ZLED7730ZI1R ZMDI, ZLED7730ZI1R Datasheet - Page 13

• Manufacturer Part Number: ZLED7730ZI1R
• Description: LED Lighting Drivers LED driver
• Manufacturer: ZMDI

Specifications of ZLED7730ZI1R

• Rohs: yes
• Input Voltage: 8.5 V to 40 V
• Operating Frequency: 1 MHz
• Maximum Supply Current: 600 uA
• Output Current: 0.35 A
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Package / Case: SOP-8
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 500 mW

2
2.1
The ZLED7x30 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 = 8.5 to 40VDC; see section 3.2.2
for important details). The ZLED7x30 provides an adjustable output current (1.2A maximum for ZLED7030; 1.0A
maximum for ZLED7330; 0.75A maximum for ZLED7530; 0.35A maximum for ZLED7730) , which is nominally set
via an external sense resistor Rs and controlled by the ZLED7x30’s integrated high-side output current-sensing
circuit and output switch. The ZLED7x30 detects external switching action on the supply line to adjust the output
current in different modes on different levels.
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 referred to 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
mended values for Rs in a typical basic application and section 3.4 for layout guidelines for Rs.
2.3
The ZLED7x30 detects external switching action on the supply line to adjust output current, allowing dimming
functionality to be achieved without changing the original lighting system circuitry. The switch dimming is imple-
mented in either two-level mode or three-level mode. The output current of each level and the total number of
levels are customer selected by setting the corresponding input conditions on the DIM1 and DIM2 pins. See
page 2 for a typical application using the DIM1 and DIM2 pins.
The output current is set at the initial 100% value determined by the sense resistor Rs the first time that power is
supplied to the chip. After the initial power up sequence, the chip adjusts the output current according to the
external switch action. After the lowest current level, the current cycles back to the initial value if subsequent
switch action is detected. If the power is switched off for longer than 2 seconds, the device will return to its initial
state and the output current will be set to the initial value the next time that power is applied.
There are two types of switch action: a normal switch, which has an off-time between each subsequent switch
action longer than 2s, and a dimming switch, which has an off-time between each subsequent switch less than 2s.
The dimmed average output current is given by
Where
OUTnom
Data Sheet
August 16, 2011
ZLED7730
High Current 40V LED Driver with Switch Dimming
Circuit Description
, the nominal average output current. Equation (1) can be used to calculate the nominal output current,
ZLED7x30 Overview
Control of Output Current via External Sense Resistor Rs
Multi-Mode Switch Dimming
I
I
OUTnom
OUT
dim
. 0
© 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.
K
Rs
V 1
X
. 0
Rs
V 1
LX
if no switch dimming condition is valid. See section 3.3.1 for recom-
IN
and I
SENSE
pins as shown in Figure 3.1, sets
(1)
(2)
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