ZXLD1360 Datasheet, PDF (1/28 Pages) Zetex Semiconductors – 1A LED driver with internal switch

ZXLD1360
1A LED driver with internal switch
Description
The ZXLD1360 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 1A. Depending upon supply
voltage and external components, this can
provide up to 24 watts of output power.
The ZXLD1360 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 30V NDMOS switch
• 1A output current
• Single pin on/off and brightness control
using DC voltage or PWM
• Internal PWM filter
• Soft-start
• High efficiency (up to 95%)
• Wide input voltage range: 7V to 30V
• 40V transient capability
• Output 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
or a gated output current. The PWM filter
components are contained within the chip.
The PWM filter provides a soft-start feature by
controlling the rise of input/output current. The
soft-start time can be increased 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
Typical application circuit
LX ¹
5 V_IN
VIN (7V - 30V)
Rs
0.1⍀
GND ²
ADJ 3
4 I_SENSE
TSOT23-5
Top view
D1
C1 4.7␮F
L1 47␮H
VIN
N/C
ADJ
ISENSE
LX
ZXLD1360
GND
GND
Issue 1 - March 2007
1
© Zetex Semiconductors plc 2007
www.zetex.com