ZXLD1350_07 ZETEX [Zetex Semiconductors], ZXLD1350_07 Datasheet
ZXLD1350_07
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ZXLD1350_07 Summary of contents
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ZXLD1350 350mA LED driver with internal switch Description The ZXLD1350 is a continuous inductive step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device operates from an ...
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Absolute maximum ratings (voltages to GND unless otherwise stated) Input voltage ( voltage (V ) SENSE SENSE LX output voltage ( Adjust pin input voltage (V ADJ Switch output current ( Power dissipation ...
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Electrical characteristics Symbol Parameter D Duty cycle range of PWM signal PWM(LF) applied to ADJ pin during low frequency PWM dimming mode Brightness control range D Duty cycle range of PWM signal PWM(HF) applied to ADJ pin during high frequency ...
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Block diagram V IN Voltage regulator C1 ADJ Vref GND Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Shutdown circuit R2 4KHz 200k 1.25V R3 4 ZXLD1350 SENSE ...
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Device description The device, in conjunction with the coil (L1) and current sense resistor (R continuous-mode buck converter. Device operation (Refer to block diagram and Figure 1 - Operating waveforms) Operation can be best understood by assuming that the ADJ ...
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voltage SENSE voltage Coil current 0V Comparator V input voltage ADJ 5V Comparator output 0V Issue 6 - April 2007 © Zetex Semiconductors plc 2007 Toff Ton 115mV 85mV 0.15V ADJ Figure 1 Operating ...
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Typical operating waveforms [V Normal operation. Output current (Ch3) and LX voltage (Ch1) Start-up waveforms. Output current (Ch3), LX voltage (Ch1) and VADJ (Ch2) Issue 6 - April 2007 © Zetex Semiconductors plc 2007 =12V, R =0.3 , L=100µH] IN ...
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Typical operating conditions For typical application circuit driving 1W Luxeon otherwise stated ...
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Typical operating conditions (continued ...
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Typical operating conditions (continued ...
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Application notes Setting nominal average output current with external resistor R The nominal average output current in the LED(s) is determined by the value of the external current sense resistor (R ) connected between 0.1/R [for ...
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Output current adjustment by PWM control Directly driving ADJ input A Pulse Width Modulated (PWM) signal with duty cycle D shown below, to adjust the output current to a value above or below the nominal average value set by resistor ...
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Shutdown mode Taking the ADJ pin to a voltage below 0.2V for more than approximately 100µs, will turn off the output and supply current will fall to a low standby level of 15µA nominal. Note that the ADJ pin is ...
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Inductor selection Recommended inductor values for the ZXLD1350 are in the range 220 H. Higher values of inductance are recommended at higher supply voltages in order to minimize errors due to switching delays, which result in increased ...
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Example: For V =12V, L=47 H, rL=0. (47e-6 x 0.105)/(12 - 3.4 - 0.672) = 0.622 (47e-6 x 0.105)/(3.4 + 0.36 + 0.322)= 1.21 s OFF This gives an operating frequency ...
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Reducing output ripple Peak to peak ripple current in the LED can be reduced, if required, by shunting a capacitor C across the LED(s) as shown below LED SENSE ZXLD1350 A value ...
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Note that the device power dissipation will most often be a maximum at minimum supply voltage. It will also increase if the efficiency of the circuit is low. This may result from the use of unsuitable coils, or excessive parasitic ...
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Evaluation PCB The picture below shows the top copper layout of the 3 LED ZXLD1350EV2 evaluation board. This board and other evaluation boards for the ZXLD1350 are available upon request. ZXLD1350EV2 k EVALUATION BOARD D1 a JP1 JP2 +VIN SD1 ...
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Dimming output current using PWM Low frequency PWM mode When the ADJ pin is driven with a low frequency PWM signal (eg 100Hz), with a high level voltage V and a low level of zero, the output of the internal ...
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High frequency PWM mode At PWM frequencies above 10kHz and for duty cycles above 0.16, the output of the internal low pass filter will contain a DC component that is always above the shutdown threshold. This will maintain continuous device ...
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Package outline - TSOT23-5 DIM Min 0.01 A2 0.84 b 0. 0.30 L2 a° 4° Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Issue 6 - ...
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Definitions Product change Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. Customers are solely responsible for obtaining the latest relevant information before placing orders. Applications disclaimer The ...