Boosting LDO Regulator for Fast Transient Gate Driver Loads
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Solution Overview
Problem
Conventional low-dropout regulators face challenges in maintaining a stable output voltage during transient high load conditions in gate driver applications, requiring high bandwidth and increased current consumption or large capacitance, which is not feasible in integrated circuit implementations.
Innovation Solution
A high-speed low-impedance boosting low-dropout regulator is introduced, utilizing a differential amplifier with a feedback circuit, a load stage, and a compensation stage to provide a first output current and a boosted output current during different intervals, compensating for voltage drops and reducing output impedance through complementary control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the bandwidth of conventional low-dropout regulator is increased to 100 MHz to handle switching transient, then the dynamic performance of gate driver is improved, but the average current consumption of integrated circuit system is substantially increased
Solution Approach 1:
The regulator dynamically switches between two operational modes: a first mode for normal operation with lower current consumption, and a second mode for transient conditions with higher current capability. The mode selection is controlled by a control signal generated in response to transitions of the input control signal, allowing the system to adapt its performance characteristics to actual load conditions rather than maintaining high bandwidth continuously
Solution Approach 2:
The regulator operates periodically in high-current mode only during transient events (when input control signal transitions occur), rather than maintaining high-current capability continuously. This periodic activation of the second mode provides necessary current during switching transients while minimizing average power consumption during steady-state operation
2Stability of the object's composition
If bypass capacitance is increased to supply necessary current during transient event, then the output voltage stability is improved, but the integrated circuit implementation becomes incompatible and may increase number of pins, bill-of-materials, or printed circuit board area
Solution Approach 1:
The regulator changes its operational parameters (current capability, impedance) dynamically based on transient conditions. During normal operation, it operates with standard current levels and impedance characteristics. Upon detecting a transient event through control signal transitions, it switches to a second mode with enhanced current capability and modified impedance characteristics, eliminating the need for large fixed bypass capacitance
3Speed
If booster amplifier is used to generate boost current in response to output voltage drop, then the response to transient load is improved, but a substantial glitch of regulator output voltage occurs due to voltage drop required to trigger boost current
Solution Approach 1:
The regulator performs preliminary action by detecting transitions of the input control signal and generating a control signal in advance of the actual transient load change. This early detection allows the regulator to switch to the second mode before the output voltage drops, providing boost current proactively rather than reactively, thereby preventing voltage glitches before they occur
Data Source
AI summary
A method for regulating a voltage reference signal includes providing a first output current during a first interval and a boosted output current during a second interval to generate a low-dropout voltage reference signal based on a first power supply voltage, a second power supply voltage, and a reference voltage level. The method includes, during the second interval, compensating for a voltage drop caused by providing the boosted output current. The first output current may be provided in a first mode of operation. The boosted output current and voltage drop compensation may be provided in a boosted mode of operation.