TB921/22/23
3-Pin Switch-Mode LED Lamp Driver ICs
General Description：
The TB921/22 are pulse width modulated (PWM) high-efficiency LED driver control ICs. They allow efficient
operation of LED strings from voltage sources ranging up to 400VDC. The TB921/22 include an internal high
voltage switching MOSFET controlled with fi xed off-time TOFF of approximately 10μs. The LED string is
driven at constant current, thus providing constant light output and enhanced reliability. The output current is
internally fi xed at 20/50mA for TB921/22. The peak current control scheme provides good regulation of the output
current throughout the universal AC line voltage range of 85 to 264VAC or DC input voltage of 20 to 400V.
Features：
● Constant Output Current:
TB921 – 20mA
TB922 – 50mA
TB923 – 30mA
● Universal 85-264VAC Operation
● Fixed OFF-Time Buck Converter
● Internal 500V Power MOSFET
Applications：
● Decorative Lighting
● Low Power Lighting Fixtures
