Pipeline ADC MDAC Amplifier Sharing for Lower Power RADAR

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Solution Overview

Problem

Designing MDAC stages for pipeline ADCs in RADAR systems with minimized power consumption while maintaining satisfactory performance is challenging due to high power consumption by amplifier circuitry during sampling periods and the resulting dead time when turning it on.

Innovation Solution

Implementing operational transconductance amplifier (OTA) circuitry with cascode devices as switching mechanism, sharing amplifier circuitry between multiple sampling networks to reduce power consumption and improve performance by always having one input pair connected, thereby minimizing dead time and switching errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If amplifier circuitry is powered on during sampling periods, then signal settling time is improved, but power consumption increases

Engineering Contradiction:

Improvesignal settling timeVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The amplifier circuitry is operated in periodic intervals, being turned on only during amplification periods and turned off during sampling periods. This periodic operation allows the amplifier to remain idle during sampling while still providing amplification when needed, thereby reducing overall power consumption without permanently compromising signal settling capability

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The amplifier circuitry transitions from a static always-on state to a dynamic state where it can be selectively enabled and disabled. By making the amplifier operation dynamic and conditional based on the operational phase (sampling vs. amplification), the system optimizes the balance between power consumption and signal settling performance

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If amplifier circuitry is turned off during sampling periods, then power consumption is reduced, but dead time increases and signal settling time is reduced

Engineering Contradiction:

Improvepower consumptionVSAvoiddead time

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The amplifier circuitry is pre-configured and ready to operate, with control logic prepared to immediately enable the amplifier when transitioning from sampling to amplification phase. This preliminary preparation minimizes the dead time by ensuring no additional setup or configuration delays occur when the amplifier needs to be activated

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The transition of the amplifier from off to on state is executed rapidly during the phase transition, minimizing the duration of any dead time. The system rushes through the state change efficiently by leveraging the natural phase boundaries in the sampling and amplification cycle, thereby reducing time loss to negligible levels

Inventive Principle:

Principle #21Skipping (Rushing through)

3Use of energy by moving object

If switches are used in amplifier circuitry, then power consumption is reduced, but additional RC poles are introduced and phase margins deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidphase margins

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

Cascode devices serve as intermediary elements that enable switching functionality without directly introducing problematic RC poles into the signal path. The cascode configuration acts as a buffer or mediator between the switching mechanism and the amplifier's critical signal paths, thereby maintaining phase margins while still enabling power-saving switching operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cascode devices are strategically placed in specific locations within the amplifier circuitry where they can provide switching functionality without adversely affecting the overall phase characteristics. By applying the switching mechanism locally rather than globally, and by using cascode topology specifically designed to minimize impact on frequency response, the system achieves power reduction without sacrificing phase margins

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10972113B1Systems with ADC circuitry and associated methods

Publication Date: 2021.04.06 SEMICON COMPONENTS IND LLC

AI summary

Systems with object detection capabilities may include a radio detection and ranging (RADAR) system. The RADAR system or other portions of the systems may include analog-to-digital converter circuitry. The analog-to-digital converter circuitry may be implemented as pipeline analog-to-digital converter circuitry having multiple stages. Each stage may include multiplying digital-to-analog converter circuitry having a sampling network and amplifier circuitry. The amplifier circuitry may be shared be shared between multiple stages. The amplifier circuitry may include cascodes for switching between different input pairs from corresponding sampling networks in corresponding stages. The amplifier circuitry may generate amplifier outputs for a first sampling network while the other sampling network performs sampling operations. This may minimize non-amplification time for the amplifier circuitry reduce power consumption in the converter circuitry. The amplifier circuitry may also include shorting switches that bring the amplifier output to a common mode voltage to more improve output slew characteristics.