ZHCSH55B December 2017 – September 2018 TPS65218D0
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
Power-good (PGOOD) is an open-drain output of the built-in voltage supervisor that monitors DCDC1, DCDC2, DCDC3, DCDC4, and LDO1. The output is Hi-Z when all enabled rails are in regulation and driven low when one or more rails encounter a fault which brings the output voltage outside the specified tolerance range. In a typical application PGOOD drives the reset signal of the SOC.
The supervisor has two modes of operation, controlled by the STRICT bit. With the STRICT bit set to 0, all enabled rails of the five regulators are monitored for undervoltage only with relaxed thresholds and deglitch times. With the STRCT bit set to 1, all enabled rails of the five regulators are monitored for undervoltage and overvoltage with tight limits and short deglitch times. Table 5-1 summarizes these details.
PARAMETER | STRICT = 0b (TYP) | STRICT = 1b (TYP) | |
---|---|---|---|
Undervoltage monitoring | Threshold (output falling) | 90% | 96.5% (DCDC1, DCDC2)
95.5% (DCDC3, DCDC4, LDO1) |
Deglitch (output falling) | 1 ms | 50 µs | |
Deglitch (output rising) | 10 µs | 10 µs | |
Overvoltage monitoring | Threshold (output falling) | N/A | 103.5% (DCDC1, DCDC2)
104.5% (DCDC3, DCDC4, LDO1) |
Deglitch (output falling) | N/A | 1 ms | |
Deglitch (output rising) | N/A | 50 µs |
The following rules apply to the PGOOD output:
Figure 5-8 shows a typical power-up sequence and PGOOD timing.