Power Supply Unit with Dual Error Amplifiers for Load Mode Switching
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Solution Overview
Problem
Existing power supply units for portable devices face challenges in efficiently switching between heavy and light load modes without consuming excessive current, particularly in sleep mode, and require external mode signals for mode switching, which not all devices support, leading to poor transient response due to common transistor control.
Innovation Solution
A power supply unit with a first and second output circuit, error amplification circuits, and a mode control signal generation system that enables or disables these circuits based on output current levels, allowing internal current detection for mode switching without external signals, reducing consumption current in light load mode while maintaining transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a voltage control section is provided to improve transient response, then transient response is improved, but current consumption increases
Solution Approach 1:
The patent applies dynamics by making the error amplifier's operating state changeable between high-speed and low-current modes based on load conditions. The error amplifier transitions from a high-transient-response state during active mode to a low-current state during sleep mode, allowing the system to adapt its characteristics dynamically to match actual operational requirements.
Solution Approach 2:
The patent changes the operating parameters of the error amplifier based on mode signals. By adjusting the error amplifier's operating state according to whether the system is in active or sleep mode, the patent optimizes the balance between transient response speed and current consumption for different operational scenarios.
2Device complexity
If a common output transistor controls both high-speed and low-speed stable voltage supply sections, then device complexity is reduced, but transient response deteriorates
Solution Approach 1:
The patent segments the control function by providing separate control paths for the first and second output circuits. The first error amplifier controls the first output circuit while the second error amplifier controls the second output circuit, allowing each to operate independently with optimized transient response characteristics for their respective load conditions.
Solution Approach 2:
The patent implements dynamic control where the first and second error amplifiers are selectively enabled or disabled based on mode signals and current detection. This dynamic switching allows the system to use the appropriate error amplifier for the current operational mode, maintaining optimal transient response without requiring both amplifiers to be always active.
3Ease of operation
If external mode signals are required for switching operational modes, then mode switching control is simplified, but adaptability to devices without mode signal support is reduced
Solution Approach 1:
The patent implements self-service by enabling the power supply unit to automatically detect its own operational state through current detection and autonomously generate mode control signals. The unit monitors its own output current and switches between active and sleep modes without requiring external mode signals, making it universally compatible with different portable devices.
Solution Approach 2:
The patent uses feedback mechanisms where the output current is detected and fed back to the control circuit. This feedback enables the system to automatically determine the appropriate operational mode and switch accordingly, eliminating the need for external mode signals while maintaining proper mode transition control.
Data Source
AI summary
A power supply unit is adapted to automatically switch its operational mode between a light load mode and a heavy load mode depending on the level of its output current. The unit has a first error amplification circuit for controlling a first output circuit in the heavy load mode, and a second error amplification circuit for controlling the second output circuit in the light load mode. The first and the second output circuits are controllably enabled and disabled in the opposite manner based on the level of the output current. Thus, the unit can operate on a reduced consumption current with an improved transient response when operating in the light load mode.