Step-Up Circuit Ground-Short Protection via Voltage Comparison
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Solution Overview
Problem
Conventional step-up circuits face increased circuit size and current consumption due to the need for ground-shorting protective functions, which hinder the reduction of size and cost, especially with components like resistance voltage dividers and comparators.
Innovation Solution
A step-up circuit configuration that includes rectifier elements and a switching element controlled by a voltage difference between capacitors, preventing the rectifier elements from turning on during short circuits and thus protecting them, and using a voltage clamping circuit to restrict ground-fault currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ground-shorting protective functions are added to prevent rectifier element degradation, then reliability is improved, but device complexity and current consumption increase
Solution Approach 1:
The step-up circuit itself provides the ground-shorting protective function through its inherent voltage comparison mechanism. The switching element automatically compares the voltage at the first capacitor connecting terminal with the voltage at the third capacitor connecting terminal, and turns off the rectifier elements when shorting is detected, eliminating the need for separate protective circuits.
Solution Approach 2:
The ground-shorting protective function is merged with the normal operating control logic of the step-up circuit. The same voltage comparison mechanism that controls the switching element during normal operation also detects ground shorts and protects the rectifier elements, combining protection functionality with the main circuit operation.
2Reliability
If ground-shorting protective functions with resistance voltage dividers and comparators are added, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The step-up circuit itself provides the ground-shorting protective function through its inherent voltage comparison mechanism. The switching element automatically compares the voltage at the first capacitor connecting terminal with the voltage at the third capacitor connecting terminal, and turns off the rectifier elements when shorting is detected, eliminating the need for separate protective circuits.
3Reliability
If conventional protective circuits are added to detect and respond to ground shorts, then reliability is improved, but current consumption increases
Solution Approach 1:
The step-up circuit itself provides the ground-shorting protective function through its inherent voltage comparison mechanism. The switching element automatically compares the voltage at the first capacitor connecting terminal with the voltage at the third capacitor connecting terminal, and turns off the rectifier elements when shorting is detected, eliminating the need for separate protective circuits.
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 simplifies the circuit, reduces size and cost, and minimizes current consumption by preventing rectifier element degradation and maintaining step-up voltage efficiency.
Implementation Method 1
a switching element provided on a portion of the current path which is between a connection point, where the third capacitor connecting terminal is connected to the current path, and the power supply terminal, wherein a control terminal for controlling ON and OFF of the switching element is connected to the first capacitor connecting terminal, the switching element is turned ON when a voltage at the first capacitor connecting terminal is higher than a voltage at the third capacitor connecting terminal by a specified voltage or larger
Implementation Method 2
using a voltage clamping circuit to restrict ground-fault currents
Implementation Method 3
a first rectifier element which is provided on a current path from the power supply terminal to the first capacitor connecting terminal such that a direction from the power supply terminal toward the first capacitor connecting terminal is a forward direction; a second rectifier element which is provided on a portion of the current path which is between the first rectifier element and the first capacitor connecting terminal
Data Source
AI summary
A step-up circuit comprises a rectifier element 11 provided on a current path from a terminal VCC applied with a voltage source voltage VCC to a terminal VP connected to one electrode of a capacitor C1 such that a direction from the terminal VCC toward the terminal VP is a forward direction, a rectifier element 12 provided on a portion of the current path which is between the rectifier element 11 and the terminal VP such that a direction from the rectifier element 11 toward the terminal VP is a forward direction, a terminal BC1 which is connected to one electrode of a capacitor C2 and is applied with an oscillating voltage, a terminal BC2 which is connected to a portion of the current path which is between the rectifier element 11 and the rectifier element 12 and is connected to the other electrode of the capacitor C2, and a switching element 14 provided on a portion of the current path which is between a connection point, where the terminal BC2 is connected to the current path, and the terminal VCC, and the switching element 14 is configured to be turned ON and OFF according to the voltage at the terminal VP with respect to the voltage at the terminal BC2.