A Hot-Swap Solution for Mini Field Test Bus

A hot-swap circuit is needed by of the function modules (FMs) for Mini Field Test Bus (MFTB). Hot-swap circuits protect the system by reducing transient currents and spike voltage. Most hot-swap circuits use N-MOSFETs and hot-swap controller, which makes the circuit complex and costly. In this article, a simple hot-swap model is established for FMs with P-MOSFETs and no additional hot-swap controller. The hot-swap circuit includes over voltage protection (OVP), under voltage protection (UVP), over current protection (OCP) and output sensing. This paper focuses on the selection of MOSFETs and verifies the selected MOSFETs from steady, output fault and start-up state. The result shows that the selected MOSFET can meet the requirements of transient currents, spike voltage and power dissipation.