o Input Voltage: 44 … 60V DC
o Output Voltage: 12 … 20V DC (programmable)
o Output Current: 12.5A (avg.) / 25A (max.)
o High efficiency: 98.2% @ 20V/12.5A output
o Low profile: 6.5 mm component height
o Temperature rise: < 40 °C @ 20 Vout with 12.5 A output
o Constant switching frequency: 400 kHz
o Re-programmable
o 150% over current for 10ms
o 200% over current for 1ms
o Fault protection:
Input undervoltage
Input overvoltage
Output over voltage
Short circuit
Over current
Applications:
• High Performance Computing – computers, displays, thin consumer electronics
The 6.5 mm thin EPC9153 power module is a 250W high-efficiency, high-performance synchronous buck converter with 60 V maximum input voltage, 12.5 A maximum output current, and programmable 12-20 V (default set to 20 V) regulated output voltage. Developed in collaboration with Efficient Power Conversion Corporation (EPC), it features the high-performance dsPIC33CK Digital Signal Controller (DSC), EPC2218 and EPC2038 eGaN® FETs.
While other reference designs such as EPC9148 have been optimized for highest power densities, this conventional non-isolated, hard-switching step-down converter is optimized for maximum output power capability at the highest efficiency (> 98.2%) with a maximum temperature rise of +40 K above ambient with passive cooling. With a total power density of only 112 W/in³, this converter is capable of providing up to 200% (500W / 25A max.) of its nominal output power for a limited amount of time at a peak efficiency of >98.2%. For test purposes, the over-power time limits have been set to 10ms for 150% and 1ms for 200% load. Each boost-mode time limit can be reconfigured and tailored to known test conditions by the user. On the other side of the load spectrum, the power consumption under no-load conditions has been minimized by applying a hysteretic standby mode, in which the converter still provides a regulated output voltage at only 280 mW total power consumption, supporting fast recovery of fixed frequency operation within 100 µsec.
The digital control loop in this design enables the non-linear switch-over between control modes across load conditions and self-protecting over-power boost modes, expanding the support of extreme load dynamics of high-performance loads like CPUs and FPGAs. The 250ps resolution fine-edge placement of the PWM module enables efficiency enhancements through dead-time optimization.
For more information on hardware related documentation, design files and purchasing information, please visit EPC’s product website:
EPC9153 – 250 W High Efficiency, Thin Power Module
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EPC9153 250W 48V Thin Profile Synchronous Buck Converter Firmware | 18 Jul 2024 | Link |
Digital Control Stage:
The default control system of the EPC9153 power module is a conventional average current mode control loop, consisting of an outer voltage loop providing the reference to an inner current loop based on the detected voltage error. The inner current loop then regulates the inductor current to correct the power delivered to the output compensating the deviation of the voltage error. The current feedback is derived from a MCP6C02 shunt amplifier, sensing the voltage drop across a shunt amplifier located at the output of the converter. As the discrete current loop is based on selective sampling, the current feedback loop can track the effective average inductor current despite the fact that the feedback signal itself is not precisely synchronous to the real inductor current but phase-shifted and with damped peaks.
Converter Design:
The synchronous buck power module features the high-performance dsPIC33CK32MP102 Digital Signal Controller DSC. This 100 MIPS single-core device is equipped with dedicated peripherals for Switched-Mode Power Supply (SMPS) applications, such as a feature-rich 4-channel (8x output), 250ps resolution pulse width modulation (PWM) logic, three 3.5 Msps Analog-To-Digital Converters (ADC), three 15 ns propagation delay analog comparators with integrated Digital-To-Analog Converters (DAC) supporting ramp signal generation, three operational amplifiers as well as Digital Signal Processing (DSP) core with tightly coupled data paths for high performance real-time control applications. The device used is the smallest derivative of the dsPIC33CK single-core and dsPIC33CH dual-core DSC families. The device used in this design comes in a 28-pin 6x6mm uQFN package, specified for ambient temperatures from -40 to +125° C. Other packages including a 28 pin uQFN package with only 4x4 mm are available with operating temperatures from -40 to +150° C. The dsPIC33CK device is used to drive and control the converter in a fully digital fashion where the feedback loops are implemented and executed in software. It implements constant frequency, average current mode control.
The board also features a GaN power stage using the EPC2218 and EPC2038 eGaN® FETs. The uP1966A gate driver that features high driving strength is used to drive the FETs. The synchronous bootstrap circuit ensures 4.9 V gate voltage is used for the high-side gate drive. Digital control that allows sub-10 ns dead-time and flexibility in control scheme development is employed. To optimize the efficiency, two small on-board switch-mode power supply circuits are used to generate the housekeeping 5 V and 3.1 V voltages for the gate driver and the digital controller respectively