May 31, 2019 by Sam Holland
Diodes Incorporated introduces the AL1665 high power factor LED driver-controller, which is for LED lighting installations up to 100 W.
This single-stage, fly-back, and buck-boost diode is meant to drive an external MOSFET (metal oxide semiconductor field effect transistor) to manage LED loads while maintaining a high power factor.
The AL1665 maintains a high switching efficiency and is a well-sized and efficient controller that will help in cutting down the number of components used in LED lighting installations.
The AL1665 uses the PSR (primary side regulation) control method, which eliminates the optocoupler and compensated components and can provide accurate CC (constant current) regulation. Using PSR means smaller solutions—those that eat up less space on the PCB—can be designed as it eliminates secondary-side feedback components, and in the long run, reduces material cost.
The AL1665 can be operated at BCM (boundary conduction mode) mode with valley switching to minimise losses. This leads to low EMI (electromagnetic interference) and high efficiency while keeping low Total Harmonic Distortion (which is <20%) and high Power Factor (which is >0.9) under universal input voltage.
The recommended AC voltage (input) is between 85VAC to 305VAC, which is a universal wide-input voltage that allows this LED driver-controller to be directly connected to the main supply in any geographical region.
The component supports both analogue and PWM (pulse-width modulation) dimming modes. The analogue dimming range is 5% to 100% while the PWM dimming range is 0.5% to 100%.
It integrates multiple internal protections that are all meant to make it more reliable. They include under voltage lockout (UVLO), over temperature protection (OTP), over current protection (OCP), user programmable NTC based thermal foldback, internal thermal foldback protection (TFP), shorted current sense protection, secondary diode short protection, CS short protection, output over voltage protection (OVP), winding short circuit protection, and output short protection (OSP). (If by any chance the controller reaches 165°C, the OTP feature will be triggered to cause a latch mode protection.)
Features low startup current and low operation current.
Has a tight LED current variation range across 85VAC to 305VAC.
The controller has been factory tested and has been tweaked to achieve <2% current accuracy for each unit. This translates to high output current accuracy.
The temperature range is −40 to 105 °C, which means the component can be used in adverse weather conditions.
When compared to other Diodes models; like the AL1663S or the AL1663RS, for example, the AL1665S provides more efficiency (>85%) and more high power factor (>0.9). Its analogue dimming range is also wider—from 0.05 to 2.5V.
The AL1665 LED Driver. Image courtesy of Diodes Incorporated.
The capability to dim between 0.5% to 100% makes this diode well suited for commercial LED applications, especially those that require the output levels to be adjusted to save on power, or for beautification purposes around malls and retail stores. The general areas include:
Normal LED lighting driver where dimming is required.
LED lighting luminaries.
LED backlighting driver.
Middle-power LED drivers.
Smart LED lighting.
General-purpose constant current source.
AL1665S works perfectly with ANSI-approved dimmers. When using a PWM input, you can adjust the output to between 0V and 10V, or between 0V and 2.5V with an analogue input voltage. This makes it simpler to come up with lighting setups that can be managed locally or remotely.
The AL1665 should be a game changer for LED lighting installations, especially because it maintains a high switching efficiency and it makes it possible to cut down on the number of components required in connected, commercial, and dimmable LED lighting installations.
