To prevent sub-harmonic oscillation and improve the stability and load capacity of the system,a piecewise linear slope compensation circuit is designed. Compared with the traditional design, this circuit provides a compensation signal whose slope varies from different duty cycles at - 40-85℃ ,and reduces the negative effect of slope compensation on the system＇s load capacity and transient response. A current mode PWM Boost DC-DC converter employing this slope compensation circuit is implemented in a UMC 0.6μm-BCD process. The results indicate that the circuit works well and effectively,and the load capacity is increased by 20%. The chip area of the piecewise linear slope compensation circuit is 0.01mm^2 ,which consumes only 8μA quiescent current,and the efficiency ranges up to 93%.
提出了一种新颖的脉宽调制(PWM)控制技术,该技术将误差放大器和PWM比较器归结为一个求和比较器来实现对电流模开关稳压器的自适应控制,使系统变得简洁,降低了成本,有利于集成。成功将该求和比较器应用于一款典型输入为5V典型输出为15V的升压型开关稳压器中,且稳压器采用低损耗的电流检测网络对峰值电流进行采样,减小了功耗。采用0.6μm30V Bi CMOS工艺,经Hspice仿真验证,结果表明稳压器的输出电压纹波在±7mV之间摆动,输出电压精度为±1.5%。
