DC-DC Converter Back Gate Control for Power Efficiency
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Solution Overview
Problem
Current DC-DC converters, particularly switching type converters, face challenges in optimizing power conversion efficiency due to on-state resistance and off-state current losses, which vary with output power levels, leading to inefficiencies in semiconductor devices and portable electronic devices.
Innovation Solution
Incorporating a transistor with a back gate electrode and a back gate control circuit to adjust the threshold voltage based on output power, using an insulating-gate-field-effect transistor with a wide band gap oxide semiconductor to minimize off-state current and on-state resistance, and employing a highly purified oxide semiconductor to reduce impurities and enhance switching element performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a switching type DC-DC converter is used to achieve high power conversion efficiency, then power conversion efficiency is improved, but on-state resistance and off-state current losses vary with output power levels causing inefficiencies at certain operating points
Solution Approach 1:
The patent applies dynamics by making the transistor threshold voltage adjustable through a back gate electrode. The threshold voltage is dynamically changed based on output power levels to optimize power conversion efficiency. At low output power levels, the threshold voltage is increased to reduce off-state current losses, while at high output power levels, the threshold voltage is decreased to reduce on-state resistance losses. This dynamic adjustment allows the converter to maintain high efficiency across varying operating conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the threshold voltage parameter of the transistor according to output power levels. A back gate control circuit monitors the output power and adjusts the back gate voltage accordingly, thereby changing the threshold voltage parameter. This parameter change enables the transistor to operate optimally at different power levels, resolving the contradiction between maintaining high efficiency and adapting to varying load conditions.
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 approach significantly reduces power loss and improves power conversion efficiency in DC-DC converters, leading to lower power consumption and extended battery life in semiconductor devices and portable electronics.
Implementation Method 1
a channel formation region of the transistor includes a semiconductor material whose band gap is wider than that of a silicon semiconductor and whose intrinsic carrier density is lower than that of silicon
Data Source
AI summary
Provided is a DC-DC converter with improved power conversion efficiency. A transistor which is incorporated in the DC-DC converter and functions as a switching element for controlling output power includes, in its channel formation region, a semiconductor material having a wide band gap and significantly small off current compared with silicon. The transistor further comprises a back gate electrode, in addition to a general gate electrode, and a back gate control circuit for controlling a potential applied to the back gate electrode in accordance with the output power from the DC-DC converter. The control of the potential applied to the back gate electrode by the back gate control circuit enables the threshold voltage to decrease the on-state resistance when the output power is high and to increase the off-state current when the output power is low.