Low dropout linear regulator based on quick short-circuit protection

Abstract

The invention discloses a low dropout linear regulator based on quick short circuit protection. The low dropout linear regulator comprises: an LDO unit comprising an error amplifier AMP, an MOS tube MP and divider resistors R1 and R2; a quick short-circuit protection unit arranged between the MOS tube MP and the power supply voltage VIN and used for realizing quick short-circuit protection of theLDO unit; and a control unit connected with the MOS transistor MP and the quick short circuit protection unit, and used for controlling the protection unit to be closed when the LDO unit works normally, and controlling the protection unit to be conducted when the LDO unit is subjected to quick short circuit. According to the low dropout linear regulator, the gate-source voltage of the MOS transistor MP is detected through the control unit, so that the quick short-circuit protection unit is controlled to be switched on and off, the MOS transistor MP is switched off during quick short circuit toachieve quick short-circuit protection, instantaneous large current in the MOS transistor MP is greatly reduced, the current maintaining time is effectively shortened, and the stability and safety ofan LDO are improved.

Description

technical field [0001] The invention belongs to the technical field of low-dropout linear voltage regulators, and in particular relates to a low-dropout linear voltage regulator based on fast short-circuit protection. Background technique [0002] Low dropout regulator (LDO) has the advantages of low output noise, simple circuit structure, small chip area occupation and small voltage ripple, etc., and has become an important circuit in power management chips. Low-dropout linear regulators can provide power with low output ripple for noise-sensitive circuits such as analog circuits and radio frequency circuits, and because of their relatively simple structure and few peripheral components, they are widely used in SoCs. [0003] ginseng figure 1 As shown, the LDO in the prior art mainly includes an error amplifier AMP, a MOS transistor MP, voltage dividing resistors R1 and R2, and a load (the load current is IL, and the output capacitor is CL). The basic principle of LDO is:...

AI Technical Summary

Problems solved by technology

There are many protection mechanisms in the LDO, including overcurrent protection, and when the output voltage VOUT is quickly short-circuited to ground, especially when the quiescent current is low IQ (1μA to several μA), the overcurrent protection circuit has not been established, and the MOS tube MP is due to The gate-to-source voltage is too high instantaneously, causing a large current to flow. figure 2 The large current shown can reach about 989mA, and the overall duration is about 218μs. The instantaneous power consumption will cause a large temperature rise and burn out the MOS tube MP

Images