Low-dropout linear voltage stabilizing circuit and low-dropout linear voltage stabilizing device

Abstract

The invention discloses a low-dropout linear voltage stabilizing circuit and a low-dropout linear voltage stabilizing device.The low-dropout linear voltage stabilizing circuit comprises a low-dropout linear voltage stabilizing unit and a zero setting resistance unit.The first input end of the low-dropout linear voltage stabilizing unit is used for receiving input work voltages, the second end of the low-dropout linear voltage stabilizing unit is used for receiving input reference voltages, and the output end of the low-dropout linear voltage stabilizing unit outputs load currents for loading work.The input end of the zero setting resistance unit is connected with the output end of the low-dropout linear voltage stabilizing unit, and the input end of the zero setting resistance unit is used for sampling the load currents, adjusting the resistance value of equivalent resistance in a self-adaption mode according to the sampled load currents and feeding the resistance value of equivalent resistance back to the feedback input of the low-dropout linear voltage stabilizing unit so that the low-dropout linear voltage stabilizing unit can adjust zero pole distribution of the low-dropout linear voltage stabilizing circuit according to the fed-back resistance value of equivalent resistance.According to the low-dropout linear voltage stabilizing circuit and the low-dropout linear voltage stabilizing device, the length or width of a PCB line does not need to be considered, and the low-dropout linear voltage stabilizing circuit can output stable voltages.

Description

technical field [0001] The invention relates to the field of power supply management, in particular to a low-dropout linear voltage stabilizing circuit and a low-dropout linear voltage stabilizing device. Background technique [0002] With the rapid development of science and technology, power supply has increasingly become the heart of electronic equipment, and power management technology has also developed into an indispensable technology in electronic systems. Among them, low dropout regulator (LDO for short) has low power consumption , are widely used in DC-DC power management chips. [0003] For LDO chips, high current and stability are the development trend of the industry, but as the output current increases, the length and width of the printed circuit board (PCB) traces around the LDO chip have an impact on the stability of the LDO. big impact. Table 1 shows the parameter values ​​of parasitic resistance R and parasitic inductance L of PCB wiring at a frequency of ...

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Problems solved by technology

It can be seen from Table 1 that the magnitude of the parasitic resistance of the PCB trace is at the Ω level, and the magnitude of the parasitic inductance of the PCB trace is at the nH level. The pole is located at about tens of MHz, which greatly affects the bandwidth of the LDO, seriously deteriorates the stability of the LDO, and makes the output of the LDO oscillate. Therefore, the length and width of the PCB trace must be strictly controlled during the design of the existing LDO , to avoid affecting the stability of the LDO due to the parasitic resistance and parasitic inductance of the PCB trace

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