SLVUC30 July 2021 TPS1HC100-Q1
The current limit resistor connected to the ILIM pin configures the current limit of the TPS1HC100-Q1 device. Based off the limit of this resistor the allowed current that passes through the high side switch can be controlled. The TPS1HC100EVM provides three different ways of configuring the effective value of the resistance on the ILIM pin:
See the Table 4-2 section for details on how to configure each one of these jumpers.
For the digital potentiometer option, the user has the ability to control the current limit via the TPL0102-100 digital potentiometer with I2C. The SDA and SCL lines of the digital potentiometer are connected to the standardized J1-9 and J1-10 pins of the BoosterPack header. Both pins are pulled up with pull-up resistors connected to the LaunchPad's 3.3-V power rail. For more details on how to program the TPL0102-100 device, refer to the TPL0102-100 data sheet.
In the TPS1HC100EVM, both channels of the digital potentiometer are connected in series with each other, allowing for a greater resolution of configurable current limit value. The slave address of the TPL0102-100 is configured to be 0x56. To configure the current limit, a simple 3-byte I2C write transaction must be performed to set the configured resistance value. The first byte should be 0x00 (corresponding to the resistance value register) and the next two bytes should be the corresponding resistance codes from the table in Appendix - TPL0102-100 Resistance Codes. These two values will add up in series to make up the total resistance connected to the ILIM pin of the TPS1HC100B-Q1. Once the STOP condition is written via the I2C line, the configured resistance value takes effect on the TPL0102-100.
For the current sense resistance connected to the SNS pin, the "SNS Pot Enable" jumper will control the source. If this jumper is populated, the "SNS" potentiometer is used to increase and decrease the resistance connected to the SNS pin. If this jumper is not populated, the solder down pad R13 should be used to provide the necessary resistance value. The output of the TPS1HC100B-Q1's SNS pin is an analog current that is a representation of the load current going through the switch. The purpose of the sense resistor is to convert this current into a voltage so that an ADC can convert it into a value for a microcontroller to use. For the TPS1HC100EVM, the voltage across the sense resistor can either be read externally via the SNS test point or from the BoosterPack's standardized analog J1-6 pin.