Current-Mode MAC Unit With Current Divider for Linear Low-Power Conversion
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Solution Overview
Problem
Hardware systems performing MAC operations face challenges due to non-linear conversions by voltage mode DACs, leading to reduced dynamic range and increased power consumption, as well as the need for multiple active stages and filters which increase device size and power usage.
Innovation Solution
The implementation of a current mode digital-to-analog converter (DAC) with a current divider and mixer to generate an output signal, reducing the number of active stages and eliminating the need for filters and drivers, thereby enhancing linearity and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage mode DAC is used for MAC operations, then conversion functionality is achieved, but linearity is reduced and power consumption increases
Solution Approach 1:
The patent replaces voltage mode DAC with a current mode DAC, substituting voltage-based conversion mechanisms with current-based conversion. This substitution eliminates the non-linear conversions inherent in voltage mode DACs, improving linearity while reducing power consumption as the current mode operation requires less energy for the same conversion task.
Solution Approach 2:
The patent changes the fundamental operating parameter from voltage mode to current mode in the DAC. This parameter change transforms the conversion characteristics, enabling linear current output that directlyproportional to the digital input, thereby improving linearity and reducing the power consumption associated with voltage swing and buffering requirements.
2Productivity
If multiple active stages and filters are used in MAC hardware, then signal processing capability is improved, but device size and power consumption increase
Solution Approach 1:
The patent extracts and eliminates the filters and drivers from the MAC hardware architecture. By using current mode DAC that directly outputs the converted signal in a usable form, the unnecessary filtering and buffering stages are removed, reducing device size while maintaining signal processing capability through the efficient current mode operation.
Solution Approach 2:
The patent merges the DAC output directly with the subsequent processing stages without intermediate filters and drivers. The current mode DAC output is directly combined with other signal paths in the MAC unit, eliminating the need for separate filtering and buffering components, thereby reducing device size and integrating functionality more efficiently.
3Reliability
If voltage mode DAC with filters and drivers is used, then signal conversion is achieved, but device size and power consumption increase
Solution Approach 1:
The patent replaces the voltage mode DAC system with a current mode DAC system, substituting the voltage-based conversion mechanism that requires filters and drivers with a current-based mechanism that outputs directly usable signals. This substitution maintains signal conversion accuracy through linear current output while eliminating the power consumption of filters and drivers.
4Reliability
If current mode DAC with current divider and mixer is used, then linearity is improved, but circuit complexity increases
Solution Approach 1:
The patent segments the current mode DAC output into multiple current paths using a current divider, allowing different portions of the current signal to be processed independently. This segmentation enables the mixer to combine currents in a controlled manner, maintaining linearity while organizing the circuit functionality into manageable segments that reduce overall complexity.
Solution Approach 2:
The current mode DAC with current divider and mixer configuration serves multiple functions simultaneously: it performs digital-to-analog conversion, signal splitting, and mixing operations in a unified current mode architecture. This multi-functionality reduces the need for separate components, thereby improving linearity without proportionally increasing circuit complexity.
Data Source
AI summary
Methods and systems to implement a multiply and accumulate (MAC) unit is described. In an example, a device can include a current mode digital-to-analog converter (DAC) configured to multiply an input signal with an input current to generate a signal. The device can further include a current divider coupled to the current mode DAC. The current divider can be configured to divide the signal into at least a first current having a first amplitude and a second current having a second amplitude. The device can further include a mixer configured to multiply the second current with a clock signal to generate a third current. The third signal can be combined with the first signal via a current summing node to generate an output signal. The output signal can be outputted to another device.