1 A constant current LED driver with PWM dimming

     ON Semiconductor's CAT4101 is a constant-current receiver that drives a string of high-brightness leds up to 1 a with an extremely low 0.5V drop at full load. The device comes in a high-power, 5-lead TO - 263 package that provides excellent heat dissipation characteristics. It does not require inductance, provides low noise operation, and minimizes the number of components.

     The LED current is set by an external resistor connected to the RSET pin. LED pins are compatible with high voltages up to 25v, allowing long strings of leds to be driven. The device ensures accurate and adjustable current in the LED, independent of changes in the power supply and the forward voltage of the LED. The PWM/EN input allows the use of an external pulse width modulation (PWM) signal to turn off the device and adjust the LED brightness. The drive features a thermal stop protection that activates whenever the die temperature exceeds 150°C.