Research And Design Of Wide Input Voltage LDO Based On BCD Process

With the rapid development of the electronics industry,various electronic products are widely used in various industries.With the rapid change of wearable devices and portable electronic products such as mobile phones and cameras,their mainstream small size and light weight have put forward new requirements on power management in terms of power consumption.At the same time,automotive electronics,medical equipment,industrial control and other industries also have different requirements for power management in terms of input voltage range,output accuracy and stability.Therefore,LDO linear regulators with a variety of excellent performances stand out in many power management chips.At present,the mainstream LDO has the problem of low input voltage,so it is necessary to research and design the LDO with wide input voltage.Based on the related theoretical research of LDO regulators,this thesis uses a 0.18μm BCD process is used to design a wide input voltage LDO regulator with an input voltage of up to 40 V,which also ensures its low quiescent current,high accuracy and high stability.The main research contents of this thesis are summarized as follows: 1.A structure of dual power tube is proposed.The wide input voltage of the power tube of the regulator is realized,the problem of accurate current sampling is solved,and a highvoltage drive circuit is designed for it.2.An overcurrent protection circuit structure that samples the output current to provide bias current is proposed.The low power consumption of the overcurrent protection circuit under no load is realized,and the quiescent current of the voltage regulator is reduced.3.Designed to improve the output accuracy circuit.This thesis adds trimming resistors to the bandgap reference circuit,and uses programmable trimming techniques to adjust the temperature characteristics and the voltage value of the reference voltage according to the actual measurement results to improve the accuracy of the output voltage.4.Designed dynamic compensation circuit.This thesis analyzes the pole-zero changes of the regulator,and designs a special compensation network that dynamically compensates by sampling the output current to ensure that the regulator has extremely high stability in the full load range.5.Designed protection circuit.In order to ensure the normal operation of the regulator,this thesis has designed an under voltage latch circuit,an over-current protection circuit,and an over-temperature protection circuit.These protection circuits can protect the regulator by shutting down the circuit when the input voltage is abnormal,the output current is too large,and the temperature is too high.The design of the wide input voltage LDO regulator is based on the Dongbu Hi Tek 0.18 um 100V BCD process.Then,the circuit has been designed and simulated by using EDA tools such as Schematic edit,Spectre of Cadence software.After completing layout design,the IC is taped out.The chip samples were tested and verified.The test data showed that the chip function was normal,and various index parameters met the design requirements.