DIODES PAM2863EV1 2A LED Driver User Guide
- June 11, 2024
- DIODES
Table of Contents
DIODES PAM2863EV1 2A LED Driver User Guide
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.
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
PAM2863EV1 Specifications
| Parameter | Value |
|---|---|
| Input Voltage | 5 to 40VDC |
| LED Current | 1.5A (Adjustable) |
| Number of LEDs | 1, 2 |
| XYZ Dimension | 1.6” x 1.2” x 0.4” |
Evaluation Board
Figure 1: Top View
**Figure 2: Bottom View
**
Connection Instructions
Input Voltage: 8 to 40VDC (VIN, GND)
LED Outputs: LED+ (White), LED- (Black)
Evaluation Board Schematic
**Figure 3: Evaluation Board Schematic
** Evaluation Board Layout
Figure 4: PCB Layout Top View
Figure 5: PCB Layout Bottom View
Quick Start Guide
- 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
#| Name| Quantity| Part number| Manufacturer|
Description
---|---|---|---|---|---
1| IC1| 1| PAM2863| Diodes Inc| LED Driver MSOP-8
2| C1,C2,CO| 3| UMK325BJ106KM-T| Taiyo| 10µF Cer
Cap 50V 10% X5R 1210
3| C3| 0| Not Fitted| |
4| R1,R2,R3| 3| RL0805FR-070R15L| Yageo| 0.15Ω
Resistor 1/8W 5% 0805 SMD
5| L1| 1| 744770133| Wurth| 33µH, 3.2A Inductor SDR127
6| D1| 1| SS34-E3/57T| Vishay| 3A/40V Schottky diode SMC
7| Vset| 0| Not Fitted| |
8| PCB| 1| PAM2863 EB07AA| |
Functional Performance (1 LED, 2 LEDs @1.5A)
Vin (DC)| Pin (W)| Vout (V)| Iout (mA)| Pout (W)|
Efficiency (%)| # of LEDs
---|---|---|---|---|---|---
5| 4.663| 3.55| 1061| 3.76| 80.73| **** 1
6| 6.175| 3.61| 1267| 4.57| 74.07
8| 6.505| 3.63| 1315| 4.77| 73.38
10| 6.228| 3.63| 1325| 4.81| 77.21
12| 6.337| 3.63| 1337| 4.85| 76.59
Vin (DC)| Pin (W)| V_out (V)| I_out (mA)| P_out (W)|
Efficiency (%)| # of LEDs
8| 8.412| 6.83| 1095| 7.48| 88.87| **** 2
12| 10.934| 6.94| 1303| 9.05| 82.74
24| 11.589| 6.96| 1370| 9.54| 82.31
30| 12.132| 6.97| 1400| 9.75| 80.40
36| 12.615| 6.97| 1420| 9.89| 78.42
40| 12.310| 6.97| 1420| 9.76| 79.25
**Figure 6 Vin (DC) vs. Iout (mA)
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 | 2000 |
| 0.067 | 1500 |
| 0.1 | 1000 |
| 0.13 | 760 |
| 0.15 | 667 |
| 0.3 | 333 |
PCB Layout Guidelines
- Connect L1, LX, D1 with short and wide connections. Minimize the switching circuit area to avoid unexpected radiation.
- Make sure the LX trace not across other sensitive traces.
- 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.
- Make sure the current flow path has a wide trace. When current path need vias, use themultiple vias to decrease impedance.
- 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.
- Pay attention to the D1 and L1 thermal dissipation.
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