The MAXREFDES1181 is centered around the MAX17501 ultra small, high-efficiency, high-voltage, synchronous stepdown DC-DC converter with integrated MOSFETs. This design provides a -5V output and up to 150mA of load current with an input voltage range of 18V to 30V. Unlike a traditional design, this reference design is configured to work in an inverting buck-boost topology to produce negative output voltage from positive input voltage.
Industrial control equipment such as programmable logic controllers, I/O modules, mass flow controllers, and various other sensors and supporting systems use analog components like amplifiers and multiplexers that operate on negative supply voltage. The MAXREFDES1181 is designed to demonstrate the operation and principles on how to use the MAX17501 to provide a negative supply voltage.
This document describes the MAXREFDES1181 variant on the MAXREFDES1174 hardware shown in Figure 1. It provides a detailed, systematic technical guide for the design of the MAXREFDES1181 using the MAX17501 synchronous step-down DC-DC converter for applications that require negative supply voltage. See the MAX17501 data sheet for device operation details. The power supply has been built and tested, details of which follow later in this document.