Voltage Regulator Bulk Control for Fast Load Transients
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Solution Overview
Problem
Voltage regulators in wearable devices face challenges in responding quickly to load changes due to the use of output transistors with lower current drivability and smaller output capacitors, which result in lower circuit response and increased power consumption.
Innovation Solution
The proposed voltage regulator design incorporates an operational amplifier, two transistors, and a capacitor, along with a current sink circuit, to rapidly adjust the current flowing to the load, using transistors and capacitors to manage the bulk voltage and threshold voltage of the transistors, thereby maintaining a constant output voltage during load changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an output transistor with lower current drivability is used to reduce power consumption, then power consumption is reduced, but the circuit response speed decreases
Solution Approach 1:
The patent divides the output transistor into two separate transistors: a first output transistor with lower current drivability for normal operation to minimize power consumption, and a second output transistor with higher current drivability that activates only during load transient conditions to provide quick response. This segmentation allows the system to optimize for both low power consumption and fast response speed by using the appropriate transistor for each operating condition.
2Ease of manufacture
If a smaller output capacitor is used to reduce manufacturing costs, then manufacturing cost is reduced, but the circuit response to load changes deteriorates
Solution Approach 1:
The patent segments the current delivery function between two transistors with different characteristics. The smaller output capacitor is sufficient for normal operation with the first transistor, reducing manufacturing cost. During load transients, the second transistor with higher current drivability compensates for the smaller capacitor's limited charge storage, maintaining fast response performance without requiring a large expensive capacitor.
3Use of energy by moving object
If transistors with lower current drivability are used to minimize power consumption, then power consumption is minimized, but the ability to respond quickly to load changes is reduced
Solution Approach 1:
The patent implements a dynamic switching mechanism where the control circuit detects load transient conditions and dynamically switches between the first output transistor (lower current drivability) for normal low-power operation and the second output transistor (higher current drivability) for fast response during load changes. This dynamic adaptation allows the system to optimize power consumption during steady-state operation while maintaining high productivity during transient conditions.
Data Source
AI summary
A voltage regulator includes an operational amplifier, a first transistor, a second transistor, a capacitor and a current sink circuit. The operational amplifier outputs a control voltage according to an amplified differential voltage between a first input terminal and a second input terminal of the operational amplifier. The first transistor includes a control terminal receiving the control voltage, a first terminal coupled to a supply terminal, a second terminal providing an output voltage, and a bulk terminal. The second transistor includes a second terminal coupled to the bulk terminal of the first transistor, and a bulk terminal coupled to the supply terminal. The capacitor includes a first terminal coupled to the bulk terminal of the first transistor, and a second terminal receiving the output voltage. The current sink circuit generates a feedback voltage according to the output voltage and output the feedback voltage to the operational amplifier.