry. The switching mechanism separates the functions of voltage adaptation and battery charging, allowing the expensive buck-boost converter to be removed while maintaining compatibility with various adapters. This extraction resolves the contradiction between adaptability and cost.
3Ease of manufacture
If a simple buck charger is used instead of a buck-boost charger, then cost and power consumption are reduced, but the ability to charge from typical 5V adapters is limited
Solution Approach 1:
The patent uses dynamic switching to enable a simple buck charger to adapt to different adapter types. The switch control circuitry monitors the input power characteristics and dynamically reconfigures the battery connections. When a 5V adapter is detected, the system configures batteries in series to match the lower voltage. When a higher-voltage fast-charging adapter is detected, the system configures batteries in parallel to accept the higher power. This dynamic adaptation resolves the contradiction between using simple hardware and maintaining broad compatibility.
4Ease of manufacture
If one battery cell is used to power the PMIC, then cost structure is improved, but an additional buck converter is required to convert two-cell voltage to one-cell voltage
Solution Approach 1:
The patent extracts and removes the unnecessary buck converter component from the system. By configuring the two battery cells in parallel during charging, the system produces a voltage that is compatible with the PMIC's single-cell input requirements. This eliminates the need for the intermediate voltage conversion stage (buck converter), directly resolving the contradiction by removing the complex component while maintaining cost-effectiveness.
Solution Approach 2:
The patent changes the electrical output parameter (voltage) of the battery charging system by switching between series and parallel configurations. When batteries are connected in parallel, the output voltage matches the PMIC's input requirements, eliminating the need for voltage conversion. This parameter change resolves the contradiction by making the voltage compatible directly, removing the need for additional converters.
Data Source
AI summary
In a portable device, a first battery has a positive terminal coupled to, through a first switch, an interface used to receive input power, and a negative terminal coupled to a reference terminal. A second battery has a positive terminal coupled to the interface, and a negative terminal coupled to the reference terminal through a second switch, and to the first battery's positive terminal through a third switch. A control circuitry controls the switches such that the device has multiple operation modes including at least a one-battery charging mode and a two-battery-in-series charging mode. In the one-battery charging mode, the circuitry turns off the third switch, and controls the other switches such that one battery is charged by the input power. In the two-battery-in-series charging mode, the control circuitry turns on the third switch and turns off the other switches, such that two batteries are charged by the input power.