Abstract: 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 0.01mm2, which consumes only 8μA quiescent current, and the efficiency ranges up to 93%.

Key words: DC-DC converter, slope compensation, piecewise linear, duty cycle