Voltage Regulator Comparator Circuit Eliminates Resistors
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Solution Overview
Problem
Conventional voltage regulators experience high current consumption and reverse current flow when the potential on the VDD terminal becomes zero, leading to short backup operation times and inability to turn off the Pch transistor.
Innovation Solution
The voltage regulator eliminates voltage dividing resistors in the comparator circuit, allowing for control of Pch transistors to prevent current flow and reduce consumption by using a comparator circuit with constant current circuits and inverters to manage the substrate potential of Pch transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage dividing resistors are used in the comparator circuit to compare VDD terminal voltage with output terminal voltage, then the comparator can function to control Pch transistor substrate potential, but current flows through the resistors when VDD terminal potential becomes zero, causing high current consumption and preventing backup operation
Solution Approach 1:
The patent extracts and removes the voltage dividing resistors (1101, 1102, 1103, 1104) from the comparator circuit. By eliminating these resistive elements, the circuit prevents current flow through the comparator when VDD terminal potential becomes zero, thereby reducing current consumption and enabling extended backup operation with the backup battery.
2Reliability
If Pch transistor substrate potential is switched to higher potential to prevent reverse current flow, then reverse current is blocked, but when VDD terminal potential becomes zero, the Pch transistor cannot be turned off and reverse current flows from output terminal to VDD terminal
Solution Approach 1:
The patent removes the voltage dividing resistors that were preventing proper transistor control. Without these resistors, the comparator circuit can properly control the Pch transistor substrate potential, enabling the transistor to be turned off when VDD terminal potential becomes zero, thus maintaining reverse current prevention capability while restoring switching functionality.
Data Source
AI summary
Provided is a voltage regulator having low current consumption, which is capable of preventing a reverse current from flowing thereto from an output terminal (122), irrespective of a magnitude of a voltage of a VDD terminal (121). The voltage regulator has a circuit configuration in which voltage dividing resistors are not used for a comparator circuit for comparing the voltage of the VDD terminal (121) with a voltage of the output terminal (122), to thereby achieve lower current consumption.