QX7138 is a PWM dimming, low dropout LED linear buck constant current driver.

QX7138 only needs an external resistor and an NMOS tube to form a complete LED constant current drive circuit. Adjusting the external resistor can adjust the output current. The adjustable range of the output current is 20mA to 3.0A.

QX7138 can also perform PWM dimming by adding an external signal to the DIM pin. The frequency range of the DIM pin input signal is 200HZ to 10KHZ. When the dimming function is not required, DIM can be left floating.

The normal operating voltage of QX7138 is 3.0V to 6.0V. When the power supply voltage is higher than 6.0V, the chip's operating voltage is clamped at 6.0V by an external clamping circuit to meet the high-voltage large-current constant-current LED drive.

QX7138 uses SOT-23-5 package.