Texas Instruments UCC28810EVM-002 User Manual

Using the UCC28810EVM-002
User's Guide
Literature Number: SLUU355A
March 2009 – Revised June 2009
SLUU355A March 2009 Revised June 2009
A 0.9-A Constant Current Supply with PFC for 100-W LED
Lighting Applications
1 Introduction
The UCC28810EVM-002 is a constant current non-isolated power supply for LED lighting applications. It will convert universal mains (90 VRMS to 264 VRMS) to a 0.9-A constant current into a 100-W load. This evaluation module will allow the customer evaluate the UCC28810/11 in a typical LED lighting application.
2 Description
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 or
power factor requirements set out by various standards, such as EN61000-3-2. The PFC circuit converts the AC input to a regulated DC voltage. This DC voltage can be configured in one of two ways. The default configuration of the module is that of a boost follower type PFC. The boost follower PFC is where the PFC regulated output DC voltage tracks the AC input peak voltage. The second configuration requires removing some components and changing a resistor value see below for more details. This second configuration removes the tracking element of the PFC circuit. The PFC DC output voltage will then be regulated 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 PFC output voltage to a fixed constant current. This circuit is capable of supplying 0.9 A into a 100-W load. It also accepts PWM dimming inputs. Alternatively the user can use the PWM circuit on the module to see the dimming function.
This module will work with most high brightness LED’s (HB-LED) that operate with 0.9 A and a total string voltage drop of between 55 V and 110 V.
User's Guide
2.1 Typical Applications
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 2009
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3 Electrical Performance Specifications
SYMBOL PARAMETER CONDITIONS MIN NOM MAX UNITS
INPUT CHARACTERSTICS
V I
IN
PF Power factor P
OUTPUT CHARACTERSTICS PFC Stage
V
LED Driver Stage
P I
OUT
SYSTEMS CHARACTERSTICS
η Full load efficiency 90% 93%
PWM Dimming
Input voltage 90 264 V
IN
Input current 0.175 1.1 A
PFC output voltage 235 415 VDC
OUT
Output power 45 80 100 W
OUT
Output current 0.84 0.9 0.96 Line regulation 0.03 Frequency 60 128 kHz
Threshold 0.72 1.3 V Frequency range 200 1000 Hz Duty cycle 0% 90%
Table 1. UCC28810EVM-002 Electrical Performance Specifications
(1)
Electrical Performance Specifications
= 80 W to 100 W 0.95 0.97
OUT
RMS RMS
A
(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 3
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++
+
Schematic
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4 Schematic
Figure 1. UCC28810EVM-002 PFC Stage Schematic
4 A 0.9-A Constant Current Supply with PFC for 100-W LED Lighting Applications SLUU355A – March 2009 – Revised June 2009
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VSENSE
EAOUT
VINS
ISENSE TZE
GND
GDRV
VDD
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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 5
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Test Setup
5 Test Setup
5.1 Test Equipment
See Figure 3 for recommended test set up.
5.1.1 Voltage Source:
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.
5.1.2 Multimeters
Three digital multimeters are recommend, one for current measurement, A1, and two for voltage measurements, V1 and V2.
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WARNING
High voltages, that may cause injury, exist on this evaluation module (EVM). Please ensure all safety procedures are followed when working on this EVM. Never leave a powered EVM unattended. The use of isolated test equipment is highly recommended.
5.1.3 Output Load
It is recommended that actual high brightness LED’s (HB-LED’s) are used for the load. They should be rated at 0.9 A. The HB-LED’s should be connected in series. Their voltage drop should be between 55 VDC and 110 VDC. Alternatively a constant voltage electronic load could be used. If using a constant voltage electronic load a 1000- µ F/250 VDC capacitor is required at the input to the electronic load. The 1000 µ F capacitor should not be used if using HB-LED’s as the load.
5.1.4 Oscilloscope
A digital or analog oscilloscope with current probe is required to view the AC current in the PFC inductor or buck inductor.
5.1.5 Signal Generator
A signal generator that can produce a square wave pulse train at between 200 Hz and 1 kHz is required to do external PWM dimming.
5.1.6 Fan
Forced air cooling is not required
5.1.7 Recommended Wire Gauge
A minimum of 18 AWG wire is recommended. Also the wire connections between the AC source and the EVM, and the EVM and load should be less than two feet long. The AC input connector accepts a standard 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 2009
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