Multi-phase Buck-Boost Charger Circuit for Portable Devices
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Solution Overview
Problem
Next-generation battery chemistries with higher voltage requirements and larger capacities necessitate battery chargers that can efficiently boost input voltage, manage voltage drops, and provide power to accessories, while minimizing size and weight for portable devices.
Innovation Solution
A multi-phase switching battery charger circuit with asymmetric inductances and switch mode power supply techniques, allowing the charger to operate in buck-boost, boost, and reverse boost modes, and incorporating a system boost converter to manage voltage and power delivery efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional 5V charging is used, then charging simplicity is maintained, but charge time increases dramatically due to high input path or cable resistances
Solution Approach 1:
The patent changes the voltage parameter dynamically by switching between buck mode (when input voltage exceeds battery voltage) and boost mode (when input voltage is below battery voltage or to overcome cable resistance). This allows the charger to maintain optimal charging current despite varying input conditions and cable resistances, dramatically reducing charge times compared to fixed 5V charging.
2Quantity of substance
If battery voltage rises to approach 5V, then battery capacity increases, but additional boost circuitry is required to fully charge the battery
Solution Approach 1:
The patent implements a universal charger circuit that can operate in multiple modes (buck, boost, and battery-powered operation) using a unified topology. The same inductor, switches, and controller serve multiple functions depending on the operating mode, eliminating the need for separate boost circuitry while supporting batteries with voltages up to and exceeding 5V.
Solution Approach 2:
The patent inverts the traditional charging approach by enabling the battery to power the input when no external source is available (reverse charging mode). The circuit can operate with the battery as the power source, converting battery voltage to the required input voltage level, thus eliminating the need for external boost circuitry in high-voltage battery scenarios.
3Use of energy by moving object
If minimum battery voltage falls below system component requirements, then battery energy density improves, but voltage boost circuitry is needed to power loads and prevent brown outs
Solution Approach 1:
The same boost circuitry that enables low-voltage charging also serves to boost battery voltage to power system components when the battery voltage drops below the minimum required level. The controller automatically switches to boost mode to maintain stable voltage for system loads, preventing brown outs without requiring separate voltage regulation circuitry.
4Adaptability or versatility
If USB OTG support is added, then device versatility improves, but additional boost circuit is required to provide steady 5V to accessories
Solution Approach 1:
The patent enables the same boost circuit to serve multiple purposes: charging the battery, powering system components, and providing USB OTG power output. The controller manages different operating modes to route power appropriately, allowing the device to function as a USB host and charge accessories without requiring a dedicated boost circuit for OTG functionality.
5Quantity of substance
If larger battery capacities are used, then device energy storage increases, but charging current requirements increase making the charger more sensitive to input resistance
Solution Approach 1:
The patent dynamically adjusts operating parameters (voltage and current) based on detected input conditions. When cable resistance is high, the controller switches to boost mode to overcome the resistance and maintain adequate charging current. This adaptability allows large-capacity batteries to be charged efficiently even with high-input resistance scenarios that would normally severely limit charging speed.
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 charger efficiently charges batteries across varying voltage ranges, reduces charge times, and provides power to accessories, while minimizing size and weight, enhancing the performance and usability of portable devices.
Implementation Method 1
Each phase has inductance that serves to transfer energy from an input to a battery for charging the battery
Data Source
AI summary
A battery charger has at least two phases and coupled switches that are controlled using switch mode power supply (SMPS) techniques. One of the phases is part of a buck-boost circuit that includes a high side switch, which is coupled between a near end of the phase and the input, and a low side switch that is coupled between a far end of the phase and ground. The far end of the phase is also coupled to a battery, through a further high side switch. A controller signals the switches into open and closed states so that the buck-boost circuit is operated in buck mode when charging the battery at a low voltage, and in boost mode when charging the battery at a high voltage. Other embodiments are also described and claimed.