User Guide 035
UG035.0
June 15, 2015
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2
Recommended Equipment
The following equipment is recommended to perform testing:
• 0V to 30V power supply with 5A source current capability
• Digital Multimeters (DMMs)
• 500MHz quad-trace oscilloscope
• Signal generator for PWM pins
Quick Setup Guide (Non I
2
C)
1. Ensure that the circuit is correctly connected to the supply.
2. Connect the VIN+ supply to both J1 = BOOST-VIN and
TP9 = VIN_IN.
3. OPEN: Jumpers JP1, JP9, J9, J10, J12, J13, J15, J16, J18, J19,
J21, J22, J24, J25, J26, J27 and J28.
4. CLOSE: Jumpers JP1A:1-2, JP2A:2-3, JP3A:2-3, JP4A:2-3,
JP5A:2-3, J6, J8, J11, J14, J17, J20, J29, J30 and J31.
5. Apply 200Hz, 0-5V, 50% duty, square wave to TP13.
6. Measure the voltage between J4 and J5. IT should read ~32V
7. Note that the 6P10S LED strings are ON.
8. Apply 5V to TP13 and trim RA1 to set the LED current in CH0
to measure 20mA using a DMM in series with J8.
9. Apply a square wave of 200Hz, 5V and vary the duty from 0%
to 100% and check that the LED varies from OFF to 100%
brightness.
10. Check that the current in J8 in step 9 varies from ~0mA to
20mA. Test complete turn OFF supplies.
Quick Setup Guide (I
2
C)
1. Ensure that the circuit is correctly connected to the supply.
2. Connect the VIN+ supply to both J1 = BOOST-VIN and
TP9 = VIN_IN.
3. OPEN: Jumpers JP1, JP9, J9, J10, J12, J13, J15, J16, J18, J19,
J21, J22, J24, J25, J26, J27, J28 and J29.
4. CLOSE: Jumper JP1A:1-2, JP2A:2-3, JP3A:2-3, JP4A:1-2,
JP5A:1-2, J6, J8, J11, J14, J17, J20, J30 and J31.
5. Connect an I
2
C controller bus to either J7 or J39.
6. Set device address to 0x58.
7. IC enable is shorted to VIN by connecting jumper JP2A:2-3, so
that the EN is driven by TP9.
8. VLOGIC level for I
2
C can be generated from VDC by
connecting jumper JP3A:2-3. VLOGIC can be driven from TP7
(VLOGIC) by shorting jumper JP3A:1-2.
9. The configuration of VIN (JP1A), EN (JP2A) and VLOGIC (JP3A)
can be quickly found by referring to the table printed on the
bottom of the evaluation board, as shown in
Figure 6 on
page 7
.
10. There are 4 different operation modes for ISL78171. The
setting for each mode is shown on the other table printed on
the bottom of the evaluation board, as shown in
Figure 6 on
page 7
.
11. For I
2
C/SMBUS and DPST mode, connect the I
2
C interface
board to the ISL78171EVAL1Z board.
12. For I
2
C/SMBUS and DPST mode, in order to enable the board,
write a hex 58 for slave address and write a hex 05 to register
01.
13. For DPST mode I
2
C dimming, write hex 01 to register 01 (see
data sheet for more details).
14. For DPST mode with PWM dimming, write hex 03 to register
01. This will allow PWM dimming in DPST mode.
15. The LED current can be programmed by varying POT R
A1
using
Equation 1
:
The measured current divided by six is the LED current per
channel. For example, 120mA measured current will correspond
to 20mA/channel.
16. The PWM dimming frequency can be adjusted by varying pot
R
A2
using
Equation 2
:
TABLE 1. LED STRINGS CONFIGURATIONS WITH DIFFERENT JUMPER
SETTINGS
LED CONFIGUATRION
6P10S
6P9S
6P8S
J6
Short
J8
Short
J11
J14
J17
JJ20
J30
J10
Open
Short
Open
J13
J16
J19
J22
J24
J9
Open
Open
Short
J12
J15
J18
J21
J23
(EQ. 1)
ILED
410.5 R
A1
R
16
+
410.5 R
13
=
=
(EQ. 2)
F
PWM
6.66 10
7
R
A2
R
12
+
=
