R

SET_V3P3

R

SET_S3

R

SET_S0

ISET_S3

ISET_V3P3

ISET_S0

IREF_HV

IREF_V3P3

OUT

VHV

4.5 - 18V

3.3V

Switch

CTRL

Logic

TPS22981

www.ti.com

SLVSBM6B – DECEMBER 2012 – REVISED NOVEMBER 2015

7.3 Feature Description

7.3.1 Current Limit

Figure 1 shows a simplified view of the TPS22981 current limit function. Both the high-voltage supply current limit

and the V3P3 supply current limit are adjustable by external resistors.

Figure 1. Simplified Current Limit Diagram

The current IREF_HV and IREF_V3P3 that set the current limit threshold are set with three external resistors as shown

in Figure 2. When the TPS22981 is passing the V3P3 voltage, the current limit is set by RSET_V3P3. The VHV path

has two modes that allow setting two different current limits. The S0 pin determines which current limit is used.

When S0 is asserted high, RSET_S0 sets the current limit. When S0 is low, RSET_S3 sets the current limit. This

allows the system to have two separate VHV current limits for different modes such as active and sleep.

Figure 2. External RSET Resistance to Set Current Limits

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