Stability and reliability of LTCC-based 5/12 V dual output DC-DC converter with high efficiency and small size

Abstract We propose a 5/12 V dual output DC-DC converter that can achieve high efficiency and a small size form factor. Using low temperature co-fired ceramic (LTCC)-based multi-layer circuits, the converter minimizes power losses caused by power and ground metal planes and reduces the size. The lateral dimension of the converter with nine LTCC layers was 35 mm × 45 mm. The proposed converter was compatible with the outputs of typical electric bike batteries, which are 48 V and 36 V. At a full-load condition of 3.1 A at 5 V output and 2 A at 12 V output, the measured efficiency was 92.9% and 93.6% with a supply voltage of 48 V and 36 V, respectively. The measured line regulation with ±20% of an input voltage was lower than 0.75% and load regulation with a 10% to 100% load change for the dual output was lower than 1.4%. Under the condition of 100 % load for one output and 25% to 100% load change for another output, the maximum cross-regulation was 1.7%. The dynamic load regulation and response was lower than 9.6% and 480 μs with 0% to 100% load change, respectively, and the maximum ripple and noise was 33.2 mVpp. Reliability tests indicated that the average efficiency degradation rate was less than 0.002%/°C. The results of an electromagnetic interference (EMI) test indicated the converter satisfies the IEC61000-6-3 class B standard. The results show that the LTCC multilayer circuit substrate is suitable for a high-efficiency, high-density, high-output stability, and high-reliability in a power converter.