一种应用于DC/DC转换器的自举电路设计

设计了一种适用于DC/DC转换器的自举升压电路.采用该电路可将功率PMOS管替换为NMOS管.在相同尺寸条件下,NMOS管具有较小的导通电阻,从而提高DC/DC转换器的效率.电路基于华宏NEC的0.35 μm BCD工艺,利用Cadence中的Spectre进行了验证.并给出了该自举电路的设计思想、电路的工作原理,以及自举电容最小值的计算.当电源电压降至1.4 V,电路仍能保持正常工作.当自举电容为10 nF,电源电压为5 V,工作频率可高达2 MHz.

Design of Self-Lift Circuit for DC/DC Converters

A self-lift boost circuit used for DC/DC converters has been presented .Using this circuit,we can replace power PMOSFET by NMOSFET. when PMOSFET and NMOSFET have the same size, NMOSFET has a smaller value of resistance. Then we can improve the converters'' efficiency. The circuit is implementded in a 0.35 um BCD process of HHNEC and is simulated by Spectre of Cadence. Then the design idea , working principle and the computing method for the minimum value of the self-lift capacitance are all presented. When the supply voltage is decreased to 1.4 V, this circuit still can be normal working. When the self-lift capacitance is 10 uF,and supply voltage is 5 V,then the operating frequency can be up to 2 MHz.