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Reliability Engineering

Reliability & Field Failure Engineering

Advanced root cause investigation, stress margin validation, and corrective hardware redesign to reduce field failures and improve long-term MTBF of power electronic systems.

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🔍 Root Cause Analysis
🌡 Thermal Validation
⚡ EMI / EMC Testing
📈 FMEA & Derating
✅ Compliance Support
SOA Monitor — Primary Switch
LIVE
Rated Limit Safe Operating Area
Before redesign
After redesign
Rated limit
Our Approach

Failure-Driven Engineering Methodology

At Infigrace, reliability engineering begins with physical failure mechanisms — not assumptions. We analyse stress interactions across semiconductor devices, magnetics, passives, and PCB structures to determine why a product failed under real operating conditions.

Our approach integrates electrical transient modelling, thermal gradient mapping, component derating validation, and environmental stress replication. The objective is not temporary correction, but permanent elimination of recurrence through structured redesign and margin reinforcement.

↓40%Average field return rate reduction after corrective redesign
25%Typical improvement in stress derating margin post-redesign
MTBF improvement through systematic reliability engineering
100%Permanent corrective action — not temporary workarounds
Investigation Methods

Deep Root Cause Analysis

Three core investigation pillars covering electrical, thermal, and field data dimensions for complete failure characterisation.

Electrical Stress Analysis

Switching transient capture and analysis, voltage overshoot investigation, inrush current profiling, MOSFET avalanche stress testing, and snubber network validation under worst-case loading conditions.

🌡

Thermal Failure Investigation

Junction temperature estimation under field load profiles, thermal runaway scenario analysis, heat dissipation path mapping, heatsink validation, and PCB copper plane thermal resistance measurement.

📈

Field Failure Data Correlation

Failure pattern clustering from field return data, MTBF evaluation and estimation, duty cycle mapping, environmental condition impact analysis, and correlation with manufacturing batch variation.

Derating Analysis

Electrical Stress & Derating Visualisation

Stress Margin Profile — Switching Device
Safe Zone
Rated Limit
Stress Curve
Rated Limit Safe Operating Area

Dynamic stress mapping ensures operational loads remain within defined derating margins — preventing premature component degradation, SOA violations, and field failures under peak load conditions.

Analytical Framework

Field Failure Reduction Framework

Structured failure investigation methodology combining statistical analysis and deep hardware diagnostics to eliminate recurrence and reduce field return rates.

Ishikawa Root Cause Analysis — 6M Model

  • Man: Design assumptions, handling errors, assembly variation
  • Machine: Test equipment calibration, manufacturing tooling
  • Method: Design validation gaps, inadequate stress testing
  • Material: Component tolerance, supplier variability
  • Measurement: Incomplete data logging, insufficient field feedback
  • Environment: Temperature, humidity, surge & grid instability

Pareto Failure Distribution

Dominant failure modes — field return analysis

  • Thermal overstress — primary switch (43%)
  • Voltage transient — snubber failure (28%)
  • Solder joint fatigue — thermal cycling (16%)
  • Capacitor ESR degradation (8%)
  • Other / incidental (5%)

5W2H Corrective Action Framework

WhatHigh thermal stress on switching device
WhyInsufficient derating under surge load
WherePrimary power stage MOSFET
WhenPeak load + high ambient temp
WhoDesign & reliability team
HowRedesign thermal path & snubber
How MuchReduce Tj by ≥15°C under worst-case; target ≤70% rated stress

Design Margin Reinforcement

Initial field analysis revealed the switching device operating at ~95% rated voltage under peak load. Following corrective redesign — snubber optimisation, parasitic inductance reduction, and enhanced thermal dissipation — stress was reduced to ~70% of rated limit.

Before redesign95% rated
After redesign70% rated
  • Lower junction temperature under surge conditions
  • Improved SOA compliance across full load range
  • Reduced transient overshoot amplitude
  • Increased long-term MTBF and field stability
Corrective Engineering

Preventive Engineering Enhancements

Structural redesign actions implemented after root cause identification to prevent recurrence and extend product life.

01

Design Margin Enhancement

Recalculation of operating margins across all critical components, stress reduction redesign, and updated derating guidelines to maintain 70% or below rated stress under worst-case conditions.

02

Snubber & Protection Optimisation

RC snubber network tuning for switching transient suppression, TVS selection and placement, surge mitigation refinement, and gate drive impedance optimisation for reduced dV/dt.

03

Thermal Architecture Redesign

Heatsink geometry optimisation, airflow path redesign, PCB copper redistribution for reduced thermal resistance, and thermal interface material selection for improved junction-to-ambient performance.

04

EMI Layout Correction

PCB layout revision to reduce parasitic inductance in switching loops, improved decoupling placement, ground plane continuity, and copper pour strategy for reduced common-mode noise.

05

Validation Protocol Update

Revised design validation test plan incorporating worst-case temperature, voltage, and load scenarios identified during failure investigation — closing the gaps that allowed the failure to reach the field.

06

Compliance Certification Support

Pre-compliance EMI/EMC testing, documentation preparation, and liaison with test labs for BIS, CE, and UL certification — ensuring corrective redesigns meet all applicable standards.

Resolve Field Failures with Engineering Precision

Engage Infigrace to diagnose, redesign, and stabilise your power electronic systems — permanently.

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