米6体育平台手机版

ZHCSNY0B May 2020 – January 2023 BQ25798

PRODUCTION DATA

9.3.5.4 Two ACFETs-RBFETs

In this scenario, both ACFET1-RBFET1 and ACFET2-RBFET2 are present. VAC1 / VAC2 is tied to the drain of ACFET1 / ACFET2, ACDRV1 / ACDRV2 is connected to the gate of ACFET1 / ACFET2. This structure is developed to support dual-input connected at VAC1 and VAC2. At POR, the charger detects both ACFET1-RBFET1 and ACFET2-RBFET2 present, then updates ACRB1_STAT and ACRB2_STAT to 1.

Figure 9-4 Two ACFETs-RBFETs Structure Supporting One Input at VAC1 and One Input at VAC2

Table 9-7 Dual Input Configuration Summary

PIN OR REGISTER FIELD	STATE
External MOSFETs	ACFET1, RBFET1, ACFET2, RBFET2
VAC1 pin	Connected to input source 1
VAC2 pin	Connected to input source 2
ACDRV1 pin	Connected to ACFET1/RBFET1 gate terminals
ACDRV2 pin	Connected to ACFET2/RBFET2 gate terminals
ACRB1_STAT	0: ACFET1/RBFET1 Open (Path Disabled) 1: ACFET1/RBFET1 Closed (Path Enabled)
ACRB2_STAT	0: ACFET2/RBFET2 Open (Path Disabled) 1: ACFET2/RBFET2 Closed (Path Enabled)
DIS_ACDRV	0: Allow ACDRV1 or ACDRV2 on if all requirements met 1: Force ACDRV1 and ACDRV2 off
EN_ACDRV1	0: Force ACDRV1 Off 1: Turn ACDRV1 On if all requirements met
EN_ACDRV2	0: Force ACDRV2 Off 1: Turn ACDRV2 On if all requirements met

In dual input mode, the ACDRV automatically turns on the ACFET-RBFET of the path where a valid input is first presented, without host intervention.If the two inputs are presented at VAC1 and VAC2 exactly at the same time, ACFET1-RBFET1 with higher priority (port #1 is primary) is turned on while ACFET2-RBFET2 stays off (port #2 is secondary). EN_ACDRV1 is automatically set to 1. If a valid input is presented on the second path while the first path is already on with a valid input, the ACFET-RBFET of the second path remains off. If desired, the host may manually perform a switch between power paths by switching the values of EN_ACDRV1 and EN_ACDRV2. Both EN_ACDRV bits may be updated in a single I²C write operation to minimize the transition time. Note that programming EN_ACDRV1 = 1, EN_ACDRV2 = 1 at the same time to turn on both ACFET1-RBFET1 and ACFET2-RBFET2 is not allowed, and will be ignored by the charger.

To transition from one input to the other, the device first turns off the initially active ACFET-RBFET pair, waits until the VBUS voltage drops lower than V_{BUS_PRESENT}, and then enables the new ACFET-RBFET pair. During this change over, the converter stops switching for a short period of time.

If two valid voltages are present at VAC1 and VAC2 and the source on the connected path becomes invalid because of VAC_UVLO, VAC_OV or IBUS_OC, the charger automatically swaps the input without any host engagement. Any time that the converter autonomously swaps the source paths, it will also update the EN_ACDRV1 and EN_ACDRV2 bits accordingly in order to indicate the active power path.

With only one valid input presented at either VAC1 or VAC2, the ACFET1-RBFET1 and ACFET2-RBFET2 can not be both turned off by setting REG0x13[7:6] = 00. Instead, the host should set DIS_ACDRV = 1 to force both ACFET-RBFET pairs off. With input sources present at both VAC1 and VAC2, the host can turn off the two ACFET-RBFET pairs by setting either REG0x13[7:6] = 00 or DIS_ACDRV = 1.