ZXLD1362EV3 EVALUATION BOARD
REFERENCE DESIGN
The ZXLD1362EV3 is configured to the reference design in Figure 2. The target application is a driver for one or more
The maximum operating voltage is 60V, and the nominal current is set at 700mA with a 0.15Ω sense resistor R1. The device operates in continuous mode at approximately 150 kHz, with a 68uH inductor.
An accurate way of determining the current, avoiding the need to insert an ammeter in the current path, is to measure the voltage on the sense resistor. A 10K resistor and a 1uF capacitor can be used to form a low pass filter and the voltage across the capacitor represents a more stable dc reading of current. Using this method, 100mV represents 0.7 Amp when using a 0.15Ω sense resistor.
The ADJ pin connects to a low pass filter within the ZXLD1362 chip to provide some decoupling, but the external capacitor C2 (100nF) is used to provide additional decoupling to reduce any high frequency noise as well as enabling the soft start function.
Both DC and PWM dimming can be achieved by driving the ADJ pin. For DC dimming, the ADJ pin may be driven between 0.3V and 1.25V. Driving the ADJ pin below 0.2V will shut down the output current. For PWM dimming, an external
For low frequency, PWM capacitor C2 should be removed on the evaluation board, to give a more accurate duty cycle.
Shorting R2 will connect the test pin ADJ to device pin ADJ if needed.
The external capacitor C2 on the ADJ pin sets the soft start time. The amount of soft start time achievable is approximately 0.2ms/nF.
For other reference designs or further applications information, please refer to the ZXLD1362 datasheet.
Schematic Diagram
Figure 2 shows the schematic for the ZXLD1362EV3 evaluation board.
Vin
ADJ
R2
C1
C4
3
R1
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| 4 |
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| 5 |
Vin | V sense | |||
ADJ ZXLD1362 LX
1
D1
L1
LED A
C3
LED K
C2
GND
GND
Figure 2: Schematic for the evaluation board ZXLD1362EV3
ZXLD1362EV3 User Guide issue 1 | 3/7 |
