DC/DC Converter Switch Control for Portable Computer Power Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
DC/DC converters in portable computers face inefficiencies in light load states, such as during suspended or hibernation modes, leading to increased power consumption and reduced battery life, as existing technologies struggle to minimize losses in switching frequency and FET operations.
Innovation Solution
The implementation of a DC/DC converter configuration that includes heavy-load and light-load electronic switches, an output current measurement circuit, and a control circuit, which selectively operates different combinations of switches based on load states to optimize switching frequency and reduce FET losses, utilizing a synchronous rectification mode and adjusting FET characteristics to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a switching regulator is used in light load state, then power consumption is reduced, but efficiency deteriorates due to switching losses
Solution Approach 1:
The patent implements dynamic switching between PWM mode and PFM mode based on load conditions. The control circuit automatically selects the appropriate operating mode to optimize efficiency across different load states, preventing the system from operating inefficiently in light load conditions while maintaining good regulation performance.
Solution Approach 2:
The patent changes the operating parameters of the switching regulator by adjusting the switching frequency and mode based on load current. In light load states, the system transitions to PFM mode with lower switching frequency to reduce switching losses, while in heavy load states it operates in PWM mode with higher frequency for better regulation, thus optimizing overall efficiency.
2Loss of energy
If switching frequency is decreased to reduce losses, then power consumption is reduced, but ripple voltage increases
Solution Approach 1:
The patent dynamically adjusts the switching frequency based on load conditions. In light load states, it operates in PFM mode with variable lower frequency to reduce losses, while in heavy load states it switches to PWM mode with higher fixed frequency to maintain low ripple voltage, thus dynamically balancing between loss reduction and ripple suppression.
Solution Approach 2:
The patent employs periodic switching action with different characteristics for different load states. In PFM mode, the switching period varies to maintain efficiency, while in PWM mode, the switching period is fixed to ensure stable ripple characteristics. This periodic action with adaptive characteristics resolves the contradiction between loss reduction and ripple control.
Data Source
AI summary
A DC/DC converter is disclosed. The DC/DC converter includes a first heavy-load electronic switch and a second heavy-load electronic switch connected in series between an input terminal and ground at a first output portion, a third light-load electronic switch and a fourth light-load electronic switch connected in series between the input terminal and ground at a second output portion, an output circuit, an output current measurement circuit, and a control circuit. The output circuit includes an inductor connected to the first and second output portions. The output current measurement circuit measures an output current. The control circuit, in response to an output of the output current measurement circuit, selects a combination of the first and second heavy-load electronic switches during a heavy load state, and selects a combination of the third and fourth light-load electronic switch during a light load state.