7021/7023 BuckPlus
Wide Range LED Power Module
DATA SHEET Page 1 of 8
TM
Product Overview
The 7021 and 7023 BuckPlus LED Power Modules are a line of true
current regulated drivers for powering LEDs. The BuckPlus line of
LED drivers are the ideal choice for powering all types of high-
brightness and high-power LED Packages and LED arrays.
The line of BuckPlus LED drivers exhibit high efficiency and require
no external current limiting resistors or additional heat sinking for
operation. A fast response current-sensing circuit makes the 7021
and 7023 ideal for applications where flashing or strobe operation of
the LED(s) is required.
A wide range of options are available including external dc analog
voltage intensity control, TTL/CMOS logic level on/off control (”E”
Version), and set-and-forget internal current limiting (”I” Version).
The standard units are fully potted in an extremely small form factor*
and are provided with a simple 7 pin SIP connection for through-hole
PCB mounting (7021) or 6” 24AWG Colored Leads (7023).
The 7021 and 7023’s built-in regulated 5V reference (E and I versions)
can provide output to power logical circuitry or microprocessor,
eliminating the need for an additional power supply on the circuit board.
Features
DC input voltage up to 32V
350mA, 500mA, 700mA, or 1.0A constant current output*
Extremely small form factor* (0.83”x0.83”x0.43”)
The 7021 has a simple 7-pin SIP connection for through-hole
PCB mounting or use with an optional wiring harness (7021Hx)
The 7023 has permanently attached wires
External analog/digital intensity control (TTL compatible)
Optional external potentiometer intensity control (0-100%)
Optional on-board trim adjustment (40-110%)
Output short circuit protection up to 15 seconds
Output open circuit protection
Pulse and strobe capable (control input)
Built-in 5V reference/output to power logic circuitry or μProcessor
Typical Applications
Solar & Landscape Lighting
Architectural Lighting
Track Lighting
Automotive & Marine Lighting
Portable Lighting & Flashlights
Point of Purchase Lighting
Desk & Reading Lamps
Signal & marker Lighting
Flashing & Strobe Lighting
Cabinet & Display Case Lighting
Sign & Channel Letters
Much More...
Pb
7-Pin SIP through-hole
PCB mounting
Optional on-board trim
adjustment (40-110%)
* - Custom units can be designed for OEM applications. Contact LUXdrive for more information.
7021
BuckPlus
with optional
wiring harness
(7021HEP)
RoHS
C o m p lia n t
2002/95/EC
LEDdynamics, Inc.
802.728.4533 P
802.728.3800 F
sales@LUXdrive.com
www.LUXdrive.com
©2010 LUXdrive, A Division of LEDdynamics, Inc. www.LUXdrive.com.
Specifications subject to change without notice. April, 2010 - Rev 2.2
Made
in
the
USA
7021/7023 BuckPlus
Wide Range LED Power Module
DATA SHEET Page 2 of 8
TM
Part Number Identification Table
Table 1
Product Selection
Part Number
7021-D-N-xxxx
7021-D-E-xxxx
7021-D-I-xxxx
7023-D-N-xxxx
7023-D-E-xxxx
DC Input
5-32V
7-32V
7-32V
5-32V
7-32V
On-Board
Trim
Control/
Dimming
Connection
Type
no
no
yes
no
no
no
yes
yes
no
yes
7-Pin SIP (4 Pins)
7-Pin SIP (6 Pins)
7-Pin SIP (6 Pins)
4 Wires
6 Wires
XXXX - Output current rating in milliamperes (mA): 350, 500, 700, 1000 or special order factory custom rating
Absolute Maximum Ratings
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32V
DC
Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32V
DC
Control Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 10V
Reference regulator current (5V
DC
) Output . . . . . . . . 20mA
7021
7023
LED +
LED -
Ctrl
Ref
Vin+
Vin -
Typical Characteristics
Output tolerance (
within specified temp. range
) . . . . . . . . . ±10%
Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95%
Input Voltage Minimum . . . . . . . . . . . . 5V
DC
(N), 7V
DC
(E or I)
Input Margin (
350mA unit
1
, add to LED Vf MAX
). . . . . . . . . . . . 2.5V
DC
Figure 1.
