MAXREFDES1196: 24V/4A DC-DC Boost Converter Using the MAX17499B Step-Up Controller
|Input Type||VIN (MIN)
The MAXREFDES1196 is a DC-DC boost power supply that delivers up to 4A at 24V from a 10V to 18V supply voltage. It is designed for equipment that needs a high-power, 24V output voltage that is generated from a 12V DC bus.
The MAXREFDES1196 employs techniques that use the boost regulators to generate voltage higher than input voltage. This document explains how the MAX17499B current-mode PWM converter can be used to generate 24V from 10V to 18V input voltage.
The MAX17499B current-mode PWM controller contains all the control circuitry required for the design of wide-inputvoltage isolated and nonisolated power supplies. The MAX17499B is well suited for low input voltage (9.5VDC to 24VDC) power supplies. An input undervoltage lockout (UVLO) is provided for programming the input-supply start voltage and to ensure proper operation during brownout conditions. An open-drain UVLO flag output with 210μs internal delay allows the sequencing of a secondary-side controller. The input-supply start voltage is externally programmable with a voltage-divider. A UVLO/EN input is used to shut down the devices. Internal digital softstart eliminates output voltage overshoot. The switching frequency for this IC is programmable with an external resistor. The MAX17499B provides a 75% maximum duty-cycle limit. This device is available in 10-pin μMAX® package and is rated for operation over the -40°C to +125°C temperature range.
Designed, Built, Tested
This document describes the hardware shown above. It provides a detailed, systematic technical guide to design a boost converter using the MAX17499B current-mode PWM controller. The power supply has been built and tested, details of which follow later in this document.