Doherty Amplifier Bonding Layout for Back-Off Impedance Control
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Solution Overview
Problem
The Doherty amplifier circuit in existing technologies experiences power loss due to impedance deviation during back-off operations, leading to increased circuit size and complexity, particularly due to the bending and extension of the drain terminal of the peak amplifier, hindering miniaturization.
Innovation Solution
The amplifier module and communication device incorporate a Doherty amplifier circuit with aligned bonding wire directions from the drain terminal of the transistor chip to the connection points of the conductors, eliminating the need for a delay line and preventing impedance deviation, thereby maintaining an open state and reducing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a delay line is disposed on the output side of the peak amplifier to maintain open impedance during back-off operation, then power loss is reduced, but circuit size increases
Solution Approach 1:
The invention extracts the delay line component from the circuit by reconfiguring the bonding wire connections. The carrier amplifier output is directly connected to the peak amplifier output through optimized bonding wire routing, eliminating the need for a separate delay line while maintaining the open impedance condition during back-off operation.
Solution Approach 2:
The invention changes the spatial arrangement of bonding wires from a planar configuration to a three-dimensional routing approach. By extending bonding wires in directions orthogonal to the circuit direction and utilizing vertical stacking of amplifier chips, the patent achieves impedance control without requiring additional horizontal space for delay lines.
2Ease of manufacture
If the drain terminal of the peak amplifier is bent to extend bonding wire in orthogonal direction, then bonding wire routing is achieved, but device complexity increases
Solution Approach 1:
Instead of bending the drain terminal to achieve orthogonal bonding wire extension, the invention inverts the approach by maintaining the drain terminal in its original orientation and extending the bonding wire in the orthogonal direction from the terminal. This eliminates the complexity of terminal bending while achieving the same routing objective.
3Reliability
If bonding wire extends in direction orthogonal to circuit direction, then impedance control is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The invention incorporates preliminary positioning features directly on the amplifier chip surfaces, such as protrusions and recesses, that pre-align the bonding wire locations before the bonding process. This preliminary action ensures that orthogonal bonding wires are accurately positioned without requiring extremely high manufacturing precision during the bonding operation itself.
Data Source
AI summary
An amplifier module includes a Doherty amplifier circuit, and the Doherty amplifier circuit includes a first transistor chip constituting a carrier amplifier, a first output signal line configured to transmit a first amplified signal outputted from the carrier amplifier, a second transistor chip constituting a peak amplifier, and a second output signal line configured to transmit a synthetic signal of the first amplified signal and a second amplified signal outputted from the peak amplifier. A direction from a drain terminal of the second transistor chip to a connection, of the first conductor of the first output signal line, with the first bonding wire is the same direction as a direction from the drain terminal of the second transistor chip to a connection, of the second conductor of the second output signal line, with the second bonding wire.