PWL Waveform Generator With Feedback Current Control
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Solution Overview
Problem
Existing devices, such as personal audio devices and wireless telephones, require precise generation of periodic waveforms with low power consumption and immunity to temperature, process, voltage, frequency, and output load variations, which existing technologies fail to achieve effectively.
Innovation Solution
A piece-wise linear (PWL) waveform generator is developed, comprising a current generator, output capacitor, clock-controlled switch network, and feedback control loop, which generates a PWL waveform by charging and discharging the output capacitor and adjusts the reference current based on the output voltage to maintain precision and reduce power consumption while mitigating glitches and harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional waveform generation methods are used, then power consumption increases, but precision and immunity to variations are compromised
Solution Approach 1:
The waveform generation is segmented into multiple linear segments rather than using a single continuous function. The output capacitor charges and discharges in discrete linear phases controlled by clock signals, achieving precise waveform control while reducing computational complexity and power consumption compared to conventional continuous methods
Solution Approach 2:
The circuit uses periodic clock signals to control the charging and discharging of the output capacitor in a repeating cycle. This periodic action generates the PWL waveform through regular charge-discharge-charge cycles, reducing power consumption by utilizing simple switching operations rather than continuous active control
2Reliability
If waveform generation is made robust against variations in temperature, process, voltage, frequency and output load, then device complexity increases
Solution Approach 1:
A feedback control loop continuously monitors the output voltage and adjusts the reference current to compensate for variations in temperature, process, voltage, frequency, and load conditions. This closed-loop feedback mechanism maintains waveform precision without requiring complex calibration circuits or multiple compensation components
Solution Approach 2:
The circuit automatically compensates for variations through its own feedback mechanism without requiring external calibration or adjustment. The feedback loop self-regulates the reference current based on actual output conditions, making the system self-correcting and reducing the need for additional complexity in design and manufacturing
3Measurement precision
If precise waveform generation is implemented, then power consumption increases
Solution Approach 1:
The circuit uses simple switching elements and basic current sources that are low-cost and low-power components. Rather than using complex high-precision analog circuits that consume significant power, the invention employs simple switches and current mirrors that can be easily fabricated and consume minimal power while achieving the required precision through the PWL approach and feedback control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high precision and low power consumption, ensuring the PWL waveform is robust against variations in loading, temperature, process, and frequency, reducing the need for calibration and minimizing harmonic distortion, thus providing accurate and efficient waveform generation.
Implementation Method 1
an output capacitor across which an output voltage is developed to form the PWL waveform, charging and discharging current sources for charging/discharging the output capacitor based on the reference current
Implementation Method 2
a feedback control loop that senses the output voltage and controls the current generator to vary the reference current based on the output voltage
Data Source
AI summary
A piece-wise linear (PWL) waveform generator includes a current generator that generates a reference current, an output capacitor across which an output voltage is developed to form a PWL waveform, charging and discharging current sources for charging/discharging the output capacitor based on the reference current, a clock-controlled switch network for controlling the charging/discharging of the output capacitor, and a feedback control loop that senses the output voltage and controls the current generator to vary the reference current based on the output voltage. A first switch controlled by a first clock signal periodically connects/disconnects a current source output to/from a load impedance and a second switch controlled by a second clock signal periodically connects/disconnects a capacitor to/from the current source while disconnected from the load impedance. The capacitor capacitance is based on a predetermined voltage to mitigate glitching when the first switch connects the current source output to the load impedance.