Pulsating Voltage Charging System for Compact Power Adapters

The patent employs pulse width modulation (PWM) to generate pulsating charging current with periodic on-off cycles. The switch unit rapidly switches between conducting and non-conducting states, creating a series of current pulses that charge the battery. This periodic action enables high power delivery without requiring large continuous current capacity, thus maintaining compact adapter size while achieving fast charging speeds.

The control unit dynamically adjusts the duty ratio parameter of the PWM signal to regulate the average charging current. By varying the duty ratio (the proportion of time the switch is conducting within each cycle), the system can deliver different power levels from the same hardware configuration, enabling adaptive charging speeds without increasing adapter size or component ratings.

The power adapter is designed with a universal switching power supply architecture that can deliver multiple power levels (5W, 10W, 15W, 25W, etc.) using the same core components. The switch unit, transformer, and control circuitry remain identical across different power configurations; only the duty ratio parameters need adjustment. This multi-functionality eliminates the need for separate adapter designs for different power levels, significantly reducing manufacturing complexity and cost.

The system achieves different power outputs by changing only the duty ratio parameter in the control signal, without requiring different hardware components. This parameter-based control simplifies manufacturing because the same physical components can be used across all power levels, reducing inventory requirements, assembly variations, and quality control complexity.

The control unit implements feedback control by monitoring the battery voltage and adjusting the duty ratio accordingly. When the battery voltage approaches the charging threshold (e.g., 4.2V), the control unit reduces the duty ratio to prevent overvoltage. This closed-loop feedback mechanism maintains voltage stability throughout the charging process, eliminating the need for additional voltage regulation stages while preserving charging efficiency.

The system dynamically adjusts the duty ratio in real-time based on battery voltage conditions. During early charging when voltage is low, the duty ratio is high to maximize charging current. As voltage approaches the threshold, the duty ratio automatically decreases to maintain stable voltage levels. This dynamic adjustment ensures both high charging efficiency and voltage stability without requiring complex regulation circuits.

The patent extracts and eliminates the electrolytic capacitor component from the traditional power adapter circuit. By using pulse width modulation to directly control the switch unit, the system achieves voltage regulation without requiring large electrolytic capacitors for filtering and smoothing. This extraction of unnecessary components simplifies the circuit architecture, reduces the number of parts, and decreases adapter size while maintaining high power handling capability.

The patent replaces passive component-based voltage regulation (using large capacitors and complex filtering circuits) with active electronic control (PWM-based duty ratio adjustment). This substitution of control mechanism eliminates the need for bulky passive components, reducing adapter complexity and size while preserving the ability to handle high power levels efficiently.