Current Mirror DAC with Bias Current Reduction
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Solution Overview
Problem
Existing digital-to-analog conversion (DAC) circuits in electronic systems suffer from high power consumption due to bias signals, especially in transmitting devices like mobile phones and laptops, which operate on batteries and experience periods of inactivity and high amplification during transmission.
Innovation Solution
The implementation of a current mirror amplifier circuit with a signal-shaping filter and a mirrored bias current reduction circuit to minimize unnecessary power consumption by reducing DC bias current components in the analog output signal, using a configuration that includes PMOS FETs, NMOS FETs, and RC filters to amplify and filter the input signal effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bias signals are used to ensure circuit elements remain in desired operating range, then linear behavior and maximum dynamic range are improved, but power consumption increases due to DC bias current components
Solution Approach 1:
The patent extracts and removes the DC bias current component from the analog output signal using a mirrored bias current reduction circuit. This circuit specifically targets and eliminates the harmful DC component while preserving the useful AC signal, thereby reducing power consumption without compromising the linear behavior provided by the bias signals during operation.
Solution Approach 2:
The patent discards the unnecessary DC bias current component from the output signal while recovering and preserving the useful AC signal components. The mirrored bias current reduction circuit separates the DC component for removal and maintains the AC signal integrity, achieving both power efficiency and signal quality.
2Reliability
If bias signals are used to ensure circuit elements remain in desired operating range, then maximum dynamic range is improved, but power consumption increases due to DC bias current components
Solution Approach 1:
The patent extracts and removes the DC bias current component from the analog output signal using a mirrored bias current reduction circuit. This circuit specifically targets and eliminates the harmful DC component while preserving the useful AC signal, thereby reducing power consumption without compromising the maximum dynamic range provided by the bias signals during operation.
Solution Approach 2:
The patent discards the unnecessary DC bias current component from the output signal while recovering and preserving the useful AC signal components. The mirrored bias current reduction circuit separates the DC component for removal and maintains the AC signal integrity, achieving both power efficiency and dynamic range performance.
3Power
If current amplification is applied to analog signal, then signal strength is improved, but power consumption increases due to amplification of DC bias currents
Solution Approach 1:
The patent extracts and removes the DC bias current component before amplification occurs in the current mirror amplifier. By eliminating the DC component that would otherwise be amplified and consume excessive power, the circuit achieves signal amplification with significantly reduced power consumption.
Solution Approach 2:
The patent discards the DC bias current component and recovers only the useful AC signal for amplification. This selective processing ensures that the current mirror amplifier amplifies only the necessary signal components, avoiding the power waste associated with amplifying DC bias currents.
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
This approach significantly reduces power consumption by minimizing DC bias current components in the output signal, making the DAC circuits more efficient and suitable for battery-operated devices by reducing power usage during both active and inactive periods.
Implementation Method 1
current mirror amplifier circuit with a signal-shaping filter and a mirrored bias current reduction circuit to minimize unnecessary power consumption
Implementation Method 2
using a configuration that includes PMOS FETs, NMOS FETs, and RC filters to amplify and filter the input signal effectively
Data Source
AI summary
A DAC using current mirrors suitable for use in a modulator. Embodiments include a current-generating circuit to provide an information signal; a bias current source; a current mirror having a mirror input transistor connected to the current generating circuit and the bias current source, and being driven by the bias current and the varying current signal and having a corresponding varying voltage signal at a control terminal; a signal shaping filter interposed between the mirror input transistor and an output mirror transistor configured to limit a bandwidth of the varying voltage signal; the output mirror transistor configured to generate a band-limited varying current signal and a mirrored bias current; and, a mirrored bias current reduction circuit connected to the output mirror transistor configured to reduce the mirrored bias current.