BQ25606 Datasheet, PDF (17/43 Pages) Texas Instruments – Standalone 3.0-A, Single Cell Battery Charger With 40V Over Voltage Protection Controller

bq25606
www.ti.com
SLUSCK6 – MAY 2017
Feature Description (continued)
8.3.2.2 Power Up REGN Regulation
The REGN LDO supplies internal bias circuits as well as the HSFET and LSFET gate drive. The REGN also
provides bias rail to TS external resistors. The pull-up rail of STAT can be connected to REGN as well. The
REGN is enabled when all the below conditions are valid:
• V_VAC above V_{VAC_PRESENT}
• V_VAC above V_BAT + V_SLEEPZ in buck mode or VBUS below V_BAT + V_SLEEP in boost mode
• After 220-ms delay is completed
If any one of the above conditions is not valid, the device is in high impedance mode (HIZ) with REGN LDO off.
The device draws less than IVBUS_HIZ from VBUS during HIZ state. The battery powers up the system when
the device is in HIZ.
8.3.2.3 Poor Source Qualification
After REGN LDO powers up, the device confirms the current capability of the input source. The input source
must meet both of the following requirements in order to start the buck converter.
• VAC voltage below V_{VAC_OV}
• VBUS voltage above V_VBUSMIN when pulling I_BADSRC (typical 30 mA)
If the device fails the poor source detection, it repeats poor source qualification every 2 seconds.
8.3.2.4 Input Source Type Detection
After the REGN LDO is powered, the device runs input source detection through D+/D– lines. The bq25606
follows the USB Battery Charging Specification 1.2 (BC1.2) to detect input source (SDP/ DCP) and non-standard
adapter through USB D+/D– lines. The bq25606 sets input current limit through D+/D- detection and ILIM pins.
8.3.2.4.1 D+/D– detection sets input current limit in limit.bq25606
The bq25606 contains a D+/D– based input source detection to set the input current limit at VBUS plug-in. The
D+/D– detection includes standard USB BC1.2 and non-standard adapter. When input source is plugged in, the
device starts standard USB BC1.2 detections. The USB BC1.2 is capable to identify Standard Downstream Port
(SDP) and Dedicated Charging Port (DCP). When the Data Contact Detection (DCD) timer expires, the non-
standard adapter detection is applied to set the input current input current limit. The non-standard detection is
used to distinguish vendor specific adapters (Apple and Samsung) based on their unique dividers on the D+/D–
pins. If an adapter is detected as DCP, the input current limit is 2.4 A. If an adapter is detected as unknown, the
input current limit is set by ILIM pin.
Non-Standard
Adapter
Divider 1
Divider 2
Divider 3
Divider 4
Table 1. Non-Standard Adapter Detection
D+ Threshold
V_D+ within V_{2P7_VTH}
V_D+ within V_{1P2_VTH}
V_D+ within V_{2P0_VTH}
V_D+ within V_{2P7_VTH}
D– Threshold
V_D– within V_{2P0_VTH}
V_D– within V_{1P2_VTH}
V_D– within V_{2P7_VTH}
V_D– within V_{2P7_VTH}
Input Current Limit (A)
2.1
2
1
2.4
Table 2. Input Current Limit Setting from D+/D– Detection
D+/D– Detection
USB SDP (USB500)
USB DCP
Divider 3
Divider 1
Divider 4
Divider 2
Unknown 5-V Adapter
Input Current Limit (IINLIM)
500 mA
2.4 A
1A
2.1 A
2.4 A
2A
Set by ILIM pin
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