Texas Instruments UCC28810EVM-002 User manual

Using the UCC28810EVM-002
User's Guide
Literature Number: SLUU355AMarch 2009 – Revised June 2009

1 Introduction
2 Description
2.1 Typical Applications
2.2 Features
User's GuideSLUU355A – March 2009 – Revised June 2009
A 0.9-A Constant Current Supply with PFC for 100-W LEDLighting Applications
The UCC28810EVM-002 is a constant current non-isolated power supply for LED lighting applications. Itwill convert universal mains (90 VRMS to 264 VRMS) to a 0.9-A constant current into a 100-W load. Thisevaluation module will allow the customer evaluate the UCC28810/11 in a typical LED lighting application.
The evaluation module uses a two stage approach to controlling the output current.
The first stage is a transition mode PFC circuit. This ensures the design meets the harmonic current orpower factor requirements set out by various standards, such as EN61000-3-2. The PFC circuit convertsthe AC input to a regulated DC voltage. This DC voltage can be configured in one of two ways. Thedefault configuration of the module is that of a boost follower type PFC. The boost follower PFC is wherethe PFC regulated output DC voltage tracks the AC input peak voltage. The second configuration requiresremoving some components and changing a resistor value see below for more details. This secondconfiguration removes the tracking element of the PFC circuit. The PFC DC output voltage will then beregulated to a fixed value in the region of 396 VDC.
The second stage also uses transition mode but is configured as a buck converter. It converts the PFCoutput voltage to a fixed constant current. This circuit is capable of supplying 0.9 A into a 100-W load. Italso accepts PWM dimming inputs. Alternatively the user can use the PWM circuit on the module to seethe dimming function.
This module will work with most high brightness LED’s (HB-LED) that operate with 0.9 A and a total stringvoltage drop of between 55 V and 110 V.
•AC Input General Lighting Applications Using HB-LED’s•Industrial, Commercial and Residential Lighting Fixtures•Outdoor Lighting: Street, Roadway, Parking, Construction and Ornamental LED Lighting Fixtures
•90 VRMS to 264 VRMS operation•Boost Follower or Fixed Output PFC Stage•PFC Disable•Output Current Disable•External or Internal PWM Dimming
A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications2 SLUU355A – March 2009 – Revised June 2009Submit Documentation Feedback

3 Electrical Performance Specifications
www.ti.com Electrical Performance Specifications
Table 1. UCC28810EVM-002 Electrical Performance Specifications
SYMBOL PARAMETER CONDITIONS MIN NOM MAX UNITS
INPUT CHARACTERSTICS
V
IN
Input voltage 90 264 V
RMS
I
IN
Input current 0.175 1.1 A
RMS
PF Power factor P
OUT
= 80 W to 100 W 0.95 0.97
OUTPUT CHARACTERSTICS
PFC Stage
V
OUT
PFC output voltage 235 415 VDC
LED Driver Stage
P
OUT
Output power 45 80 100 WI
OUT
Output current 0.84 0.9 0.96
ALine regulation 0.03Frequency 60 128 kHz
SYSTEMS CHARACTERSTICS
ηFull load efficiency 90% 93%
PWM Dimming
(1)
Threshold 0.72 1.3 VFrequency range 200 1000 HzDuty cycle 0% 90%
(1)
The PWM dimming signal is inverted, 0% duty cycle is 100% LED current.
SLUU355A – March 2009 – Revised June 2009 A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications 3Submit Documentation Feedback

4 Schematic
++
+
Schematic www.ti.com
Figure 1. UCC28810EVM-002 PFC Stage Schematic
4A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications SLUU355A – March 2009 – Revised June 2009Submit Documentation Feedback

VSENSE
EAOUT
VINS ISENSE TZE
GND
GDRV
VDD
www.ti.com Schematic
Figure 2. UCC28810EVM-002 Buck Stage Schematic
SLUU355A – March 2009 – Revised June 2009 A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications 5Submit Documentation Feedback

