Texas Instruments UCC28060EVM Manuale utente

1 Description

2 Thermal Requirements

3 Electrical Characteristics

User's GuideSLUU280B – May 2007 – Revised July 2008

UCC28060EVM 300-W Interleaved PFC Pre-Regulator

The UCC28060 is a dual-phase, transition-mode Power Factor Correction (PFC) pre-regulator. TheUCC28060EVM is an evaluation module (EVM) with a 390-V, 300-W, dc output that operates from auniversal input of 85 V

RMS

to 265 V

RMS

and provides power-factor correction.

Throughout this document, the acronym EVM and the phrases evaluation board and evaluation moduleare synonymous with the UCC28060EVM.

The pre-regulator uses the UCC28060 PFC interleaved controller to shape the input current wave toprovide power-factor correction. This device uses TI’s Natural Interleaving™ technology to interleaveboost phases.

This user’s guide provides the schematic, List of Materials list, assembly drawing for a single-sided printedcircuit board application, and test set-up information necessary to evaluate the UCC28060 in a typicalPFC application.

This evaluation module will operate up to 300 W without external cooling in ambient tempatures of 25 °C.

Table 1 summarizes the electrical specifications of the UCC28060EVM.

Table 1. UCC28060EVM Electrical Specifications

UCC28060EVMPARAMETER CONDITIONS UNITSMIN TYP MAX

RMS input voltage (ac line) 85 265 V

RMS

Output voltage, V

OUT

390 VLine frequency 47 63 HzPower factor (PF) at maximum load 0.9Output power 300 WAC line = 115 V 94%Full load efficiency

AC line = 230 V 97%

Natural Interleaving is a trademark of Texas Instruments.All other trademarks are the property of their respective owners.

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4 Schematics

Schematics

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Figure 1 and Figure 2 show the schematics for this EVM. See the List of Materials for specific values.

To evaluate inductor ripple currents, Jumpers JP8 and JP9 can be removed and replaced with currentloops.

Figure 1. Interleaved PFC Power Stage

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Schematics

Figure 2. Controller Circuitry

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5 Test Setup and Power-Up/Power-Down Instructions

Isolation Transformer

0 to 300W Load

13V Bias Supply

Test Setup and Power-Up/Power-Down Instructions

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WARNINGThere are high voltages present on the pre-regulator. It should onlybe handled by experienced power supply professionals. Toevaluate this board as safely as possible, the following testconfiguration should be used:•Connect an isolation transformer between the source and unit•Attach a voltmeter and a resistive or electronic load to the unitoutput before supplying power to the EVM.

A separate 13-V bias supply is required to power the UCC28060 control circuitry. The unit will start upunder no-load conditions. However, for safety, a load should be connected to the output of the devicebefore it is powered up. The unit should also never be handled while power is applied to it or when theoutput voltage is above 50-V dc. Refer to Figure 3 for a recommended test setup diagram.

CAUTION

There are very high voltages on the board. Components can and will reachtemperatures greater than 100 °C. Use caution when handling the EVM.

Figure 3. Test Setup

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6 Typical Performance Data

Efficiency

90.0%

91.0%

92.0%

93.0%

94.0%

95.0%

96.0%

97.0%

98.0%

99.0%

100.0%

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Output Pow er

Efficiency (%)

Efficency at Vin 85V RMS

Efficency at Vin = 265V RMS

Efficiency at Vin = 115V RMS

91.0%

92.0%

93.0%

94.0%

95.0%

96.0%

97.0%

98.0%

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Output Power

Efficiency (%)

With Phase M anage m ent

Without Phase Management

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Typical Performance Data

Figure 4 through Figure 7 present characteristic performance data for the UCC28060EVM.

Figure 4. Efficiency at 85V

RMS

and 265V

RMS

The UCC28060 control device has phase management capability to improve light load efficiency. Todemonstrate the light load efficiency, the unit efficiency was measured with phase management enabledand disabled at 115 V

RMS

and 230 V

RMS

input voltages. Phase management improved the light loadefficiency up to 3%. Refer to the UCC28060 data sheet for details on how to use the phase managementfunction of this device.

Figure 5. Efficiency at 115 V

RMS

, With and Without Phase Management

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Efficiency at Vin = 230V RMS

85.0%

87.0%

89.0%

91.0%

93.0%

95.0%

97.0%

99.0%

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Output Power

Efficiency (%)

With Phase M anage m ent

Without Phase Management

1.40706

1.17256

0.93805

0.70354

0.46904

0.23453

0.00002

Amplitude (A)

0 6 12 18 24 30 36 42 48

Harmonic No.

V = 230V

IN RMS

Typical Performance Data

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Figure 6. Efficiency at 230 V

RMS

, With and Without Phase Management

Figure 7. Current Harmonics

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6.1 Output Ripple Voltage at Full Load

6.2 Input Ripple Current Cancellation

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Typical Performance Data

Figure 8 illustrates the output ripple voltage.

Figure 8. V

OUT

Ripple, P

OUT

= 300 W

Figure 9 through Figure 14 show the input current (M

= I

+ I

), Inductor Ripple Current (I

, I

) versusrectified line voltage. From these graphs, it can be observed that interleaving reduces the magnitude ofinput ripple current caused by the inductor ripple current.

Figure 9. Inductor and Input Ripple Current at Figure 10. Inductor and Input Ripple Current85 V

RMS

at Peak of Line Voltage at 85 V

RMS

Input at Half the Line Voltage

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Typical Performance Data

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Figure 11. Inductor and Input Ripple Current Figure 12. Inductor and Input Ripple Currentat 265 V

RMS

Input at Peak Line Voltage at 265 V

RMS

Input at Half Peak Line Voltage

Figure 13. Inductor and Input Ripple Current Figure 14. Inductor and Input Ripple Currentat V

= 85 V

RMS

, P

OUT

= 300 W at V

= 265 V

RMS

, P

OUT

= 350 W

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6.3 Startup Characteristics

6.4 Brownout Protection

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Typical Performance Data

Figure 15 and Figure 16 illustrate the UCC28060EVM startup characteristics.

Figure 15. Start-Up at V

= 85 V

RMS

, P

OUT

= Figure 16. Start-Up at V

= 265 V

RMS

, P

OUT

= 0350 W W

The UCC28060 has a brownout protection that shuts down both gate drives (GDA and GDB) when theVINAC pin detects that the RMS input voltage is too low. This EVM was designed to go into a brownoutstate when the line drops below 64 V

RMS

. Once the UCC28060 control device has determined that theinput is in a brownout condition, a 400-ms timer starts to allow the line to recover before shutting down thegate drivers. After 400 ms of brownout, both gate drivers turn off, as shown in Figure 17 and Figure 18 .

Figure 17. Brownout at 85 V

RMS

Figure 18. Brownout at 265 V

RMS

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6.5 Line Transient

Typical Performance Data

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A line transient test was conducted with an ac source on the reference design. The line was varied from230 V

RMS

to 115 V

RMS

to 230 V

RMS

and the transient response was evaluated in each case. From theoscilloscope image in Figure 19 , it can be observed that the output recovered from line transients within300ms at full load.

Figure 19. Line Transient, P

OUT

= 300W