Thermal

Shutdown

Current

Limit

Bandgap

GND

OUT

SENSE

IN

EN

Internal

Supply

IN

OUT

FB

GND

EN

TPS79801

Load

V

IN

R

P

RETURN

OFF

-48V

FB

OUT

IN

EN

TPS79801

GND

1 F

m

1 F

m

R

SET

ON

TPS79801-Q1, TPS79850-Q1

www.ti.com

SLVS822E – MARCH 2009 – REVISED SEPTEMBER 2015

7 Detailed Description

7.1 Overview

The TPS798xx-Q1 is a 50-mA high-voltage LDO regulator with micropower quiescent current and shutdown. The

device is capable of supplying 50 mA at a dropout voltage of 300 mV (typical). The low operating quiescent

current (40

μA) drops to 1 μA in shutdown. In addition to the low quiescent current, the TPS798xx-Q1

incorporates several protection features that make it ideal for battery-powered applications.

The device is protected against both reverse-input and reverse-output voltages. In battery-backup applications,

where the output can be held up by a backup battery when the input is pulled to ground, the TPS798xx-Q1 acts

as if it has a diode in series with its output and prevents reverse current flow. Figure 14 and Figure 15 illustrate

two typical applications.

–48 V can vary from –4 V to –50 V

Figure 14. Constant Brightness for Indicator LED Over Wide Input Voltage Range

Figure 15. Kelvin Sense Connection

7.2 Functional Block Diagram

Figure 16. Fixed Voltage Output Version

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Product Folder Links: TPS79801-Q1 TPS79850-Q1