N-Channel Depletion Transistor Power Supply Ripple Suppression

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Solution Overview

Problem

Existing power supply circuits face challenges in achieving high ripple suppression performance with a simple configuration, often requiring multiple components that increase power consumption and complexity.

Innovation Solution

A power supply circuit design that includes an N-channel depletion type transistor inserted between the input and internal supply power terminals, with the gate connected to the output terminal, and a regulator generating the output voltage using the internal supply voltage, allowing for improved ripple suppression by controlling the gate voltage based on the output voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple components are used to achieve high ripple suppression performance, then ripple suppression performance is improved, but device complexity increases

Engineering Contradiction:

Improveripple suppression performanceVSAvoidcomponent count

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the ripple suppression function with the existing power supply circuit by inserting a transistor into the circuit path. The transistor's gate is connected to the output terminal, allowing it to work in conjunction with the regulator to suppress ripples without requiring separate dedicated suppression components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The inserted transistor uses the output voltage itself as its gate voltage (or a derived version), allowing the circuit to automatically regulate and suppress ripples based on its own output conditions without external control signals or additional control circuitry.

Inventive Principle:

Principle #25Self-service

2Reliability

If multiple components are used to achieve high ripple suppression performance, then ripple suppression performance is improved, but power consumption increases

Engineering Contradiction:

Improveripple suppression performanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The transistor is integrated into the existing power supply path, sharing the circuit infrastructure with the regulator. This merging approach allows ripple suppression to be achieved using the same power delivery path without adding separate power-consuming suppression circuits.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transistor operates using the output voltage already present in the circuit, converting it to control the transistor's conductivity. This self-service mechanism avoids the need for additional power sources or active control circuits that would increase overall power consumption.

Inventive Principle:

Principle #25Self-service

3Reliability

If multiple components are used to achieve high ripple suppression performance, then ripple suppression performance is improved, but manufacturing cost increases

Engineering Contradiction:

Improveripple suppression performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The transistor is integrated into the existing power supply circuit path, sharing the same substrate and interconnect structure with the regulator. This integration approach reduces the need for additional discrete components, simplifying the manufacturing process and reducing assembly costs.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10996696B2Power supply circuit, power supply device, and vehicle

Publication Date: 2021.05.04 ROHM CO LTD

AI summary

A power supply circuit that outputs via an output terminal an output voltage based on an input voltage applied to an input terminal includes: an inserted transistor of an N-channel depletion type inserted between the input terminal and an internal supply power terminal; and a regulator configured to generate the output voltage by using as a supply voltage a voltage applied to the internal supply power terminal. The gate of the inserted transistor is connected to the output terminal.