A High-PSRR Low Dropout Regulator for LNB Using the First-Stage Reference-Included Coarse-Filtering Technique

作者：Li, Fanyang^*; Jiang, Hao

来源：Journal of Circuits, Systems, and Computers, 2015, 24(2): 1550022.

DOI：10.1142/S021812661550022X

• Coarse filtering
• the cascaded feedback loops
• low dropout regulator
• LNB

A high-PSRR low dropout regulator using the first-stage reference-included coarse-filtering technique is presented, for the reduced output ripple of the low noise block (LNB) power supply in the satellite set-top box. Compared with the conventional system, the regulator with the technique is characterized by the two successive negative feedback loops, so as to alleviate the output ripple of the power supply caused by the preceding DC-DC converter's modulation signal. With the technique, the ripple near to the frequency of the LNB supply voltage tuning signal (22 kHz) can be significantly alleviated. To further enhance the PSRR performance without the reference-by-pass capacitor, the bipolar-loop buffer amplifier and the reference-included coarse-filtering regulator are proposed. The circuits are extracted from the LDO layout and simulated with a 0.35 mu m BCD process in Cadence. With the typical 16.3V input supply voltage and loading current 100 mA, the line regulation corresponding to the DC supply voltage is achieved at -72 dB; the PSRR performance of the supply voltage ripple up to the frequency (100 kHz) is better than -70 dB; Moreover, the quiescent current without the loading impedance is less than 153 mu A.

• 出版日期2015-2
• 单位福州大学