ABCelectronique : portail d'information dans le domaine de l'électronique
 
 
Numéro de sérieZXLD1352
CategoriePower Management => Lighting Controllers
Description7V-30V Input, 350mA LED Driver With Internal Switch
The ZXLD1352 is a continuous mode 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 input supply between 7V and 30V and provides an externally adjustable output current of up to 350mA. Depending upon supply voltage and external components, it can provide up to 8 watts of output power
SociétéZetex Inc.
DatasheetTélécharger ZXLD1352 datasheet
 
 
  • Description courte

  • 350mA LED driver with internal switch and enhanced PWM dimming range
    Description

    The is a continuous mode 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 input supply between 7V and 30V and provides an externally adjustable output current to 350mA. Depending upon supply voltage and external components, this can provide to 8 watts of output power. The ZXLD1352 includes the output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current. Output current can be adjusted above, or below the set value, by applying an external control signal to the 'ADJ' pin. The ADJ pin will accept either a DC voltage or a PWM waveform. DC voltages between 0.3V and 2.5V allow adjustment of output current from 200% of nominal. 1000:1 adjustment of output current is possible using PWM control. Applying a voltage 0.2V or lower to the ADJ pin turns the output off and switches the device into a low current standby state. The device is assembled a TSOT23-5 pin package.

    Features

    · Simple low parts count Internal 30V NDMOS switch 350mA output current Single pin on/off and brightness control using DC voltage or PWM 1000:1 PWM dimming range Soft-start High efficiency (up to 95%(*)) Wide input voltage range: 30V 40V transient capability Output shutdown to 1MHz switching frequency Inherent open-circuit LED protection Typical 4% output current accuracy

    Applications

    · Low voltage halogen replacement LEDs Automotive lighting Low voltage industrial lighting LED back-up lighting Illuminated signs

    Using standard external components as specified under electrical characteristics. Efficiency is dependent upon the number of LEDs driven and on external component types and values.

    Absolute maximum ratings (voltages to GND unless otherwise stated)

    Input voltage (VIN) ISENSE voltage (VSENSE) LX output voltage (VLX) Adjust pin input voltage (VADJ) Switch output current (ILX) Power dissipation (Ptot) (Refer to package thermal de-rating curve on page 18) Operating temperature (TOP) Storage temperature (TST) Junction temperature (Tj MAX) +30V (40V for 0.5 sec) to -5V (measured with respect to VIN) +30V (40V for 0.5 sec) to 150°C

    These are stress ratings only. Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce device reliability.

    Electrical characteristics (test conditions: VIN=12V, Tamb=25°C unless otherwise stated)

    Input voltage Internal regulator start-up threshold VIN rising Quiescent supply current with output off Quiescent supply current with output switching Mean current sense threshold voltage (defines LED current setting accuracy) ADJ pin grounded 20 ADJ pin floating f=250kHz Measured on ISENSE pin with respect to VIN VADJ µA mV

    VSENSEHYS Sense threshold hysteresis ISENSE VREF /T VADJ VADJoff ISENSE pin input current Internal reference voltage Temperature coefficient of VREF External control voltage range on ADJ pin for dc brightness control DC voltage on ADJ pin to switch device from active (on) state to quiescent (off) state DC voltage on ADJ pin to switch device from quiescent (off) state to active (on) state Resistance between ADJ pin and VREF Continuous LX switch current LX Switch `On' resistance LX switch leakage current VADJ falling 0.3 0.15 VSENSE =VIN -0.1 Measured on ADJ pin with pin floating 1.21

    Electrical characteristics (test conditions: VIN=12V, Tamb=25°C unless otherwise stated) (continued)

    Duty cycle range of PWM signal applied to ADJ pin during PWM dimming mode Brightness control range
    1000:1 ADJ pin floating @ VLED=3.4V Driving 1 LED LX switch `ON' LX switch `OFF' ns
    Operating frequency (See graphs for more detail)

    Minimum switch `ON' time Minimum switch `OFF' time Recommended maximum operating frequency Recommended duty cycle range of output switch at fLXmax Internal comparator propagation delay

    NOTES: Production testing of the device is performed at 25°C. Functional operation of the device and parameters specified over to +105°C temperature range, are guaranteed by design, characterization and process control. 100% brightness corresponds to VADJ = VADJ(nom) = VREF. Driving the ADJ pin above VREF will increase the VSENSE threshold and output current proportionally.

    Drain of NDMOS switch Ground (0V) Multi-function On/Off and brightness control pin:· Leave floating for normal operation.(VADJ= VREF =1.25V giving nominal average output current IOUTnom=0.1/RS)· Drive to voltage below 0.2V to turn off output current· Drive with DC voltage (0.3V Device ZXLD1352ET5TA Reel size (mm) 180 Reel width (mm) 8 Quantity per reel 3,000 Device mark 1352