BQ24190_15 Datasheet, PDF (14/52 Pages) Texas Instruments – bq2419x I2C Controlled 4.5-A Single Cell USB/Adapter Charger with Narrow VDC Power Path Management and USB OTG

bq24190, bq24192, bq24192I
SLUSAW5B – JANUARY 2012 – REVISED DECEMBER 2014
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Feature Description (continued)
1. VBUS voltage below 18 V (not in ACOV)
2. VBUS voltage above 3.8 V when pulling 30 mA (poor source detection)
Once the input source passes all the conditions above, the status register REG08[2] goes high and the PG pin
(bq24192, bq24192I) goes low. An INT is asserted to the host.
If the device fails the poor source detection, it will repeat the detection every 2 seconds.
9.3.1.3.3 Input Current Limit Detection
The USB ports on personal computers are convenient charging source for portable devices (PDs). If the portable
device is attached to a USB host, the USB specification requires the portable device to draw limited current (100
mA/500 mA in USB 2.0, and 150 mA/900 mA in USB 3.0). If the portable device is attached to a charging port, it
is allowed to draw up to 1.5 A.
After the PG is LOW or REG08[2] goes HIGH, the charger device always runs input current limit detection when
a DC source plugs in unless the charger is in HIZ during host mode.
The bq24190 follows battery charging specification 1.2 (bc1.2) to detect input source through USB D+/D– lines.
The bq24192 and bq24192I set input current limit through PSEL and OTG pins.
After the input current limit detection is done, the host can write to REG00[2:0] to change the input current limit.
9.3.1.3.4 D+/D– Detection Sets Input Current Limit in bq24190
The bq24190 contains a D+/D– based input source detection to program the input current limit. The D+/D-
detection has two steps: data contact detect (DCD) followed by primary detection.
D+
VDP_SRC
VLGC_HI
IDP_SRC
CHG_DET
IDM_SINK
VDAC_REF
D-
RDM_DWN
Figure 10. USB D+/D- Detection
DCD (Data Contact Detection) uses a current source to detect when the D+/D– pins have made contact during
an attach event. The protocol for data contact detect is as follows:
• Detect VBUS present and REG08[2] = 1 (power good)
• Turn on D+ I_{DP_SRC} and the D– pull-down resistor R_{DM_DWN} for 40 ms
• If the USB connector is properly attached, the D+ line goes from HIGH to LOW, wait up to 0.5 sec.
• Turn off I_{DP_SRC} and disconnect R_{DM_DWN}
The primary detection is used to distinguish between USB host (Standard Down Stream Port, or SDP) and
different type of charging ports (Charging Down Stream Port, or CDP, and Dedicated Charging Port, or DCP).
The protocol for primary detection is as follows:
• Turn on V_{DP_SRC} on D+ and I_{DM_SINK} on D– for 40 ms
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