Power Supply Circuit Voltage Selection Eliminates Series Switch Drops
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Solution Overview
Problem
Conventional power supply circuits experience voltage drops due to switches and diodes inserted in series between the battery and load, leading to inefficiencies and increased chip area requirements.
Innovation Solution
A power supply circuit design that eliminates the need for switches and diodes by using a series regulator step-down power circuit and a charge pump step-up power circuit, with a voltage selection circuit that compares input and output voltages to determine which circuit to activate, thereby avoiding voltage drops and reducing chip area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switches and backflow prevention diodes are inserted in series between battery and load to switch power circuits, then power circuit selection is enabled, but voltage drops occur due to on-resistances and forward voltage drops
Solution Approach 1:
The patent removes the switches and backflow prevention diodes from the series path between battery and load. Instead, it uses the backflow prevention function of each power circuit's output transistor and controls circuit activation through ground connections to the switch elements, eliminating the voltage drops caused by series switches and diodes while maintaining power circuit selection capability
Solution Approach 2:
The patent introduces a mode selection circuit as an intermediary that controls which power circuit is activated by connecting or disconnecting the ground terminal from the switch elements. This mediator enables power circuit selection without requiring switches in the main power path, thus avoiding voltage drops
2Ease of operation
If switches and diodes are used to switch power circuits, then power supply mode control is achieved, but chip area increases due to additional components
Solution Approach 1:
The patent extracts and removes the unnecessary switches and backflow prevention diodes from the circuit. The power supply mode control is achieved using only the essential components (power circuits with their inherent backflow prevention transistors and a simple mode selection circuit), significantly reducing chip area while maintaining ease of operation
Solution Approach 2:
The patent makes the power circuit output transistors serve dual functions: as the main power switching elements and as backflow prevention diodes. This multi-functionality eliminates the need for separate backflow prevention diodes and reduces the number of components required for mode switching, thereby reducing chip area
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 configuration allows for efficient power supply to the load without voltage drops, reducing chip area and current consumption by eliminating the need for switching elements, and enabling flexible operation between series regulator and charge pump circuits.
Implementation Method 1
a series regulator step-down power circuit which has an input connected to the input terminal and an output connected to the output terminal
Implementation Method 2
a charge pump step-up power circuit which has an input connected to the input terminal and an output connected to the output terminal
Implementation Method 3
a voltage selection circuit to which a voltage of the input terminal and a voltage of the output terminal are supplied and configured to output a higher voltage of the voltage of the input terminal and the voltage of the output terminal
Data Source
AI summary
Provided is a power supply circuit including a series regulator step-down power circuit, a charge pump step-up power circuit, and a voltage selection circuit to which a voltage of an input terminal and a voltage of an output terminal are supplied and configured to output a higher voltage from the supplied voltages. A connection point of a first resistor and a second resistor which are connected between the output terminal and a ground terminal is connected to an input of a differential amplifier circuit. An output of the differential amplifier circuit is connected to a gate terminal of an output transistor via a first switch. An output of the voltage selection circuit is connected to the gate terminal of the output transistor via a second switch. The output of the voltage selection circuit is connected to a substrate electrode of the output transistor.