LDO Regulator IC with Versatile Ground Pin for Low Dropout
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Solution Overview
Problem
Existing linear voltage regulator integrated circuits (ICs) lack versatility in the connection of their ground pin, limiting their application range, especially at low input voltages and high voltage applications, where they cannot regulate voltage close to the system ground or Vin without additional voltage sources.
Innovation Solution
A positive voltage LDO regulator IC with an on-chip current source and user-selectable Rset resistor sets the reference voltage, allowing the op amp's power terminals to be connected optimally to Vin, Vout, or system ground, enabling regulation across a wider voltage range and flexibility in ground pin configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Vcontrol pin is tied to Vin pin, then the regulator can be used in high voltage applications with floating operation, but the dropout voltage increases to 1.4V and regulation close to Vin is not achievable
Solution Approach 1:
The patent makes the ground pin connection dynamic by allowing it to be connected to different voltage references (system ground, Vout, or another voltage source) depending on the application requirements. This dynamic reconfigurability enables the regulator to achieve low dropout voltage when regulating close to Vin, while maintaining high voltage capability when connected to system ground, thus resolving the contradiction between reliability in high voltage applications and energy efficiency through low dropout voltage.
Solution Approach 2:
The ground pin is designed to serve multiple functions by being able to connect to different voltage references. It can function as a system ground reference for high voltage applications, as a Vout reference for low dropout operation, or as a flexible reference for other voltage sources. This multi-functionality allows a single regulator design to cover both high voltage reliability requirements and low dropout energy efficiency requirements.
2Stability of the object's composition
If the ground pin is tied to system ground, then the regulator operates with stable reference, but it cannot regulate voltage within 1.4V of Vin due to op amp power requirements
Solution Approach 1:
The ground pin connection is made dynamic, allowing users to switch between system ground connection (for stable reference in high voltage applications) and Vout or other voltage source connections (for extended regulation range within 1.4V of Vin). This dynamic reconfigurability resolves the contradiction by enabling the system to achieve both stable reference operation and extended voltage regulation range depending on application needs.
Solution Approach 2:
The patent changes the reference voltage parameter by allowing the ground pin to connect to different voltage levels (system ground, Vout, or other sources). This parameter change enables the regulator to adapt its operating range, allowing it to regulate within 1.4V of Vin when connected to Vout while maintaining stable reference operation when connected to system ground, thus resolving the contradiction between reference stability and regulation range.
3Loss of energy
If additional voltage sources are used to enable regulation close to Vin, then dropout voltage decreases, but device complexity and component count increase
Solution Approach 1:
The regulator uses its own Vout as the reference for the ground pin, eliminating the need for external voltage sources or additional components. This self-service approach allows the regulator to achieve low dropout voltage operation within 1.4V of Vin without increasing device complexity, as the Vout pin already exists as part of the basic regulator functionality. The solution leverages existing circuit elements rather than adding new components.
Solution Approach 2:
The ground pin's ability to connect to Vout repurposes an existing output pin for an additional function as a voltage reference, eliminating the need for separate voltage sources. This multi-functionality reduces device complexity while enabling low dropout operation, as the same Vout pin serves both its primary function of providing regulated output and its secondary function of serving as a reference for low dropout regulation.
4Ease of manufacture
If the ground pin has fixed connection, then manufacturing and application are simplified, but application range is limited
Solution Approach 1:
The ground pin connection is made dynamic with multiple configurable options (system ground, Vout, or other voltage sources), allowing the same regulator design to be manufactured and applied across diverse applications. This dynamic reconfigurability maintains ease of manufacture through a single standardized component while dramatically expanding application range to include both high voltage floating applications and low dropout applications requiring regulation within 1.4V of Vin.
Solution Approach 2:
The ground pin is designed with multi-functionality to serve different reference purposes in different applications. It can function as a system ground reference, a Vout reference, or connect to other voltage sources, making the regulator universally applicable across high voltage, low dropout, and intermediate voltage applications without requiring different manufactured components, thus maintaining ease of manufacture while expanding application range.
Data Source
AI summary
A linear regulator integrated circuit may be formed having four external terminals including a voltage input (Vin) terminal, a voltage output (Vout) terminal, a Set terminal, and an operational amplifier (op amp) power terminal. A user connects an external resistor to the Set terminal for creating a reference voltage. An op amp controls a pass (or series transistor) to cause an output voltage at the Vout terminal to equal the reference voltage. The op amp has a first power supply terminal internally coupled to the Vin terminal and a second power supply terminal coupled to the op amp power terminal. The op amp power terminal allows a user to externally couple the op amp second power supply terminal to either the Vout pin (for high voltage applications), system ground (for medium voltage applications), or another voltage (to provide additional headroom in very low voltage applications).