qx9921 is a high efficiency, stable and reliable high-brightness led lamp constant current drive control chip, built-in high-precision comparator, fixed off-time control circuit, constant current drive circuit, etc., especially suitable for high-power, multiple high-brightness led lights string constant current drive.
qx9921 adopts the peak current control method with fixed off time, and its operating frequency can be up to 1mhz, which can reduce the volume of external inductors and filter capacitors, improve efficiency, and save pcb area. the turn-off time can be adjusted by an external capacitor, and the operating frequency can also be adjusted according to user requirements. add a pwm signal to the en terminal to adjust the brightness of the led light.
qx9921 sets the current flowing through the led lamp by adjusting the resistance of the external current detection resistor. it supports linear dimming of the applied voltage. the current flowing through the led lamp can vary from tens of milliamperes to 2.5 amperes.
qx9921 adopts esop8 package, and the heat sink is built-in to sw pin.
ø built-in 100v power tube
ø wide input voltage range: 5v ~ 100v
ø high efficiency: up to 92%
ø maximum working frequency: 1mhz
ø peak current sampling voltage: 250mv
ø brightness adjustable: pwm dimming at en and linear dimming at dim
ø adjustable off time
ø built-in current sampling leading-edge blanking circuit
typical application circuit diagram
stay tuned for updates!
ø flat panel display led backlight
ø bicycle light
ø led spotlight
ø glare flashlight