Variable Gain Amplifier Biasing for Low-Voltage Gain Range
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Solution Overview
Problem
Current variable gain amplifiers (VGAs) experience a reduction in variable-gain range when operating at low power, limiting their functionality as the power supply voltage drops, necessitating a solution to maintain gain range without increasing voltage.
Innovation Solution
Incorporating at least one amplifier circuit, one current-steering circuit, and one bias voltage circuit, where each bias voltage circuit provides a positive bias voltage to its corresponding current-steering circuit, thereby increasing the control voltage range and steering current, thus enhancing the adjustable variable-gain range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power supply voltage is reduced to save power, then power consumption is reduced, but the variable-gain range of the VGA becomes smaller
Solution Approach 1:
The patent applies parameter changes by introducing a body bias voltage (Vbs) to the current-steering circuit that is independent of the power supply voltage. By controlling Vbs separately, the patent can maintain the variable-gain range even when the power supply voltage is reduced, thus resolving the contradiction between low power consumption and maintaining gain range.
2Duration of action of stationary object
If the power supply voltage is reduced to extend battery life, then battery life is extended, but the VGA function becomes limited
Solution Approach 1:
The patent changes the biasing parameters of the current-steering circuit by introducing a separate body bias voltage control. This allows the VGA to maintain its full functionality and variable-gain range even when operating from a low-voltage battery, thus extending battery life without limiting VGA function.
3Use of energy by moving object
If the power supply voltage is reduced, then power consumption is reduced, but the control voltage range and steering current decrease
Solution Approach 1:
The patent introduces a body bias voltage (Vbs) as an additional control parameter that is independent of the power supply voltage. By adjusting Vbs, the patent can maintain the control voltage range and steering current characteristics even when the power supply voltage is reduced, thus maintaining ease of operation while reducing power consumption.
Data Source
AI summary
A variable gain amplifier (VGA) is provided. The VGA includes at least one amplifier circuit, at least one current-steering circuit and at least one bias voltage circuit. Each current-steering circuit is coupled to its corresponding amplifier circuit. Each bias voltage circuit is coupled to its corresponding current-steering circuit to provide a positive bias voltage to each current-steering circuit.