Design and simulation of a high-frequency, microcontroller-monitored synchronous buck converter for wide input voltage applications. The project focuses on power stage dimensioning, efficiency optimization, thermal behavior, power supply management, user interfaces, PCB layout and 3D integration, and ADC signal conditioning for embedded monitoring.
- Topology: Synchronous Buck Converter
- Input Voltage: 30 V – 60 V
- Output Voltage: 3.3 V
- Output Current: up to 8 A
- Switching Frequency: 400 kHz
- Control & Monitoring: External microcontroller with ADC ([LPC1313FHN33 (NXP)])
- Simulation Tool: Simetrix
- PCB & Mechanical Design: Fusion 360
This project was developed as part of the course Design of Electronic Circuits and Systems, with emphasis on practical power electronics design choices and engineering trade-offs.
- Achieve high efficiency over a wide input voltage range
- Maintain low output voltage ripple suitable for digital loads (< 50 mV)
- Ensure continuous conduction mode (CCM) over full operating range
- Implement a structured power supply management architecture
- Provide basic user interfaces for system status control
- Design an EMI-aware PCB layout suitable for high-frequency switching
- Integrate electrical and mechanical aspects through 3D PCB modeling
- Verify thermal behavior of power components
Main components:
- High-side and Low-side MOSFETs: [IAUCN10S7L040]
- Gate driver: [UCC27282DRCR]
- Inductor: [SRP1038WA-4R7M]
- Input capacitors: 2xMLCCs [GRM55ER72A475KA01] + 1xElectrolytic [MAL213639479E3]
- Output capacitors: 2xMLCCs [GRM21BR61C226ME44]
The power stage was fully dimensioned considering:
-
Inductor value selection based on ripple current and saturation limits
-
MLCC output capacitor sizing including DC bias derating
-
MOSFET selection based on:
- Conduction losses
- Switching losses
- RDS(on) and gate charge
-
Gate driver compatibility with 400 kHz operation
A dedicated power supply management architecture was implemented to ensure stable and safe system operation.
Main elements:
- Primary DC-DC converters: 60 V → 12 V [R-78HB12-0.5] + 12 V → 5 V [LT8610AB]
- Auxiliary regulators: 12 V → 10 V [LM2940] + 5 V → 3.3 V [AP7387Q]
The design ensures:
- Correct power-up sequencing
- Stable supply rails for analog and digital sections
- Reduced noise coupling between power and signal domains
- Operational amplifier: [TLV2781]
To enable accurate voltage monitoring via a microcontroller ADC, a dedicated analog front-end was designed, including:
- Precision voltage divider for 3.3 V ADC compatibility
- RC anti-aliasing filter for noise reduction
- Rail-to-rail operational amplifier buffer to ensure ADC driving capability
The design balances bandwidth, noise attenuation, and ADC sampling constraints.
Basic user interfaces were implemented to support system monitoring and debugging.
Interfaces include:
- Buttons: Reset and Wakeup operations
- Display: [NHD-C0216CiZ-FSW-FBW-3V3]
Thermal behavior of the circuit was analyzed considering:
- Power dissipation on MOSFETs
- Inductor copper and core losses
- Impact of switching frequency on thermal stress
The analysis confirms safe operation within component thermal limits under nominal load conditions.
All simulations were performed using Simetrix, validating both steady-state and dynamic behavior.
-
Efficiency:
- Up to 91.5% at 30 V input
- Above 85% at 60 V input
-
Output Voltage Ripple:
- Less than 15 mV peak-to-peak
-
Operating Mode:
- Continuous Conduction Mode (CCM) across full Vin range
The complete PCB was designed in Fusion 360, focusing on both electrical performance and mechanical integration.
Key aspects of the PCB design include:
-
Optimized high-current power paths
-
Minimized switching loops for EMI reduction
-
Proper component placement for thermal dissipation
-
Ground plane strategy for signal integrity
-
3D PCB visualization to verify:
- Component clearances
- Mechanical constraints
- Overall form factor
- Simulation: Simetrix
- PCB & Mechanical Design: Fusion 360
- Power Electronics: DC-DC converters, MOSFETs, gate drivers
- Analog Design: Op-amps, filters, signal conditioning
- Embedded Context: MCU ADC interfacing
MSc Students in Electronic Engineering – Double Degree University of Naples Federico II & Lodz University of Technology