Texas Instruments' LM3421 and LM3423 are versatile high voltage N-channel MosFET controllers for LED drivers. They can be easily configured in buck, boost, buck-boost, and SEPIC topologies. This flexibility, along with an input voltage rating of 75V, makes the LM3421 and LM3423 ideal for illuminating LEDs in a large family of applications.
Adjustable high-side current sense voltage allows for tight regulation of the LED current with the highest efficiency possible. The LM3421 and LM3423 use predictive off-time (PRO) control, which is a combination of peak current-mode control and a predictive off-timer. This method of control eases the design of loop compensation while providing inherent input voltage feed-forward compensation.
The LM3421 and LM3423 devices include high-voltage startup regulators that operate over a wide input range of 4.5 V to 75 V. The internal PWM controller is designed for adjustable switching frequencies of up to 2.0 MHz, thus enabling compact solutions.
- LM3421Q1/LM3423Q1 are automotive grade products that are AEC-Q100 grade 1 qualified (-40°C to 125°C operating junction temperature) and similarly LM3421Q0/LM3423Q0 are AEC-Q100 grade 0 qualified (-40°C to 150°C operating junction temperature)
- Vin range from 4.5 V to 75 V
- High-side adjustable current sense
- 2 Ω, 1 A peak MosFET gate driver
- Input under-voltage and output over-voltage protection
- PWM and analog dimming
- Cycle-by-cycle current limit
- Programmable switching frequency
- "Zero current" shutdown and thermal shutdown
- LED output status flag (LM3423/23Q1/23Q0 only)
- Faults status flag and timer (LM3423/23Q1/23Q0 only)
- LED drivers - buck, boost, buck-boost, and SEPIC
- Indoor and outdoor area SSL
- General illumination
- Constant-current regulators