Push-pull output stage LDO (low dropout regulator) circuit

Abstract

The invention discloses a push-pull output stage LDO (low dropout regulator) circuit and belongs to the technical field of electronic circuit. The push-pull output stage LDO circuit utilizes CLASS-ABoutput staged error amplifier to drive a NMOS power tube and a PMOS power tube at the same time to form push-pull output stage LDO circuit, excessive current can be loaded into or absorbed, the control and adjustment ability to the output voltage is enhanced, and the output is stabler. A third NMOS tube, a third PMOS tube, a first capacitance and a second capacitance form a transmission door to enables the transient response of the system to be faster. A current subtraction circuit is used to reduce the power dissipation of the LDO circuit, and a slew-rate enhancement circuit in practical cases enables the transient response of the whole circuit to be faster. In different working status, the conducting of the NMOS power tube and the PMOS power tube of push-pull output stage LDO circuit isdifferent, only one conducting exists in the both power tubes, and the both are shut off at the time of on-load, and then the output and the static power consumption are extremely low. The push-pulloutput stage LDO circuit has the advantages of strong ability in controlling the output power, stable output, fast transient response and low power dissipation.

Description

technical field [0001] The invention relates to electronic circuit technology, in particular to an LDO circuit of a push-pull output stage. Background technique [0002] Traditional low-dropout linear regulators (LDOs) usually only have CLASS-A output stages, that is, the output stages of most LDOs have only one PMOS transistor or one NMOS transistor, which means that this kind of LDO circuit can only provide current to the output stage , but cannot draw current from the output stage, resulting in a circuit structure that has weak control over the output voltage and a slow response speed. This structure severely limits the application of the LDO. In addition, the traditional LDO structure still has the situation that the output stage power is too large. Contents of the invention [0003] According to the problems of slow response, large power consumption and weak control ability to the output voltage caused by the structure of the output stage in the above-mentioned tradi...

AI Technical Summary

Problems solved by technology

[0002] Traditional low-dropout linear regulators (LDOs) usually only have CLASS-A output stages, that is, the output stages of most LDOs have only one PMOS transistor or one NMOS transistor, which means that this LDO circuit can only provide current to the output stage , but cannot draw current from the output stage, resulting in weak control ability of the circuit structure to the output voltage and slow response speed, this structure seriously limits the application of LDO

In addition, the traditional LDO structure still has the situation that the output stage power is too large.

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