Source-Follower LDO With Temperature Compensation for Stable Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing low dropout regulators (LDOs) have complex structures and high power consumption, making them unsuitable for applications requiring low power consumption.
Innovation Solution
The LDO design omits the operational amplifier and resistor divider feedback network, incorporating a reference voltage generating circuit and a source follower to generate a temperature-changing reference voltage, which offsets voltage changes, resulting in a simple circuit structure and ultra-low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LDO includes an operational amplifier and resistor divider feedback network, then the output voltage can be stabilized, but the circuit structure becomes complicated and power consumption increases
Solution Approach 1:
The patent extracts and removes the operational amplifier and resistor divider feedback network from the traditional LDO structure, retaining only the essential voltage regulation function through a simplified circuit that uses a reference voltage source and a single transistor, thereby reducing complexity while maintaining stability
Solution Approach 2:
The patent uses a bandgap reference source to generate a temperature-compensated reference voltage that copies and compensates for temperature variations in the output, eliminating the need for complex feedback networks while maintaining voltage stability
2Reliability
If the LDO includes an operational amplifier and resistor divider feedback network, then the output voltage can be stabilized, but power consumption becomes high
Solution Approach 1:
The patent removes the power-hungry operational amplifier from the circuit, replacing it with a simple transistor-based voltage regulation stage that consumes minimal power while maintaining output voltage stability through the temperature-compensated reference voltage
Solution Approach 2:
The patent replaces expensive and power-consuming operational amplifiers with inexpensive, low-power transistor circuits that achieve the same voltage regulation function with significantly reduced power consumption
3Reliability
If a temperature-changing reference voltage is used to offset voltage changes, then the output voltage remains stable with temperature variations, but the circuit requires precise temperature compensation
Solution Approach 1:
The bandgap reference source generates a reference voltage that copies the temperature characteristics of the output stage and provides automatic compensation, achieving temperature stability without requiring external temperature sensors or complex compensation 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 approach allows for a stable output voltage that does not change with temperature, enabling the LDO to be applied in low power consumption scenarios while maintaining a simple circuit structure.
Implementation Method 1
the reference voltage generating circuit is configured to generate a reference voltage that changes with temperature to offset a voltage change caused by a voltage between a first terminal and a second terminal of the source follower changing with the temperature
Data Source
Figure 1~2
Figure 3
AI summary
The present application provides an LDO, an MCU, a fingerprint module and a terminal device. The LDO includes: a reference voltage generating circuit and a source follower connected to the reference voltage generating circuit. The reference voltage generating circuit is used to generate a reference voltage that changes with temperature to offset a voltage change caused by a voltage between a first terminal and a second terminal of the source follower changing with time, so that an output voltage of the second terminal of the source follower does not change with temperature. The LDO provided by embodiments of the present application omits an operational amplifier EA and a resistor divider feedback network in the prior art, which not only has a simple circuit structure, but also can achieve ultra-low power consumption, and in the meantime, can also achieve an output voltage that does not change with temperature, and thus can be applied to application scenarios with a requirement of low power consumption.