DC-DC Buck Converter Design Example Using MIC28515
The MIC28515 is a high-performance switching regulator designed for applications requiring robust power management. It can handle a wide input voltage range from 4.5V to 75V and supports an adjustable output voltage from 0.6V to 32V, constrained by the duty cycle. With a current capability of 5A, it's suited for high power demands.
Key features include:
Adaptive Constant On-Time Control (ACOT), which optimizes efficiency across load and line conditions
Switching frequency adjustable between 270 kHz and 800 kHz, allowing for flexibility in design to balance between size and efficiency
An internal 0.6V reference for precision regulation
A high voltage internal low-dropout (LDO) for operation from a single supply, simplifying design
Supports pre-bias startup, which is critical for sensitive applications where output voltage is already present
Internal compensation to ease PCB layout and design
An enable function for power management, reducing standby current when disabled
Programmable soft start to control inrush current, protecting components during startup
Programmable current limit for overcurrent protection
Thermal shutdown with hysteresis to prevent thermal damage
The device operates in Continuous Conduction Mode (CCM) only, which helps in reducing noise at low output currents
Options for High Light Load (HLL) or CCM operation for efficiency at different load conditions
Comes in a compact 6 x 6 mm VQFN package, suitable for space-constrained applications
Operational over a broad temperature range of -40°C to +125°C
This regulator is ideal for industrial, automotive, and telecom applications where high efficiency, wide input range, and robust performance are necessary.
The MIC28515 is an excellent design example for the MPLAB® Mindi™ Analog Simulator , showcasing its capabilities in power management. Specifically, this example illustrates how to simulate a Constant On-Time (COT) buck regulator with external ripple injection. Using this example, users can explore the startup behavior, observe the effects of varying load conditions, and analyze the switching and output voltage waveforms. This simulation helps in understanding the stability and load step response of the system, providing a practical insight into designing efficient power solutions before moving to hardware prototyping.