Abstract: With a few op amps and some external components, you can build a pulse generator with variable frequency and duty cycle. The natural choice for generating a pulse of variable frequency and duty cycle is a good bench-top pulse generator. If you don't have a generator or must build one into your system, however, you can do it with a few op amps and some external components (Figure 1). Figure 1. This simple and versatile pulse generator includes only 15 components. U1 and Q1 form a voltage-controlled oscillator (VCO) with a square-wave output and a triangle-wave output. The square wave feeds back to control the charge and discharge of integrating capacitor C1, and is also useful as a sync-signal output. The triangle wave drives the non-inverting input of duty-cycle controller U2-2. R2 fully adjusts the output duty cycle (from 0% to 100%) by controlling U2-2's inverting input. U2-2 generates the output signal directly. U2-1 buffers R1's wiper voltage, which controls the VCO frequency. A change in supply voltage (V+) varies the output swing without effecting the output frequency or duty cycle, and the circuit operates equally well with a single supply or with dual supplies. The frequency range shown is 20Hz to 13kHz, but you can modify that range by changing the value of C1. The dual op amps (designed for controlling power amplifiers) are chosen for their high output drive, rail-to-rail input and output capabilities, single-supply operation, and exceptional open-loop behavior. A similar version of this article appeared in the January 20, 2003 issue of EET magazine. 相关型号   APP 1960: Mar 26, 2003 MAX4232 高输出驱动、10MHz、10V/µs、满摆幅输入/输出运算放大器，带有关断，SC70封装 完整的数据资料 (PDF, 1.3MB) 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 (28kB)  AN1960, AN 1960, APP1960, Appnote1960, Appnote 1960