关键词: LDO, DCDC转换器, 带隙基准电路, 电源切换

Abstract: According to the application requirements of high-voltage DCDC converters, this paper designs an on-chip LDO circuit with switchable power supply. The paper proposes an LDO circuit architecture consisting of a bandgap reference circuit and an LDO circuit. The paper uses a bandgap reference circuit to generate a temperature independent reference voltage. The reference voltage is transmitted to the LDO to generate a stable internal power supply for the DCDC converter. The bandgap reference circuit uses a large resistor to reduce voltage, which can effectively reduce circuit power consumption. The LDO circuit has designed a power supply switching circuit. It can switch the power supply according to the external voltage, effectively improving the efficiency of the LDO circuit. The simulation results show that within the input voltage range of 5~65 V, the output of LDO is 3.4 V. The temperature coefficient of LDO is 10.71 ppm·℃^-1 within the temperature range of -40~125 ℃. The gain of LDO is 69.25 dB, and the phase margin is 85.64°. The paper uses a power supply switching circuit to improve circuit performance. When powered by input voltage, the linear adjustment rate is 71.85 μV·V^-1 and the power consumption is 14.76 μW. When the circuit is powered by an external power source, the linear adjustment rate is 44.94 μV·V^-1, the power consumption is 16.85 μW.

Key words: LDO, DCDC converter,  bandgap, power switching