Simple Techniques Minimize CrossCoupling in （简单的技术CrossCoupling最小化）.pdfVIP

LM2586,LM2588,LM2596,LM2671,LM2672, LM2675 Simple Techniques Minimize Cross-Coupling in Distributed Power Systems Literature Number: SNVA561 Simple Techniques Minimize Cross-Coupling in Distributed Power Systems Ravindra Ambatipudi National Semiconductor Corporation Introduction: Distributed power supplies convert the AC line voltage to a lower unregulated DC voltage by using a transformer and a diode-bridge rectifier. As shown in Figure 1, this unregulated DC voltage is then converted to two or more tightly regulated DC voltages by using switching and/or linear regulators. VOUT1 Line Voltage Unregulated Switching VOUT2 and/or Linear 90-270VAC DC Voltage Regulators VOUT3 Figure 1 Typical Distributed Power System Figure 2 shows a distributed power system that generates regulated 5V and 3.3V outputs. The unregulated DC voltage, generated from the AC line, varies between 12V and 25V and is converted to tightly regulated DC voltages using two Simple SwitcherTM buck regulators. A flyback converter could have been used to perform this conversion, but it was not used because of the need for better output regulation. The two buck regulators are designed using the associated Simple Switcher design software, and their design specifications are as shown in Table 1. Table 1: Specifications LM2596 LM2675