PIN FUNCTIONS

N.

Name

Description

1

H1STRAP

Section 1 section bootstrap capacitor connection

Device supply voltage. From 5.0 to 25V

3

SREG5

Signal 5V. It should be connected to PREG5 pin.

4

V1SW

Alternative device supply voltage.

5

V1SNS

This pin connects to the (-) input of the section 1 internal current sense comparator

6

I1SNS

This pin connects to the (+) input of the section 1 internal current sense comparator

7

COMP1

Feedback input for the section 1.

8

SOFT1

Soft-start input of the section 1. The soft-start time is programmed by an external capacitor

connected between this pin and SGND. Approximately, 1ms/nF @ full load.

9

CRST

Input used for start-up and shut-down timing. A capacitor defines a time of 2ms/nF.

10

PWROK1

Power-good diagnostic signal. This output is driven high when section 1 is enabled and

running properly, after a delay defined by the CRST capacitor.

11

RUN1

Control input to enable/disable the section 1. A high level (>2.4V) enables this section, a low

level (<0.8V) shuts it down

12

VREF

Internal +2.5V high accuracy voltage generator. It can source 5mA to external load. Bypass to

ground with a 4.7

µF capacitor to reduce noise.

13

SGND

Signal ground. Reference for internal logic circuitry. It must be routed separately from high

current returns.

14

NOSKIP

Pulse skipping mode control. A high level (>2.4V) disables pulse skipping at low load current,

a low level (<0.8V) enables it.

15

OSC

Oscillator frequency control: connect to 2.5V to select 300KHz operation, to ground or to 5V

for 200KHz operation. A proper external signal can synchronize the oscillator

16

RUN2

Control input to enable/disable the section 2. A high level (>2.4V) enables this section, a low

level (>0.8V) shuts it down.

17

SOFT2

Soft-start input for the section 2. The soft-start time is programmed by an external capacitor

connected between this pin and GND. Approximately, 1ms/nF @full load.

18

COMP2

Feedback input for the section 2.

19

I2SNS

This pin connects to the (+) input of the section 2 internal current sense comparator

20

V2SNS

This pin connects to the (-) input of the section 2 internal current sense comparator

21

V13IN

12V regulator input supply voltage, included between 13 and 20V. This voltage can be

supplied by a flyback winding.

22

REG12

12V regulator output voltage. It can source up to 150mA to an external load

23

PWROK2

Power good diagnostic signal. This output is driven high when section 2 is enabled and

running properly, after a delay defined by CRST capacitor

24

H2STRAP

Section 2 bootstrap capacitor connection

25

H2GATE

Gate- driver output for the section 2 high-side N-MOS

26

H2SRC

Section 2 high-side N-MOS source connection

27

R2GATE

Gate- driver output for the section 2 low- side N-MOS (synchronous rectifier).

28

PGND

Current return for drivers

29

PREG5

+5V regulator supply. Used mainly for bootstrap capacitors. It should be bypassed to ground.

30

R1GATE

Gate-driver output for the section 1 low-side N-MOS (synchronous rectifier).

31

H1SRC

Section 1 high-side N-MOS source connection

32

H1GATE

Gate-driver output for the section 1 high-side N-MOS

L5994

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