中文摘要：

针对传统开关型DC-DC控制芯片软启动电路需使用片外电容,且难以实现全片上集成的缺点,提出一种全数字方式实现的片上软启动电路,可实现软启动功能的全片上集成。集成了该电路的控制芯片具有启动平稳、对启动瞬间的电压过冲和电流浪涌具有良好抑制功能等特点。由于减少了芯片的引脚和省去了片外电容,还有利于缩小整机体积,降低系统设计的复杂度和成本。数字电路的可移植性使得此软启动电路可方便地应用于各类DC-DC开关电源。该电路已成功集成在一PWM（Pulse width modulation）型Buck控制芯片中,该芯片在TSMC 0.35μm工艺下流片。测试结果表明芯片成功实现了8 ms的软启动过程,展现了对于过冲电压和浪涌电流的良好抑制能力。

英文摘要：

To avoid using the off-chip soft-start capacitor adopted by conventional switching DC-DC controller so that to implement a fully integrated on chip DC-DC controller,a novel digital on-chip soft-start circuit is proposed in this paper.A controller chip with this on-chip soft-start cell could provide a smooth start up as well as the initial overshoot voltage suppression and inrush current limitation.Moreover,since it reduces chip pins and obviates off-chip capacitors,it is possible to reduce device volume as well as the complexity and cost of system design.Owing to the good portability of digital circuits,this soft-start cell could be widely applied to different switching converters.The proposed on-chip soft-start circuit is implemented in a PWM Buck controller chip.The chip is fabricated in TSMC 0.35 μm process.And the test results show that a 8 ms soft-start and the good overshoot voltage suppression as well as inrush current limitation are successfully achieved.