D类音频功放中线性三角波发生器设计

Design of a Linear Triangular Waveform Generator in Class D Audio Power Amplifier

利用内部VDD/2基准电压产生恒定电流对电容进行充放电控制,实现了一种应用于D类功放的CMOS电流控制线性三角波发生器。理论推导和spectre仿真验证结果显示,其振荡频率与电源电压无关,而波形峰峰值随电源电压线性变化,且对结温变化、工艺漂移不敏感。电路采用CSMC0.5μm5V双阱双多晶硅CMOS工艺,测试结果表明该三角波稳定性、线性度良好。

A CMOS current-controlled linear triangular waveform Generator for class D amplifier application is presented, in which constant-current sources generated from VDD /2 reference voltage are used to charge and discharge the capacitor. Theoretical derivation and spectre simulations show that, the oscillation frequency is supply-independent and the waveform peak-to-peak value is direct proportional to supply voltage, junction temperature insensitive and process deviation insensitive. The proposed circuit is realized in CSMC 0.5μm 5V twin well twin poly CMOS process, and test results show that the triangular wave is well stable and linear.