ZHCSKK3B December 2019 – February 2022 TPS6594-Q1
PRODUCTION DATA
The residual voltage (RV) checking feature ensures the voltage level at the buck or LDO regulators is below VTH_SC_RV before it can be ramped up to the target output voltage. If BUCKn/LDOn_RV_SEL=1 by default, then the residual voltage is also checked before the device enters the BOOT_BIST state. If the residual voltage at the output of the regulators is greater than VTH_SC_RV, then the device waits until voltage goes below VTH_SC_RV before starting BOOT_BIST or the voltage ramp up.
This feature is enabled by the BUCKn_VMON_EN and BUCKn_RV_SEL bits for each buck regulator, and by the LDOn_VMON_EN and LDOn_RV_SEL bits for each LDO regulator. The Voltage Monitor (VMON) of the corresponding regulator remains on after the regulator is disabled and for the RV_TIMEOUT period when the RV checking feature is enabled. After the RV_TIMEOUT period elapses, the Voltage Monitor (VMON) compares the output voltage of the regulator with the short circuit (SC) threshold of VTH_SC_RV and assert the corresponding BUCKn_SC_INT or LDOn_SC_INT interrupt bits, if the residual voltage is still higher than the threshold voltage. The RV_TIMEOUT period for the BUCK regulators is automatically calculated by the digital controller inside the device by Equation 3. The RV timeout period of the LDO regulator is configured by the LDOn_RV_TIMEOUT[3:0].
The residual voltage check can also be performed on external rails when they are connected to the VOUT_LDOn pins of unused LDO regulator outputs, or connected to FB_Bn pins of unused buck regulators, or connected to FB_Bn pins of BUCK3 or BUCK4 regulators in Multi-Phase operation.
Figure 8-10 shows the timing diagram of the residual voltage checking operation which results in pass or fail results.