Understanding the loadtransient response of （理解的loadtransient响应）.pdf

Texas Instruments Incorporated Power Management Understanding the load-transient response of LDOs By Brian M. King Advanced Analog Products Introduction Figure 1. Typical LDO components Low-dropout linear regulators (LDOs) are commonly used to provide power to low-voltage digital circuits, where point-of- load regulation is important. In Input Pass Element these applications, it is common for the digital circuit to have Reference + several different modes of opera- Error tion. As the digital circuit switches Input Amplifier Output from one mode of operation to Capacitor – Feedback Capacitor Dynamic another, the load demand on the Network Load LDO can change quickly. This quick change of load results in a temporary glitch of the LDO out- put voltage. Most digital circuits do not react favorably to large voltage transients. For the digital circuit designer, minimizing an LDO’s transient response is an important task. LDOs are available in a wide variety of output voltages and current capacities. Some LDO compensation LDOs are tailored to applications where a good response to The primary feedback loop of the LDO, consisting of the a fast transient is important. The TPS751xx, TPS752xx, output capacitor, feedback network, error amplifier, and TPS753xx, and TPS754xx families of LD