MAX1954EUB+

PMIC - Voltage Regulators - DC DC Switching Controllers

The MAX1954EUx+ is a high-efficiency DC-DC switching controller designed to simplify the design of power-supply systems. It features high efficiency, fast transient response, low output noise, fast current limiting, and low output voltage ripple. This controller has a wide applicability, making it suitable for a variety of application fields.

Features

• High input voltage range (9V to 75V)
• Output current range of 1A to 35A
• Low RDS(on) Digital Current Limiting
• Extended PWM frequency range from 100kHz to 500kHz
• Programmable Over Temperature, Under Voltage Lockout, and Fault Flags
• Input & output OVP, OCP, and UVP
• On-chip thermal shutdown
• A low-voltage site over-temperature monitor (OTMT) to protect external MOSFETs
• Digital PFM Mode
• Selectable Frequency Foldback (FF) operation.
• EMI filterless operation at 2MHz.

Applications

The MAX1954EUx+ has high performance and flexibility. It is suitable for a wide range of applications, such as:

• Automotive battery chargers
• Multi-output power supplies
• Hybrid electric vehicles
• Portable medical equipment
• Variable LED lighting
• Industrial robots
• Telecommunications power supplies

Working Principle

The MAX1954EUx+ is a voltage-mode DC-DC switching controller. Its internal circuitry generates a reference signal, which is compared with a predetermined feedback voltage across a sense resistor connected between the output of the power supply and ground. The MAX1954EUx+ switches off the external power MOSFETs when the feedback voltage reaches the reference signal, and switches them on when the feedback voltage drops below the reference signal. This results in the Pulse-Width Modulation (PWM) operation.

In addition to PWM, the MAX1954EUx+ features two other modes of operation, namely Frequency Foldback (FF) and Pulse Frequency Modulation (PFM) modes. In FF mode, the operating frequency is set initially by the external resistor and capacitor, and is then folded back as the load current increases. PFM mode is enabled when the load current reaches a certain threshold. In PFM mode, the device switches off at lower on-time intervals and switches on at higher off-time intervals, resulting in lower output ripple and lower power consumption.

The MAX1954EUx+ also features Digital Current Limiting (DCL) protection. In the event of an overload condition, the device reduces the output current to protect the external MOSFETs and the load. It also features built-in protection for output voltage over-voltage (OVP), under-voltage (UVP), and over-temperature (OT) conditions. It also features a low-voltage site over-temperature monitor to protect external MOSFETs.