Abstract: A discrete-component external charge pump enables the PFM-controlled DC-DC converter of Figure 1 to generate dual outputs with moderate regulation and high efficiency. The circuit accepts input voltages between 2V and 12V (typically 5V) and delivers simultaneous 0mA to 100mA outputs at ±12V (Figure 2). Efficiencies range between 80% and 90%. A discrete-component external charge pump enables the PFM-controlled dc-dc converter of Figure 1 to generate dual outputs with moderate regulation and high efficiency. The circuit accepts input voltages between 2V and 12V (typically 5V) and delivers simultaneous 0mA to 100mA outputs at ±12V (Figure 2). Efficiencies range between 80% and 90%. Figure 1. An external charge pump (C3, C5, D1, and D3) enables this dc-dc step-up converter to generate ±12V dual outputs. Figure 2. "Pseudoregulation" stabilizes the -12V output in Figure 1. IC1 regulates 12V via its V+ terminal, but the -12V output has no direct feedback connection. Nevertheless, changes in -12V load current are coupled via "flying capacitor" C3, where they affect the switching frequency just as 12V load changes do-via current-limited, minimum-off-time, pulse-frequency modulation of the chip's internal switching MOSFET. The resulting pseudo-regulation is impressive: a load change of 10mA to 100mA at either output causes only a 4% change in the negative output (from -11.36V to -10.96V). 相关型号   APP 974: Oct 01, 1996 MAX761 12V/15V或可调、高效率、低IQ、升压型DC-DC转换器 完整的数据资料 (PDF, 136kB) 免费样品 自动更新 需要自动接收最新发布的应用笔记吗？请订阅EE-Mail™ (English only)。 我们期待您的反馈！ 喜欢？不喜欢？有待改善？或为我们提供建议？请与我们联系 — 我们将根据您的意见或建议改善我们的工作。 网页评价或提供建议   下载，PDF格式 (29kB)  AN974, AN 974, APP974, Appnote974, Appnote 974