The ZD1937 is a constant frequency, current mode PWM, inductor based step-up (boost) converter especially designed to drive multiple white LED’s in series. The LED current is regulated in this converter design so that all LED’s have the same current and therefore have inherently matched light output. The converter design operates at high frequency (1.2MHz) operation so that a small, low profi le inductor can be used as well a small value output integrating capacitor. The ZD1937 has built-in over-voltage protection (OVP) with internal thermal shutdown ability to prevent device from overvoltage or an open circuit condition at the voltage output. The ZD1937 is available in either a space saving SC70, a SOT25, or ThinSOT25 package for very small board space applications.