CAT4237

CAT4237 High Voltage CMOS Boost White LED Driver Description The CAT4237 is a DC/DC step−up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a constant switching frequency of 1 MHz allows the device to be used with small value external ceramic capacitors and inductor. LEDs connected in series are driven with a regulated current set by the external resistor R1. LED currents up to 40 mA can be supported over a wide range of input supply voltages from 2.8 V to 5.5 V, making the device ideal for battery−powered applications. The CAT4237 high−voltage output stage is perfect for driving six, seven or eight white LEDs in series with inherent current matching in LCD backlight applications. LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power−down mode with “zero” quiescent current. In addition to thermal protection and overload...