is a Synchronous Buck Converter implementing Intersil's wide input range PWM controller ISL8115. Utilizing voltage mode control with input feed forward, the ISL8115EVAL2Z maintains a constant loop gain for optimal transient response, especially for applications with a wide input voltage range. For a more detailed description of the ISL8115 functionality, refer to the ISL8115 data sheet. This application note includes the test setup, typical performance waveforms, schematic, layout and bill of materials (BOM).
Wide VIN range operation: to 5.5V output and 30A load current per phase. Fast transient response - Voltage-mode PWM leading-edge modulation with non-linear control - Input voltage feed-forward Integrated 5V high speed 4A MOSFET gate drivers - Internal bootstrap diode Oscillator programmable from 1.5MHz - Frequency synchronization to external clock signal Diode emulation mode for light load efficiency improvement Output OVP/UVP; OCP and OTP Power-good open drain output Adjustable soft-start Pre-bias start-up function Excellent output voltage regulation 0.6V �1.0% internal reference 0.6V �0.7% internal reference (-40�C~105�C) - Differential voltage sensing
TABLE 1. EVALUATION BOARD ELECTRICAL SPECIFICATIONS SPEC VIN VOUT IOUT IOC Fsw DESCRIPTION Board Input Range Output Voltage Output Rated Current Overcurrent Threshold Switch Frequency MIN 25 TYP MAX UNIT 36 kHz V %
Input UVP Rising threshold Falling threshold Efficiency at 50% loadApplications
Power supply for datacom/telecom and POL Wide input voltage range buck regulators High current density power supplies RF power amplifier bias compensation
Input power source to 36V supply voltage with 125W power supply ability. Electronic load with 100W power sinking ability Voltmeters and ammeters 100MHz quad-trace oscilloscope
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-468-3774 | Copyright Intersil Americas LLC 2013. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners.
1. Ensure that the Evaluation board is correctly connected to the power supply and the electronic load prior to applying any power. Please refer to Figure 2 for proper set-up. 2. Set the input voltage to 28V, turn on the power supply and observe output voltage. The output voltage should variation should be within 5%. 3. Adjust load current within 20A. The output voltage variation should be within 5%. 4. Use oscilloscope to observe output ripple voltage and phase node ringing. For accurate measurement, please refer to Figure 3 for proper set-up. Note: Test points TP8; TP9 are for voltage measurement only. Do not allow high current through these test points.
The ISL8115EVAL2Z is optimized for to 36V input voltage range. However, the evaluation board can be modified to support multiple applications due to the customer requirements. Please refer to the datasheet for the detailed information.
The output voltage can be set by the resistor R1. In order to keep the existing compensation parameters unchanged, adjust R4 to set the output voltage by the following Equation 1:
VMON monitors the output for UVP and OVP, the resistor divider value of R11/R8 should be the same with the R1/R4.
ISL8115EVAL2Z board can be synchronized with an external clock. Apply a clock signal to 90% duty cycle) in the range 1.5MHz to the FSET pin makes the internal frequency synchronized with the external clock. Please remove R27 when the sync function is implemented.
