USB Power Supply Current Limiting with Adjustable Capacitance
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Solution Overview
Problem
Current USB interface power supply methods for time division multiple access load systems require high capacitance to manage burst mode currents, leading to increased costs and inefficiencies, particularly in traditional DC-DC converters where voltage considerations are not adequately addressed.
Innovation Solution
A USB interface power supply device with a DC-DC direct current conversion circuit, a soft-start circuit, and a capacitor for current limiting, where the capacitance value is calculated based on working and non-working voltages, maximum output current, input voltage, and working period, and adjusted using a switch group to optimize energy compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high capacitance is used to manage burst mode currents, then reliable power supply is achieved, but cost increases
Solution Approach 1:
The patent changes the parameter of capacitance value from fixed high capacitance to dynamically adjustable capacitance. By using a switch group connected to multiple capacitors with different capacitance values, the system can select appropriate capacitance based on working conditions (working state or non-working state), thereby reducing the minimum required capacitance while maintaining power supply reliability during burst mode operations.
2Reliability
If traditional current limiting is used at DC-DC converter input, then current protection is achieved, but voltage considerations are ignored
Solution Approach 1:
The patent implements feedback control by monitoring the voltage at the input terminal of the DC-DC converter and using this information to control the switch group. The control circuit adjusts the capacitance value based on voltage feedback, ensuring that voltage considerations are properly managed while maintaining current protection functionality. This creates a closed-loop system that coordinates current limiting with voltage management.
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
This solution reduces the minimum capacitance required, ensuring reliable USB interface operation while considering costs, and is applicable to both USB2.0 and USB3.0 protocols, leveraging the actual power supply ability of the USB interface for universal application.
Implementation Method 1
a capacitor for current limiting, wherein a first end of the capacitor is connected between the soft-start circuit and the DC-DC direct current conversion circuit, a second end of the capacitor is set to be grounded, and the capacitor is used for limiting an input current of the DC-DC direct current conversion circuit
Data Source
AI summary
A USB interface power supply method and power supply device for a time division multiple access load system reduce costs of using the capacitance while guaranteeing the performance. The USB interface power supply device includes: a USB interface, a soft-start circuit and a DC-DC direct current conversion circuit that are connected in sequence, wherein, an output of the DC-DC direct current conversion circuit supplies power to the time division multiple access load system. The power supply device also includes a capacitor, wherein: a first end of the capacitor is connected between the soft-start circuit and the DC-DC direct current conversion circuit, a second end of the capacitor is set to be grounded, and the capacitor is used for limiting an input current of the DC-DC direct current conversion circuit.