Constant-Current LED Driver ICs: Buck and Boost Topologies for Lighting
An LED's brightness is set by its current, not its voltage — and its forward voltage drifts with temperature and bin. That is why lighting designs use constant-current (CC) drivers rather than plain voltage regulators. Feeling Technology's LED driver family spans buck and boost CC topologies across SOT23-6 to DFN-10 packages, all in stock as an independent distributor.
Buck CC drivers: when the LED string sits below the input
In a buck LED driver the switch, inductor and LED form a current-chopping loop that averages to the programmed current. Use it whenever the string forward voltage is below the input rail — 12 V or 24 V input driving one to a few LEDs. The family is broad: FP8013XR-G11 and FP7102DR-LF / FP7103XR-LF in SOP-8(EP) for higher power, the SOT23-6 FP7126LR-G1, FP7127 / FP7128 in SOP-8(EP), the SOT23-6 FP7130 / FP7130A and SOP-8(EP) FP7132, the FP7135L / FP7135D pair in SOT23-6 and SOP-8, and the DFN-10L FP7153 for compact, thermally demanding boards.
Boost CC drivers: when the string needs more voltage than you have
Long strings — LED tube retrofits, automotive daytime running lights, high-voltage backlights — need the driver to step up. Boost CC topology pumps the inductor energy into the string above the input rail. Feeling's boost CC parts include FP7208 and FP7209 in SOP-8(EP) and the TSSOP-14 FP7209M for feature-rich designs.
Dimming: PWM or analog
- PWM dimming switches the LED current fully on/off at a fast rate — colour temperature stays constant across the dimming range, which matters for RGB and tunable-white fixtures.
- Analog dimming scales the current setpoint — simpler EMI behaviour, but the LED colour can shift at low currents.
- Many FP7xxx parts accept both via a dimming pin; check the pin function and frequency range on the datasheet for your chosen part.
Selection quick-reference
| Need | Topology | Candidate parts |
|---|---|---|
| 12/24 V input, short string | Buck CC | FP7126 / FP7130 / FP7135 / FP8013 |
| Higher current, good thermal path | Buck CC, EP package | FP7102 / FP7103 / FP7132 / FP7153 |
| String voltage above input | Boost CC | FP7208 / FP7209 / FP7209M |
Layout notes for CC drivers
- The current-sense resistor sets accuracy — use a low-TCR part and Kelvin-route it.
- Keep the power loop tight and the sense trace away from the switch node.
- EP packages (SOP-8(EP), DFN-10L(EP)) need copper pour underneath; LED drivers run hot by design.
Sourcing
- All parts are listed under Power Management Chips with live quantities and date codes.
- Upload your BOM for a full lighting-board quote, or contact us for volume pricing.
Questions & Answers
Why do LEDs need a constant-current driver instead of a voltage regulator?
LED forward voltage varies with temperature and manufacturing bin, so a fixed voltage causes large current swings. A constant-current driver holds brightness stable and protects the LED.
How do I choose between a buck and a boost LED driver?
If the LED string's total forward voltage is below the input rail, use a buck driver (FP7xxx). If the string needs more voltage than the input provides, use a boost driver (FP7208/7209/7209M).
What is the difference between PWM and analog dimming?
PWM switches the LED current fully on and off at high frequency, keeping colour constant across the range. Analog dimming scales the current setpoint, which is simpler but can shift LED colour at low currents.
Do you supply Feeling Technology LED drivers in volume?
Yes — we are an independent distributor holding spot stock of the FP7xxx and FP8013 families. Quantities and date codes are on each product page; request a quote.
Trademark & Disclaimer
MST, Feeling Technology and all part numbers are trademarks or registered trademarks of their respective owners. Jingteng Electronics is an independent distributor and is not affiliated with, endorsed by, or authorized by Feeling Technology. Brand names and part numbers on this page are used solely for identification and cross-reference. Electrical specifications must be confirmed against the original manufacturer datasheet before use. See our Legal Notice / Trademark Disclaimer.
Recommended next steps
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