High-Voltage LDO Regulator with Pre-Regulation for Fast Transients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing low dropout (LDO) regulators with high voltage input suffer from reduced bandwidth and slow transient response due to high impedance nodes, which are exacerbated by the use of low voltage gate-source voltage and high voltage rails, necessitating the use of external decoupling capacitors for improved performance.
Innovation Solution
A pre-regulator circuit and a high speed LDO regulator are combined, utilizing a first MOSFET and a second MOSFET to provide a low voltage supply and output voltage, respectively, with a dual amplifier feedback loop structure to enhance transient response without external capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low voltage gate-source voltage devices are used with high voltage rails, then the LDO regulator can handle high voltage input, but the bandwidth and transient response are reduced due to high impedance nodes
Solution Approach 1:
The LDO regulator is divided into two separate circuits: a pre-regulator circuit that handles the high voltage input and generates a low voltage supply, and a high-speed LDO regulator that uses this low voltage supply to provide the final regulated output. This segmentation allows each circuit to be optimized for its specific voltage range, with the pre-regulator handling high voltage and the LDO providing fast transient response at low voltage, thereby resolving the contradiction between high voltage capability and fast transient response.
2Speed
If external decoupling capacitors are added to improve transient response, then the bandwidth and speed are improved, but the device complexity increases
Solution Approach 1:
The pre-regulator circuit performs preliminary voltage regulation by converting the high voltage input to a low voltage supply before it reaches the LDO regulator. This preliminary action ensures that the LDO regulator operates with a stable low voltage supply, enabling it to achieve fast transient response without requiring external decoupling capacitors, thus improving speed while avoiding increased device complexity.
Data Source
AI summary
A low dropout (LDO) regulator circuit is provided. The LDO regulator circuit may include a pre-regulator circuit to receive a high voltage input voltage and provide a low voltage supply voltage, and an LDO regulator to receive the low voltage supply voltage and provide a low voltage output voltage. The pre-regulator circuit may include an input stage, an output stage coupled to the input stage, and a first MOSFET coupled to the output stage to provide the low voltage supply voltage. The input stage and first MOSFET may receive the high voltage input voltage. The LDO regulator may include a second MOSFET coupled to the first MOSFET, and may receive the low voltage supply voltage and provide the low voltage output voltage.