LDO (Low Dropout Regulator) with wide input voltage range and high power supply rejection ratio

Abstract

The invention discloses a LDO (Low Dropout Regulator) with a wide input voltage range and a high power supply rejection ratio and belongs to the technical field of power electronics. The LDO comprisesan error amplifier, a power module, a pre-step-down module, a high voltage resistant module and a power supply rejection ratio enhancement module, wherein the pre-step-down circuit module is utilizedfor preprocessing an input voltage of the LDO to obtain a low power supply voltage used for supplying power to a low-voltage circuit part; power is supplied to the error amplifier and the high voltage resistant module so as to obtain a high power supply rejection ratio by utilizing the low power supply voltage, and the input voltage range of the LDO is widened by virtue of the high voltage resistant module; meanwhile, by utilizing the power supply rejection ratio enhancement module inside the LDO circuit, the power supply rejection ratio of the LDO at a high frequency end is further improved;finally the input voltage of the LDO is processed by utilizing the power module, a feedback voltage is obtained to control a positive input end of the error amplifier so as to obtain enough loop gainfor improving the output accuracy of the LDO, and the output voltage of the power module is a final output voltage of the LDO. The LDO disclosed by the invention is wide in input range, small in chipoccupied area and high in power supply rejection ratio.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to the design of a low-voltage linear regulator (LDO), which can be applied to high power supply voltage or low power supply voltage, and has the characteristics of high power supply rejection ratio, wide input voltage range and large load current , mainly used in power supply voltage conversion that requires high output voltage accuracy. Background technique [0002] Among many power management ICs, low-dropout linear regulators (LDOs) are widely used in various electronic devices to provide stable power supply due to their high output voltage accuracy, small ripple and low power consumption. The input voltage of the LDO is the adjusted power supply voltage, which often comes from a switching converter such as a Buck converter, etc., and its variable range is generally relatively large, which puts forward requirements on the input voltage range of the LDO. Wh...

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Problems solved by technology

[0004] Aiming at the disadvantages of the above-mentioned traditional LDO that the input voltage range is not wide enough and the chip area is too large, the present invention proposes an LDO circuit with a wide input voltage range, which can work under high input voltage or Under low input voltage; only one LDO main structure is used, which reduces the number of peripheral components of the LDO chip and occupies a small chip area; at the same time, it also has a high power supply rejection ratio under large current loads, which improves the output voltage accuracy of the LDO

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