Using the UCC24610EVM-693 User's Guide Literature Number: SLUU450 September 2010
User's Guide SLUU450 – September 2010 UCC24610EVM-693 Secondary-Side Synchronous Rectifier Controller Diode Replacement Demonstration Board 1 Introduction This demonstration board is intended for use to evaluate efficiency improvements gained by synchronous rectification compared with schottky diode rectification in low-power 5-V output circuits. System output power level should be limited to 10 W or less (depending on the MOSFET used).
Installation www.ti.com 2 Installation To install the demonstration board, remove the diode to be emulated. Connect the VS pin of the board to the anode pad of the host circuit, and connect the VD pin of the board to the cathode pad of the host circuit. Connect the VCC terminal to the 5-V output with a short piece of wire. For DCM applications, the installation is complete. VCC + 5V - VS VD VS VD + 5V - VCC Figure 2.
Detailed Installation Instructions for use of SR Demonstration Board 3 www.ti.com Detailed Installation Instructions for use of SR Demonstration Board The SR Demonstration Board is pre-programmed for: 1. TON = ~1ms using 66.5 kΩ, and 2. TOFF = ~5.5 µs using 154 kΩ. Adjust TON and TOFF resistor values for your system board by the following procedure: 1. Observe the ringing at turn-on of the schottky diode during the flyback period under maximum-load, low-line conditions.
CCM Applications www.ti.com 5 CCM Applications For CCM applications, it is important to feed forward a SYNC signal from the primary side to turn-off the SR-MOSFET to prevent cross-conduction with the primary-side MOSFET. Attach SYNC “pad” to a synchronization signal derived on the system board. The UCC24610 controller requires a negative-going SYNC signal referenced to VCC to trigger turn-off of the SR-MOSFET.
CCM Applications www.ti.com See UCC24610 datasheet for SYNC application design information and capacitance selection. Figure 6. Component Placement Figure 7. Schematic of Demonstration Card Notes: 1. Do not exceed 50 V across VD to VS. 2. Connect VS to anode pad of diode (GND). 3. Connect VD to cathode pad of diode. 4. Connect VCC to 5-V output of mother board. 5. Connect SYNC (if used) with capacitor network to primary-side MOSFET drain.
List of Materials www.ti.com 6 List of Materials Table 1. List of materials (1) COUNT (1) (2) (3) 7 REF DES DESCRIPTION PART NUMBER MFR 1 C1 Capacitor, ceramic, 0.33 µF, 16 V, X7R, ±10%, 0805 Std Std 1 Q1 (2) MOSFET, N-channel, 55 V, 42 A, 8 mΩ, DPAK IRLR3705ZPBF International Rectifier 1 R1 (3) Resistor, chip, 66.5 kΩ, 1/8 W, ±1%, 0805 Std Std 1 R2 Resistor, chip, 154 kΩ, 1/8 W, ±1%, 0805 Std Std 1 R3 Resistor, chip, 2.
Evaluation Board/Kit Important Notice Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must have electronics training and observe good engineering practice standards.
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