5 Test Setup
5.1 Test Equipment
5.1.1 Voltage Source:
5.1.2 Multimeters
5.1.3 Output Load
5.1.4 Oscilloscope
5.1.5 Signal Generator
5.1.6 Fan
5.1.7 Recommended Wire Gauge
Test Setup www.ti.com
WARNINGHigh voltages, that may cause injury, exist on this evaluationmodule (EVM). Please ensure all safety procedures are followedwhen working on this EVM. Never leave a powered EVMunattended. The use of isolated test equipment is highlyrecommended.
See Figure 3 for recommended test set up.
•Source 1: Isolated AC voltage source or VARIAC, capable of 90 VRMS to 264 VRMS at 150 W.•Source 2: A 3.3-V DC source capable of 100 mA.
Three digital multimeters are recommend, one for current measurement, A1, and two for voltagemeasurements, V1 and V2.
It is recommended that actual high brightness LED’s (HB-LED’s) are used for the load. They should berated at 0.9 A. The HB-LED’s should be connected in series. Their voltage drop should be between 55VDC and 110 VDC. Alternatively a constant voltage electronic load could be used. If using a constantvoltage electronic load a 1000- µF/250 VDC capacitor is required at the input to the electronic load. The1000 µF capacitor should not be used if using HB-LED’s as the load.
A digital or analog oscilloscope with current probe is required to view the AC current in the PFC inductoror buck inductor.
A signal generator that can produce a square wave pulse train at between 200 Hz and 1 kHz is requiredto do external PWM dimming.
Forced air cooling is not required
A minimum of 18 AWG wire is recommended. Also the wire connections between the AC source and theEVM, and the EVM and load should be less than two feet long. The AC input connector accepts astandard IEC320-C13 connector with ground pin.
A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications6 SLUU355A – March 2009 – Revised June 2009Submit Documentation Feedback

5.2 Recommended Test Setup
TP3
Buck bias voltage monitor
TP4 & TP5
PFC output voltage
TP1 & TP2
Loop injection point
CL2
Current Probe:
Buck inductor
ripple current
monitor
J3
Short pins to Enable
On Board Dimming
+
L N
V2
CL1
Current Probe:
PFC inductor
ripple current
monitor
1000uF
250V
A1
V1
J4
Pin 1: Buck Shutdown
Pin 2: GND
Pin 3 External PWM dimming input
J2
Pin 1: PFC Shutdown
Pin 2: GND
IEC320
-C13
Plug
90 - 265
VRMS
AC Source
Constant
Voltage
Load
+ -
5.3 List of Test Points
www.ti.com Test Setup
Figure 3. UCC28810EVM-002 Recommended Test Set Up
Note: The 1000- µF/250-V capacitor on the output is not required if the load is a string of HB-LED’s.
Table 2. Test Point Functions
TEST POINTS NAME DESCRIPTION
TP1 Loop injection pointTP2 Loop injection point, PFC outputTP3 VCC_BK Buck bias voltage outputTP4 PFC+ PFC output voltageTP5 PFC- PFC output voltage groundTP6 VCC_BK Buck bias voltage inputTP7 GND Buck bias voltage groundTP8 GND Ground connectionTP9 EN Buck enableTP10 GND Buck input voltage groundTP11 BK_IN Buck input voltageJ2-1 PFC shutdown Apply 3.3 V to this pin to shutdown PFC stageJ2-2 GNDJ4-1 BK_Shutdown Apply 3.3 V to this pin to shutdown buck stageJ4-2 GNDJ4-3 PWM Dim Input for external PWM dimmingShort the two pins on J3 to enable on board PWM diming. R26J3 On board dim
varies dimming duty cycle
SLUU355A – March 2009 – Revised June 2009 A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications 7Submit Documentation Feedback

6 Test Procedure
6.1 Applying Power to the EVM
6.2 Line/Load Regulation and Efficiency Measurement Procedure
6.3 PFC Disable
Test Procedure www.ti.com
All tests will use the set up described in Section 5 of this user guide. Ensure potentiometer R26 is rotatedcompletely clockwise.
WARNINGHIGH VOLTAGE levels are present on this evaluation modulewhenever it is energized. Proper precautions must be observedwhenever working with this module. There is an energy storagecapacitor (C17) on this module which must be discharged beforethe board can be handled. Serious injury can occur if proper safetyprocedures are not followed.
1. Set up the EVM as described in Section 5 of this user guide.2. Ensure the AC source is off.3. Ensure potentiometer R26 is rotated completely clockwise.4. Set constant voltage load to between 55 V and 110 V. If using a HB-LED string ensure the voltagedrop, when operating, is between 55 V to 110 V nominal. Note the 1000- µF/250 V capacitor is notrequired on the output if using a HB-LED string.5. Set AC source to 90 VRMS.6. Turn on AC source.7. Monitor PFC output voltage at TP4 and TP5, V2.8. Monitor output current at A1.9. Monitor output voltage at V1.10. The EVM is now ready for testing.
1. Apply power to the EVM per Section 6.1 .2. Vary the constant voltage load from 110 V to 55 V.3. Observe output current on A1 stays constant.4. Vary AC source from 90 VRMS to 264 VRMS.5. Observe output current on A1 stays constant.6. PFC inductor ripple current can be measured at CL1 using an oscilloscope and current probe.7. The buck output inductor current can be measured at CL2 using an oscilloscope and current probe.8. See Section 7 for some typical test results.
1. Ensure the AC source is off.2. Connect a DC source to J2.3. Set DC source to 0 V.4. Apply power to the EVM per Section 6.1 .5. Increase DC source to 3.3 V. This input can accept up to 12 V.6. Observe PFC output voltage reduces, V2.7. PFC inductor ripple current looses high frequency component.
A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications8 SLUU355A – March 2009 – Revised June 2009Submit Documentation Feedback

