LM27964SQ-A Integrated Circuits (ICs)

LM27964SQ-A Application Field and Working Principle

LM27964SQ-A is a high precision, monolithic integrated light-emitting diode (LED) driver IC. It is an application of power management integrated circuit (PMIC), and it has a wide range of applications in LED modules, vehicle lamps, and LED lighting.

This driver IC provides a constant-current driver circuit of 1.05A and has a high precision of ±1.8%. It is designed based on a common-mode operating voltage of 3V-40V, optimized control power of 40mW, low current accuracy of ±0.15%, and voltage drop at 0.1V. Additionally, it can work with a wide voltage range of either 20V or 40V, making it ideal for use in devices with high power requirements.

The internal architecture of the LM27964SQ-A driver is based on an adjustable resistor network. The network consists of two separate resistor strings: one connected to the output pin and the other to the input pin. The two resistors strings provide an adjustable current level to the output and thus can control the output current. The feedback voltage across the resistor strings is regulated by the internal IC to maintain a constant current at the output.

The output current of the LM27964SQ-A can be adjusted via the external resistor (RFB), which establishes the feedback voltage. The magnitude of the feedback voltage is when the output current is adjusted. Furthermore, the output current is inhibited from overshooting because the voltage at the input pin is also regulated. This is due to an internal voltage comparator, which constantly monitors the difference between the input and output voltages. In this way, the output current remains constant even when the input voltage fluctuates.

To ensure reliable operation, the LM27964SQ-A is built with multiple safety features. The internal circuitry has built-in protection against overvoltage and undervoltage, as well as over-temperature protection and fault detection. Additionally, it is designed with power limiting, which prevents the output current from exceeding a preset limit. This ensures that only the required amount of current is delivered to the LED module.

In summary, the LM27964SQ-A is a high-precision, monolithic integrated LED driver IC. Its wide operating voltage range, high current accuracy, and built-in safety features make this IC an ideal choice for large current applications. It is perfect for use in LED modules, vehicle lamps, and LED lighting, where the output current must remain within the designated range.