Self-Powered BJT Driver Circuit for Off-Line Switchers
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Solution Overview
Problem
Non-isolated off-line power supplies face inefficiencies and high costs due to the use of high voltage processes for providing auxiliary power to control circuitry and power switchers, as they often rely on additional circuitry such as high voltage linear regulators or output voltage bootstrap diodes.
Innovation Solution
A self-powered driver circuit utilizing a high voltage semiconductor switch and a driver configuration with switches, diodes, and capacitors to efficiently provide auxiliary power to the off-line switcher, eliminating the need for high voltage processes by using a high voltage semiconductor switch and a driver that includes a first switch coupled to the semiconductor switch and ground, a second switch coupled to the semiconductor switch, and a diode to charge a capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If additional circuitry such as high voltage linear regulators or output voltage bootstrap diodes is used to provide auxiliary power, then the power supply can operate, but the efficiency decreases and manufacturing cost increases due to high voltage processes
Solution Approach 1:
The driver circuit is designed to be self-powered by utilizing the high voltage semiconductor switch itself as the power source. The circuit extracts and stores energy from the switch's operation through the capacitor connection, eliminating the need for external high voltage power supply circuitry and achieving self-sustained operation.
Solution Approach 2:
The high voltage semiconductor switch serves dual functions: it acts as the power switch for the off-line power supply and simultaneously serves as the power source for driving itself. This multi-functionality eliminates the need for separate auxiliary power circuitry, reducing both cost and efficiency losses.
2Reliability
If additional circuitry is used to provide auxiliary power, then the power supply can operate, but the device complexity increases
Solution Approach 1:
The invention extracts the essential power function from the high voltage semiconductor switch and uses it to drive the circuit. By taking out the power provision function from a separate auxiliary circuit and embedding it within the switch's own operation, the design eliminates complex external power supply circuitry while maintaining operational reliability.
Solution Approach 2:
The driver circuit merges the power switch and its driver into a single integrated system where the switch provides power to itself. This consolidation eliminates the need for separate auxiliary power circuitry, reducing device complexity while ensuring reliable operation through self-sustained power delivery.
3Ease of manufacture
If high voltage processes are used to provide auxiliary power, then the power supply can operate, but manufacturing cost and process complexity increase
Solution Approach 1:
The invention uses a simple capacitor as an energy storage element that can be easily manufactured and replaced if needed. This approach avoids the need for complex high voltage power supply circuitry that would require sophisticated manufacturing processes, opting instead for simple, cost-effective components that achieve the same functional result.
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 solution enables efficient and cost-effective provision of auxiliary power to off-line switchers, reducing inefficiencies and operational costs associated with high voltage processes, while maintaining reliable operation.
Implementation Method 1
a diode to charge a capacitor
Data Source
AI summary
An apparatus for providing auxiliary power to an off-line switcher. The apparatus includes a high voltage semiconductor switch and a driver for the high voltage semiconductor switch. The driver includes a first switch, the first switch coupled to the a third terminal of the high voltage semiconductor switch and to ground, a second switch coupled to a first terminal of the high voltage semiconductor switch, a third switch coupled to the first terminal of the high voltage semiconductor switch and to ground. The driver further includes a diode, the anode of the diode coupled to the third terminal of the high voltage semiconductor switch and the cathode of the diode coupled to the second switch.