Integrated Start-Up Circuit for High-Frequency Switching Power Supplies
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Solution Overview
Problem
Conventional power supply control devices face challenges in miniaturization and high-frequency operations due to the need for multiple chips and complex chip integration, particularly in start-up circuits which increase chip area and power consumption.
Innovation Solution
A power supply control device is designed with a drive switch circuit formed by cascade-connecting a depletion type GaN-FET and an enhancement type MOSFET, integrated with a control circuit and start-up circuit, which includes a switching circuit and comparison circuit to control the power supply voltage, reducing the number of chips and enhancing high-frequency operation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional start-up circuits are used with multiple chips, then the power supply control device can be implemented, but the chip area increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the start-up circuit and control circuit onto a single chip, eliminating the need for separate chips. The start-up circuit includes a start-up transistor that charges the power supply voltage, and this is integrated with the control circuit that drives the switching element, thereby reducing chip area while maintaining full functionality.
Solution Approach 2:
The single chip is designed to perform multiple functions: the start-up transistor charges the power supply voltage, the control circuit drives the switching element, and the integrated structure provides both start-up and control functionalities in one device, reducing the need for multiple specialized chips.
2Reliability
If conventional start-up circuits with multiple chips are used, then the power supply control device can operate, but the number of chips and integration complexity increases
Solution Approach 1:
The patent merges the start-up circuit and control circuit into a single integrated chip, eliminating the need for multiple chip interconnections. The start-up transistor, control circuit, and power supply voltage charging function are all integrated, significantly reducing integration complexity.
3Reliability
If conventional designs are used, then the power supply control device can be implemented, but high-frequency operation capability is limited
Solution Approach 1:
The patent employs a depletion-type start-up transistor with specific electrical characteristics that enable faster charging of the power supply voltage, and the control circuit is designed with parameters optimized for high-frequency switching operations, allowing the power supply control device to operate at higher frequencies.
Data Source
AI summary
A power supply control device includes: a drive switch circuit formed by cascade-connecting a depletion type first transistor and an enhancement type second transistor, and configured to drive a transformer of an insulated switching power supply; a control circuit configured to control the second transistor; and a start-up circuit configured to charge a power supply voltage of the control circuit by using a source voltage of the first transistor.