1 Introduction
Many medium voltage LED applications are powered by off-line AC-DC power supplies, batteries or electronic transformers with low voltage AC outputs. But some of these power supplies, such as lead-acid batteries, have only undergone simple regulation. Therefore, there is a need for an LED driver solution that can operate over a wide input voltage range and can be configured in a variety of topologies to support LED load requirements. Depending on the current and operating conditions of the LED, a linear or switching regulator LED driver solution can be used. ON Semiconductor offers a wide range of topologies for medium voltage LED applications for landscape lighting, low voltage track lights, solar powered lighting, automotive lighting, emergency vehicle lighting, marine lighting, 12Vac/Vdc MR16 lights, aircraft interior lighting Various general lighting requirements such as logo backlighting, billboard text circuits and signs.
2 Medium voltage LED general topology and power supply
Medium voltage LED lighting applications require an optimized driver solution. ON Semiconductor offers medium voltage LED driver solutions in three different topologies, including inductive, charge pump and linear, to meet different application needs. See Figure 1. There are several power supplies for medium voltage LED applications, each with its main purpose. Among them, offline AC voltage regulator adapter, common voltage is 12Vdc, 24Vdc, 36Vdc, 48Vdc, voltage regulation accuracy of ± 5%, suitable for low to medium power applications with low safety requirements. Sealed lead-acid batteries are widely used for automotive lighting only with simple regulation, 8Vdc to 14Vdc; 7Vdc-27Vdc for automotive, solar, and marine lighting. 12Vdc and 12Vac power supplies, common in indoor lighting, track lights, outdoor lighting, landscape lighting, etc.
3 ON Semiconductor Medium Voltage LED Universal Lighting Solution
(1) Linear LED Driver Solutions
Linear solutions are the first choice for many lighting applications because they are designed to be simple and intuitive, and allow LEDs to be driven with precision currents, regardless of how the LED forward voltage or input power changes. Because these LED drivers are linear, they must match the power requirements of the application. ON Semiconductor supplies a variety of constant current linear LED drivers with currents from 10mA to 1A. The channel output current is 10mA-50mA with NSI50010Y, NSI45020JZ, NSI 4 5 0 2 0 , NSI 4 5 0 2 0A, NSI 4 5 0 2 5 , NSI 4 5 0 2 5A, NSI45025AZ, NSI45025Z, NSI45030, NSI45030A, NSI45030AZ NSI45030Z, NSIC2020B, NSIC2030B, NSIC2050B and NCV7680; 60mA-350mA with NSI45060JD, NUD4011, NSI45090JD and CAT4104; and NUD4001 (500mA) and CAT4101 (1000mA) with larger channel output current.
Take the linear constant current regulator NSI45 series as an example. This is a two-terminal or three-terminal linear constant current regulator. Based on ON Semiconductor's patented self-biasing transistor technology, it is ideal for a wide range of LED applications with different input voltages. For example, driving currents in building, automotive and industrial signage LED lighting applications. It operates over a wide input voltage range, giving engineers a simple, cost-effective, current-stable solution for their application without sacrificing performance. The constant current regulator series stabilizes current over a wide range, ensures constant brightness over the operating voltage range, and has a negative temperature coefficient characteristic that protects the LED from thermal runaway at extreme voltages and operating temperatures. influences.
Another typical application for the NSI45 is the constant current regulator linear LED driver used as a display and billboard text circuit. Features include a low starting voltage, precise current regulation regardless of the forward voltage (Vf), and a negative temperature coefficient to protect the LED.
(2) LED MR16 bulb solution
The NCL30100 is a step-down LED driver controller with energy-efficient, peak current control adaptive fixed off-time for low-power and space-constrained applications where space and energy efficiency are critical. The solution has an oscillating frequency adjustable characteristic. The continuous conduction mode (CCM) eliminates the output capacitance, provides up to 95% energy efficiency, and provides natural LED open circuit protection.
The driver controller has a switching frequency of up to 700kHz and does not require an output capacitor. The Vcc operates from 6.35V to 18V and can drive one or more high-power LEDs. It is mainly used in MR16 LED lighting, ambient lighting, solar LED, traffic lighting, Applications such as outdoor lighting and LED strips. The PCB with the NCL30100 is very compact and fits into the lamp holder of the MR16 lamp. The hysteresis control feature of the NCL30100 provides fast response during load transients, eliminating the need for small signal control loop compensation components. Protection features include the ability to set LED current, LED short circuit protection, undervoltage lockout, and thermal shutdown.