UPD1002

DS00001760B-page 30

 2014 Microchip Technology Inc.

3.4.1.2

Overvoltage Condition

Using VMON, the device monitors the voltage on VBUS to detect an overvoltage condition on the supply output. The

overvoltage condition is determined when the predefined overvoltage threshold is crossed, as detailed in Table 3-5.

The VSELx_N pins are used to set the overvoltage protection (OVP) voltage on the VMON pin. The OVP fault will trig-

ger when the measured voltage on VMON is 10% above the selected voltage setting.

On the occurrence of the overvoltage condition:

• The supply output will turned off and discharged.

•The FAULT_N pin will be strobed approximately every 500ms.

• If more than 3 consecutive exceptions occur within a 4 second period, FAULT_N will be strobed approximately

every 5 seconds.

3.4.1.3

Undervoltage Condition

Using VMON, the device monitors the voltage on VBUS to detect an undervoltage condition on the supply output. The

undervoltage condition is determined when the predefined undervoltage threshold is crossed, as detailed in Table 3-6.

On the occurrence of the undervoltage condition:

• The supply output will turned off and discharged.

•The FAULT_N pin will be strobed approximately every 500ms.

• If more than 3 consecutive exceptions occur within a 4 second period, FAULT_N will be strobed approximately

every 5 seconds.

3.4.2

IMON

The integrated current monitor utilizes the IMON pin to read a voltage representation of the power supply output current.

This pin should be fed by a current sense amplifier tuned to output 3.0 V when 6.0 A is flowing on VBUS. On connection

of a port partner and the completion of a negotiated power contract, the overcurrent threshold is set based on the nego-

tiated current. When the device is not connected to a port partner, the overcurrent threshold will be set to the default

level. On the occurrence of an overcurrent condition:

• The supply output will turned off and discharged.

•The FAULT_N pin will be strobed approximately every 500ms.

• If more than 3 consecutive exceptions occur within a 4 second period, FAULT_N will be strobed approximately

every 5 seconds.

TABLE 3-5:

VMON OVERVOLTAGE THRESHOLDS

Voltage Threshold (V)

Min.

Typical

Max

5V

-6.0

6.9

9V

-

10.4

12.0

12 V

-

13.7

15.8

16 V

-

18.1

20.9

20 V

-

22.5

26.9

TABLE 3-6:

VMON UNDERVOLTAGE THRESHOLDS

Voltage Threshold (V)

Min.

Typical

Max

5V

-4.5

-

9V

-8.1

-

12 V

-

10.8

-

16 V

-

14.4

-

20 V

-

18.0

-