SBVS304B June 2017 – October 2021 TPS7A83A
PRODUCTION DATA
The load-step transient response is the output voltage response by the LDO to a step in load current, whereby output voltage regulation is maintained. There are two key transitions during a load transient response: the transition from a light to a heavy load and the transition from a heavy to a light load. The regions shown in Figure 9-9 and described in Table 9-9 are broken down in this section. Regions A, E, and H are where the output voltage is in steady-state.
REGION | DESCRIPTION | COMMENT |
---|---|---|
A | Regulation | Regulation |
B | Output current ramping | Initial voltage dip is a result of the depletion of the output capacitor charge |
C | LDO responding to transient | Recovery from the dip results from the LDO increasing its sourcing current, and leads to output voltage regulation |
D | Reaching thermal equilibrium | At high load currents the LDO takes some time to heat up. During this time the output voltage changes slightly. |
E | Regulation | Regulation |
F | Output current ramping | Initial voltage rise results from the LDO sourcing a large current, and leads to the output capacitor charge to increase |
G | LDO responding to transient | Recovery from the rise results from the LDO decreasing its sourcing current in combination with the load discharging the output capacitor |
H | Regulation | Regulation |
The transient response peaks (VOUT(max) and VOUT(min)) are improved by using more output capacitance; however, doing so slows down the recovery time (Wrise and Wfall). Figure 9-10 shows these parameters during a load transient, with a given pulse duration (PW) and current levels (IOUT(LO) and IOUT(HI)).