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ManualsBrandsON SEMICONDUCTOR ManualsDev KitsPCB design board

January, 2011 − Rev. 3

1 Publication Order Number:

NCL30100/D

NCL30100

Fixed Off Time Switched

Mode LED Driver Controller

The NCL30100 is a compact switching regulator controller intended

for space constrained constant current high−brightness LED driver

applications where efficiency and small size are important. The

controller is based on a peak current, quasi fixed−off time control

architecture optimized for continuous conduction mode step−down

(buck) operation. This allows the output filter capacitor to be

eliminated. In this configuration, a reverse buck topology is used to

control a cost effective N−type MOSFET. Moreover, this controller

employs negative current sensing thus minimizing power dissipation

in the current sense resistor. The off time is user adjustable through the

selection of a small external capacitor, thus allowing the design to be

optimized for a given switching frequency range. The control loop is

designed to operate up to 700 kHz allowing the designer the flexibility

to use a very small inductor for space constrained applications.

The device has been optimized to provide a flexible inductive

step−down converter to drive one or more high power LED(s). The

controller can also be used to implement non−isolated buck−boost

driver topologies.

Features

• Quasi−Fixed OFF Time, Peak Current Control Method

• N−FET Based Controller Architecture

• Up to 700 kHz Switching Frequency

• Up to >95% Efficiency

• No Output Capacitor Needed

• V

Operation from 6.35 − 18 V

• Adjustable Current Limit with Negative Sensing

• Inherent Open LED Protected

• Very Low Current Consumption at Startup

• Undervoltage Lockout

• Compact Thin TSOP−6 Pb−Free Package

• −40 to + 125°C Operating Temperature Range

• This is a Pb−Free Device

Typical Applications

• Low Voltage Halogen LED Replacement (MR 16)

• LED Track Lighting

• Landscape Lighting

• Solar LED Applications

• Transportation Lighting

• 12 V LED Bulb Replacement

• Outdoor Area Lighting

• LED Light Bars

PIN CONNECTIONS

MARKING

DIAGRAM

TSOP−6

(SOT23−6, SC59−6)

SN SUFFIX

CASE 318G

IVC

2GND

Gate

(Top View)

ORDERING INFORMATION

Device Package Shipping

†

TSOP−6

(Pb−Free)

†For information on tape and reel specifications,

including part orientation and tape sizes, please

refer to our Tape and Reel Packaging Specifications

Brochure, BRD8011/D.

http://onsemi.com

NCL30100SNT1G 3000 / Tape & Reel

AAA = Specific Device Code

A =Assembly Location

Y = Year

W = Work Week

G = Pb−Free Package

AAAAYWG

(Note: Microdot may be in either location)

Summary of content (27 pages)

