Integrated Zener Diode and Depletion-Mode Transistor for Startup Circuits

Solution Overview

Problem

Conventional startup circuits for semiconductor power devices require multiple components, which complicates their design and reduces their robustness and reliability, especially in miniature system applications where multiple functions need to be integrated on a single chip.

Innovation Solution

Integration of a Zener diode and a depletion-mode transistor, such as a MOSFET or JFET, onto a single chip, where the Zener diode controls the transistor's operation by regulating the input voltage, enabling efficient current flow and detection through a series connection and adjustable breakdown voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple components are used in startup circuits, then functional requirements can be met, but device complexity increases and reliability decreases

Engineering Contradiction:

Improvefunctional requirementsVSAvoidcircuit design

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines a Zener diode and a depletion-mode transistor into a single integrated device structure. The Zener diode portion and transistor portion share a common substrate and are formed in close proximity, with the Zener diode anode connected to the transistor drain and cathode connected to the transistor source. This integration reduces the number of discrete components while maintaining the voltage detection and control functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated device performs multiple functions: the Zener diode portion provides voltage regulation and detection, the transistor portion provides current control, and together they enable brown-out detection, startup sequencing, and voltage monitoring. This multi-functional integration eliminates the need for separate discrete components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple components are used in startup circuits, then functional requirements can be met, but reliability decreases

Engineering Contradiction:

Improvefunctional requirementsVSAvoidrobustness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines a Zener diode and a depletion-mode transistor into a single integrated device structure. The Zener diode portion and transistor portion share a common substrate and are formed in close proximity, with the Zener diode anode connected to the transistor drain and cathode connected to the transistor source. This integration reduces the number of discrete components while maintaining the voltage detection and control functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated device includes protection structures such as guard rings and isolation regions that prevent latch-up and electrostatic discharge damage. These protective features are built into the device structure beforehand to enhance reliability under stress conditions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If multiple discrete components are used, then circuit functionality is achieved, but power loss increases

Engineering Contradiction:

Improvecircuit functionalityVSAvoidpower loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent combines a Zener diode and a depletion-mode transistor into a single integrated device structure. The Zener diode portion and transistor portion share a common substrate and are formed in close proximity, with the Zener diode anode connected to the transistor drain and cathode connected to the transistor source. This integration reduces the number of discrete components while maintaining the voltage detection and control functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated device eliminates the need for external resistors and capacitors that would be required in discrete implementations. The internal structure provides direct coupling between the Zener diode and transistor, reducing the number of intermediate components that contribute to power loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This integration simplifies the circuit design, enhances robustness, and increases reliability by reducing power loss and component count, while allowing for adjustable detection thresholds, thus improving the robustness and reliability of power driver circuits for various applications.

Implementation Method 1

a Zener diode ZD1 has a cathode connected to a terminal that receives the input voltage... if the input voltage at the detect terminal is higher than the breakdown voltage of the Zener diode ZD1

Methodology Applied

Scientific EffectZener breakdown: Avalanche Breakdown

Data Source

PatentUS9543292B2Field effect transistor with integrated Zener diode

Publication Date: 2017.01.10 ALPHA & OMEGA SEMICONDUCTOR INC

AI summary

One or more Zener diodes and a field effect transistor having a drain connected in series with the one or more Zener diodes are integrally formed by a plurality of doped regions in the same P-type semiconductor substrate and separated by a punch through stop region. An N-type region is formed under the one or more Zener diodes.