6.4 Buck Disable
6.5 Internal Dimming Function
6.6 External Dimming Function
6.7 Configuring the PFC Stage for Fixed Output
6.8 Equipment Shutdown
www.ti.com Test Procedure
1. Ensure the AC source is off.2. Connect a DC source to J4, pins 1 and 2.3. Set DC source to 0 V.4. Apply power to the EVM per Section 6.1 .5. Increase DC source to 3.3 V. This input can accept up to 12 V.6. Observe output current, A1, drops to zero.7. PFC voltage, V2, does not change.
1. Ensure the AC source is off.2. Ensure jumper is present on J3.3. Apply power to the EVM per Section 6.1 .4. Rotate R26 potentiometer slowly anti clockwise.5. Observe output current on A1 reduce from nominal 0.9 A to 0.1 A. If LED string is attached observeLED’s dim.
1. Ensure the AC source is off.2. Ensure jumper is removed from J3.3. Connect signal generator to J4, pins 3 and 2.4. Set signal generator to generator a pulse from 0 V to 3.3 V at 200 Hz with variable duty cycle. Notewhen the PWM signal is high the LED light is reduced. 100% duty cycle will turn LED off.5. Apply power to the EVM per Section 6.1 .6. Vary the duty cycle of the signal generator output.7. Observe output current, A1, changes. If an LED string is attached observe LED’s dim.
The EVM ships configured as a boost follower PFC. Using a soldering iron some simple componentmodifications can change the PFC configuration from boost follower to fixed output voltage.1. Remove R1, R3, R4, R6, C1 and Q1.2. Change R11 to 6.49 k Ω.3. The EVM now uses a fixed output voltage PFC stage. Repeat tests to see functionality.
1. If DC sources are connected to shutdown pins, J2 and J4, ensure they are set to 0 V.2. Ensure load is at maximum, this will help discharge C17.3. Turn off AC source.4. Monitor PFC output voltage V2. Do not handle EVM until V2 reads less than 50 VDC.
SLUU355A – March 2009 – Revised June 2009 A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications 9Submit Documentation Feedback

7 Performance Data and Typical Characteristic Curves
80 100 120 140 200 220 260
VRMS - Line Voltage - V
0.88
0.98
1.00
160 180 240
0.92
0.94
PF - Power Factor and Efficiency - %
EFFICIENCY/POWER FACTOR
vs
LINE VOLTAGE
Efficiency
Power Factor
0.90
0.96
0
2
4
10
12
6
8
THD - Total Harmonic Distortion - %
80 100 120 140 200 220 260
VRMS - Line Voltage - V
160 180 240
TOTAL HARMONIC DISTORTION
vs
LINE VOLTAGE
7.1 Transient
Ch2:
Buck VDS
Ch4:
LED Voltage
0.5 A/div.
Ch3:
LED Current
Ch1:
Buck VIN
TRANSITION MODE BUCK PWM RESPONSE
(Ch1 and Ch 4 share GND reference)
Ch2:
Buck VDS
Ch4:
LED Voltage
0.5 A/div.
Ch3: LED
Current
Ch1:
Buck VIN
TRANSITION MODE BUCK PWM RESPONSE EXPANDED
(Ch1 and Ch4 share GND reference)
Performance Data and Typical Characteristic Curves www.ti.com
Figure 4 through Figure 8 present some typical performance curves for the UCC28810EVM-002 with 30Cree XRE LED’s at 900 mA.
Figure 4. Figure 5.
Figure 6. Figure 7.
A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications10 SLUU355A – March 2009 – Revised June 2009Submit Documentation Feedback