Band-Gap Reference Circuit With Boosted Fast Wake-Up
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Solution Overview
Problem
Conventional band-gap voltage reference circuits have slow wake-up times, which are linked to higher power consumption, posing a challenge for designers to optimize wake-up times while maintaining power consumption within acceptable limits.
Innovation Solution
A low-power fast wake-up band-gap reference voltage circuit is designed, comprising a one-shot timer, a band-gap voltage reference circuitry with an operational amplifier and a boost circuitry. The boost circuitry is connected during the wake-up phase to increase bandwidth and power consumption temporarily, then disconnected for steady-state operation at a lower power level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the bandwidth of the operational amplifier is increased to reduce wake-up time, then the wake-up time is improved, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by making the operational amplifier's bandwidth adjustable rather than fixed. The op-amp transitions between low-power mode (during steady-state operation) and high-performance mode (during wake-up phase), allowing the system to optimize both power consumption and wake-up time by adapting the amplifier's characteristics to the operational phase
Solution Approach 2:
The patent uses periodic action through the enable signal that periodically activates the band-gap circuit. During each activation cycle, the circuit transitions from a dormant state to an active wake-up state, utilizing higher power temporarily only during the wake-up phase, then returning to a low-power steady-state operation
2Stability of the object's composition
If the compensation capacitor size is increased to improve stability, then the stability is improved, but the wake-up time increases
Solution Approach 1:
The patent applies dynamics by making the compensation capacitor's effective value adjustable. Different capacitor values are selected based on the operational phase: smaller capacitance during wake-up to reduce time constant and speed up response, and larger capacitance during steady-state to enhance stability and reduce noise
3Loss of time
If the slew rate of the operational amplifier is increased to reduce wake-up time, then the wake-up time is improved, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by making the operational amplifier's slew rate adjustable. During the wake-up phase, the op-amp operates in a high-slew-rate mode to quickly charge/discharge capacitors and establish stable voltages. During steady-state operation, it transitions to a low-power mode with reduced slew rate, minimizing power consumption while maintaining adequate performance
Data Source
AI summary
The low-power fast wake-up band-gap reference voltage circuit operates in three phases: dormant, wake-up, and steady-state phases. The circuit enters wake-up subsequent to receipt of an enable signal which causes a one-shot timer to generate a slew enable signal pulse having a predetermined period. To a band-gap voltage reference circuitry comprising an operational amplifier, there is connected, at the wake-up phase, a boost circuitry, operative under the control of the slew enable signal that connects one or more of the one or more boost circuits to a band-gap voltage reference. Thereby, during the brief wake-up phase, more current is consumed to accelerate the response of the circuit. Upon completion of the wake-up phase the boost circuitry is disconnected under the control of the slew enable signal and for as long as the enable signal is active, the circuit is operative in a low-power mode.