ZXLD1350ET5 Diodes Inc, ZXLD1350ET5 Datasheet - Page 13

• Manufacturer Part Number: ZXLD1350ET5
• Description: IC, LED DRIVER, BUCK, TSOT-23-5
• Manufacturer: Diodes Inc

Specifications of ZXLD1350ET5

• Led Driver Application: Automotive Lighting, Illuminated Signs
• No. Of Outputs: 1
• Output Current: 350mA
• Output Voltage: 30V
• Input Voltage: 7V To 30V
• Dimming Control Type: PWM / DC
• Topology: Buck
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ZXLD1350
Document number: DS33468 Rev. 8 - 2
Application Information (Continued)
Output Current Adjustment by PWM Control
Directly driving ADJ input
A Pulse Width Modulated (PWM) signal with duty cycle D
output current to a value above or below the nominal average value set by resistor R
Driving the ADJ input via open collector transistor
The recommended method of driving the ADJ pin and controlling the amplitude of the PWM waveform is to use a small NPN
switching transistor as shown below:
This scheme uses the 200k resistor between the ADJ pin and the internal voltage reference as a pull-up resistor for the
external transistor.
Driving the ADJ input from a microcontroller
Another possibility is to drive the device from the open drain output of a microcontroller. The diagram below shows one
method of doing this:
The diode and resistor suppress possible high amplitude negative spikes on the ADJ input resulting from the drain-source
capacitance of the FET. Negative spikes at the input to the device should be avoided as they may cause errors in output
current, or erratic device operation.
PWM dimming can be further split into high frequency and low frequency PWM dimming and how the device responds to
these.
V
0V
ADJ
PWM
MCU
GND
GND
PWM
10k
ADJ
ADJ
ADJ
ZXLD1350
ZXLD1350
ZXLD1350
GND
GND
GND
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PWM
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can be applied to the ADJ pin, as shown below, to adjust the
30V 350mA LED DRIVER with AEC-Q100
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© Diodes Incorporated
ZXLD1350
March 2011