SLVUBV4A December 2020 – December 2021 TPS272C45
While the TPS272C45EVM can be used as a standalone evaluation board without the need of any external microcontroller, the EVM also comes populated with BoosterPack headers (J1, J2, J3, J4) to enable easy interface with a Texas Instruments microcontroller. The 40-pin headers of the BoosterPack headers are used, however all signals can be accessed using headers J1 and J2 enabling use with the 20-pin header. Additionally by populating jumper J19 the user has the ability to power the underlying LaunchPad through the integrated 3.3-V LDO on the TPS272C45EVM. A list of pins connected to the BoosterPack header can be seen below in Table 3-1:
| BoosterPack Pin | Function | Note |
|---|---|---|
| J1-1 | 3.3-V power rail | Disconnect J19 if powering LaunchPad via USB. |
| J1-2 | Current sensing through the SNS pin | Populate a Zener diode on D7 if it is required to limit analog signal of pin |
| J1-5 | DIA_EN pin used to enable diagnostics | Can be used to multiplex multiple TPS272C45 switches to one analog pin |
| J1-8 | SEL pin used to change measurement reported on SNS pin | |
| J2-11 | LATCH pin used to change fault behavior | |
| J2-12 | ILIM1 pin used to enable a10-kΩ resistor R13 for ILIM1 | Active high. Do not enable at same time as J2-13. |
| J2-13 | ILIM2 pin used to enable a 4.99-kΩ resistor R14 for ILIM1 | Active high. Do not enable as same time as J2-12. |
| J2-17 | FLT pin used to detect faults | Open drain input. Pull-up source can be controlled using jumper J18. |
| J2-18 | EN2 to enable VOUT2 | Active high. Can be connected to PWM. |
| J2-19 | EN1 to enable VOUT1 | Active high. Can be connected to PWM. |
| J2-20 | Module GND | Do not connect to IC ground if ground network is used |
Note that for all IO and analog signals being attached to the BoosterPack, the relevant 4.7-kΩ protection resistors are populated in series with the pin.
To power the attached LaunchPad from the on-board LDO of the TPS272C45EVM, connect the jumper J19. Note that this feeds the output of the 3.3-V LDO on the TPS272C45EVM into the 3.3-V rail on the LaunchPad. If there is another power supply trying to power the LaunchPad (such as the integrated USB power on the LaunchPad itself) this can potentially cause issues with the separate power sources fighting for contention.
Jumpers J8 through J12 are used to manually configure the control signals going into the TPS272C45. When using a microcontroller to control these signals these jumpers must be unpopulated to allow for the microcontroller to drive them high or low. Additionally the header labeled J18 can be used to configure how the FAULT pin is pulled up. This pin is an open drain output used to report faults on the TPS272C45 such as overcurrent or open load. If J18 is connected to the pin marked BP on the silkscreen the FAULT pin is pulled up through the 1-kΩ resistor R9 to the 3.3-V rail of the BoosterPack. Similarly if the jumper labeled J17 is connected to the BP pin the Vdd rail of the TPS272C45 is connected to the 3.3-V rail of the BoosterPack. If J17 is populated to be fed from the LDO or BoosterPack, it cannot be supplied externally from the J6 banana jack.
Note that one useful feature of the TPS272C45 EVM is the ability to sense the from the SNS pin of the TPS272C45 through the analog input of the microcontroller attached to the BoosterPack headers. A 1.0-kΩ resistor is connected to convert the current coming out of the SNS pin to a voltage, however care must be given to ensure that this value does not violate the input maximum of the microcontroller's analog input. To mitigate, a Zener diode can be soldered to D7 (do not populate by default) to regulate the voltage going into the microncontroller's analog input.