MM-Wave Tripler Biasing With Replica Feedback for PVT Stability
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Solution Overview
Problem
Maintaining mixer performance across varying local oscillator signals is challenging due to process, voltage, and temperature variations, leading to inefficiencies in mm-wave frequency multiplication circuits.
Innovation Solution
A frequency multiplication circuit with a PVT-insensitive biasing scheme that uses a replica device and feedback loop to regulate the bias voltage, ensuring consistent LO output power across process, voltage, and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional biasing schemes are used in frequency multiplication circuits, then the circuit can operate with simple structure, but the output power varies significantly across process, voltage, and temperature variations
Solution Approach 1:
The patent uses a replica frequency multiplication circuit that copies the structure and characteristics of the main circuit. This replica circuit is used to sense PVT variations and generate compensating bias signals, allowing the main circuit to maintain consistent output power without requiring complex external calibration circuits
Solution Approach 2:
The patent implements a feedback mechanism where the output of the replica circuit is fed back to adjust the bias signals applied to the main frequency multiplication circuit. This closed-loop feedback automatically compensates for PVT variations, maintaining reliable output power consistency without manual intervention
2Reliability
If manual calibration and additional buffer stages are added to maintain mixer performance, then output power consistency improves, but area and power consumption increase
Solution Approach 1:
The replica circuit serves itself and the main circuit by automatically sensing PVT variations and generating compensating bias signals without external intervention. This self-service mechanism eliminates the need for manual calibration and additional buffer stages, reducing both power consumption and circuit area while maintaining reliable mixer performance
3Manufacturing precision
If manual calibration procedures are implemented, then output power variation across PVT is reduced, but manufacturing time and complexity increase
Solution Approach 1:
The replica circuit is designed to automatically perform the calibration function in real-time during operation. By preliminarily establishing the replica structure that mirrors the main circuit, the system prepares the compensation mechanism in advance, eliminating the need for time-consuming manual calibration procedures during manufacturing and deployment
Data Source
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AI summary
A biasing scheme for a frequency multiplication circuit, and transceiver using LO signals provided by the frequency multiplication circuit are described. A frequency doubler is cascaded with a mixer to provide a mm-wave oscillator signal. The combination provides a frequency triple that of the LO frequency supplied to the frequency doubler from a PLL. A small-sized replica of the frequency doubler is used to determine biasing of transconductance devices of the frequency doubler. A voltage output of the replica is amplified and the difference between the output and a reference voltage is supplied as feedback to the control terminal of the transconductance devices to bias the transconductance devices to near threshold. The biasing is replicated at the frequency doubler to compensate for PVT variations. A PTAT current source tied to the output of the replica regulates an average output current of the frequency multiplication circuit.