BQ24392_15 Datasheet, PDF (8/22 Pages) Texas Instruments – bq24392 Dual SPST USB 2.0 High Speed Switch with USB Battery Charging Specification Revision 1.2 Detection

bq24392
SLIS146C – JUNE 2012 – REVISED JANUARY 2015
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Feature Description (continued)
When a micro or mini-USB accessory is inserted into the connector and once VBUS is greater than V_{VBUS_VALID}
threshold, the BQ24392 will enter into the Data Contact Detection (DCD) state which includes a 600-ms timeout
feature that is prescribed in the USB Battery Charging Specification version 1.2 (BCv1.2). If the micro or mini-
USB accessory is determined to be USB BCv1.2 compliant, a 130-ms debounce period will initiate and the
BQ24392 will proceed to its primary detection and then secondary detection states to determine if a Dedicated
Charging Port (DCP), Standard Downstream Port (SDP), or Charging Downstream Port (CDP) is attached to the
USB-port. The minimum detection time for a DCP, SDP, and CDP is 130 ms, but can be as long as 600 ms due
to the slow plug in effect.
If the GOOD_BAT pin is high, the USB 2.0 switches are automatically closed to enable data transfer after the
device detects a Standard Downstream Port (SDP) or Charging Downstream Port (CDP) was connected.
If Data Contact Detection (DCD) fails, the BQ24392 proceeds to detect whether an Apple or TomTom charger
was inserted by checking the voltage level on DP_CON and DM_CON. Thus, for Apple and TomTom chargers,
detection time typically takes ~600 ms.
The 3 output pins CHG_AL_N, CHG_DET, and SW_OPEN change their status at the end of detection. Table 1 is
the detection table with the GPIO status for each type of supported charger. More information on how to use the
GPIOs is available in Using the BQ24932 GPIOs .
Device
Type
VBUS
DP_CON
(D+)
Table 1. Detection Table
DM_CON
(D–)
GOOD_BA
T
CHG_AL_N
(Input)
(Output)
CHG_DET
(Output)
Standard
Downstrea
m Port
> 3.5 V
Pull-down R to
GND
Pull-down R to
GND
Charging
Downstrea
m Port
> 3.5 V
Pull-down R to
GND
V_{DM_SRC}
Dedicated
Charging
Port
Apple
Charger
TomTom
Charger
PS/2
Charger
Non-
compliant
USB
Charger
Any Device
Any Device
DBP
Timer
Expired
> 3.5 V
> 3.5 V
> 3.5 V
> 3.5 V
> 3.5 V
< 3.5 V
> 3.5 V
Short to D–
Short to D+
2.0 < V_{DP_CON} <
2.8
2.0 < V_{DP_CON} <
3.1
Pull-up R to V_VBUS
2.0 < V_{DM_CON} <
2.8
2.0 < V_{DM_CON} <
3.1
Pull-up R to
V_VBUS
Open
Open
Open
Open
X
X
HIGH
LOW
HIGH
LOW
X
X
X
X
X
X
LOW
LOW
LOW
LOW
LOW
LOW
LOW
LOW
LOW
LOW
High-Z
High-Z
LOW
LOW
HIGH
HIGH
HIGH
HIGH
HIGH
LOW
LOW
LOW
LOW
SW_OPEN
(Output)
Switch Status
Charge
Current
LOW
High-Z
LOW
High-Z
Connected
Charge with
100 mA/
Change the
input current
based on
enumeration
Not Connected
Charge with
100 mA
Connected
Charge with full
current
Not Connected
Charge with
100 mA
High-Z
Not Connected
Charge with full
current
High-Z
High-Z
High-Z
Not Connected
Charge with full
current
Not Connected
Charge with full
current
Not Connected
Charge with
100 mA
High-Z
Not Connected
Charge with
100 mA
High-Z
Not Connected No Charge
High-Z
Not Connected No Charge
If a charge has been detected and the GOOD_BAT pin is low, a Dead Battery Provision (DBP) timer is initiated.
If the GOOD_BAT continues to be low for 30 minutes (maximum of 45 minutes), charging is disabled and
CHG_AL_N goes into the High-Z state to indicate this. Toggling GOOD_BAT high after the DBP timer expires re-
starts detection and the DBP timer.
7.4 Device Functional Modes
The BQ24392 has two functional modes USB switch ON and USB switch OFF.
8
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