Mixer Circuit Gain Control Using Shared DAC and Held Analog Potentials
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Solution Overview
Problem
Mixer circuits in audio codecs face challenges with increased circuit area and power consumption as the number of channels grows, due to the need for gain control circuits that include analog-digital converters and control circuits.
Innovation Solution
A semiconductor device with a mixer circuit incorporating digital-analog converters, control circuits, power source control switches, and multiple Gilbert circuits, where the Gilbert circuits utilize oxide semiconductors for low leakage current and efficient power management, reducing the need for continuous power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gain control circuits with analog-digital converters are added for each channel, then gain control capability is improved, but circuit area increases
Solution Approach 1:
A single digital-analog converter circuit is designed to serve multiple Gilbert circuits across different channels. The converter receives channel selection signals and effector signals, converts them to analog voltages, and supplies the appropriate gain control voltage to the selected channel's Gilbert circuit, eliminating the need for separate converters per channel.
Solution Approach 2:
The patent combines the gain control functionality for multiple channels into a unified control architecture. The control circuit integrates channel selection logic, effector signal processing, and analog-digital conversion into a single block that manages gain control across all channels, reducing the total circuit area compared to distributed per-channel implementations.
2Adaptability or versatility
If gain control circuits with analog-digital converters are added for each channel, then gain control capability is improved, but power consumption increases
Solution Approach 1:
The power source control switch implements periodic or conditional power supply to the control circuit based on update requirements. When the effector signal or channel selection changes, power is supplied to update the analog potential; when no changes occur, power supply is stopped, eliminating continuous power consumption while maintaining gain control functionality.
Solution Approach 2:
The analog potential holding circuit maintains the converted analog voltage without requiring continuous power supply to the control circuit. The held potential automatically controls the Gilbert circuit's gain until an update is triggered, allowing the system to maintain its state autonomously without active power consumption during stable operation periods.
3Speed
If continuous power supply is provided to control circuits, then gain control responsiveness is improved, but power consumption increases
Solution Approach 1:
The power source control switch provides power supply in periodic or event-driven manner rather than continuously. Power is activated only when the holding circuit detects changes in effector signals or channel selection, ensuring responsive gain control updates while consuming power only when necessary for updates.
Solution Approach 2:
The control circuit prepares and holds the analog control voltage in advance using the analog potential holding circuit. This pre-prepared voltage is immediately available when needed for gain control, ensuring rapid responsiveness without requiring continuous power supply to the conversion circuitry.
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 configuration inhibits the increase in circuit area and power consumption, enabling efficient gain control across multiple channels while maintaining signal integrity and reducing power usage.
Implementation Method 1
the first transistor includes a semiconductor layer including an oxide semiconductor in a channel formation region
Data Source
AI summary
A semiconductor device with a novel structure is provided. The semiconductor device includes a mixer circuit including a digital-analog converter circuit, a control circuit for controlling the digital-analog converter circuit, a power source control switch, and a plurality of Gilbert circuits. The plurality of Gilbert circuits each include an analog potential holding circuit for holding an analog potential output from the digital-analog converter circuit. The control circuit has a function of outputting a signal for controlling the analog potential holding circuit and the digital-analog converter circuit. The power source control switch has a function of stopping supply of a power source voltage to the control circuit in a period during which the analog potential held in the analog potential holding circuit is not updated. The analog potential holding circuit includes a first transistor. The first transistor includes a semiconductor layer including an oxide semiconductor in a channel formation region.