Abstract: This article demonstrates how to achieve current limit for the MAX1692 PWM step-down regulator by using a MAX4173H current-sense amplifier. Additional Information: Quick View Data Sheet for the MAX1692 Quick View Data Sheet for the MAX4173 Samples and Literature Order Form Technical Support: Power A current limit can be added to a step-down converter by using a MAX4173H current-sense amplifier to inject current into the feedback network. D1 sharpens the threshold of current limit by converting the current sense feedback signal from linear to exponential. This current-limit circuit can be scaled for any output current by adjusting R3. In this case, the MAX1692 provides up to 600mA output and the MAX4173H limits the output current by decreasing the output voltage for output current above 300mA. IL (mA) VOUT (V) 0 3.827 100 3.729 200 3.701 258 3.637 (-5%) 300 3.503 312 3.444 (-10%) 347 3.254 (-15%) 380 3.062 (-20%) 400 2.951 414 2.862 (-25%) 450 2.630 500 2.305 550 1.977 600 1.732 Related Parts   APP 478: Dec 01, 2000 MAX1692 Low-Noise, 5.5V Input, PWM Step-Down Regulator Full Data Sheet (PDF, 160kB) Free Samples Automatic Updates Would you like to be automatically notified when new application notes are published in your areas of interest? Sign up for EE-Mail™. We Want Your Feedback!   Download, PDF Format (31kB)  AN478, AN 478, APP478, Appnote478, Appnote 478