ZHCSJR3B February 2019 – November 2019 BQ25887
PRODUCTION DATA.
The device has 1.5-MHz switching frequency to allow the use of small inductor and capacitor values. The inductor saturation current should be higher than the input current (IIN) plus half the ripple current (IRIPPLE):
The inductor ripple current (IRIPPLE) depends on input voltage (VVBUS), duty cycle (D = VBAT/VBUS), switching frequency (fSW) and inductance (L):
The maximum inductor ripple current happens in the vicinity of D = 0.5. Usually inductor ripple is designed in the range of (20 – 40%) maximum charging current as a trade-off between inductor size and efficiency for a practical design.