RF Module Balun Layout for Power-Line Noise Isolation
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Solution Overview
Problem
In radio frequency modules, when the power supply voltage to a differential amplifier is switchable, noise easily enters the power supply line and couples into the matching circuit, leading to deterioration of radio frequency module characteristics.
Innovation Solution
A radio frequency module design that includes a module substrate with a balun, power amplifiers, a matching circuit, switchable power supply terminals, and a switch circuit, where the balun is positioned to minimize noise leakage by placing the matching circuit away from the power supply line and the switch circuit, and the power supply line is routed to connect between the switch circuit and the primary coil, with specific regional placement on the substrate to enhance noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a switchable power supply voltage configuration is employed for the differential amplifier, then power consumption can be optimized, but noise easily enters the power supply line and couples into the matching circuit, deteriorating radio frequency module characteristics
Solution Approach 1:
A noise prevention circuit is introduced as an intermediary component between the switchable power supply voltage and the differential amplifier. This circuit includes a first switch connected in series with the power supply line and a second switch connected in parallel with the differential amplifier, creating a noise isolation mechanism that prevents noise from coupling into the matching circuit while maintaining power consumption optimization capabilities
Solution Approach 2:
The noise prevention circuit applies preliminary anti-action by preemptively blocking noise paths before noise can couple into the matching circuit. The first switch controls power supply connection in advance, and the second switch provides parallel protection, preventing noise from affecting the differential amplifier and subsequent stages before the harmful coupling occurs
2Area of stationary object
If the power supply line is routed closer to the matching circuit for compact layout, then device area is reduced, but noise leakage from the power supply line to the matching circuit increases
Solution Approach 1:
The noise prevention circuit acts as an intermediary barrier between the power supply line and the matching circuit. Even when the power supply line is routed close to the matching circuit for compact layout, the noise prevention circuit (comprising the first and second switches) creates an electrical isolation mechanism that prevents noise leakage, allowing compact design without sacrificing noise performance
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 effectively suppresses the deterioration of radio frequency module characteristics by reducing noise leakage from the power supply line to the matching circuit, even when switching between power supply voltages, thereby maintaining performance.
Implementation Method 1
a balun that is disposed in the module substrate and includes a primary coil connected between an output end of the first power amplifier and an output end of the second power amplifier and a secondary coil connected between the matching circuit and a ground
Data Source
AI summary
A radio frequency module includes a module substrate, an integrated circuit including power amplifiers, a matching circuit, a balun including a primary coil connected between output ends of the power amplifiers and a secondary coil connected between the matching circuit and the ground, power supply terminals switchably connected to a connection portion of the primary coil, a switch circuit connected between each of the power supply terminals and the primary coil, and a power supply line connecting an output terminal of the switch circuit and the connection portion of the primary coil. In plan view of the module substrate, a first distance between the power supply line and the matching circuit along a Y direction is longer than a second distance between the power supply line and a point on an outer edge of the balun along the Y direction.