A high speed buck control IC for constant LED current regulation. A continuous mode hysteretically controlled buck regulator monitors the load current using an accurate on-chip band-gap voltage reference. This style of current regulation allows the designer to dispense with large and sometimes bulky output capacitors. The IC is inherently protected against short circuit conditions, and an additional circuit provides open circuit protection. An external high side bootstrap circuit aids in driving the buck switching element especially at high frequencies. A low side driver is also provided for use, e.g. in synchronous rectifier designs. All functions are realized within a small 8 pin DIP or SOIC package.