ZLED7520ZI1R ZMDI, ZLED7520ZI1R Datasheet - Page 13

• Manufacturer Part Number: ZLED7520ZI1R
• Description: LED Lighting Drivers LED driver
• Manufacturer: ZMDI

Specifications of ZLED7520ZI1R

• Rohs: yes
• Input Voltage: 6 V to 40 V
• Operating Frequency: 1 MHz
• Maximum Supply Current: 600 uA
• Output Current: 0.75 A
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Package / Case: DFN-5
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 500 mW

2
2.1
The ZLED7x20 is a continuous-mode inductive step-down converter LED driver for driving single or multiple
series-connected LEDs from a voltage input higher than the LED voltage (Vin = 6 to 40 VDC; see section 3.2.2 for
important details). The ZLED7x20 provides an adjustable output current (1.2A maximum for ZLED7020; 1.0A
maximum for ZLED7320; 0.75A maximum for ZLED7520; 0.35A maximum for ZLED7720), which is nominally set
via an external sense resistor Rs and controlled by the ZLED7x20’s integrated high-side output current-sensing
circuit and output switch. An external control signal (e.g., DC voltage, PWM waveform, or microprocessor signal)
on the ADJ pin can be used to linearly adjust the output for continuous, variable, or gated-output current. See
page 3 for a block diagram of the ZLED7x20.
The output can be turned off by applying a voltage ≤0.2V (typical) to the ADJ pin, which puts the ZLED7x20 in a
low-current standby state. See section 2.6 for a description of this shutdown mode.
Only a resistor, a diode, an inductor, and three capacitors are needed for a typical basic application. Refer to the
application circuits in section 3 for the location of the components referenced in the following sections.
2.2
External sense resistor Rs, which is connected between the V
I
which is the LX switch output current I
recommended values for Rs in a typical basic application and section 3.4 for layout guidelines for Rs. Note that
the peak I
2.3
An external DC voltage (V
below the nominal average current I
from 25% to 100% of I
R
The nominal average output current I
equation (2) where 0.3V≤ V
Brightness is 100% if V
floating (1.2V, typical). If V
maximum V
OUTnom
ADJ
Data Sheet
August 12, 2011
ZLED7520
High Current 40V LED Driver with Internal Switch
(500k ± approximately 25%; internal pull-up resistor to V
Circuit Description
, the nominal average output current. Equation (1) can be used to calculate the nominal output current,
ZLED7x20 Overview
Control of Output Current via External Sense Resistor Rs
Control of Output Current via an External DC Control Voltage on the ADJ Pin
I
I
OUTnom
OUTdc
OUTnom
ADJ
= 6V.
including ripple (see section 3.3.5) must not exceed the maximum current specifications (1.3.10).
. 0
0
083
© 2011 Zentrum Mikroelektronik Dresden AG — Rev. 1.2
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without
the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
Rs
1 .
V
R
OUTnom
ADJ
S
V
ADJ
ADJ
ADJ
= V
ADJ
. The DC voltage source must be capable of driving the ADJ pin’s input impedance
) input on the ADJ pin can control brightness by setting the output current to a value
≥1.2V, current is automatically clamped at 100% brightness. Note: Absolute
REF,
≤1.2V:
the internal reference voltage, which can be measured on the ADJ pin when it is
OUTnom
OUTdc
LX
resulting from an external DC control voltage V
determined by R
if the ADJ pin is floating (V
S
. With this method, the output current can be adjusted
REF
IN
). See Figure 3.2 for a typical application circuit.
and I
ADJ
SENSE
= V
pins as shown in Figure 3.1, sets
REF
=1.2V). See section 3.3.1 for
ADJ
can be calculated via
(1)
(2)
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