MAXREFDES1220: Bootstrap, 5V/2A, step-up DC-DC converter with 90% efficiency, using MAX16990

This reference design boosts a single-cell battery voltage input to a 10W output using the MAX16990 controller in bootstrapped mode. In order to use the part below 4.5V, the part needs a bootstrap on the input, ensuring there is a minimum of 4.5V on the supply pin to turn on the IC. Therefore, this reference design has a low input range of 2.5V to 4.5V and can be used to generate up to 2A at 5V.

The MAX16990 IC is a current-mode PWM controller with very low shutdown current used for wide input-voltage range boost/SEPIC converters. The IC’s 4.5V to 36V input operating voltage range makes this device ideal in automotive applications. An internal low-dropout regulator with a 5V output voltage enables the MAX16990 to operate directly from an automotive battery input. As mentioned, the input operating range can be extended to as low as 2.5V when the converter output is applied to the SUP input. It is available in compact 12-pin TQFN and 10-pin μMAX® packages.