DEI1090 device is a 16 pin bipolar integrated circuit designed to drive eight LEDs and provide Pulse Width Modulated (PWM) dimming control according to the luminance curve of incandescent lamps. All eight LEDx pins are driven with an average current proportional to the square of the input dimming voltage to control the LED brightness. Drivers can be cascaded to synchronously drive additional LED groups. The dimming control input may be a DC or AC voltage.
- Emulates incandescent lamp ‘Square Law’ luminance curve.
- LED dimming controlled by Pulse Width Modulation ranging from 50HZ to 200HZ.
- Maximum LED current adjustable from 10mA to 20mA.
- 200:1 Dimming Range at 50Hz. 40:1 Dimming Range at 200Hz
- Drives 8 LED outputs with matched current drive.
- Drivers can be cascaded to synchronously drive additional LEDs.
- Package Options
- Plastic 16 lead SOIC
- 20L QFN 5 X 5
Functional Description The input voltage from a dimming bus is scaled at the VIN control pin to a range between 0 and 2.5V. The load on the dimming bus is kept to a minimum since the DEI1090 is locally powered through the VDD pin. A peak detector/filter is provided to allow use of either a DC or AC control input. The optional filter is set by an external resistorand capacitor at the FILT pin. A resistor load must be used even in DC applications. (Recommended 100kΩ) The ENABLE pin enables the part when high and must be tied to VDD when not used. When the ENABLE pin is low, the part is put into a standby state and all LEDs are set to off. Eight LED driver outputs are provided. Each is driven with a Pulse Width Modulated (PWM) current waveform that has an average current proportional to the square of the voltage at the VIN pin. The PWM frequency is set with an external capacitor at the FSET pin. The peak LED current at 100% duty cycle is a multiple of the Iset current which is set with an external resistor at the ISET pin. The PWM pin is provided to allow cascading multiple DEI1090s to expand the number of synchronously controlled LED driver output.