An on-chip soft-start circuit based on a switched-capacitor for DC-DC switching regulator is presented. A ramp-voltage, which is generated by a switched-capacitor, is used to make pulse width slowly increase from zero, in order to eliminate the inrush current and the overshoot voltage during start-up. The post simulation results show that the regulator soft starts well with the proposed soft-start circuit.

In prior work, contact welding phenomena were observed in automotive relays during break of motor inrush current. The switching performance of the type of relay investigated could be correlated with the parameters: over-travel, coil suppression, and the break current. In the present work the author further explores the impact of both the contact material (silver tin oxide versus fine grain silver) and the contact surface topography (brand new and pre-aged contacts). He further assesses the robustness of the system "relay" with those parameters using the Taguchi methods for robust design. Furthermore, the robustness of two alternative automotive relay types will be discussed.

Electromechanical switching devices such as relays may be surprisingly forgiving to occasional, but temporary, electrical stress beyond specification. Consequently delayed openings due to welded contacts on the order of milliseconds usually have been unnoticed and hence have not been reason for concern. However, as electrical systems of vehicles are getting "smarter" and more and more diagnostic routines are being implemented, even such short delay times may be translated as errors. Pre-conditioning contact surfaces has been explored as a measure to increase the welding resistance and eliminate contact opening delays. The 20-A-class relay investigated has been optimized to break occasional current peaks up to 80 ADC.

We have developed a high-efficiency charge-pump power supply circuit with large output current capability for mobile equipment. However, during the commercialization phase, we found that the large inrush current of 270 mA at charge-pump circuit startup-time could cause problems. In this paper we analyze the mechanism that causes this inrush current, and we propose circuitry to reduce it. We show SPICE simulation and measurement results for our proposed circuitry that confirm its effectiveness. By incorporating this circuitry, startup-time inrush current was reduced to 30 mA.