1 Introduction
PR735 is an interleaved biphase transfer mode PFC converter, when it operates at up to 1.5A 85VRMS ~ 265VRMS AC input power, provides a fixed output of 400V. The reference design requires an additional bias voltage is a 100mA, 15V power supply to the device is UCC28060. PR735 is designed to show a typical off-line performance by high power applications UCC28060 UCC28060 to highlight the characteristics of. Such as UCC28060 contains Natural Interleaving? Innovative characteristics, and can be used for a variety of applications, please see the following section 2.1.
2 Description
PR735 by the two boards: a power supply circuit board comprising a magnetic element, a high-power transistors, and other components; the other is a controller board and from the various components UCC28060 integrated circuit and the filter circuit thereof. The controller board is connected via a pin (header) and a power supply circuit board, when the PFC output in regulation, J1.A status LED controller board will light emission instruction. For more information about the operation of the device, see the UCC28060 product manual.
warn
Because there are abundant high-pressure, non-professionals do not experience the power to carry out the design work on the circuit.
2.1 Applications:
LCD, plasma and DLP TV
Computer Power
Entry-level servers
2.2 features:
Input voltage range 85VRMS ~ 265VRMS
Fixed output 400V
1.5A steady state DC output current
Using TI Natural Interleaving? patented technology
Phase management to improve efficiency at light loads
Power-down protection
3 PR735 Specification
3.1 Electrical Characteristics
3.2 cooling requirements
The reference design can operate at an ambient temperature of 25 ℃, 600W power up, without the need for external cooling. The user should ensure that all the high power components (MOSFET, rectifiers, etc.) to avoid normal cooling temperature is too high. In order to reduce the high output power levels of thermal stress component may be used when an external cooling.
4 Schematic
Principle on the next page diagram illustrates the reference design of PR735. For clarity, each on a separate page of the power stage and control circuit has been described.
4.1 power stage
FIG power stage 1 PR735
Note: for reference only. For specific values, see Table 2 bill of materials. Test points are limited to assessment, the converter is not required for the operation.
Controller circuit 4.2
2 PR735 controller circuit of FIG.
Note: for reference only. For specific values, see Table 3 bill of materials.
5 PR735 Typical performance data
Figures 3 to 5 show typical performance data of PR735. Since the actual performance data affected by measurement techniques and environmental changes, so these curves are for reference only, and may differ from field measurements values.
5.1 Efficiency
The following figure illustrates PR735 efficiency at low line pressure and high line conditions over the entire output power range.
3 and in FIG. 85VRMS efficiency when the 265VRMS
Harmonic current input of 5.2 230 VRMS
PR735 contain very low current harmonic content is consistent with EN61000 standards. Most harmonic content are included in the base may result in harmonics in the low THD. The following figure illustrates the current harmonics and PR735 EN61000 standard of comparison.
Harmonic FIG PR735 4 230 VRMS input
Output voltage ripple at the maximum load of 5.3
As can be seen from the figure the output voltage ripple is about 10V (peak to peak).
FIG 5 PR735 output ripple voltage (5V / DIV, AC coupling)
5.4 input ripple current cancellation
The following figure illustrates the elimination PR735 converter input ripple voltage of each of the input line cycle different situations. M4 is the input current oscillator signal, which is a two-phase value of the inductor current.
FIG 6 85VRMS time (the line voltage peak) input voltage and the input inductor ripple current of PR735
FIG 7 85VRMS time (half the peak line voltage) inductor and the input voltage of the input ripple current PR735
FIG 8 265VRMS time (the line voltage peak) input voltage and the input inductor ripple current of PR735
FIG 9 265VRMS time (half the peak line voltage) inductor and the input voltage of the input ripple current PR735
10 85VRMS enter, POUT = 300W when PR735 inductance and ripple current input
5.5 Startup Characteristics
The following figure illustrates the startup characteristics PR735 converter at different input voltages and output power conditions.
FIG 12 VIN = 85VRMS, POUT = 600W when the startup characteristics of PR735
5.6 Power failure protection
The following figure shows the power-down protection features UCC280660. If the AC voltage VIN drops down to a threshold voltage, then the down converter filter time (typically 440ms) after the conversion is stopped.
FIG PR735 brownout protection PR735 FIG. 13 85VRMS when power failure protection at 15 265VRMS
6 EVM and layout of the assembly of FIG.
PR735 following figure illustrates the design of a printed circuit board. The controller board consists of a single layer PCB, all of the components are mounted on top of the circuit board; a power supply circuit board composed of a single layer PCB, and the assembly is mounted on top of the wiring circuit board at the bottom of the circuit board.
7 power stage and controller-level bill of materials
7.1 power level bill of materials
Table 2 lists the EVM assembly configured according to principles shown in FIG. 1 FIG.
7.2 controller-level bill of materials
Table 3 lists the EVM assembly configuration according to the principles shown in FIG. 2 FIG.
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