What Problem This Class of Device Solves
LED driver ICs supply constant-current drive to LED loads, converting an unstable input voltage into a current held within a set accuracy — used in lighting, display backlighting, and indicator applications. The core requirement is keeping LED brightness stable as input voltage and temperature vary, with dimming support where the application needs it.
How to Read the Key Parameters
Input voltage (Vin): catalog parts span a wide 1.3V–60V (tiers such as 5–24V, 5–42V, 3–24V, 1.3–60V, 4.5–42V). Pick the tier whose margin matches the supply rail feeding the LED load, such as an automotive 12V/24V bus or a wide-voltage application.
Output current setting (Io Setting): catalog parts split into two types — fixed-tier parts with a discrete current table (e.g. 15/20/25…60mA) and adjustable (Adj) parts spanning ranges like 15–150mA, 15–200mA, 15–350mA. Fixed-tier parts need no precision external resistor; adjustable parts use one external resistor/current to cover a wider range flexibly.
Current-setting method (Current Setting): catalog parts flagged "Y" support external-resistor current adjustment — this directly affects whether the BOM needs an added precision resistor.
PWM dimming: only some adjustable-type parts support it (flagged "Y"); most fixed-current-tier parts have no PWM dimming input. Whether the end product needs dynamic dimming decides which branch to pick.
Output current accuracy (Io Accuracy): catalog parts are uniformly rated at ±5%, the baseline figure for judging brightness uniformity across parallel/series LED strings.
Three Steps to Select
- Bound the Vin tier by the supply-rail voltage feeding the LED load.
- Pick a fixed-tier part (discrete Io Setting table) or an adjustable part (Adj range) based on the target current and whether fine adjustment is needed.
- If the end product needs dynamic/stepless dimming, favor parts flagged "Y" for PWM Dimming, and confirm package group fits the PCB space.
Common Pitfalls
- Forcing a non-standard current value out of a fixed-tier table — those are discrete values; use an Adj part when fine adjustment is required.
- Overlooking how current accuracy affects parallel/series matching — even at a uniform ±5%, multiple parallel LEDs can still show visible brightness mismatch, so evaluate whether extra current-balancing is needed.
- Confusing the Vin range with the LED string's forward-voltage requirement — Vin is the driver IC's own supply range, not a direct ceiling on the LED string voltage it can drive; that depends on the circuit topology.
To filter parts by specific parameter ranges, use the online selection tool on this site, or contact our engineers for support.