Bottom view Pinout of the
7021/7023 BuckPlus
Figure 2.
Efficiency vs. Vin
1 - Margin increases with higher current units.
Figure 3.
Output current vs. control voltage
©2010 LUXdrive, A Division of LEDdynamics, Inc. www.LUXdrive.com.
Specifications subject to change without notice. April, 2010 - Rev 2.2
LEDdynamics, Inc.
802.728.4533 P
802.728.3800 F
sales@LUXdrive.com
www.LUXdrive.com
Made
in
the
USA
7021/7023 BuckPlus
Wide Range LED Power Module
DATA SHEET Page 3 of 8
TM
Specifications
Output current, 7021-x-x-350, 7023-x-x-350 . .
Output current, 7021-x-x-500, 7023-x-x-500 . .
Output current, 7021-x-x-700, 7023-x-x-700 . .
Output current, 7021-x-x-1000, 7023-x-x-1000
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350mA
1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500mA
1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700mA
1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000mA
1
Control Pin, adjustment threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.65 V ±5%
Control Pin, shutoff threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 V ±5%
Control Pin, propagation delay to output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <15 μs
Control Pin, input impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5k ohm
Reference voltage (V
in
= 7V or greater) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V
DC
±5%
2
Optional trim pot adjustment range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40%-110%
External pot adjustment range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0%,1-100%
2
Maximum flash frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 kHz
Minimum strobe pulse width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 μs
Output rise time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10 μs
3
Output fall time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <350 μs
3
Quiescent current (no load or control pin high) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <4.5 mA
3
Operating temperature (Tcase). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40-+80°C
Storage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40-+125°C
Application Information
Description
The 7021/7023 Wide Range LED Power Module is a high efficiency dc to dc converter which delivers a fixed output
current by varying the output voltage as required to maintain the specified current . A fast response current-sensing
circuit permits the unit to be used in applications where flashing or pulsing of the LEDs is required. Several options
are available allowing for use with many types of LEDs and in a variety of operating modes
Fixed Current Drive
The fixed output versions of the 7021/7023 are designed to supply their rated current to one or more LED junctions.
For example, a 350 mA rated unit will drive up to six white 350mA LEDs connected in series at 24VDC. Due to the
nature of the buck regulator, the input voltage must always be higher than the total forward voltage drop of the
LEDjunction(s) connected in series (2.5V. Thus, for a series string of six junctions having an average forward drop of
3.5V each, the required minimum input voltage will be 21V
DC
. A standard 24V
DC
power supply is a good choice for this
application.
Figures 4 through 6 show 700mA and 1000mA rated units driving multiple LEDs. Note that parallel strings of LEDs
can be driven directly with no additional circuitry required to insure current sharing. The nature of the LEDs
themselves will provide sufficient current sharing if the parallel strings comprise 3 or more junctions each.
1 - Measured with single emitter; output current drops slightly with additional series junctions to limit maximum power dissipation.
2 - When Vin > 7VDC
3 - Actual value varies greatly based on input and/or output voltages. Value shown is for V
in
= 24V
DC
V
OUTt
=20V
DC
LED load. Actual values will be smaller in most applications.
©2010 LUXdrive, A Division of LEDdynamics, Inc. www.LUXdrive.com.
Specifications subject to change without notice. April, 2010 - Rev 2.2
LEDdynamics, Inc.
802.728.4533 P
802.728.3800 F
sales@LUXdrive.com
www.LUXdrive.com
Made
in
the
USA
7021/7023 BuckPlus
Wide Range LED Power Module
DATA SHEET Page 4 of 8
Adjustable Current - On-Board Control - “I” Model
TM
Where the ability to adjust the output current to an intermediate value is required, all output current ratings are
available with an on-board potentiometer. This permits the output current to be varied from approximately 40%
to 110% of the rated value. When measuring the output is required to determine a particular set point, the
following method is recommended:
Temporarily place a 0.1 ohm, 1% resistor in series with the LEDs.
Read the voltage across the 0.1 ohm resistor.
The voltage, in millivolts X 10, will equal the output current in mA.
Because there is a small, high-frequency component in the 7021/7023 output, many multi-meters may give an
incorrect reading when used in the current mode. It has been found that the method described above yields a far
more accurate measurement.