PAGE 1
NCL30100 Fixed Off Time Switched Mode LED Driver Controller The NCL30100 is a compact switching regulator controller intended for space constrained constant current high−brightness LED driver applications where efficiency and small size are important. The controller is based on a peak current, quasi fixed−off time control architecture optimized for continuous conduction mode step−down (buck) operation. This allows the output filter capacitor to be eliminated.
PAGE 2
NCL30100 6.5 – 24 V + C1 R1 LED2 R2 LED1 IC1 NCL30100 R3 CS − D1 LEDX DRV L1 GND VCC CT IVC C2 D2 C3 Q1 R4 Figure 1. Typical Application Example of the LED Converter PIN FUNCTION DESCRIPTION Pin N5 Pin Name Function Pin Description 1 CS Current sense input 2 GND Ground 3 CT Timing capacitor 4 IVC Input voltage compensation 5 VCC Input supply Supply input for the controller.
PAGE 3
NCL30100 IVC Input Voltage Regulator VOffset VDD Reference Regulator Iref Undervoltage Lockout VCC 6.35/5.85 V OFF Time Comparator 0−3.9 V CT 50 mA CS Gate Driver Set 12.5−50 mA S Q R Q DRV SET CLR Reset GND Current Sense Comparator Figure 2. Simplified Circuit Architecture MAXIMUM RATINGS Rating Symbol Value Unit Power Supply Voltage VCC 18 V IVC Pins Voltage Range IVC −0.3 to 18 V CS and CT Pin Voltage Range Vin −0.
PAGE 4
NCL30100 ELECTRICAL CHARACTERISTICS (VCC = 12 V, for typical values TJ = 25°C, for min/max values TJ = −40°C to +125°C, unless otherwise noted) SUPPLY SECTION Parameter Conditions Symbol Min Typ Max Unit V(offset) 1.10 1.30 1.45 V INPUT VOLTAGE COMPENSATION Offset Voltage CT Pin Voltage IVC Current = 25 mA (Including V(offset)) VCT−25mA 1.69 2.08 2.47 V CT Pin Voltage IVC Current = 50 mA (Including V(offset)) VCT−50mA 2.12 2.6 3.
PAGE 5
NCL30100 6.260 30 28 26 6.255 6.250 ICC1 (mA) VCC(on) (V) 24 6.245 22 20 18 16 14 6.240 12 6.235 −40 −20 0 20 40 60 80 100 10 120 −20 0 20 40 60 80 100 TEMPERATURE (°C) Figure 3. Vstartup Threshold vs. Junction Temperature Figure 4. Startup Current Consumption vs. Junction Temperature 12.6 5.780 12.5 5.775 12.4 120 5.770 12.3 12.2 VCC(off) (V) ICS(min) (mA) −40 TEMPERATURE (°C) 12.1 12.0 11.9 5.765 5.760 5.755 5.750 11.8 5.745 11.7 11.
PAGE 6
55 1.350 50 1.345 45 1.340 V(offset) (V) Vth (mV) NCL30100 40 35 30 1.335 1.330 1.325 25 −40 −20 0 20 40 60 80 100 1.320 −40 120 20 40 60 80 100 TEMPERATURE (°C) Figure 9. Comparator Threshold Voltage vs. Junction Temperature Figure 10. Offset Voltage vs. Junction Temperature 85 51.0 75 50.5 120 50.0 ROH 55 49.5 ICT (mA) RESISTANCE (W) 0 TEMPERATURE (°C) 65 45 35 49.0 48.5 48.0 25 ROL 15 5 −40 −20 0 20 47.5 40 60 80 100 47.
PAGE 7
NCL30100 APPLICATION INFORMATION The NCL30100 implements a peak current mode control scheme with a quasi−fixed OFF time. An optional input feedforward voltage control is provided to enhance regulation response with widely varying input voltages. Only a few external components are necessary to implement the buck converter.
PAGE 8
NCL30100 Once the external MOSFET is switched on, the inductor current starts to flow through the sense resistor RCS. The current creates a voltage drop VCS on the resistor RCS, which is negative with respect to GND. Since the comparator connected to CS pin requires a positive voltage, a voltage Vshift is developed across the resistor Rshift by a current source which level−shifts the negative voltage VCS. The level−shift current is in the range from 12.
