CMOS LED IC is a drop-in replacement for bipolar drivers

Designed as a direct socket replacement for bipolar components, the TSCR4 family of linear CMOS LED driver ICs is available from Taiwan Semiconductor.

These linear constant current drivers provide stable LED current over a wide range of conditions including source voltage variations, changes in load or temperature variations. They offer a higher current set point accuracy and stability, lower quiescent current, tighter output compliance voltage and improved temperature co-efficient compared to legacy bipolar LED drivers, says Taiwan Semiconductor.

The TSCR4 ICs enable upgrades of existing designs for higher performance with no re-design effort required while offering designers benefits and improvements over competing bipolar devices such as improved accuracy and more precise output voltage drop. They ICs’ higher accuracy of output current improves manufacturing yields in mass production. The quiescent current is lower than competing bipolar devices – for example it provides 300mA compared with 1.0A at 24V DC, reports Taiwan Semiconductor. This lowers power dissipation and reduces battery standby and operating power consumption.

Another feature is more precise output voltage drop, which enables CMOS control of voltage drop for operation closer to the rail.

The higher stability of output current delivers consistent brightness control and extends LED life.

An improved temperature co-efficient (-0.07 per cent per degrees C). This controls the output current with temperature increases to eliminate risk of thermal runaway.

AEC-Q100 qualified TSCR4 parts are available for basic automotive lighting applications. Pulse width modulation dimming is possible up to 10kHz digital input for zero to 100 per cent dimming (the TSCR421CX6/H IC).

To support large LED arrays, the ICs supply up to 40V.

Applications include automobile, lorry and bus interior and exterior lighting, architectural lighting, signage, advertising and decorative lighting, lighting in refrigerators, freezer cases, kiosks and vending machines, emergency lighting systems.

Samples are in-stock now and available from distributors Digi-Key and Mouser.

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