Texas Instruments UCC28600 User manual

UCC28600 120-W Evaluation Module
User's Guide
October 2006 Power Supply MAN
SLUU256A

UCC28600 120-W Evaluation Module
User's Guide
Literature Number: SLUU256AAugust 2006 – Revised October 2006

1 Description
1.1 Applications
User's GuideSLUU256A – August 2006 – Revised October 2006
UCC28600 120-W Evaluation Module
The UCC28600 evaluation module (EVM) is a 120-W off-line quasi-resonant flybackconverter providing a 19.4-V regulated output at 6.2 A of load current, operating from auniversal ac input. The front-end power factor correction (PFC) stage is controlled bythe UCC28051 and accommodates an input line voltage range of 85 VRMS to 265VRMS and is designed to meet EIC61000-3-2 harmonic emissions requirements. Themodule uses the UCC28600 Quasi-Resonant Flyback Green-Mode Controller whichintegrates built-in state of the art energy saving features with high level protectionfeatures to provide cost effective solutions for energy efficient power supplies.
The UCC28600EVM highlights the many benefits of using the UCC28600 Quasi-Resonant FlybackGreen-Mode Controller. Low system parts count and multifunction pins in this green-mode controllerprovide a cost-effective solution while meeting stringent world-wide energy efficiency requirements. Lowvoltage switching reduces switching losses and improves efficiency. Green-mode and frequency-foldbackmode operation reduces the operating frequency at light loads and no-load operation. A dedicatedSTATUS pin is used to disable the PFC controller when the converter has entered standby.
This user’s guide provides the schematic, component list, assembly drawing for a single-sided PCBapplication, artwork, and test set up necessary to evaluate the UCC28600 in a typical off-line converterapplication.
The UCC28600 is suited for use in isolated off-line systems requiring high-efficiency and advanced faultprotection features including:•Bias supplies for LCD monitors, LCD TV, PDP TV, and set top boxes•AC/DC adapters•Offline battery chargers•Energy efficient power supplies up to 200 W
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1.2 Features
Description
The UCC28600EVM features include:•120-W, 19.4-V output•Universal off-line input voltage range•Power factor correction controlled by the UCC28051•Multi-mode operation•Current-mode control– Cycle-by-cycle power limit•Programmable over voltage protection•Internal over temperature protection•Less than 500-mW input power during standby•Programmable soft start•PFC disable using the STATUS pin of the UCC28600•Regulation down to zero output current•Single-sided board layout
CAUTION
High voltage levels are present on the evaluation module whenever it isenergized. Proper precautions must be taken when working with the EVM. Thelarge bulk capacitor across the +DC IN and -DC IN terminals, and the outputcapacitor bank must be completely discharged before the EVM can be handled.Serious injury can occur if proper safety precautions are not followed.
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2 UCC28600EVM Electrical Performance Specification
UCC28600EVM Electrical Performance Specification
Table 1. UCC28600EVM Performance Summary
PARAMETERS TEST CONDITION MIN TYP MAX UNITS
Input Characteristics
Input voltage range V
IN
85 265 V
RMS
Maximum input V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 1.3
A
RMScurrent
V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 0.7Input power factor V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 0.998correction
V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 0.972
Output Characteristics
Output voltage 85 V
RMS
≤V
IN
≤265 V
RMS
, 0 A ≤I
OUT
≤6.2 A 19.0 19.4 19.8 VOutput load current 85 V
RMS
≤V
IN
≤265 V
RMS
0 6.2 ALine regulation 85 V
RMS
≤V
IN
≤265 V
RMS
, I
OUT
= 3 A 3Load regulation 0 A ≤I
OUT
≤6.2 A, V
IN
= 115 V
RMS
15 mV0 A ≤I
OUT
≤6.2 A, V
IN
= 230 V
RMS
15Output voltage ripple V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 190V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 190
mV
pk=pkOutput voltage noise V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 190V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 190Output over voltage V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 23.4
Vlimit
V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 23.6
Control Loop Characteristics
Control loop V
IN
= 115 V
RMS
, I
OUT
= 3 A
2.6 kHzbandwidth
Phase margin 70 degrees( °)
Efficiency
Peak efficiency V
IN
= 265 V
RMS
, I
OUT
= 6 A 87.4%Full load efficiency V
IN
= 115 V
RMS
, I
OUT
= 6.2 A 82.7%V
IN
= 230 V
RMS
, I
OUT
= 6.2 A 86.4%No load power V
IN
= 115 V
RMS
, I
OUT
= 0 A 230
mWconsumption
V
IN
= 230 V
RMS
, I
OUT
= 0 A 420
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3 Schematic
Schematic
A schematic of the UCC28600EVM is shown in Figures 1 and 2. Terminal block J1 is the ac input voltagesource connector, J2 is the 19.4-V output, and J3 is the output voltage return. The +DC IN and –DC INconnectors are used to monitor the PFC output voltage or can be used to supply a dc input voltage whenthe PFC stage is disabled.
Figure 1 shows the PFC controller, the UCC28051, with all the discrete circuitry for configuring the powerfactor correction at the universal line input range. The bias to the UCC28051 controller is provided by theauxiliary winding of the quasi-resonant flyback inductor and controlled by the STATUS output of theUCC28600 controller. During light load operation, the bias to the PFC controller is removed, enabling theconverter to operate at high efficiencies.
Figure 2 shows the green-mode controller, the UCC28600, with all the discrete circuitry for configuring theisolated quasi-resonant flyback converter using the PFC output voltage as its input. The auxiliary windingprovides the bias to the controllers and provides over voltage protection and valley switching information,as well as bias to the UCC28600 and UCC28051. The series resistor connected between the currentsense pin and the current sense resistor programs the power limit of the converter. The seriescombination of R41 and D18 adds an offset voltage to the current sense signal that effectively reducesaudible noise during standby operation by limiting the current in the transformer during operation in theaudible frequency range.
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4A Fuse
F1
+
Schematic
Figure 1. PFC Portion of the UCC28600EVM
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+
+
+ +
+
Schematic
Figure 2. Quasi-Resonant Flyback Portion of the UCC28600EVM
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4 EVM Test Setup
AC SOURCE
POWER METER DMM 1VOUT
DMM 2IOUT
Electronic Load
++++++ −
−
−
−
−
−
−
+
DMM3
VBULK
+ −
Ripple Scope
AHIAEXT ALO
VHI VLO
FAN
EVM Test Setup
Figure 3 shows the basic test set up recommended to evaluate the UCC28600EVM with a load. Figure 4shows the equipment set up when measuring the input power consumption when the EVM is in standbymode. Note the addition of the 10- Ωshunt in Figure 4. The power analyzer should also be set for longaveraging in order to include several cycles of operation and an appropriate current scale factor for usingthe external shunt must be used.
Figure 3. Recommended HPA126 EVM Test Configuration for Operation with a Load.
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AC SOURCE
POWER METER DMM 1
VOUT
+ + ++ −
−
−−
−
+
DMM3VBULK
+ −
AHI AEXT
ALO
VHI VLO
FAN
10
EVM Test Setup
Figure 4. Equipment Set Up for HPA126 Evaluation During No-Load.
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