PAGE 9
NCL30100 VCC and I3 represent different delays depending on the magnitude of IVC. Current Mirror 1:1 Gate Driver The Gate Driver consists of a CMOS buffer designed to directly drive a power MOSFET. It features unbalanced source and sink capabilities to optimize switch on and off performance without additional external components. The power MOSFET is switched off at high drain current, to minimize its switch off losses the sink capability of the gate driver is increased for a faster switch off.
PAGE 10
NCL30100 The current sense characteristic can be seen in Figure 22. As illustrated, by varied the IVC current between 0 − 50 mA, the sourcing current can range from 12.5 to 50 mA. V CS Pin Source Current 50 mA 12.5 mA 0 mA 50 mA 100 mA mA 140 mA IVC Pin Sink Current Figure 22. Current Sense Regulation Characteristic Biasing the controller t on + L @ The NCL30010 Vcc input can range up to 18 V.
PAGE 11
NCL30100 Reverse Buck Operating Description Figure 23 illustrates a typical application schematic and Figure 24 displays simplified waveforms illustrate the converter in steady state operation for critical circuit nodes. Imag D1 Vin ICS Rshift ICT Idemag IC1 NCL30100 1 CS 2 GND 3 CT 6 DRV VCC 5 IVC 4 L1 Q1 VCS Vsense CT VCT VDRV Rsense Figure 23. Simplified Application Schematic http://onsemi.
PAGE 12
NCL30100 Vcc VDRV 0 Ipk Imag 0 Idemag Imin 0 I LED 0 50 uA ICT 0 VCT 0 0 V Sense I CS 0 VCS 38 mV 0 Figure 24. Voltage and Current Nodes in the Application Circuit The current follows the red line in Figure 23 when Q1 is turned on. The converter operates in continuous conduction mode therefore the current through the inductor never goes to zero. When the switch is on, the current creates a negative voltage drop on the Rsense resistor.
PAGE 13
NCL30100 Application Design Example: A typical step down application will be used to illustrate the basic design process based on nominal design parameters: • Input voltage: Vin − 12 Vac (12 V dc after the bridge) • • • • • Nominal LED current: 700 mA (rms) LEDripple: 120 mA (peak−to−peak) VLED: 3.2 V Freewheel diode Vf: 0.
PAGE 14
NCL30100 600 1000 900 500 800 400 ILED (mA) ILED (mA) 700 600 Rivc = 300k 500 Rivc = 510k 400 Rivc = 1 Meg Rivc = 300k 200 Rivc = 1 Meg Rivc = 510k Rivc = 1.5 Meg 300 Rivc = 1.5 Meg Rivc = 2.2 Meg 200 100 300 Rivc = 3.7 Meg Rivc = infinity 7 8 9 10 Rivc = 2.2 Meg 100 11 12 13 14 15 INPUT VOLTAGE (V) 16 17 0 18 Rivc = 3.7 Meg Rivc = infinity 7 Figure 26. Rivc Impact versus Vin for ILED = 700 mA Nominal −0.097 @ X 2 ) 24.5 @ X ) 1358.1 [V] 976.8 (eq. 13) −0.097 @ 7.
PAGE 15
NCL30100 Ipeak Ics ILED ΔiL td (Vin-VLED) -VLED - Vdiode L L ton toff Figure 28. A Current Error Between the Intended Peak Current and the Actual Peak Current V+ di @ L dt å I delay + V@t L + Using the PDIE, we can calculate junction temperature: 8.8 @ 215 @ 10 −9 47 @ 10 −6 (eq. 18) Temp IC + T A ) P DIE @ R qJA + T A ) 0.0399 @ 178 ^ 0.0402 A + T A ) 7.
PAGE 16
NCL30100 Figure 29. PCB Design the Circuit Calculated Above. Only Single Layer PCB is Used for the Application. Figure 30. The Component Side (Several Transistor Packages are Possible to Use) BILL OF MATERIALS FOR THE SINGLE LAYER EVALUATION BOARD (NCL30100ASLDGEVB) Designator Qty Description Value Tol Footprint Manufacturer Manufacturer Part Number Substitution Allowed Pb−Free C1 1 Capacitor 2.
