PAM2863 User Guide

PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
General Description
The PAM2863 is a continuous mode
inductive step-down converter, designed
for driving single or multiple series
connected °Cs efficiently from a voltage
source higher than the °C voltage. The
device operates from an input supply
between 4.5V and 40V and provides an
externally adjustable output current output
current of up to 2A.
A bill of material, schematics, and layout
are included that describes the parts used
on this demonstration board along with
measured performance characteristics.
These materials can be used as a reference
design.
PAM2863EV1 Specifications
Parameter
Value
Input Voltage
LED Current
Number of LEDs
XYZ Dimension
5 to 40VDC
1.5A (Adjustable)
1, 2
1.6” x 1.2” x 0.4”
Evaluation Board
GND
LED-
Vin
LED+
Key Features









Low Components Count
Internal 40V NDMOS Switch
2A Output Current
Analog and PWM Dimming
Efficiency up to 97%
Soft Start
Up to 1MHz Switching Frequency
Open/Short Protection
Thermal Shutdown
Applications


High End LED Flashlight
LED Light Bar
Figure 1: Top View
Vin
LED+
GND
LEDFigure 2: Bottom View
Connection Instructions
Input Voltage: 8 to 40VDC (VIN, GND)
LED Outputs: LED+ (White), LED- (Black)
PAM2863EV1 Rev1
March 2015
www.diodes.com
Page 1 of 6
PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
Evaluation Board Schematic
Figure 3: Evaluation Board Schematic
Evaluation Board Layout
Figure 4: PCB Layout Top View
PAM2863EV1 Rev1
March 2015
www.diodes.com
Figure 5: PCB Layout Bottom View
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PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
Quick Start Guide
1.
2.
3.
4.
5.
6.
By default, the evaluation board is preset at 2A LED Current by R1, R2, R3 (0.15 Ohm).
Ensure that the DC source is switched OFF or disconnected.
Connect the 5 to 40VDC DC line wires of power supply to Vin and GND on the board.
Connect the anode wire of external LED string to LED+ output test point.
Connect the cathode wire of external LED string to LED- output test point.
Turn on the main switch. LED string should light up.
Bill of Material
#
1
2
3
4
5
6
7
8
Name
IC1
C1,C2,
CO
C3
R1,R2,
R3
L1
D1
Vset
PCB
Quantity
1
Part number
PAM2863
Manufacturer
Diodes Inc
Description
LED Driver MSOP-8
3
0
UMK325BJ106KM-T
Not Fitted
Taiyo
10µF Cer Cap 50V 10% X5R 1210
3
1
1
0
1
RL0805FR-070R15L
744770133
SS34-E3/57T
Not Fitted
PAM2863 EB07AA
Yageo
Wurth
Vishay
0.15Ω Resistor 1/8W 5% 0805 SMD
33µH, 3.2A Inductor SDR127
3A/40V Schottky diode SMC
Functional Performance (1 LED, 2 LEDs @1.5A)
Vin (DC)
5
6
8
10
12
Vin (DC)
8
12
24
30
36
40
Pin (W)
4.663
6.175
6.505
6.228
6.337
Pin (W)
8.412
10.934
11.589
12.132
12.615
12.310
PAM2863EV1 Rev1
March 2015
www.diodes.com
V_out (V)
3.55
3.61
3.63
3.63
3.63
V_out (V)
6.83
6.94
6.96
6.97
6.97
6.97
I_out (mA)
1061
1267
1315
1325
1337
I_out (mA)
1095
1303
1370
1400
1420
1420
P_out (W)
3.76
4.57
4.77
4.81
4.85
P_out (W)
7.48
9.05
9.54
9.75
9.89
9.76
Efficiency (%)
80.73
74.07
73.38
77.21
76.59
Efficiency (%)
88.87
82.74
82.31
80.40
78.42
79.25
# of LEDs
1
# of LEDs
2
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PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
I_out(mA) vs Input Voltage
Vin=5-40VDC; OUT=1/2 LEDs
Efficiency(%) vs Input Voltage
1 LED
Vin=5-40VDC; OUT=1/2 LEDs
2 LEDs
1 LED
1500
90
1400
87
Efficiency (%)
I_out(mA)
2 LEDs
1300
1200
1100
84
81
78
75
1000
72
4
10
16
22
28
34
40
Input Voltage (VDC)
Figure 6 Vin (DC) vs. Iout (mA)
4
10
16
22
28
34
Input Voltage (VDC)
Figure 7 Vin (DC) vs. Efficiency (%)
Application Information
Setting the Output Current:
The internal feedback (FB) voltage is 0.1V (Typical). The output current is calculated as below:
ILED = 0.1/RS where RS = R1//R2//R3
The output Current is given by the following table.
RS (Ω)
ILED (mA)
0.05
0.067
0.1
0.13
0.15
0.3
2000
1500
1000
760
667
333
.
PAM2863EV1 Rev1
March 2015
www.diodes.com
Page 4 of 6
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PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
PCB Layout Guidelines
(1) Connect L1, LX, D1 with short and wide connections. Minimize the switching circuit area to
avoid unexpected radiation.
(2) Make sure the LX trace not across other sensitive traces.
(3) Place the Iset resistor R1, R2, R3 as close to the sense pin as possible. This resistor will
flow through large current, pay attention to the thermal dissipation.
(4) Make sure the current flow path has a wide trace. When current path need vias, use the
multiple vias to decrease impedance.
(5) PAM2863 integrates the power MOSFET and has a thermal pad. Make sure the thermal
pad is soldering to PCB and heat dissipation area is large enough.
(6) Pay attention to the D1 and L1 thermal dissipation.
PAM2863EV1 Rev1
March 2015
www.diodes.com
Page 5 of 6
PAM2863EV1 User Guide
2A LED DRIVER with INTERNAL SWITCH
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www.diodes.com
PAM2863EV1 Rev1
March 2015
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