DataSheet.es    


PDF ZXLD1350 Data sheet ( Hoja de datos )

Número de pieza ZXLD1350
Descripción 350mA LED driver
Fabricantes Zetex Semiconductors 
Logotipo Zetex Semiconductors Logotipo



Hay una vista previa y un enlace de descarga de ZXLD1350 (archivo pdf) en la parte inferior de esta página.


Total 24 Páginas

No Preview Available ! ZXLD1350 Hoja de datos, Descripción, Manual

ZXLD1350
350mA LED driver with internal switch
www.DataSheet4U.com
Description
The ZXLD1350 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 ZXLD1350 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. 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.
The device is assembled in a TSOT23-5 pin
package.
Features
Applications
• Simple low parts count
• Low voltage halogen replacement LEDs
• Internal 30V NDMOS switch
• Automotive lighting
• 350mA output current
• Low voltage industrial lighting
• Single pin on/off and brightness control • LED back-up lighting
using DC voltage or PWM
• Internal PWM filter
• Illuminated signs
• 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
(*) 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 VIN
VIN (12V - 30V)
Rs
0.33
GND 2
ADJ 3
4 ISENSE
TSOT23-5
Top view
C1 1F
D1
ZLLS1000
L1 47H
N/C
VIN
ADJ
GND
ISENSE
ZXLD1350
GND
LX
Issue 6 - April 2007
© Zetex Semiconductors plc 2007
1
www.zetex.com

1 page




ZXLD1350 pdf
ZXLD1350
Device description
The device, in conjunction with the coil (L1) and current sense resistor (RS), forms a self-oscillating
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 pin of the device is unconnected and
the voltage on this pin (VADJ) appears directly at the (+) input of the comparator.
When input voltage VIN is first applied, the initial current in L1 and RS is zero and there is no
output from the current sense circuit. Under this condition, the (-) input to the comparator is at
ground and its output is high. This turns MN on and switches the LX pin low, causing current to
flow from VIN to ground, via RS, L1 and the LED(s). The current rises at a rate determined by VIN
and L1 to produce a voltage ramp (VSENSE) across RS. The supply referred voltage VSENSE is
forced across internal resistor R1 by the current sense circuit and produces a proportional current
in internal resistors R2 and R3. This produces a ground referred rising voltage at the (-) input of
the comparator. When this reaches the threshold voltage (VADJ), the comparator output switches
low and MN turns off. The comparator output also drives another NMOS switch, which bypasses
internal resistor R3 to provide a controlled amount of hysteresis. The hysteresis is set by R3 to be
nominally 15% of VADJ.
When MN is off, the current in L1 continues to flow via D1 and the LED(s) back to VIN. The current
decays at a rate determined by the LED and diode forward voltages to produce a falling voltage
at the input of the comparator. When this voltage returns to VADJ, the comparator output switches
high again. This cycle of events repeats, with the comparator input ramping between limits of
VADJ ± 15%.
Switching thresholds
With VADJ =VREF, the ratios of R1, R2 and R3, define an average VSENSE switching threshold of
100mV (measured on the ISENSE pin with respect to VIN). The average output current IOUTnom is
then defined by this voltage and Rs according to:
IOUTnom=100mV/RS
Nominal ripple current is ±15mV/RS
Adjusting output current
The device contains a low pass filter between the ADJ pin and the threshold comparator and an
internal current limiting resistor (200k nom) between ADJ and the internal reference voltage. This
allows the ADJ pin to be overdriven with either DC or pulse signals to change the VSENSE
switching threshold and adjust the output current. The filter is third order, comprising three
sections, each with a cut-off frequency of nominally 4kHz.
Details of the different modes of adjusting output current are given in the applications section.
Output shutdown
The output of the low pass filter drives the shutdown circuit. When the input voltage to this circuit
falls below the threshold (0.2V nom), the internal regulator and the output switch are turned off.
The voltage reference remains powered during shutdown to provide the bias current for the
shutdown circuit. Quiescent supply current during shutdown is nominally 15A and switch
leakage is below 1A.
Issue 6 - April 2007
© Zetex Semiconductors plc 2007
5
www.zetex.com

5 Page





ZXLD1350 arduino
ZXLD1350
Typical operating conditions (continued)
Vref vs Vin over nominal supply voltage range
1.2425
1.242
1.2415
5
10 15 20 25
Vin (V)
500
400
300
200
100
0
0
Supply Current vs Vin (Operating)
5 10 15 20 25
Vin (V)
30
30
Output Current vs VADJ
350
300
250
200 Rs=0.3 Ohm
Rs=0.56 Ohm
150 Rs=1 Ohm
100
50
0
0 0.5 1 1.5 2 2.5 3
VADJ (V)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
Vref vs Vin at low supply voltage
12 3 4 56 7 8
Vin (V)
9 10
20
15
10
5
0
0
Supply Current vs Vin (Quiescent)
5 10 15 20 25 30
Vin (V)
Issue 6 - April 2007
© Zetex Semiconductors plc 2007
11
www.zetex.com

11 Page







PáginasTotal 24 Páginas
PDF Descargar[ Datasheet ZXLD1350.PDF ]




Hoja de datos destacado

Número de piezaDescripciónFabricantes
ZXLD1350350mA LED driverZetex Semiconductors
Zetex Semiconductors
ZXLD135030V 350mA LED DRIVERDiodes
Diodes
ZXLD1350QAUTOMOTIVE GRADE 350mA BUCK LED DRIVERDiodes
Diodes
ZXLD1352350mA LED driverZetex Semiconductors
Zetex Semiconductors

Número de piezaDescripciónFabricantes
SLA6805M

High Voltage 3 phase Motor Driver IC.

Sanken
Sanken
SDC1742

12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.

Analog Devices
Analog Devices


DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.


DataSheet.es    |   2020   |  Privacy Policy  |  Contacto  |  Buscar