JAJSMG2C November 2023 – October 2024 TPS6287B10 , TPS6287B15 , TPS6287B20 , TPS6287B25 , TPS6287B30
PRODUCTION DATA
When the voltage on the VIN pin exceeds the positive-going UVLO threshold, the device initializes as follows:
When initialization is complete, the device enables I2C communication and releases the EN pin. The external circuitry controlling the EN pin now determines the behavior of the device:
Figure 8-7 shows the start-up sequence when the EN pin is pulled up to VIN.
Figure 8-8 shows the start-up sequence when an external signal is connected to the EN pin.
The SSTIME[1:0] bits in the CONTROL2 register select the duration of the soft-start ramp:
If you program new output voltage setpoint (VOUT[7:0]), output voltage range (VRANGE[1:0]), or soft-start time (SSTIME[1:0]) settings when the device has already begun the soft-start sequence, the device ignores the new values until the soft-start sequence is complete. For example, if you change the value of VSET[7:0] during soft-start, the device first ramps to the value that VSET[7:0] had when the soft-start sequence began and then, when soft-start is complete, ramps up or down to the new value.
The device can start up into a prebiased output. In this case, only a portion of the internal voltage ramp is seen externally (see Figure 8-9).
Note that the device always operates in DCM/PFM allowed during the start-up ramp, regardless of other configuration settings or operating conditions.