ZXLD1352 Datasheet, PDF (1/22 Pages) Zetex Semiconductors – 350mA LED driver with internal switch and enhanced PWM dimming range

A Product Line of
Diodes Incorporated
ZXLD1352
350mA LED driver with internal switch and enhanced PWM dimming
range
Description
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, this
can provide up 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.
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
25% to 200% of nominal. 1000:1 adjustment of
output current is possible using PWM control.
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.
The device is assembled in a TSOT23-5 pin
package.
Output current can be adjusted above, or
below the set value, by applying an external
control signal to the 'ADJ' pin.
Features
Applications
• 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: 7V to 30V
• 40V transient capability
• Low voltage halogen replacement LEDs
• Automotive lighting
• Low voltage industrial lighting
• LED back-up lighting
• Illuminated signs
• Output shutdown
• Up to 1MHz switching frequency
• Inherent open-circuit LED protection
• Typical 4% output current accuracy
(*) 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.
Pin connections
Typical application circuit
LX ¹
5 V_IN
VIN
(12V - 30V)
D1
ZLLS1000
Rs
0.33
GND ²
ADJ 3
4 I_SENSE
TSOT23-5
Top view
C1 1␮F
PWM
VIN
ADJ
GND
L1 47␮H
ISENSE
LX
ZXLD1352
GND
Issue 1 - August 2008
1
© Diodes Incorporated 2008
www.zetex.com
www.diodes.com