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ZXLD1350EV4
ZXLD1350EV4 EVALUATION BOARD USER GUIDE
DESCRIPTION
The ZXLD1350EV4, Figure 1, is an evaluation board for evaluating the ZXLD1350 350mA LED driver with internal
switch. The evaluation board can be used to drive 1, 2 or 3 one-watt LEDs, or an external choice of LEDs. The
number of external connected LEDs depends on the forward voltage of the LEDs connected. The LEDs fitted on this
evaluation board are from the Osram range.
The operating voltage is nominally 24V. For three 1W series-connected LEDs, the voltage can be from 12V minimum
to 30V maximum. The 100uH inductor used in the circuit is based on a nominal 24V supply, which should be
connected across +VIN and GND pins. Note: The evaluation board does not have reverse battery protection. The
nominal current for the evaluation board is set at 300mA with a 0.33Ω sense resistor, Rs.
Jumpers J1, J2 and J3 allow the selection of the number of LEDs to be connected in series. Jumper on at J1
bypasses LED D1. Jumper on at J3 bypasses LED D3. Removing jumper J2 disconnects all the on-board LEDs from
the current flow path. Jumper 2 also doubles as a connection point for an ammeter to measure the LED current.
Before connecting external LEDs across test pins LED+ and LED-, or across J1, remove jumper J2. Jumpers J1 and
J2 can be on or off.
Test point ADJ provides a connection point for DC or PWM dimming and shutdown.
Warning: At 24V nominal operation with 300mA output, the LEDs and the PCB may be hot and the LEDs will be very
bright.
Figure 1: ZXLD1350EV4 evaluation board
ZXLD1350EV4 User Guide Iss. 1
1/8
10-04-07
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Summary of Contents for Zetex ZXLD1350EV4
- Page 1 DESCRIPTION The ZXLD1350EV4, Figure 1, is an evaluation board for evaluating the ZXLD1350 350mA LED driver with internal switch. The evaluation board can be used to drive 1, 2 or 3 one-watt LEDs, or an external choice of LEDs. The number of external connected LEDs depends on the forward voltage of the LEDs connected.
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Page 2: Device Applications
Input voltage: 7V to 30V. Decouple to ground with a 1uF or higher ceramic capacitor. ORDERING INFORMATION EVALBOARD ORDER NUMBER DEVICE ORDER NUMBER ZXLD1350EV4 ZXLD1350E5TA Please note: Evaluation boards are subject to availability and qualified leads. ZXLD1350EV4 User Guide Iss. 1 10-04-07... - Page 3 ZXLD1350EV4 EVALUATION BOARD REFERENCE DESIGN The ZXLD1350EV4 is configured to the reference design in Figure 2. The target application is a driver for one or more series-connected 1W white LEDs for torches and other high powered LED driving applications. The operating voltage is a nominal 24V. For three 1W series-connected LEDs, the voltage can be from 12V minimum to 30V maximum.
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Page 4: Evaluation Board
ZXLD1350EV4 Materials List for the ZXLD1350EV4 evaluation board. Value Package Part Number Manufacturer Notes 0.33R 0805 NCST10FR330FTRF NIC components 1%,200ppm R1,R2 Not fitted 0805 Not fitted C1,C2 1uF, 50V, X7R 1206 C1206C105K5RAC7800 Kemet GRM31MR71H105K5KA88K Murata NMC1206X7R105K50F NIC components Not fitted... -
Page 5: Other Features
Do not use a resistor value lower than 0.27Ω. The dimming ratio is around 6:1. Note: as the voltage approaches 0.2V on the ADJ pin, the ZXLD1350 will shut down. Follow the ‘ZXLD1350EV4 Power Up’ sequence. ZXLD1350EV4 User Guide Iss. 1 10-04-07... - Page 6 Follow the ‘ZXLD1350EV4 Power Up’ sequence. Connect the ADJ pin to GND to turn off the output current. Follow the ‘ZXLD1350EV4 Power Up’ sequence. The ZXLD1350 internal switch remains switched off (output current off) whilst the ADJ pin is pulled to GND.
- Page 7 Rs = the sense resistor value in ohms. Do not use a resistor value lower than 0.27Ω. 0.1V is the nominal sense voltage with ADJ open circuit or set to 1.25V. Follow the ‘ZXLD1350EV4 Power Up’ sequence. Using external LEDs or loads Switch off the power supply.
- Page 8 Zetex products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Zetex Semiconductors plc. As used herein: Life support devices or systems are devices or systems which: 1.