TPS6734I

FIXED 12-V 120-mA BOOST-CONVERTER SUPPLY

SLVS127A – AUGUST 1995 – REVISED JANUARY 1999

3

POST OFFICE BOX 655303

functional block diagram

EN

1

EN

7

EN

FB

_

+

4

COMP

Voltage

Reference

x3.5

SS

Clamp

Error

Amplifier

PWM

Comparator

R

S

170-kHz

Oscillator

VCC

Power Switch

Drive Latch

Σ

2

REF

3

SS

x6

Current

Sense Amplifier

Overcurrent

Comparator

Driver

VCC

OUT

GND

8

6

5

+

1 M

Ω

–

Q

Terminal Functions

TERMINAL

DESCRIPTION

NAME

NO.

DESCRIPTION

EN

1

Enable. EN

≥ 2 V turns on the TPS6734. EN ≤ 0.4 V turns it off and reduces the supply current to 3 µA max.

REF

2

1.22-V reference voltage output. REF can source 100

µA for external loads.

SS

3

Soft Start. A capacitor between SS and GND brings the output voltage up slowly at power-up.

COMP

4

Compensation connection. A 0.001-

µF capacitor between COMP and FB stabilizes the feedback loop.

GND

5

Ground

OUT

6

N-channel MOSFET drain connection

FB

7

Feedback voltage. FB is connected to the converter output for the feedback loop.

VCC

8

Supply voltage input