PAGE 17
NCL30100 BILL OF MATERIALS FOR THE SINGLE LAYER EVALUATION BOARD (NCL30100ASLDGEVB) Designator Qty Q3 1 R1 Description Value Tol Footprint Manufacturer Manufacturer Part Number Substitution Allowed Pb−Free Comments Power MOSFET NU − SOT−23 ON semiconductors NTS4001NT1G No Yes Option 1 Resistor 1.
PAGE 18
NCL30100 Figure 34. Current Through LED if 50% Dimming at 1 kHz is Applied Figure 35. The Dimming Detail at 95%. No Overshoot in LED Current is Observed real world application is dependent on the characteristics of the actual dimmer and the electronic transformer used to generated to chopped AC waveform Figures 36 and 37 illustrate leading edge and trailing edge waveforms from a chopped AC source.
PAGE 19
NCL30100 Figure 38. ILED and Vin Waveform if No Dimming is Used 84 83 680 82 CURRENT (mA) EFFICIENCY (%) 690 DC Voltage Efficiency (No Bridge Rectifier) 81 80 79 78 77 7 670 660 650 640 630 8 9 10 11 12 13 INPUT VOLTAGE (V) 14 15 620 16 LED Current Variation 7 Figure 39. Efficiency Measurement for the Demoboard (Vf = 3.2 Nominal) 8 9 10 11 12 13 INPUT VOLTAGE (V) 14 15 16 Figure 40.
PAGE 20
NCL30100 12 V X2 A D3 D7 D4 D1 R1 C1 D5 X3 D6 R2 R3 NCL30100 R5 GND VCC CS CT DRV L1 Q1 K IVC C2 C4 C3 D2 R4 Figure 41. Schematic MR 16 Application Figure 42. PCB Top Side MR 16 Application Figure 43. PCB Top Side Devices Placement Figure 44. PCB Bottom Side MR 16 Application http://onsemi.
PAGE 21
NCL30100 Figure 45. PCB Bottom Side Devices Placement Figure 46. Top Side Photo Figure 47. Bottom Side Photo http://onsemi.
PAGE 22
NCL30100 BILL OF MATERIALS FOR THE MR 16 EVALUATION BOARD (NCL30100ADLMGEVB) Designator Qty Description Value Tol Footprint Manufacturer Manufacturer Part Number Substitution Allowed Pb−Free C1 1 Capacitor 2.2 mF / 25 V 10% 0805 AVX 08053C225KAT2A Yes Yes C2 1 Capacitor 33 pF 5% 0603 Kemet C0603C330J5GACTU Yes Yes C3 1 Capacitor 4.
PAGE 23
NCL30100 D1 MRA4003 Vac L1 A 100u R1 24k C1 CX1 D3 MRA4003 C2 47n 2.2u 2.2n D4 MRA4003 IC1 NCL30100 R3 150k Vac CS D6 MRA4003 D2 MURA130 R2 24k D5 1N4148 L2 DRV Q1 1mH GND VCC R4 5.6k C3 10p CT C4 560p MTD6N20ET IVC C5 1u R5 R33 DIMM 0/5 V R6 5.6k K Q2 BC817−16L D7 16V GND R7 10k Figure 48. Design Example Schematic of 115 Vac Converter by resistors R3, R4 and R5. In this case Rsense is 0.33 W to reach higher accuracy.
PAGE 24
NCL30100 Figure 51. ILED and Vin Waveform Figure 52. ILED at the Peak of Sinusoidal Voltage http://onsemi.
PAGE 25
NCL30100 Figure 53. Input Voltage and Input Current http://onsemi.
PAGE 26
NCL30100 BILL OF MATERIALS FOR THE NCL30100 115 Vac Designator Qty Description Value Tol Footprint Manufacturer Manufacturer Part Number Substitution Allowed Pb−Free C1 1 Capacitor 2.2 mF / 200 V 10% E3.5−8 Koshin KR1 2.2u 200V 8X11.
PAGE 27
NCL30100 PACKAGE DIMENSIONS TSOP−6 CASE 318G−02 ISSUE U D H 6 E1 5 ÉÉÉ 1 NOTE 5 2 L2 4 GAUGE PLANE E 3 L b C DETAIL Z e 0.05 M A SEATING PLANE c A1 DETAIL Z NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. CONTROLLING DIMENSION: MILLIMETERS. 3. MAXIMUM LEAD THICKNESS INCLUDES LEAD FINISH. MINIMUM LEAD THICKNESS IS THE MINIMUM THICKNESS OF BASE MATERIAL. 4. DIMENSIONS D AND E1 DO NOT INCLUDE MOLD FLASH, PROTRUSIONS, OR GATE BURRS.