ST ISA056V1 User Manual

STEVAL-ISA056V1

6 rows - 30 mA LEDs driver with boost converter for LCD panels

backlight evaluation board based on the PM6600

Features

■ Boost section

– 4.5 V to 28 V input voltage range
– Internal Power MOSFET
– Internal +5 V LDO for device supply
– Up to 36 V outp ut voltage
– Constant frequency peak current-mode ctrl
– 200 kHz to 1 MHz adjustable switching

frequency
– External sync for multi-device application
– Pulse-skip power saving mode at light load
– Programmable soft-start
– Programmable OVP protection
– Single ceramic output capacitor
– Latched thermal shutdown

■ Backlight driver section

– Six rows with 30mA maximum current

capability (adjustable)
– Up to 10 W LEDs per row
– Rows disable option
– Less than 500 ns minimum dimming time

(1% minimum dimming duty-cycle at 20

kHz dimming frequency)
– ±2.0% current matching between rows
– LED failure (open and short circuit)

detection

managed). The device allows to detect and
manage the open and shorted LED faults and to
let unused rows floating. Basic protections
(output over-voltage, internal MOSFET over­current and thermal shutd own) are pr ovided.

STEVAL-ISA056V1

Data Brief

Description

This evaluation board based on the PM6600
consists of a high efficiency monolithic boost
converter and six controlled current generators
(rows) specifically designed to supply LEDs
arrays used in the backlight of LCD panels. The
device can manage an output voltage up to 36 V
(i.e. ten white-LEDs per ro w).

The generators can be externally programmed to
sink up to 30 mA and can be dimmed via a PWM
signal (1% dimming duty-cycle at 20 kHz can be

March 2008 Rev 1 1/4

For further information contact your local STMicroelectronics sales office .

www.st.com

4

Circuit schematic STEVAL-ISA056V1

AV

PG

OVSE

DI

660

EA

R

IN

60

10

80

VBOOS

N.

IN

AV

DI

SLOP

N.

PS

10

D,

RI

OVSE

33

AV

AV

1 Circuit schematic

Figure 1. Schematic

T

VBOOS

TP7

8

7

456

8

J8

DER

HEA

3

1

2

GND

M.

C4

N.

C3

2u2

C2

2u2

k

R8

D1

680

p

E

C13

22p

R1

510k

1L40M

STPS

L1 6u8

VIN

C1

10u

C10

560

SLOP

R2

16k

L

OVSE

18

L

LX

19

OVSE

VIN

8

SYSYNC

23

AVCC

U1

6

CC
AV

CC
AV

0n

C6 10

AVCC

0k

R9

10

12

J2

LED_EN

3mA

R11 1k2

RED,

D2

TP8

12

15

9

17

16

ND
PG

SLOPE

25

11

14

13

THPD

ROW2

ROW5

ROW1

ROW4

ROW6

ROW3

0

PM660

M
DI

EN

LDO5

FAULT

7

22

4R7

R4

FAULT

21

C5 1u

D3

NM

C12

NM

COMP1MODE

5

20

COMP

CC
AV

ROW6

ROW5

ROW4

ROW3

ROW2

ROW1

SGSGND

10

BILIM

3

RIRILIM

2

FSW

4

SS

24

SS

CC
AV

C7

2k4

R3

SW2

MODE

RES

SW3

4n7

C11

R7

180k

BILIM

LIM

R6

51k

RI

SW1

FSW

TP13

FSW

0k

R5 33

3n3

C8

4n7

M.

C9

N.

100k

+

VIN

SYNC

R12

NM

R13

NM

M

EN

DI

R10

-

VIN

2/4