Low dropout regulator

Abstract

The invention relates to the power supply circuit technology, in particular to a low dropout regulator (LDO) capable of quick response. Grids of power tubes are driven by an OTA high in pendulum rate, and a pendulum-rate enhancement circuit is adopted to quicken potential changes of the grids of the power tubes, so that when output voltage jumps, the grids of the power tubes can be supplied with large charging and discharging currents in very short period of time, grid voltage of the power tubes is allowed to change rapidly, the shortcoming of low pendulum rate due to large parasitic capacitance of the grids of the power tubes is greatly overcome, the pendulum rate of the LDO is greatly increased, and output voltage spikes are reduced. The low dropout regulator has the advantages that a circuit structure is simple; by the adoption of the on-chip integration technology, large off-chip load capacitance is no longer needed, and cost of peripheral application of a system is lowered.

Description

technical field [0001] The present invention relates to power supply circuit technology, in particular to a fast response low dropout linear regulator (Low Dropout Regulator, LDO). Background technique [0002] Low-dropout linear regulator is the basic component of on-chip power supply system. Due to its advantages of low cost, low output noise, simple circuit structure, small occupied chip area and low power consumption, it is widely used in wireless communication occasions such as mobile phones and notebook computers. and other power management systems. [0003] In order to meet the system stability requirements, the traditional low-dropout linear regulator needs to connect a large load capacitor outside the LDO chip, which will increase the number of off-chip components and increase the application cost of the system, and is not suitable for OSC and other integrated systems. In order to overcome this problem, at present, low-dropout linear regulators without off-chip la...

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Problems solved by technology

In order to overcome this problem, at present, low-dropout linear regulators without off-chip large capacitors are being studied more and more. In order to have a strong load capacity, the area of ​​the power tube in the general LDO is relatively large. The gate forms a capacitance up to tens of pF. At the same time, in order to reduce the power consumption of the LDO, the quiescent operating current is very small, so that the slew rate of the LDO is very small, so the gate voltage of the power tube changes slowly, resulting in the drain of the power tube The current also changes slowly. When the output current jumps, the output voltage needs a long time to recover and stabilize, and a large voltage spike will occur.

In order to increase the slew rate of LDOs without off-chip large capacitors, some LDOs use complex structures to increase the charge and discharge speed of the power tube gate. Voltage spikes and undershoot voltage spikes are still large, so traditional techniques cannot be used for high-precision applications

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