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DS00001824A-page 15

USB375x

For the USB3750, EnableMux1 or EnableMux2 should not be set while charger detection operations are performed.

During the automatic charger detection EnableMux1 or EnableMux2 will be disabled. These will need to be disabled by

4.2.2

AUTOMATIC CHARGER DETECTION

Automatic charger detection will be begin after VBUS crosses the UVLO threshold, and will follow the flow charts shown

below in Figure 4-4 and Figure 4-6. The flow chart timing can be found in Section 3.3.2. When automatic charger detec-

tion has completed, the INT_B signal will go low, and the type of charger that was detected will be reflected in the Char-

FIGURE 4-4:

CHARGER DETECTION FLOW CHART (USB3750-1)

Start Chrg Detection

ChrgDetComplete = 0

Drive DP

Detect?

DCP

Detected

Exit Chrg Detection

ChrgDetComplete = 1

=1

Any UVLO or OVLO Exit Chrg Detection

SE1 Low

Current

Charger

Enable

100mA after

Wait

SE1?

=1

Release and

Default USB

Mux setting

=0

CDP

Detected

SE1 High

Current

Charger

RxHiCurr?

=1

=0

SDP

Detected

UVLO < VBUS < OVLO

Enable OVP

Switch

=0

Disable

100mA

current limit

Clear Charger

Detection

Register

Wait for DP

Low or

Disable

=1

Detect?

Drive DM

=0

=1