Integrated AC to DC Rectifier Circuit with Parasitic BJT Protection
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Solution Overview
Problem
Conventional AC to DC conversion in electronic circuits requires discrete diodes, which cannot be integrated with other electronic devices to form an integrated circuit, limiting the integration of low DC voltage circuits.
Innovation Solution
An integrated device with AC to DC conversion function is created using a substrate of a first conductivity type and well regions of a second conductivity type, forming diodes that allow for the integration of AC to DC conversion within a circuit operating under low DC voltage, incorporating MOS transistors to prevent parasitic BJT formation and stabilize DC voltage supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If discrete diodes are used for AC to DC conversion, then the rectification function is achieved, but the devices cannot be integrated with other electronic devices to form an integrated circuit
Solution Approach 1:
The patent merges multiple discrete components (diodes, transistors, resistors) into a single integrated device structure. The P-type substrate with N-type well regions integrates the rectifier diodes, while N-type substrate with P-type well regions integrates the protection diodes and MOS transistors, achieving full integration of AC-DC conversion functionality.
Solution Approach 2:
The integrated device performs multiple functions simultaneously: full-wave rectification, voltage regulation, and parasitic BJT protection. The well regions serve dual purposes as both diode structures and isolation regions, while MOS transistors provide both switching and protection functions.
2Adaptability or versatility
If well regions are used to form diodes, then integration is achieved, but parasitic BJT formation may occur
Solution Approach 1:
MOS transistors are introduced as intermediary protection devices between the well region diodes and the substrate. These MOS transistors prevent parasitic BJT formation by providing controlled current paths and isolation, eliminating the harmful effects while maintaining the integrated structure.
Solution Approach 2:
The protection diodes and MOS transistors are pre-configured in the integrated device structure to counteract parasitic BJT effects before they can occur. The P-type well regions in N-type substrate create protection diodes that clamp voltages and prevent parasitic transistor activation.
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
Enables the integration of majority of rectifier devices with low voltage circuits into a single integrated circuit, providing stable DC voltage levels and eliminating parasitic BJT effects, while only external resistors remain separate.
Implementation Method 1
In each well region of the second conductivity type, a diode is formed by the heavily doped regions of the first and second conductivity type and the well region, such that four diodes are formed by four well regions
Data Source
AI summary
The present invention discloses an integrated device with AC to DC conversion function, and an integrated circuit using the device. The integrated circuit comprises: a circuit operating under low DC voltage; and an integrated device with AC to DC conversion function, the device including first, second, third and fourth diodes, wherein the first diode has a cathode coupled to an anode of the second diode at a first node which receives an input of an AC voltage; the third diode has a cathode coupled to an anode of the fourth diode at a second node which receives another input of the AC voltage; the first diode has an anode coupled to an anode of the third diode at a third node which provides a low level of a DC voltage; and the second diode has a cathode coupled to a cathode of the fourth diode at a fourth node which provides a high level of the DC voltage.