The potentiometers used for the on-board adjustable units are rated for a limited number of rotations (typically
100) and are intended for "set it and forget it" applications. Where frequent adjustments of output current are
needed, the use of units with external adjustment capabilities is recommended.
Adjustable Current - External Control - “E” Model
Figures 10 and 11 show external adjustment configurations. Both use a 5Kohm, linear taper potentiometer. In
Figure 10, the potentiometer is connected between the internal 5V
DC
reference (Ref) output and the control (Ctrl)
input. When using this configuration, it is important that Vin be 7V
DC
or higher. Figure 11 shows the control
potentiometer being powered by an external 5V
DC
source. When using an external power source for the
potentiometer, the source ground must be common to the LED- output pin. In either configuration, connect the
potentiometer such that clockwise rotation increases the resistance. Note that, because the current through the
potentiometer is less than 5mA, a low power potentiometer may be used.
External On/Off Control
Where a manual on/off control is desired, the potentiometer in Figures 10 and 11 may be replaced by a pushbutton
or toggle switch. The output current will be zero when the switch is closed. Figures 12 and 13 show external
dimming control combined with on/off control. The circuit in Figure 13 uses a 2N3906 or equivalent PNP
switching transistor.
External Pulse/Strobe Control
Figures 14 and 15 show two methods for low speed pulsing or high speed flashing operation. In Figure 14, a
5V TTL/CMOS logic signal is applied directly to the control (Ctrl) input of the 7021/7023. The output current will be
zero when the control signal is high. Note that the input needs to source a minimum of 4.75V
DC
into a 1.5Kohm
input impedance. Also, as is the case with a dc control signal, the logic input ground should to be common to the
LED- output terminal.
Figure 15 shows an inverted input configuration using a 2N3906 or other PNP switching transistor. In this case, a
logic high will cause the output to be "on". In either configuration, the rise time of the output will be 10μsec or
less. A pulse frequency up to 10kHz may be used.
©2010 LUXdrive, A Division of LEDdynamics, Inc. www.LUXdrive.com.
Specifications subject to change without notice. April, 2010 - Rev 2.2
LEDdynamics, Inc.
802.728.4533 P
802.728.3800 F
sales@LUXdrive.com
www.LUXdrive.com
Made
in
the
USA
7021/7023 BuckPlus
Wide Range LED Power Module
DATA SHEET Page 5 of 8
Microprocessor Control
TM
Figure 16 shows a typical interface for a Microchip PIC® or similar μcontroller. The reference output provides the
operating voltage for the processor (5V at up to 20mA current).
Other Control Applications
In addition to the configurations described above, the 7021/7023 may also be driven by a D to A converter. As in
the cases above, the analog control signal should have its ground common to LED-. Figure 2 shows the effective
controlrange of the analog input signal.
Connections
In all cases, the LEDs being driven should be located as close to the 7021/7023 LED output as possible. When the
use of long leads is required, use heavier gauge wire. For strobe or pulse applications, a wire length not
exceeding 6" should be used to maintain accurate timing.
The power input wires/traces should also be kept short. Where DC input units are located more than 18" from the
source, a 220μF, 50V capacitor should be placed across the input terminals as shown in Figure 18.
For applications where the use of header pins is inconvenient, a mating connector with 6" leads is available as an
accessory, or the 7023 part number may be used, which is supplied with 6” colored leads.
7021HN
- Harness for “N” type (4-wire)
7021HE
- Harness for “E” & “I” type (6-wire)
7021HEP
- Harness for “E” & “I” w/pot (6-wire w/pot)
Application Figures
LED+
7021/7023
Vin
LED-
LED+
7021/7023
Vin
LED-
Figure 4.
700 MA unit driving 6 High Power LEDs
(VIN > 12VDC)
Figure 5.
700mA unit driving 12 High Power LEDs
(VIN > 24VDC)
©2010 LUXdrive, A Division of LEDdynamics, Inc. www.LUXdrive.com.
Specifications subject to change without notice. April, 2010 - Rev 2.2
LEDdynamics, Inc.
802.728.4533 P
802.728.3800 F
sales@LUXdrive.com
www.LUXdrive.com
Made
in
the
USA