Feed-Forward Converter Current Compensation for Supply Variation
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Solution Overview
Problem
Conventional digital signal processing devices face supply current variations due to codeword changes, leading to performance degradation, harmonic distortion, and increased power consumption when addressing these issues with existing solutions such as reducing output impedance, increasing voltage regulator speed, or adding decoupling capacitance, which result in increased costs and power consumption.
Innovation Solution
A device and method that utilize a feed forward circuit to generate a second codeword based on the first codeword, allowing for precise current injection to the converter circuit to compensate for supply current variations, eliminating harmonic distortion and reducing power consumption by decoupling from traditional voltage supplies, and enabling over-compensation and pre-distortion independent of process, voltage, and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the impedance of the supply is lowered to reduce supply voltage variations, then the supply voltage stability is improved, but the size of the LDO and current consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by generating a compensation current in advance based on the input digital signal characteristics before the supply voltage variations occur. The compensation current is prepared and injected to counteract the expected voltage drops, preventing performance degradation before it happens.
Solution Approach 2:
The patent introduces an intermediary compensation current between the power supply and the converter circuit. This compensation current acts as a mediator that offsets the harmful voltage variations without requiring changes to the power supply impedance or adding large decoupling capacitances.
2Speed
If the speed of the voltage regulator is increased to reduce supply variations, then the supply response time is improved, but the power consumption increases significantly
Solution Approach 1:
The compensation current serves as an intermediary that provides rapid response without requiring a high-speed voltage regulator. By injecting this intermediate compensation current, the system achieves fast response to signal changes without the power consumption penalty of speeding up the main voltage regulator.
3Reliability
If on-chip decoupling capacitance is increased to reduce supply variations, then the supply noise is reduced, but the required area becomes very large
Solution Approach 1:
Instead of using large physical decoupling capacitances, the patent introduces an intermediary compensation current that electronically counteracts supply variations. This current-based approach achieves noise reduction without requiring large on-chip capacitor areas.
4Reliability
If dummy DAC cells are added to keep current consumption constant, then the supply current stability is improved, but the overall current consumption increases
Solution Approach 1:
The patent uses an intermediary compensation current that is dynamically adjusted based on the actual signal requirements. Unlike dummy cells that continuously consume maximum current, this compensation current is activated only when needed and scaled to the actual demand, achieving stability without the penalty of constant maximum consumption.
Solution Approach 2:
The compensation current parameter is dynamically changed based on the input signal characteristics. The system adjusts the compensation current magnitude and timing to match the actual signal variations, optimizing the balance between stability and power consumption rather than maintaining a fixed maximum level.
Data Source
AI summary
The present invention provides a device for processing digital signals. The device comprises a digital signal source configured to output codewords, a converter circuit configured to generate an output signal based on a first codeword received from the digital signal source, and a feed forward circuit configured to generate an output current based on a second codeword received from the digital signal source. The output current generated by the feed forward circuit is connected to a current supply of the converter circuit. The digital signal source is configured to generate the second codeword based on the first codeword in order to compensate for variations of a supply current of the converter circuit.