Using the UCC28250EVM-501 User's Guide Literature Number: SLUU429B June 2010 – Revised December 2010
User's Guide SLUU429B – June 2010 – Revised December 2010 Half-Bridge DC-to-DC Converter With Primary-Side Control 1 Introduction This EVM is to help evaluating UCC28250 PWM device with primary-side control in DC-to-DC symmetrical half-bridge converter topology. The targeted application is telecom module design with nominal 48-V input. UCC28250 is a PWM controller that can be used for primary-side control or secondary-side control.
Electrical Performance Specifications www.ti.com 3 Electrical Performance Specifications Table 1. UCC28250EVM-501 Electrical Performance Specifications PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Input Characteristics Voltage range Maximum input current 36 48 VIN = 36 V and IOUT = 23 A 72 2.35 No load input current 50 V A mA Output Characteristics Output voltage, VOUT Output current = 0 A 3.25 3.
Schematic Schematic + + 4 www.ti.com Figure 1.
Test Setup www.ti.com 5 Test Setup 5.1 Test Equipment Voltage Source: HP 6015A DC Power Supply Multimeters: Fluke 45 Dual Display Multimeter Output Load: HP 6060A DC Electronic Load Oscilloscope: Tektronix TDS 460 A, 400 MHz Fan: 200 LFM minimum compatible Recommended Wire Gauge: AWG #18 for input voltage connection. AWG #16 for output load connection. Recommended Test Setup + V1 + - - V2 5.2 A1 - Load 1 3.3V/25A + DC Source + FAN Figure 2.
Test Setup 5.3 www.ti.com List of Test Points Table 2.
Test Procedure www.ti.com 6 Test Procedure Set up the EVM based on Figure 2. CAUTION !! Caution: High voltage and high temperature present when the EVM is in operation !! 6.1 Line/Load Regulation and Efficiency Measurement Procedure 1. Connect the ammeter A1 (0 A to 10 A range) between DC source and J1 as shown in Figure 2. 2. Prior to connecting the DC source, it is advisable to limit the source current to 3 A maximum.
Performance Data and Typical Characteristic Curves 7 www.ti.com Performance Data and Typical Characteristic Curves Figure 3 through Figure 11 present typical performance curves for UCC28250EVM-501. 7.1 Efficiency EFFICIENCY vs LOAD CURRENT 95 90 36 VIN 85 48 VIN 72 VIN Efficiency - % 80 75 70 65 60 55 50 0 2 4 6 8 10 12 14 16 18 20 22 Load Current - A Figure 3. Efficiency 7.2 Load Regulation OUTPUT VOLTAGE vs LOAD CURRENT 3.35 VOUT - Output Voltage - V 3.
Performance Data and Typical Characteristic Curves www.ti.com 7.3 Bode Plot GAIN/PHASE vs FREQUENCY 100 225 80 180 Gain - dB 135 40 90 20 45 0 0 -20 -45 Gain -40 -90 -60 -135 0.1 Phase - Degrees Phase 60 1.0 10.0 F - Frequency - kHz 100.0 Figure 5. Loop Response Gain and Phase 7.4 Transient Response Figure 6.
Performance Data and Typical Characteristic Curves 7.5 www.ti.com Output Ripple Figure 7. Output Ripple 7.6 Gate Drive Signal and Switch Node Voltage Figure 8.
Performance Data and Typical Characteristic Curves www.ti.com 7.7 Turn-On Waveform Figure 9. Enable Turn-On Waveform 7.8 Turn-Off Waveform Figure 10.
Performance Data and Typical Characteristic Curves 7.9 www.ti.com Secondary-Side Switching Waveform VGS VDS Figure 11.
EVM Assembly Drawing and PCB layout www.ti.com 8 EVM Assembly Drawing and PCB layout Figure 12 through Figure 17 shows the design of the UCC28250EVM-501 printed circuit board. PCB dimensions: L x W = 3.4 in x 2.3 in, PCB material: FR406 or compatible, four layers and 2-oz copper on each layer. Figure 12. Top Layer Assembly Drawing (top view) Figure 13.
EVM Assembly Drawing and PCB layout www.ti.com Figure 14. Top Copper (top view) Figure 15.
EVM Assembly Drawing and PCB layout www.ti.com Figure 16. Internal Layer 2 (top view) Figure 17.
List of Materials 9 www.ti.com List of Materials The EVM components list according to the schematic shown in Figure 1. Table 3. UCC28250EVM-501 List of Materials REF DES 16 QTY DESCRIPTION MFR PART NUMBER C1, C8, C17, C18, C19, C20, C26, C28, C32, C37, C38, C41, C43 13 Capacitor, ceramic, 16 V, X5R, ±10%, 1 µF std std C10 1 Capacitor, ceramic, 50 V, X7R, ±10%, 470 pF std std C2, C5, C11, C12, C13, C14, C15, C16 8 Capacitor, ceramic, 2.
List of Materials www.ti.com Table 3. UCC28250EVM-501 List of Materials (continued) REF DES QTY DESCRIPTION MFR PART NUMBER R11 1 Resistor, chip, 1/16 W, 1%, 7.5 Ω std std R14, R15, R50 3 Resistor, chip, 1/8 W, 1%, 100 kΩ std std R16, R24 2 Resistor, chip, 1/8 W, 1%, 1.96 kΩ std std R17 1 Resistor, chip, 1/4 W, 1%, 59.0 kΩ std std R18, R19 2 Resistor, chip, 1/16 W, 1%, 19.
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