STEVAL-ISA056V1
6 rows - 30 mA LEDs driver with boost converter for LCD panels backlight evaluation board based on the PM6600
Data Brief
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 output 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
STEVAL-ISA056V1 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 shutdown) are provided.
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 row). 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
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www.st.com 4
For further information contact your local STMicroelectronics sales office.
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LED _EN SY SYN C R ED , 3mA D, 6 AVC C SLOPE 7 LD O5 F A U LT EN DIM MOD E C OMP SS F SW R I LI M BI LI M SG SGN D TH PD 25 PGN D 17 22 21 20 5 AVC C C OMP 1 SW 2 24 SS 4 2 3 AVC C F SW C9 N . M. 4n7 TP13 C8 3n3 R I LI M 10 R3 2k 4 MOD E C7 R OW 6 R OW 5 R OW 4 R OW 3 R OW 2 R OW 1 16 15 14 13 12 11 9 OVSEL 18 VI N R9 100k C 6 100n LX D2
U1 8
19
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Circuit schematic
Figure 1.
D1 VBOOST C1 10u STPS1L40M VI N R1 510k R8 680k C 13 22p L1 6u8 TP7
Schematic
VI N +
SY N C J2 R 11 1k 2 2 OVSEL R2 16k C 10 560p 1 AVC C C2 2u2 AVC C AV AVC C SLOPE C3 2u2 C4 N . M.
Circuit schematic
F AU LT C5 1u
R4 4R 7
GN D
R 13 NM
C 12 NM
EN
TP8
R 12 NM
D3 NM
PM6600
DIM
8 7 6 5 4 3 2 1 J8 H EAD ER 8
C 11
SW 3
R 10
4n7
R ES
100k
R OW 1 BI LI M
R OW 2
R OW 3
R OW 4
R OW 5
R OW 6
R 5 330k SW 1 F SW
R6 51k
R7 180k
STEVAL-ISA056V1
VI N -
STEVAL-ISA056V1
Revision history
2
Revision history
Table 1.
Date 10-Mar-2008
Document revision history
Revision 1 Initial release. Changes
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STEVAL-ISA056V1
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