UVLO /

Internal

Regulator

Diode

VIN

Slope

Compensation

S

R

Q

IFB1

PWM/EN

Comp

SW

IFB2

IFB3

IFB4

IFB5

IFB6

EA

R1

RSET

EN

VIN

C2

1uF

Current Sink

C3

4.7uF

OVP

PGND

IFB1

IFB2

IFB3

IFB4

IFB5

IFB6

GND

C1

2.2uF

VOUT

OVP

OVC

COMP

R2

VLDO

Optional

L

C4

0.47uF

Error

Amp

Detector

Duty

Control

Circuit

PWM Signal

Generator

Current

Mirror

Analog

Dimming

PWM

dimming

Dimming

Control

Current Sink

Current Sink

Current Sink

Current Sink

Current Sink

LED

Current

regulation

IFB no use

Open /Short

LED

OVP

Disable

Detection

Shut Down

OSC

Short to GND

Protection

OCP

S

OSC

PWM

decoding

circuit

Dimming Mode

Selection

C5

100pF

51k

82k

MODE/FAULT

Dimming Mode

Detection

R3

1M

R4

43k

Fault protection

C6

2.2uF

TPS61176

SLVSBM5B – DECEMBER 2012 – REVISED AUGUST 2015

www.ti.com

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Supply Voltage

The TPS61176 can support single-cell Li-ion battery input directly. It has a built-in linear regulator to generate

supply for internal analog and logic circuits. The VLDO pin, output of the regulator, should be connected to a 1-

µF bypass capacitor for the regulator to be controlled in a stable loop. VLDO pin does not have current sourcing

capability for external use.

If the device is used in a multi-cell battery system, the battery cannot be connected to VIN pin directly. In this

case, connect a 3.3-V or 5-V power rail to bias the VIN pin and connect the battery voltage to the inductor. The

VIN pin only consumes less than 3 mA for normal operation. Refer to Application and Implementation for more

details.

10

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