Half-Bridge Gate Driver Voltages From a Single On-Chip Regulator
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Solution Overview
Problem
Conventional methods for generating positive and negative gate control voltages for high-side and low-side gate drivers in a half-bridge configuration are either expensive, require redesign for different voltage levels, or increase power dissipation due to the use of external power supplies and low-dropout voltage regulators.
Innovation Solution
A method and system that utilize a single external positive power supply and integrated programmable voltage regulators to generate both positive turn-on and negative turn-off voltages for high-power drive devices, reducing power dissipation and simplifying power supply design by reusing switch turn-off current and tolerating low-frequency variations in negative turn-off voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external power supplies and low-dropout voltage regulators are used to generate positive and negative gate control voltages, then voltage regulation precision is improved, but power dissipation increases and device complexity increases
Solution Approach 1:
The patent combines the functions of positive voltage generation and negative voltage generation into a single integrated circuit. The positive voltage output circuit and negative voltage output circuit share common components including the isolated power supply, voltage regulators, and control logic, eliminating the need for separate external power supplies and reducing overall power dissipation while maintaining voltage regulation precision.
Solution Approach 2:
The isolated power supply circuit serves multiple functions: it provides isolated power to both the positive voltage output circuit and negative voltage output circuit, enables bidirectional voltage regulation, and supports both source-following and sink-following operating modes. This multi-functionality reduces the total number of components and lowers power dissipation compared to using separate dedicated power supplies for each function.
2Measurement precision
If external power supplies are used for each gate driver, then voltage regulation is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple power supply functions into a single integrated power supply circuit. The isolated power supply unit provides regulated power to both positive and negative voltage output circuits, eliminating the need for multiple external power supplies and reducing system complexity while maintaining precise voltage regulation through integrated control mechanisms.
Solution Approach 2:
The integrated power supply circuit is designed to serve multiple functions: it provides isolated power delivery, regulates both positive and negative voltage outputs, and adapts to different operating modes (source-following and sink-following). This universal design reduces the overall number of components and simplifies the power supply architecture while maintaining regulation precision.
3Device complexity
If a single external power supply is used, then device complexity is reduced, but power dissipation increases due to lack of independent regulation
Solution Approach 1:
The patent segments the single external power supply into multiple isolated power supply circuits, each serving specific functions. The external power supply is divided into a first isolated power supply for the positive voltage output circuit and a second isolated power supply for the negative voltage output circuit. This segmentation enables independent voltage regulation for each output, reducing power dissipation while maintaining simple external power supply configuration.
Solution Approach 2:
The patent introduces isolated power supply circuits as intermediary components between the external power supply and the voltage output circuits. These intermediary circuits provide galvanic isolation and enable independent voltage regulation, allowing the system to use a single external power supply while achieving efficient power management and reduced power dissipation through internal isolation and regulation.
4Reliability
If conventional isolated power supplies are used for high-side and low-side gate drivers, then isolation is achieved, but power dissipation increases and regulation precision deteriorates for unregulated outputs
Solution Approach 1:
The patent combines the isolation function with the voltage regulation function in an integrated manner. The isolated power supply circuits provide both galvanic isolation and precise voltage regulation simultaneously, eliminating the need for separate isolation components and unregulated voltage outputs. This integration reduces power dissipation by eliminating redundant components and optimizing power delivery paths.
Data Source
AI summary
A technique for powering gate drivers in a half-bridge configuration uses a single external power supply to power each gate driver. A single on-chip regulator regulates the positive turn-on voltage for each switch. The regulator overhead, is also used as the negative voltage for turn-off, thus transferring the low-frequency variation of the external power supply to the negative turn-off voltage. Accordingly, a single on-chip regulator generates both the positive turn-on voltage and the negative turn-off voltage. In at least one embodiment, reuse of the switch turn-off current further reduces on-chip power dissipation. The on-chip regulator's output filter capacitor discharges during turn-on of the external power switching device. During turn-off, the current that discharges the switch gate capacitance recharges the regulator filter capacitor.