Switching Power Supply Dead Time Control for GaN HEMTs
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Solution Overview
Problem
GaN HEMT devices experience significant voltage drops during reverse conduction, leading to increased losses during dead time periods in switching power supplies, necessitating advanced control technologies for improved efficiency.
Innovation Solution
A control circuit with a time-to-digital converter and digital signal processor is introduced to measure and correct nanosecond-scale time differences between switching voltages, enabling precise control of switching transistors and optimizing dead time management in GaN-based switching power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If GaN HEMT is used as a switching element, then high frequency characteristics and low operation resistance are improved, but voltage drop during reverse conduction increases causing higher loss during dead time
Solution Approach 1:
The patent adjusts the dead time parameter dynamically to optimize performance. By changing the dead time duration based on operating conditions, the system minimizes the energy loss during reverse conduction while maintaining the benefits of GaN HEMT's low operation resistance and high frequency characteristics.
2Loss of energy
If dead time is extended to reduce voltage drop loss, then energy efficiency improves, but switching frequency and productivity decrease
Solution Approach 1:
The patent implements dynamic dead time adjustment rather than using a fixed dead time value. The dead time is varied in real-time based on operating conditions, allowing the system to minimize energy loss during dead time while maintaining high switching frequency and productivity.
Solution Approach 2:
By changing the dead time parameter adaptively, the system achieves optimal balance between reducing energy loss and maintaining high switching frequency. This parameter adjustment allows the power supply to operate efficiently without sacrificing productivity.
3Loss of energy
If nanosecond-scale dead time control is implemented, then energy efficiency improves, but device complexity and measurement precision requirements increase
Solution Approach 1:
The patent replaces complex hardware-based timing control with software-controllable digital signal processing. This substitution reduces device complexity by using programmable logic and software algorithms to achieve nanosecond-scale dead time control, rather than requiring complex hardware timing circuits.
Solution Approach 2:
The patent introduces a time-to-digital converter as an intermediary component that bridges the analog timing requirements and digital control domain. This mediator enables precise nanosecond-scale measurement and control while keeping the overall system architecture manageable and reducing complexity in the control circuit.
4Measurement precision
If time-to-digital converter is added for precise time measurement, then dead time control precision improves, but device complexity increases
Solution Approach 1:
The time-to-digital converter serves as a specialized intermediary that provides precise time measurement capability while maintaining a clean separation between measurement and control functions. This modular approach adds minimal complexity to the overall system while enabling nanosecond-scale measurement precision.
Solution Approach 2:
The patent replaces complex analog timing and measurement circuits with a digital time-to-digital converter and software-based processing. This substitution achieves high measurement precision while reducing overall device complexity through the use of integrated digital components and programmable control.
Data Source
AI summary
A control circuit controls a switching power supply that includes a switching transistor. A first switching detection pin is connected to a first node in the switching power supply, and a second switching detection pin is connected to a second node N in the switching power supply. A time-to-digital converter generates a digital value that represents time difference between a notable edge of a first switching voltage that appears at the first switching detection pin and a notable edge of a second switching voltage that appears at the second switching detection pin. A DSP generates a control pulse that instructs on/off of the switching transistor, with reference to at least the digital value.