This paper presents a compact configurable power control system for safety-critical applications, which operates in harsh environments. This heterogeneous integrated mixed digital, analog and high-voltage design for power applications is implemented in a system-in-package (SiP) module using a lowtemperature co-fired ceramics (LTCC) substrate. A comparison between technologies for SiP designs shows that LTCC is advantageous in terms of integration density, thermal and electrical performances, as well as signal and power integrity. In addition, this work proposes layout and fabrication techniques for the enhancement of thermal, electrical performances and integration density specific to LTCC-based designs, such as chipcovering, multi-layer routing of power signals and self-damped transmission lines. An improvement of 59% in available area, 32% reduction of temperature due to self-heating, 65% loss reduction and 22% reduction in interference coupling were obtained when compared to a baseline design.