Bi-Directional Battery Charger With Isolation Switching for Compact Power Flow

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Solution Overview

Problem

Consumer electronic devices face challenges with large size, weight, and cost due to the simultaneous operation of battery chargers and converters, which consume significant power and require substantial space.

Innovation Solution

A bi-directional buck-boost charger with isolation switches and a controller enables power flow in both charging and discharging modes, eliminating the need for separate charger and converter components, thereby reducing size, weight, and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate battery charger and converter components are used, then charging and discharging functions are provided, but device size and weight increase

Engineering Contradiction:

Improvecharging and discharging functionVSAvoiddevice weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent combines the battery charger and DC-DC converter into a single integrated power management IC. The power stage includes switches, inductors, and capacitors that can operate in both charging mode (powering the battery from the charger) and discharging mode (powering the load from the battery), eliminating the need for separate components and reducing overall device weight.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated power management IC is designed to perform multiple functions: it can charge the battery from an external power source, discharge the battery to power loads, and regulate voltage in both directions. The single device replaces what would traditionally require separate charger and converter components, providing universal power management capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate battery charger and converter components are used, then charging and discharging functions are provided, but device complexity increases

Engineering Contradiction:

Improvecharging and discharging functionVSAvoidcomponent complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates the control logic and power stage into a single power management IC. The controller within the IC manages both charging and discharging operations, coordinating the power stage components (switches, inductors, capacitors) to perform both functions without requiring separate control circuits or components, thereby reducing overall system complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If separate battery charger and converter components are used, then charging and discharging functions are provided, but power consumption increases

Engineering Contradiction:

Improvecharging and discharging functionVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The integrated power management IC shares common components such as the power stage, control logic, and supporting circuitry between charging and discharging operations. This shared architecture eliminates redundant power consumption that would occur with separate components, as the same hardware resources are utilized for both functions rather than maintaining separate operational circuits.

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides efficient battery charging and discharging while minimizing the printed circuit board footprint and overall system size, weight, and cost, making it suitable for compact consumer electronic devices.

Implementation Method 1

The first isolation switch and the second isolation switch may each include a pair of N-channel metal oxide semiconductor field effect transistors (MOSFETs) which are connected back-to-back in a common-source configuration for reverse-current blocking

Methodology Applied

Scientific EffectReverse-current blocking: Diode

Data Source

PatentUS12456879B2Bi-directional power flow control using a single battery charger

Publication Date: 2025.10.28 RENESAS ELECTRONICS AMERICA INC

AI summary

Systems and methods for bi-directional power flow control using a single battery charger are described. According to one example, a semiconductor device is generally described. The semiconductor device may include a charger configured to supply power from a charging interface to a battery in a forward mode, and supply power from the battery to a load in a reverse mode. The semiconductor device may include a first isolation switch disposed between the charging interface and the charger, a second isolation switch disposed between the charger and the load, and a controller configured to enable the first isolation switch and operate the charger in the forward mode, and enable the second isolation switch and operate the charger in the reverse mode.