Employ TPS62175 in inverting buck boost topology
The inverting buck boost topology is very similar to the buck topology. In the buck configuration shown in a figure in this application note, the positive connection is connected to the inductor and the return connection is connected to the integrated circuit (IC) ground. However, in the inverting buck boost configuration shown in another figure in this document, the IC ground is used as the negative output voltage pin. What used to be the positive output in the buck configuration is used as the ground. This inverting topology allows the output voltage to be inverted and is always lower than the ground.
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Originally published by Texas Instruments at www.ti.com as "Using the TPS62175 in an Inverting Buck Boost Topology".