Monolithic GaN High-Side Level Shifter for Low-Noise Switching
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Solution Overview
Problem
Existing power conversion circuits using gallium nitride (GaN) devices face challenges with substrate noise, increased power losses due to quiescent current, and signal integrity issues between separate low side and high side dies, limiting operational frequency and efficiency.
Innovation Solution
Integration of capacitive level shifter circuits on a monolithic GaN die, using metal-insulator-metal (MIM) capacitors for level shifting, which are less susceptible to substrate noise and consume minimal quiescent current, reducing power losses and enabling higher operational frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate low side and high side dies are used in GaN power conversion circuits, then device functionality is achieved, but substrate noise and signal integrity issues increase
Solution Approach 1:
The patent integrates the capacitive level shifter circuits directly on the high side GaN die, merging previously separate low side and high side dies into a single monolithic device. This integration eliminates substrate noise issues between separate dies and improves signal integrity by reducing the physical distance and coupling between components.
2Power
If traditional level shifter circuits are used, then voltage level conversion is achieved, but quiescent current increases causing power losses
Solution Approach 1:
The patent replaces traditional transistor-based level shifter circuits with capacitive level shifters. This substitution eliminates the need for continuous bias currents required by transistor operation, thereby reducing quiescent current and improving power efficiency while maintaining voltage level conversion functionality.
3Productivity
If GaN devices operate at higher frequencies, then power conversion efficiency improves, but substrate noise and signal integrity issues worsen
Solution Approach 1:
By integrating all circuits including capacitive level shifters on a single monolithic GaN die, the patent minimizes the physical distance between components. This integration allows operation at higher frequencies up to 8 MHz while reducing substrate noise coupling that would otherwise increase with frequency in separate die configurations.
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
The monolithic GaN device achieves reduced power losses, higher operational frequencies up to 8 MHz, and improved manufacturability by minimizing substrate noise and signal integrity issues, while eliminating the need for noise filters.
Implementation Method 1
a first input terminal coupled to the first output terminal via a first capacitor and having a second input terminal coupled to the second output terminal via a second capacitor
Data Source
AI summary
Monolithic high side GaN-based circuits using capacitors for level shifting. In one aspect, a power converter includes a GaN-based die, a switch formed on the GaN-based die and having a gate terminal, where the switch is arranged to be selectively conductive according to a driver signal applied to the gate terminal, a buffer circuit formed on the GaN-based die and arranged to receive an input signal and generate a corresponding differential output signal at a first output terminal and at a second output terminal, and a voltage level converter formed on the GaN-based die and having a first input terminal coupled to the first output terminal via a first capacitor and having a second input terminal coupled to the second output terminal via a second capacitor, where the first and second capacitors are formed on the GaN-based die, and the voltage level converter is arranged to generate the driver signal.