Low-dropout linear voltage regulator LDO circuit with over-current protection

Abstract

The invention discloses an LDO circuit with over-current protection and belongs to the technical field of power management. According to the LDO circuit, a first PMOS tube is driven through a source follower formed by adding an output detection module and an NMOS tube, so that the characteristics of response of the circuit to responsible transient variation is improved; meanwhile, by means of the output detection module, a built-in current detection module simple in structure and a current comparison module, the situation that a chip is failed to be started due to the malfunction of over-current protection can be avoided; after the chip is in an over-current state, the output current can be defined at a set value instead of directly turning the chip off, and the speed at which the normal work of the chip is recovered is increased after the over-current state is relieved.

Description

technical field [0001] The invention belongs to the technical field of power management, and in particular relates to a low dropout linear regulator (English: Low Dropout Regulator, LDO for short) circuit including overcurrent protection. Background technique [0002] LDO is usually used to realize the function of stepping down or enhancing the stability of the unstable or over-voltage power supply around the chip to meet the requirements of the internal modules of the chip. A typical LDO control loop such as figure 1 shown, including: error amplifier A 0 , power regulator tube MP1, output filter capacitor C OUT , output voltage divider resistors R1 and R2. The basic working principle is: the voltage dividing resistors R1 and R2 sample the output voltage, and then feed it back to the positive terminal of the error amplifier A0, and the difference between the feedback signal and the reference signal is amplified by the error amplifier and used to adjust the gate of the pow...

AI Technical Summary

Problems solved by technology

The protection methods are divided into two categories: one is to completely shut down the chip when an overcurrent situation occurs, and the circuit can only resume work after a manual restart. The set working current, so this mode may trigger over-current protection during chip startup, making the chip unable to start normally

The other is to limit the output current below a certain set value instead of shutting down the chip when the over-current situation occurs, so that when the abnormal load disappears, the chip can resume normal operation without restarting, but due to current limiting The existence of the circuit increases the complexity of the chip

[0005] In short, when the traditional LDO circuit uses an overcurrent protection circuit to solve the problem of excessive overshoot and undershoot peaks when the load changes, if the overcurrent protection circuit shuts off the chip after the chip is overcurrent, it will cause a slow return to normal operation. , if the overcurrent protection circuit limits the output current below a certain set value, the structure of the protection circuit will be complicated

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