LDO Leakage Reduction via Gate Voltage Offset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-stage amplifiers, such as low-dropout (LDO) regulators, experience excessive power consumption and overvoltage events due to leakage currents, especially at low load currents and high temperatures, which affect regulation and stability.
Innovation Solution
Incorporating leakage reduction circuitry that offsets the gate voltage of the pass device using a core voltage higher than the supply voltage, and a current sink to adaptively compensate remaining leakage within the regulation loop, ensuring a negative source-gate voltage and eliminating leakage during the OFF state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the pass device is used to provide load current at low voltages, then the regulator can operate with small input-output differential voltages, but leakage currents increase excessively leading to power consumption and overvoltage events
Solution Approach 1:
The patent applies preliminary anti-action by proactively counteracting leakage currents before they cause harmful effects. A leakage compensation circuit is implemented that actively generates compensating currents to cancel out the leakage currents in the pass device. This is achieved by monitoring the leakage current and applying an equal and opposite compensation current through additional circuitry, thereby preventing power loss and overvoltage events before they occur.
Solution Approach 2:
The patent converts the harmful leakage current into a beneficial effect by using the leakage current information to drive a compensation mechanism. The leakage compensation circuit measures the leakage current and uses this information to generate a compensating signal that actively counteracts the leakage. This transforms the harmful leakage phenomenon into a controllable parameter that can be used to drive the compensation system, thereby eliminating the net power loss.
2Productivity
If the pass device gate voltage is increased to provide more drive current, then the load current capability is improved, but leakage current through the pass device increases
Solution Approach 1:
The patent applies dynamics by implementing adaptive control of the pass device gate voltage. Rather than using a fixed gate voltage, the system dynamically adjusts the gate voltage based on operating conditions including load current requirements and temperature. The leakage compensation circuit continuously monitors conditions and adjusts compensation in real-time, allowing the system to optimize between drive current capability and leakage minimization depending on the current operating state.
Solution Approach 2:
The patent changes the gate voltage parameter dynamically based on operating conditions. The leakage compensation circuit modifies the gate voltage to maintain optimal performance across different load and temperature conditions. By adjusting the gate voltage parameter adaptively and implementing leakage compensation, the system achieves high load current capability when needed while minimizing leakage during low-load conditions, thereby resolving the contradiction between productivity and energy loss.
3Temperature
If the regulator operates at high temperatures, then the operating temperature range is extended, but leakage currents increase significantly affecting regulation stability
Solution Approach 1:
The patent implements feedback control to maintain regulation stability at high temperatures. The leakage compensation circuit continuously monitors the output voltage and leakage current, and uses this feedback information to adjust compensation levels in real-time. Temperature sensors provide feedback about thermal conditions, allowing the system to increase compensation strength at higher temperatures where leakage is more severe, thereby maintaining stable regulation across the full operating temperature range.
Solution Approach 2:
The patent applies preliminary action by preparing compensation mechanisms before temperature-induced leakage becomes problematic. Temperature compensation is implemented in advance, with the leakage compensation circuit pre-configured to counteract expected leakage at various temperature levels. By anticipating and compensating for temperature effects before they degrade regulation, the system maintains reliability across extended temperature ranges.
Data Source
AI summary
The present document relates to multi-stage amplifiers, such as linear regulators (e.g. low-dropout regulators). A method and a circuit for reducing leakage current of such multi-stage amplifiers is presented. A voltage regulator is described. The voltage regulator comprises a pass device configured to provide a load current at a regulated output voltage to an output node of the voltage regulator. A source of the pass device is coupled to a first potential of the voltage regulator. Furthermore, the voltage regulator comprises drive circuitry configured to control the pass device via a gate of the pass device, based on a reference voltage and based on a feedback voltage derived from the output voltage. In addition, the voltage regulator comprises leakage reduction circuitry configured to pull-up the gate of the pass device using a second potential; wherein the second potential is higher than the first potential.