Evaluates: MAX17606 MAX17606 Synchronous Flyback Evaluation Kit General Description Quick Start The MAX17606 evaluation kit (EV kit) is a fully assembled Recommended Equipment and tested circuit board that demonstrates an isolated 15W One 18V36V DC, 2A power supply synchronous flyback DC-DC converter. The circuit uses Load capable of sinking 3A the MAX17606 secondary synchronous rectifier driver in a 6-pin SOT23 package, as well as the MAX17597 peak Four digital multimeters (DMM) current mode flyback controller in a 16-pin TQFN package. MAX17606 SYNC FB EVKITA The EV kit circuit is configured to deliver an isolated +5V output Warning: voltage and provides up to 3A of output current. The EV kit is 1) Do not turn on the power supply until all connections programmed to operate at a 200kHz switching frequency. An are completed. optocoupler, along with the transformer, provides the galvanic isolation between input and output, up to 1875V . RMS 2) Wear protective eye gear at all times. 3) Do not touch any part of the circuit with bare hands or Features conductive materials when powered up. 18V to 36V DC Input Range 4) Make sure all high-voltage capacitors are fully discharged Isolated Output: +5V DC, 3A before handling. Allow 5 minutes after disconnecting input Compact Design with High (200kHz) Switching Frequency power source before touching circuit parts. 90% Peak Efficiency Equipment Setup and Test Procedure Low-Cost Flyback Design 1) Set the power supply to +24VDC. Disable the power supply output. Galvanic Isolation up to 1875V RMS 2) Connect the positive terminal of the power supply to the Proven PCB Layout V PCB pad and the negative terminal to the nearest IN Fully Assembled and Tested PGND PCB pad. Connect the positive terminal of the 3A load to the V PCB pad and the negative terminal to OUT Ordering Information appears at end of data sheet. the nearest GND0 PCB pad. 3) Connect two DMMs, configured in voltmeter mode, across the input and output terminals to measure the input and output voltage, respectively. 4) Connect two DMMs configured in ammeter mode at the input and output to measure the input current and output current. 5) Enable the power supply. 6) Verify that the output voltmeter displays 5V and the output load current is 3A. 7) If required, vary the input voltage from 18V to 36V, the load current from 0mA to 3A, and verify that the output voltage is 5V. 19-7805 Rev 0 11/15Evaluates: MAX17606 MAX17606 Synchronous Flyback Evaluation Kit The device has a provision to program the turn-off trip Detailed Description point of the secondary synchronous rectifier. An external The MAX17606 EV kit provides a proven design to resistor (R25) connects the drain of the external MOSFET evaluate the MAX17606. The device is a secondary-side to the ICs DRN pin. This resistor sets the turn-off trip synchronous driver and controller specifically designed point with a precise internal current source. Once the for the isolated flyback topology. By replacing the synchronous rectifier is turned off, the MAX17606 uses secondary diode with a MOSFET, the MAX17606 improves resistor R26 (connected between the T pin and OFF efficiency and makes thermal management easier. The GND0) to program the turn-off time in order to provide device EV kit is configured for a 5V output voltage, immunity from DCM ringing. For the selection of R25 and supplying up to 3A of current. R26 resistors, refer to the MAX17606 data sheet. This EV kit uses the peak current mode, pulse-width Note: The EV kit is shipped with frequency dithering modulating (PWM) controller IC MAX17597 in a 16-pin disabled and the DITHER/SYNC pin shorted to SGND by TQFN package with an exposed pad as the primary-side a 0 resistor. To set the desired frequency dither, replace flyback controller. This PWM controller varies the duty R23 with a capacitor of appropriate value, as detailed in cycle to compensate for the variation in input voltage (V ) IN the MAX17595/6/7 data sheet. The DITHER /SYNC PCB and the output load to maintain a constant output voltage. pad is available for monitoring the signal at the DITHER/ The detailed description of flyback design calculations are SYNC pin. described in Application Note 5504, Designing Flyback Converters Using Peak Current-Mode Controllers. The details of soft-start time programming, programming output voltage, peak-current limit setting, switching frequency setting and the EN/UVLO, OVI settings are described in the MAX17595/6/7 data sheet. The MAX17606 has a wide range of input voltage from 4.5V to 36V. The input range makes it simple to drive using one of the following two methods. When the output voltage is 5V and greater, V can be used to directly OUT drive V . When the output voltage is less than 5V, use IN the rectified drain voltage of the secondary synchronous MOSFET to drive V . The EV kit circuit has an option IN for both of these configurations. By default, the EV kit is programmed to run from the rectified drain voltage of the synchronous MOSFET. When running the MAX17606 from the output voltage is required, remove R1 and set R31 to 10. Maxim Integrated 2 www.maximintegrated.com