ZXLD1362 Datasheet, PDF (1/32 Pages) Zetex Semiconductors – 1A LED driver with internal switch

ZXLD1362
1A LED driver with internal switch
Description
The ZXLD1362 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 6V and 60V and
provides an externally adjustable output
current of up to 1A. Depending upon supply
voltage and external components, this can
provide up to 48 watts of output power.
The ZXLD1362 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.
Features
• Simple low parts count
• Internal 60V NDMOS switch
• Up to 1A output current
• Single pin on/off and brightness control
using DC voltage or PWM
• PWM resolution up to 3000:1
• Soft start capability
• High efficiency (up to 95%)
• Wide input voltage range: 6V to 60V
• 65V transient capability
• Low power shutdown
• Up to 1MHz switching frequency
• Inherent open-circuit LED protection
• Typical 4% output current accuracy
Pin connections
The ADJ pin will accept either a DC voltage or a
PWM waveform. Depending upon the control
frequency, this will provide either a continuous
(dimmed) or a gated output current. Soft-start
can be forced using an external capacitor from
the ADJ pin to ground.
Applying a voltage of 0.2V or lower to the ADJ
pin turns the output off and switches the device
into a low current standby state.
Applications
• Low voltage halogen replacement LEDs
• Automotive lighting
• Low voltage industrial lighting
• LED back-up lighting
• Illuminated signs
• Emergency lighting
• SELV lighting
• LCD TV backlighting
Typical application circuit
LX ¹
5 V_IN
VIN (24V)
Rs
0.1⍀
GND ²
ADJ 3
4 I_SENSE
TSOT23-5
Top view
D1
C1 4.7␮F
L1 68␮H
VIN
100nF
ADJ
GND
ISENSE
LX
ZXLD1362
GND
Provisional version B - July 2007
1
© Zetex Semiconductors plc 2007
www.zetex.com