The TPSM365R6 is a 3.5 × 4.5 mm2 0.6-A rated synchronous step-down power module that features a wide operating input range from 3.6 V to 65 V with an adjustable output voltage range from 1 V to 13 V. The TPSM365R6 can be configured into an inverting buck-boost (IBB) topology with the output voltage inverted with respect to input voltage. This application report shows how the TPSM365R6 EVM board can be configured for an inverting application. Additional level-shifter circuitry for the EN and PGOOD pins are also included in this application note.
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In a standard buck configuration, the positive connection VOUT, is connected to the internal inductor, and the return connection is connected to the device ground.
In the IBB configuration, SYS_GND is connected to TPSM365R6's VOUT pin and the device return is now the negative output voltage, -VOUT. This shift in topology allows the output voltage to be inverted with respect to the input voltage. Pins connected to the TPSM365R6 IC GND in the standard buck configuration can still be referenced to the same pin in the inverting buck boost configuration. However, to use the EN and PGOOD pins, an appropriate level shifter must be added, which are detailed in the sections Section 5.1 and Section 5.2.