SLAAEA6 February   2025 CSD19538Q3A , LM25148 , MSP430FR2355 , TLV5624

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 LED Lighting in Medical Systems
    2. 1.2 Key Challenges of LED Drivers in Medical Applications
  5. 2Proposed LED Drive Designs With Analog Dimming
    1. 2.1 Drive LED With Linear Constant-Current Source
    2. 2.2 Drive LED With a DC-DC Regulator
    3. 2.3 Drive LED With TPS92640 or TPS92641
  6. 3Summary
  7. 4References

2.3 Drive LED With TPS92640 or TPS92641

TI also has the single-chip, TPS92640 and TPS92641 LED drivers with analog and PWM dimming capacity. The difference between TPS92640 and TPS92641 is that TPS92641 devices include a shunt FET dimming input and MOSFET driver for high-resolution PWM dimming. Both parts have 500:1 analog dimming capacity. With the integrated 2Ω, 1Apeak MOSFET gate drivers, the designer can drive LEDs with the expected current capacity by selecting a good external MOSFET in theory. The external DAC60501 can be connected to an analog dimming terminal IADJ to adjust the LED current as Equation 6 shows. IADJ can be set to any value up to 2.54V.

Equation 6. I L E D = V D A C 10 × R C S

This single-chip design provides the lowest cost, but the resolution is lower than the previously mentioned scheme.

TLV5624,CSD19538Q3A,LM25148,MSP430FR2355 Driving LED With TPS92640 or TPS92641 With Analog Dimming Figure 2-5 Driving LED With TPS92640 or TPS92641 With Analog Dimming