IRDC2085S-DF DEMO BOARD EVALUATION PROCEDURE International Rectifier * 233 Kansas Street, El Segundo, CA 90245 USA Overview This document describes how to connect and evaluate the supplied IRDC2085S-DF demo board. The demo board incorporates a new DC Bus Converter chipset in a fixed-frequency, open-loop isolated half-bridge DC-DC converter with 6:1 input to output voltage conversion ratio. The chipset consists of a primary side IC (IR2085S), two 80V primary side FETs (IRF7493), two 30V secondary side FETs (IRF6618), a primary side biasing FET (IRF7380) and a secondary side gate clamp FET (IRF9956). The front side of the demo board is shown in Fig. 1. - Vout - Vin + Vout + Vin *IRDC2085S-DF 150W DC Bus Demo Board Fig. 1 Front side of the DC Bus Converter demo board with IR2085S ChipSet with marked input and output pins. This version of the Demo Board employs DirectFET Power MOSFETs for secondary synchronous rectification * IRDC2085S-DF Quick Evaluation Procedure To evaluate the operation and performance of the IRDC2085S-DF demo board, connect a power supply to its input terminals, and a power load to its output terminals. Input and output terminals are marked in Fig. 1. To duplicate the performance data reported on page two, approximately 400 LFM of airflow is needed across the module. The circuit will start to operate as soon as the primary Vcc reaches about 9V - typically at 12Vin. At this low input voltage, the output voltage will be only about 2V, and the secondary Vcc will be insufficient to fully enhance the secondary side synchronous rectifier MOSFETs. To avoid excessive body diode conduction losses, output current during slow input voltage ramp-up should be set at less than 2A. IRDC2085S-DF Demo Board Description and circuit capability The circuit is designed to deliver continuous 20A output current in 36V - 60V input voltage range, with 400 LFM of airflow. Output voltage for this input voltage range will vary from 6V to 10V, and the total available output power from the module will range from around 120W at 36V to up to 200W at 60V input. The circuit design is optimized in order to demonstrate true performance of the IR2085S control IC, IRF7493 primary FETs and IRF6618 secondary DirectFETs. Therefore, no test pins are available on the board. To probe the circuit waveforms use an oscilloscope probe with minimal length for the ground pin and connect directly to the pins of the IC / MOSFET device. To measure circuit efficiency, voltage and current at the input and output of the demo board need to be accurately measured. Use of calibrated shunts for input and output current measurements is strongly recommended, as is use of a thermal camera for thermal performance evaluation International Rectifier A complete schematic of the demo board is shown in Fig. 2. Typical efficiency and a thermal image for 150W output power at 48Vin are shown in Fig. 3. Inputs and outputs of two or more modules can be connected in parallel to provide required output power higher than 150W. Due to natural output voltage droop associated with open-loop operation, no additional circuitry is required for relatively accurate current sharing (in the range of +/10%). Rb2 Rb1 NM6 IRF7380 Db3 200 36~60Vinput Rb9 39k Db5 3V Db1 15V T D R 56k IC1 IR2085S C6 47 CS VB OSC HO GND VS LO VCC Cb2 .1u Db2 9V Rg2 100k NM1 IRF7493 C5 1u NM3 Rg3 10k 6~10Vout C1 3.3u C3 NM5 IRF9956 1u C2 3.3u Vcc C7 22u C8 22u IRF6618 or IRF7832 Remote Shutdown 36~60Vinput C4 1u Cb1 .1u Vcc D4 Vcc Rb10 39k Db4 200 NM4 NM2 IRF7493 L Rg4 10k IRF6618 or IRF7832 Fig. 2 Complete schematic of IRDC2085S-DF Demo Board IRF7493 Primary Side and IRF6618 Secondary ElectricaL Efficiency [%] 97 96.5 IRF6618 72 96 64 95.5 71 62 68 64 95 94.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 Output Load Current, Io [A] Fig. 3 Efficiency and Thermal image at 48Vin, 150W out max, @ 400LFM *IR2085S demo board has (2) versions: - IRDC2085S-DF (uses IRF6618 DirectFET MOSFETs for secondary synchronous rectifiers NM3 & NM4) - IRDC2085S-S (uses IRF7832 SO8 MOSFET for secondary synchronous rectifiers NM3 & NM4) International Rectifier IRDC2085S-DF Demo Board PCB Layout (Total of 8 layers) Top Layer Bottom Layer Layer #1 Layer #2 Layer #3 Layer #4 Layer #5 Layer #6 Note : The above Gerber file is available upon request International Rectifier IRDC2085S-DF DC Bus Converter Demo Board BOM List Item No Ref. Designator Description Part Number Value Package 1 2 IC1 NM1, NM2 Controller IC Single N-Channel Power MOSFET IR2085S IRF7493 100V, +/- 1.0A 80VN, 15mOhm 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 NM3, NM4 NM5 NM6 Db4 D, Db3 Db1, Db6 Db2 Db5 C1, C2 C3 C7, C8 CB1,CB2 C4,C5 C6 Rg3, Rg4 Rb9, Rb10 R Rg2 Rb1, Rb2 Single N-Channel Power MOSFET Dual N-Channel Power MOSFET Dual N-Channel Power MOSFET Dual Rectifier Diode Rectifier Diode Zener Diode Zener Diode Zener Diode Ceramic cap Ceramic cap Ceramic cap Ceramic cap Ceramic cap Ceramic cap Resistor Resistor Resistor Resistor Resistor IRF6618 IRF9956 IRF7380 BAT54S BAV16WDICT-ND BZT52C15SDICT-ND BZT52C9V1SDICT-ND BZT52V3V0SDICT-ND THCR50E1H335ZT ECJ5YB2A105M GRM43E61C226KE01B PCC1840CT-ND PCC2224CT-ND PCC1470ACVCT-ND P10KGCT P39KACT P51KGCT P100KGCT P200ECT 22 23 24 25 Tr_a, Tr_ 2.4 mil Gap Lo_a Lo_a PQ20/16-3F3 200FN919 E14/3.5/5-3F3 E14/3.5/5-3F3-A160-E 26 27 28 PCB Tab Connector PQ Transformer Core, grinded PQ core center gaped(cut to fit) material Inductor Core, non-gaped half Inductor Core, gapped half PCB (8 layers: 3 Oz Cu top & bottom layers, 4 Oz Cu center layers, 2.125"x0.8125") For input & output connection Banana Jack, Insulated Nylon, Red & Black 30VN, 2.2mOhm DirectFET 30VN, 100mOhm SO8 80VN, 73mOhm SO8 30V SOT23 75V SOD123 15V SOD323 9V SOD323 3V SOD323 3.3u, 50V 1812 1u, 100V 1812 22u, 16V 1210 0.1u, 25V 805 1u, 16V 805 47pf 603 10K 603 39K 805 51K 603 100K 603 200 1206 Window width = 2.4mm grinded Kapton Polyimide Film 3125-2-00-01-00-00-08-0 J151-ND International Rectifier SO8 SO8 Vendor IR IR IR IR IR IR Digi-key Digi-key Digi-key Digi-key Digi-key Panasonic Digi-key Digi-key Digi-key Digi-key Digi-key Digi-key Digi-key Digi-key Digi-key Feroxube Dupont Feroxube Feroxube Mill-Max Digi-key