TPS22981

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SLVSBM6 – DECEMBER 2012

REVERSE CURRENT BLOCKING

The VHV switch blocks reverse current flow from OUT to VHV when the switch is off.

THERMAL SHUTDOWN

state on power up once the junction temperature has dropped by 10C. Connect thermal vias to the exposed

GND pad underneath the device package for improved thermal diffusion.

UVLO and ENABLE

When ENHVU is low, the TPS22981 is enabled by the logical AND of the EN input, the V3P3 UVLO, and the

Thermal Shutdown. When the V3P3 UVLO threshold has been crossed, the device is not in thermal shutdown,

and the EN input is high, the device will enable. When the V3P3 UVLO triggers, regardless of the states of any

digital logic controls, the device will open all switches.

ENHVU adds the VHV UVLO to the logical decision enabling the device. When ENHVU is high, the TPS22981 is

enabled by the logical AND of the EN input, the V3P3 UVLO, the VHV UVLO, and the Thermal Shutdown. When

both UVLO thresholds have been crossed, the device is not in thermal shutdown, and the EN input is high, the

device will enable. When either UVLO triggers, regardless of the states of any digital logic controls, the device

will open all switches. Table 2 shows the pin and voltage configurations for enabling the device. Note, a 1 for the

UVLO columns means the device is in a UVLO condition.

Table 2. Device Enable Control (when in an under-voltage condition, UVLO = 1)

EN

ENHVU

HV_EN

V3P3 UVLO

VHV UVLO

OUT

0

X

X

X

X

OPEN

1

X

X

1

X

OPEN

1

1

X

X

1

OPEN

1

0

0

0

X

V3P3

1

1

0

0

0

V3P3

1

X

1

0

0

VHV

1

0

1

0

1

V3P3

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