MAX17596 Evaluation Kit Evaluates: MAX17596 General Description Quick Start The MAX17596 evaluation kit (EV kit) is a fully assembled Recommended Equipment and tested circuit board that demonstrates an isolated One 18V36V DC, 2A power supply 20W fly-back DC-DC converter. The circuit uses the Electronic load devices peak current-mode controller in a 16-pin TQFN package with an exposed pad. The EV kit demonstrates Four digital multimeters (DMM) the ICs cycle-by-cycle current limit, soft-start, and EN/ MAX17596 24V EVKITB UVLO features. Warning: The EV kit circuit output is configured for an isolated +24V Do not turn on the power supply until all connections and provides up to 833mA of output current. The EV kit are completed. is configured to operate at a 200kHz switching frequency. An optocoupler, along with the transformer, provides Wear protective eye gear at all times. galvanic isolation between the input and output, up to Do not touch any part of the circuit with bare hands 1500V . RMS or conductive materials when powered up. Make sure all high-voltage capacitors are fully Features discharged before handling. Allow 5 minutes after 18V to 36V Input Range disconnecting input power source before touching Isolated Output: 24V DC at 20W circuit parts. Cycle-by-Cycle Current Limit Equipment Setup and Test Procedure Resistor Programmable UVLO/OVI Threshold 1) Set the power supply to +24VDC. Disable the power Low-Cost Flyback Design supply output. Galvanic Isolation Up to 1500V RMS 2) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the Proven PCB Layout nearest PGND PCB pad. Connect the positive terminal Fully Assembled and Tested of the electronic load to the VOUT PCB pad and the negative terminal to the nearest GND0 PCB pad. 3) Set the electronic load to constant-current mode and disable the electronic load. 4) Connect a DMM configured in voltmeter mode across the VOUT PCB pad and the nearest GND0 PCB pad. Ordering Information appears at end of data sheet. 5) Connect another DMM configured in voltmeter mode across the VOUT PCB pad and the GND0 PCB pad. 6) Enable the power supply. 7) Enable the load and adjust the current to 833mA. 8) Verify that the output voltmeter displays 24V 9) If required, vary the input voltage from 18V to 36V, the load current from 0mA to 833mA, and verify that the output voltage is 24V. 19-7708 Rev 0 7/15toc2 MAX17596 Evaluation Kit Evaluates: MAX17596 The detailed description of flyback design methodology Detailed Description and the calculations for component value selection are The MAX17596 EV kit provides a proven design to evaluate described in Application Note 5504: Designing Flyback the high-efficiency, DC-DC, flyback converter in a space- Converters Using Peak-Current-Mode Controllers. The saving, 16-pin TQFN package. The EV kit is configured details of soft-start time programming, programming output for a 24V output voltage that can supply up to 840mA voltage, peak-current-limit setting, switching frequency of current. The EV kit features a 200kHz fixed switching setting, and the EN/UVLO,OVI settings are described in frequency for optimum efficiency and component size. the MAX17595/MAX17596/MAX17597 IC data sheet. This EV kit uses the peak-current-mode, pulse-width- Note: The EV kit is shipped with the frequency dithering modulating (PWM) controller IC in a 16-pin TQFN disabled and the DITHER/SYNC pin shorted to SGND by package with an exposed pad. This PWM controller a 0 resistor. To set the desired frequency dither, replace varies the duty cycle to compensate for the variation resistor R23 with a capacitor of appropriate value, as in input voltage (V ) and the output load to maintain a IN detailed in the MAX17595/MAX17596/MAX17597 IC constant output voltage. The duty cycle determines the data sheet. The DITHER/SYNC PCB pad is available for on/off duration of the MOSFET (Q1). monitoring the signal at the DITHER/SYNC pin. EV Kit Performance Report EFFICIENCY vs. LOAD CURRENT OUTPUT VOLTAGE vs. LOAD CURRENT toc1 100 24.05 90 24 80 70 V = 24V V = 36V IN IN 23.95 V = 18V IN 60 50 23.9 V = 36V IN 40 V = 18V IN V = 24V IN 23.85 30 20 23.8 10 0 23.75 0 100 200 300 400 500 600 700 800 0 100 200 300 400 500 600 700 800 LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD TRANSIENT RESPONSE (LOAD CURRENT STEPPED BODE PLOT toc4 FROM 400 TO 833mA) toc3 PHASE 500mV/div V (AC) OUT F = 5.954KHz, CR PHASE MARGIN = 77.65 500mA/div I OUT 4.00mS/div Maxim Integrated 2 www.maximintegrated.com EFFICIENCY (%) OUTPUT VOLTAGE (V)