一种具有死区控制功能的自举电荷泵设计

Design of a self-boost charge pump with dead-time control function

智能功率集成电路(SPICs)已成为工业自动化、汽车电子、电机系统等领域的关键产品。智能高侧功率开关作为智能功率集成电路的代表性产品,具有复用性高、可靠性强和可集成化等优点,其通常集成电荷泵实现功率管的栅极电压抬升以减小导通损耗。针对传统自举电荷泵使用电阻对自举管的栅电容充电而导致额外功率损耗的问题,设计了一种具有死区控制功能的自举电荷泵。将传统自举电荷泵中的电阻更换为P-LDMOS,并结合低功耗的高侧浮动电源轨电路和死区控制电路进行合理的死区控制,从而在实现电压自举泵升和高侧驱动功能的同时,显著降低了自举电荷泵在工作过程中使用电阻造成的额外功率损耗。基于0.18μm BCD工艺,使用Virtuoso进行电路的设计与仿真,仿真结果表明,该电路可使外置高侧功率管实现自举上电并具备100%占空比的高侧栅极驱动,P-LDMOS的平均功耗为1.8 mW,在相同的工作条件下,其相较于传统的电阻结构降低了约90%。

Smart Power Integrated Circuits(SPICs)have become the key products in industrial automation,automotive electronics,motor systems and other fields.As a representative product of SPICs,intelligent high-side power switch has the advantages of high reusability,strong reliability and integrability.It usually integrates the charge pump to realize the gate voltage lift of the power tube to reduce the conductivity loss.In order to solve the problem that traditional bootstrap charge pump uses the resistance to charge the gate capacitor of the bootstrap tube,which leads to extra power loss,a bootstrap charge pump with dead-time control function was designed.The resistance in the traditional bootstrap charge pump was substituted by P-LDMOS,and the high side of the floating rail circuit with low power consumption and the dead zone control circuit were combined to control the reasonable dead zone.As a result,the voltage bootstrap pump rise and high side drive function were realized.At the same time,the additional power loss of the bootstrap charge pump,which is caused by the resistance,was significantly reduced.Based on the 0.18μm BCD process,Virtuoso was used to design and simulate the circuit.The simulation results show that the circuit can enable the external high-side power tube to realize bootstrapping and have the high-side gate drive with 100%duty cycle.The average power consumption of P-LDMOS is 1.8 mW.Compared with the traditional resistance structure,the resistance is reduced by about 90%.