Second-generation one chip li-ion battery protection IC with an Asymmetric Bidirectional Trench Lateral Power MOSFET

Due to the wide distribution of cellular phones, lithium-ion battery protection ICs are required to further reduce their sizes and costs. Because of asymmetric requirement of short-circuit current capability, an Asymmetric Bidirectional Trench Lateral Power MOSFET (AB-TLPM) is proposed as integrated switches. The AB-TLPM has an asymmetric P+/N+ source design and improves maximum current density by 70% during the short-circuit mode. The AB-TLPM with reduced channel length achieves an excellent specific on-resistance of 7.4 mΩ-mm2, which is 40% better than the first generation bidirectional TLPM (Bi-TLPM). The die size is 20% smaller than the first-generation one even though the integrated switch exhibits a better on-resistance of 38mΩ with sufficient short-circuit handling capability.